CN106844853A - The subchannel analysis method of effect is mixed comprising screen work with reference to resistance and Energy distribution - Google Patents

Abstract

The subchannel analysis method of effect is mixed comprising screen work with reference to resistance and Energy distribution, by collecting experimental data of the various mixing grillworks comprising reactor core mixing grillwork to be analyzed under different operating modes, fitting can reflect that mixing grillwork critical component mixes the momentum source term relational expression and energy source n-th-trem relation n formula of performance, and the momentum source term relational expression is added in corresponding momentum conservation equation, the energy source n-th-trem relation n formula is added in corresponding energy conservation equation；By solving mass-conservation equation, momentum conservation equation and energy conservation equation, reactor in-core more accurately local thermal technology's hydraulic parameters are obtained, so that the prediction of critical heat flux density (CHF) value and CHF positions is more accurate.The present invention is not limited by channel program structure and solution, can be widely used in various types of channel programs calculating, is mainly used in the channel program of two-fluid model.

Description

The subchannel analysis method of effect is mixed comprising screen work with reference to resistance and Energy distribution

Technical field

The invention belongs to reactor fuel assemblies hydrodynamic analogy and analysis technical field, and in particular to one kind is combined Resistance and Energy distribution mix the subchannel analysis method of effect comprising screen work.

Background technology

In the design and operation of nuclear power station, critical heat flux density (CHF), critical power are that limitation nuclear power station runs most One of important parameter.Below critical power, nuclear energy safely can be converted into electric energy by reactor to greatest extent.Fuel rod Beam CHF is closely related with local thermal technology's hydraulic parameters of reactor core, in view of the complicated geometry of reactor core subchannel and The operating condition of parameter area wide, can not completely provide analytic solutions to CHF in theory.

The CHF relational expressions of traditional core fuel bundle are the localized heats calculated based on cluster experimental data and channel program The exploitation of work hydraulic parameters is obtained.And in order to obtain the experimental data under these reactor operating modes need to expend sizable financial resources and compared with Time cycle long.Nuclear fuel is and guided to design for carrying out nuclear power station operation safety analysis based on this CHF relational expression developed. Subchannel analysis method is that peace examines indispensable instrument at present, with the local thermal technology's hydraulic parameters for calculating reactor core and uses and does Go out safety analysis and assess its CHF limit value, this is the committed step of reactor safety analysis.At present except because lumped parameter is put down It is the absence of in most reactor cores beyond the inaccuracy that equal effect is produced, one of the drawbacks of subchannel analysis is main Using screen work the simulation and calculating of mixing performance.Therefore, all channel programs are calculating local thermal-hydraulic ginseng at present Generally existing very big uncertainty and error during number.This uncertain and error, when the exploitation of CHF relational expressions is drafted, warp Need to often be made up by a large amount of cluster CHF experimental datas, and cause the limitation of its CHF relational expression range of application drafted.Together When, in safety analysis, uncertainty of this channel program when local thermal technology's hydraulic parameters are calculated also often results in CHF Very big error in calculating, and thus produce very big limiting design value and design deviation so that reactor operation efficiency it is relatively low or Safety coefficient reduction.

Due to lacking cognitive to mixing grillwork function, current all of channel program simplifies the simulation of mixing grillwork It is so-called " mixing coefficient " (β or the TDC) of common form drag coefficient or bulking property, completely cannot each critical component on plaid matching frame The difference of (such as mixing the wing, just spring, convex and solder joint) mixes performance simulation.Additionally, it is proposed that in subchannel point In analysis method, using the form drag Relationship of Coefficients formula developed based on Reynolds number come instead of original form drag coefficient constant.And use upper Method is stated, because form drag Relationship of Coefficients formula used is still unrelated with screen work geometry, still can not accurately reflect screen work Mix characteristic, it is impossible to eliminate the inaccuracy that local thermal technology's hydraulic parameters are calculated.

The content of the invention

It is an object of the present invention to provide the subchannel analysis side that a kind of combination resistance and Energy distribution mix effect comprising screen work Method, the method can reflect that mixing grillwork critical component mixes momentum source term relational expression and energy the source item pass of performance by fitting It is formula, and the momentum source term relational expression is added in corresponding momentum conservation equation, the energy source n-th-trem relation n formula is added to In corresponding energy conservation equation, new conservation equation is solved, so as to obtain reactor in-core more accurately local thermal technology's water Force parameter so that the prediction of CHF values and CHF positions is more accurate.

Technical solution of the invention is：

A kind of combination resistance and Energy distribution mix the subchannel analysis method of effect comprising screen work, comprise the following steps：

1) degree of accuracy of the predicted value of the CHF values and CHF positions of reactor core to be analyzed is preset；

2) experimental data of the mixing grillwork under different operating modes is collected；

The mixing grillwork is the mixing grillwork of reactor core to be analyzed, or is stirred comprising reactor core to be analyzed Mixed screen work is in interior various mixing grillworks；

The experimental data includes at least four classes：The first kind and Equations of The Second Kind experimental data are that cluster is axially and radially non-homogeneous CHF values and CHF positions that CHF experiments under heating cycle are obtained, remaining experimental data is in the distribution of cluster channel pressure, cluster Channel velocity is distributed, mixes optional at least two classes in the Exit temperature distribution and cluster channel flow field temperature of experiment acquisition；

3) take following either method set up the mixing grillwork of reactor core to be analyzed momentum source term relational expression and Energy source n-th-trem relation n formula：

Method A) utilize at least four class experimental datas of the mixing grillwork of reactor core to be analyzed under different operating modes Directly it is fitted momentum source term relational expression and energy source n-th-trem relation n formula；

Method B) utilize at least four class experimental datas of the mixing grillwork of reactor core to be analyzed under different operating modes Calibrated and calculated fluid dynamics software, then local thermal technology's hydraulic parameters are calculated in the range of demarcation with the software, it is fitted momentum Source item relational expression and energy source n-th-trem relation n formula；

Method C) utilize at least four class fitting experimental datas and institute of the collected various mixing grillworks under different operating modes Momentum source term universal correlation function and energy source item universal correlation function that the various mixing grillworks collected match, then by be analyzed Experimental data of the mixing grillwork of reactor core under different operating modes tries to achieve momentum source term universal correlation function and energy source item is logical It is final to obtain the momentum source term relational expression and energy source for reflecting that the mixing grillwork critical component mixes performance with the coefficient of relational expression N-th-trem relation n formula；The critical component includes mixing the wing, just band, convex, spring and solder joint；

4) in channel program add step 3) obtain momentum source term relational expression and energy source n-th-trem relation n formula, then use this Channel program calculates the thermal-hydraulic parameter of reactor core to be analyzed, therefrom obtains under reactor core difference operating mode CHF values and the predicted value of CHF positions；

5) judge the predicted value and step 2 of CHF values under reactor core difference operating mode respectively) in collected CHF values Between ratio, and under different operating mode CHF positions predicted value and step 2) in difference between collected CHF positions be It is no to meet step 1) in the default degree of accuracy；If any one is unsatisfactory for, channel program is optimized and/or right CHF relational expressions are improved, and repeat step 4) and 5)；

6) the CHF values of reactor core to be analyzed and the predicted value of CHF positions are exported.

Above-mentioned steps 3) method C) in fitting momentum source term relational expression and energy source n-th-trem relation n formula method it is specific as follows：

C1) the same class experimental data of collection is contrasted, is found out and is mixed performance-relevant geometry ginseng with screen work Number and local thermal-hydraulic parameter；

C2) multiple geometrical structure parameters of selection mixing grillwork and local thermal-hydraulic parameter are logical respectively as momentum source term With relational expression and the variable of energy source item universal correlation function；

C3 the variable of the experimental data and selection collected) is combined, using least square fitting momentum source term total relation Formula and energy source item universal correlation function；

C4) experimental data for reactor core mixing grillwork to be analyzed determines momentum source term universal correlation function and energy Coefficient in amount source item universal correlation function, finally gives momentum source term relational expression and energy source n-th-trem relation n formula.

Above-mentioned steps C3) in the momentum source term universal correlation function that is fitted include axial momentum source item universal correlation function Φ_A With transverse momentum source item universal correlation function Φ_L, it is specific as follows：

In formula：

A″_WWetted perimeter when being comprising screen work, unit is m；

ρ is fluid density, and unit is kg/m³；

V_totalIt is flow field local velocity, unit is m/s；

A_RWetted perimeter when being not comprising screen work, unit is m；

θ is the angle of flow field local velocity and cluster direction, and unit is degree；It is the local axial velocity and part in flow field The function of lateral velocity, its calculating formula can be expressed as follows：

D″_VSubchannel equivalent diameter when being comprising screen work, unit is m；

P is the wetted perimeter of subchannel, and unit is m；

U is cluster axial direction component velocity, and unit is m/s；

V is cluster cross stream velocity component, and unit is m/s；

u₁It is to mix wing tangential-velocity component, unit is m/s；

v₁It is to mix wing normal direction component velocity, unit is m/s；

α is the angle for mixing the wing and cluster direction, and unit is degree；

K_u, K_v, K_u1And K_v1It is the mixing grillwork of corresponding reactor core to be analyzed in momentum source term universal correlation function Coefficient；K_u, K_v, K_u1And K_v1Value it is closely related with the geometry of the mixing grillwork, by the mixing grillwork experimental data come It is determined that；

The step C3) in the energy source item universal correlation function that is fitted with the interfacial area of gas-liquid two-phase, liquid phase specific enthalpy, Gas phase specific enthalpy, liquid velocity, gas phase velocity, pressure are closely related, specific as follows：

In formula：

Subscript l represents liquid phase, and subscript g represents gas phase；

ρ_lAnd ρ_gIt is respectively density of liquid phase and density of gas phase, unit is kg/m³；

h_lAnd h_gIt is respectively liquid phase specific enthalpy gentle compared to enthalpy, unit is kJ/kg；

V_lAnd V_gIt is respectively liquid velocity and gas phase velocity, unit is m/s；

L is to mix chord degree, and unit is m；

E₁, E₂And E₃It is the coefficient of the mixing grillwork of corresponding reactor core to be analyzed in energy source item universal correlation function； E₁, E₂And E₃Value it is related with the geometry of the mixing grillwork and the flow pattern in flow field, including bubble flow, slug flow, Dispersed Flows and Annular flow, under different flow pattern operating modes, E₁, E₂And E₃Value it is different, it is necessary to according to the experimental data under different flow pattern operating modes come It is determined that.

Above-mentioned steps 4) it is specific as follows：

4.1) in channel program add step 3) obtain momentum source term relational expression and energy source n-th-trem relation n formula；Together When, determine the geometrical condition of reactor core to be analyzed and calculate the residual error to be met requirement；The geometrical condition includes Fuel rod number, fuel rod diameter, fuel rod center spacing, cluster length and cluster circulation area, screen work spacing；The residual error Require to include and solve the residual error to be met when mass-conservation equation, momentum conservation equation or energy conservation equation requirement；

4.2) in the channel program that with the addition of momentum source term relational expression and energy source n-th-trem relation n formula, by reactor core Flow field according to its axial power distribution, lateral direction power distribution and geometrical condition be divided into it is many with subchannel as flow area Individual axial control volume；The subchannel is as shown in Fig. 2 enclosed by the line of centres of adjacent fuel rod surface and consecutive fuel rod Into minimum circulation passage A, or enclosed by the extension line of the line of centres of adjacent fuel rod surface, wall and consecutive fuel rod Into minimum circulation passage B or C；

4.3) the fuel model for solving the reactor core obtains thermal boundary condition, or according to the hot-fluid of the reactor core Density obtains thermal boundary condition；

4.4) energy conservation equation, momentum conservation equation and mass-conservation equation are solved, the institute of residual error requirement is met There is the thermal-hydraulic parameter in axial control volume；The solution of wherein momentum conservation equation is needed the momentum source term of the mixing grillwork Relational expression is added in the momentum conservation equation of corresponding fluid gas-phase, liquid phase and/or drop phase, the solution of energy conservation equation Need to keep the energy source n-th-trem relation n formula of the mixing grillwork added to the energy of corresponding fluid gas-phase, liquid phase and/or drop phase In permanent equation；

4.5) local thermal technology's hydraulic parameters are extracted from the thermal-hydraulic parameter in all axial control volume for obtaining is solved, Therefrom obtain the reactor core difference operating mode under CHF values and CHF positions predicted value.

Above-mentioned steps 4.4) the first solution is specific as follows：

4.4.1) with each axial control volume as unit, the energy of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the energy source n-th-trem relation n formula of the mixing grillwork in the reactor core is added to corresponding fluid gas-phase, liquid Mutually and/or in the energy conservation equation of drop phase；The energy conservation equation is solved further according to thermal boundary condition, each axial direction is obtained The specific enthalpy of control volume, fuel rod surface temperature, fluid density and fluid temperature (F.T.)；

4.4.2) with each axial control volume as unit, the momentum of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the momentum source term relational expression of the mixing grillwork in the reactor core is added to corresponding fluid gas-phase, liquid Mutually and/or in the momentum conservation equation of drop phase；Specific enthalpy, fuel rod surface temperature further according to each axial control volume, fluid Density and fluid temperature (F.T.), solve the momentum conservation equation, obtain transverse flow speed and pressure；

4.4.3) with each axial control volume as unit, the quality of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation；According to transverse flow speed and pressure in each axial control volume, the mass-conservation equation is solved, obtain axially stream Speed；

4.4.4) judge whether mass-conservation equation, momentum conservation equation and energy conservation equation meet residual error requirement, if Be unsatisfactory for, then according to step 4.4.1) to step 4.4.3) order iterated, if meeting, obtain each and axially control The internal thermal-hydraulic parameter of system；The thermal-hydraulic parameter includes fuel rod surface temperature, axial flow velocity, transverse flow speed, pressure Power, fluid density, fluid temperature (F.T.), specific enthalpy.

Above-mentioned steps 4.4) the second solution is specific as follows：

4.4.1) with each axial control volume as unit, the momentum of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the momentum source term relational expression of the mixing grillwork in the reactor core is added to corresponding fluid gas-phase, liquid Mutually and/or in the momentum conservation equation of drop phase；The momentum conservation equation is solved further according to thermal boundary condition, initial horizontal stroke is obtained To flow velocity and axial flow velocity；

4.4.2) with each axial control volume as unit, the quality of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, according to the transverse flow speed and axial flow velocity of each axial control volume, solves the mass-conservation equation, after being updated Transverse flow speed, axial flow velocity and pressure；

4.4.3) with each axial control volume as unit, the energy of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the energy source n-th-trem relation n formula of the mixing grillwork in the reactor core is added to corresponding fluid gas-phase, liquid Mutually and/or in the energy conservation equation of drop phase；Further according to transverse flow speed, axial flow velocity after being updated in each axial control volume And pressure, the energy conservation equation is solved, obtain specific enthalpy；

4.4.4) judge whether momentum conservation equation, mass-conservation equation and energy conservation equation meet residual error requirement, if Be unsatisfactory for, then according to step 4.4.1) to step 4.4.3) order iterated, if meeting, obtain each and axially control The internal thermal-hydraulic parameter of system；The thermal-hydraulic parameter includes axial flow velocity, transverse flow speed, pressure, fluid density, fluid Temperature, specific enthalpy.

Above-mentioned steps 4) in the addition of momentum source term relational expression channel program momentum conservation equation it is specific as follows：

Axial momentum conservation equation：

In formula：

Subscript i and j are subchannel numberings, and wherein i represents the subchannel of required solution, and j represents the son adjacent with subchannel i Passage；

m_iIt is the axial flow in subchannel i, unit is kg/s；

T is the time, and unit is s；

Z is the axial height of single axial control volume, and unit is m；

ρ_iIt is the fluid density in subchannel i, unit is kg/m³；

A_iIt is the circulation area of subchannel i, unit is m²；

w_ijIt is the horizontal flow from subchannel i to subchannel j, unit is kg/ (m*s)；w_ijBe on the occasion of when represent horizontal stream Amount flows to subchannel j, w from subchannel i_ijRepresent that horizontal flow flows to subchannel i from subchannel j during for negative value；

u^*It is the axial flow velocity in donor unit control volume, unit is m/s；Its expression of significance such as following formula：

f_TIt is that lateral turbulence mixes coefficient of friction, unit is 1；

w′_ijIt is the turbulent flow amount of mixing from subchannel i to subchannel j, unit is kg/ (m*s)；

w′_jiIt is the turbulent flow amount of mixing from subchannel j to subchannel i, unit is kg/ (m*s)；

u′_iIt is the fluctuation velocity of subchannel i, unit is m/s；

u′_jIt is the fluctuation velocity of subchannel j, unit is m/s；

p_iIt is the pressure in subchannel i, unit is Pa；

G is acceleration of gravity, and unit is m/s²；

F is axial rub coefficient, and unit is 1；

D_hIt is the equivalent diameter of subchannel, unit is m；

Φ_AIt is the axial momentum source item relational expression for mixing performance for reflecting the mixing grillwork；

Transverse momentum conservation equation：

In formula：

L is the equivalent length of transverse momentum control volume, and unit is m；

v^*It is the transverse flow speed in donor unit control volume, unit is m/s；Its expression of significance such as following formula：

K_GIt is lateral flow resistance coefficient, unit is 1；

S_ijIt is the gap width between subchannel i and subchannel j, unit is m；

p_iAnd p_jIt is respectively the pressure in subchannel i and subchannel j, unit is Pa；

Φ_LIt is the transverse momentum source item relational expression for mixing performance for reflecting the mixing grillwork；

Above-mentioned steps 4) in the addition of energy source n-th-trem relation n formula channel program energy conservation equation it is specific as follows：

In formula：

h_iAnd h_jIt is respectively the specific enthalpy in subchannel i and subchannel j, unit is kJ/kg；

h^*It is the specific enthalpy in donor unit control volume, unit is kJ/kg；Its expression of significance such as following formula：

λ_iIt is the flow thermal conductivity coefficient in subchannel i, unit is W/ (m*K)；

T_iAnd T_jRespectively the fluid temperature (F.T.) in subchannel i and subchannel j, unit for DEG C；

L_CIt is geometric corrections constant, unit is 1；

N is the heating wall number adjacent with subchannel i, and unit is 1；

It is the heating wall area adjacent with subchannel i, unit is m²；

q_nIt is the heat flow density of the heating wall adjacent with subchannel i, unit is J/ (m²*s)；

Θ is to reflect that the mixing grillwork mixes the energy source n-th-trem relation n formula of performance；When energy conservation equation represents the energy of gas phase During quantitative change law, the symbol before Θ is just, when energy conservation equation represents the energy variation rule of liquid phase, before Θ Symbol is negative.

Advantages of the present invention：

1st, the present invention represents the parameter that mixing grillwork influences by introducing, including mixes chord degree, mix wing area, mix Wing angle and represent band, just convex, spring and solder joint stream field influence coefficient, so as to more accurately reflect mix lattice The influence that the geometric properties of frame and its stream field bring, improves subchannel method prediction reactor core part thermal-hydraulic The accuracy of parameter；

2nd, the present invention represents the parameter of mixing grillwork geometry by introducing, including mix chord degree, mix wing area, Mix wing angle and represent the coefficient of band, just convex, spring and the influence of solder joint stream field, and collect multiple mixing grillworks Experimental data carry out the exploitation of momentum source term universal correlation function and energy source item universal correlation function, therefore can be widely used in not The analysis of same type mixing grillwork stream field influence, can reflect the influence of different type mixing grillwork stream field, improve son The applicability of passage method；

3rd, the local thermal technology's hydraulic parameters that effect is mixed comprising screen work obtained by the present invention is calculated, calculate than conventional method Resulting local thermal technology's hydraulic parameters are more accurate, and local thermal technology's hydraulic parameters are the key factors of CHF relational expressions exploitation One of, thus the present invention calculate obtained by the local thermal technology's hydraulic parameters for mixing effect comprising screen work can be used for it is more accurately anti- Reflect the exploitation of the CHF relational expressions of screen work effect；

4th, the local thermal technology's hydraulic parameters that effect is mixed comprising screen work obtained by the present invention is calculated, calculate than conventional method Resulting local thermal technology's hydraulic parameters are more accurate, and local thermal technology's hydraulic parameters be CHF values and position prediction it is crucial because The local thermal technology's hydraulic parameters for mixing effect comprising screen work obtained by one of element, therefore present invention calculating can be used for more accurately Prediction CHF values and CHF positions；

5th, the present invention can reflect the influence of particular type mixing grillwork stream field, it is possible to provide more reliable safety analysis, Safety coefficient is improved, increases economic benefit；

6th, the present invention can reflect the influence of different type mixing grillwork stream field, the work that can be designed and developed as screen work Tool.

Brief description of the drawings

During Fig. 1 is the universal correlation function of axial momentum source item described in claim 3 and transverse momentum source item universal correlation function Partial Variable schematic diagram.

Fig. 2 is small range (5x5) test subchannel schematic diagram that nuclear power plant's typical reaction heap reactor core is represented in the present invention.

Fig. 3 and Fig. 4 are two kinds of flow charts of the subchannel analysis that resistance distribution (DRM) mixes effect comprising screen work.

Fig. 5 is that 5x5 clusters subchannel is divided and numbering schematic diagram.

Fig. 6 is the transverse flow speed curve map between subchannel (2,8).

Fig. 7 is the transverse flow speed curve map between subchannel (9,10).

Specific embodiment

The present invention is to mix the subchannel analysis method of effect comprising screen work with reference to resistance and Energy distribution, including following step Suddenly：

1) degree of accuracy of the predicted value of the CHF values and CHF positions of reactor core to be analyzed is preset；

The degree of accuracy of the predicted value of the CHF values can be represented by the formula：

CHF in formula_mIt is the CHF values of experiment acquisition, CHF_pIt is the predicted value of the CHF values being calculated, ε is default CHF values Predicted value the degree of accuracy；

The degree of accuracy of the predicted value of the CHF positions can be represented by the formula：

|L_m-L_p| ＜ δ (12)

L in formula_mIt is the CHF positions of experiment acquisition, L_pIt is the predicted value of the CHF positions being calculated, δ is default CHF The degree of accuracy of the predicted value put；

2) experimental data of the mixing grillwork under different operating modes is collected；

The mixing grillwork is the mixing grillwork of reactor core to be analyzed, or comprising reactor core to be analyzed Mixing grillwork is in interior various mixing grillworks；

The experimental data includes at least four classes：The first kind and Equations of The Second Kind experimental data are that cluster is axially and radially non-homogeneous CHF values and CHF positions that CHF experiments under heating cycle are obtained, remaining experimental data are led in the distribution of cluster channel pressure, cluster Road velocity flow profile, mix experiment obtain Exit temperature distribution and cluster channel flow field temperature in optionally at least two classes；It is required that The experimental data of the every kind of mixing grillwork collected comprises at least more than 200 points of experimental data.

3) take following either method set up the mixing grillwork of reactor core to be analyzed momentum source term relational expression and Energy source n-th-trem relation n formula：

Method A) utilize at least four class experimental datas of the mixing grillwork of reactor core to be analyzed under different operating modes Directly it is fitted momentum source term relational expression and energy source n-th-trem relation n formula；

Method B) utilize at least four class experimental datas of the mixing grillwork of reactor core to be analyzed under different operating modes Calibrated and calculated fluid dynamics software, then local thermal technology's hydraulic parameters are calculated in calibration range with the software, it is fitted momentum source N-th-trem relation n formula and energy source n-th-trem relation n formula；Calibration range refers to pressure, temperature and the flow velocity that experimental data correspondence operating mode is included Scope, calculating of the computational fluid dynamics software in calibration range is only accurately and reliably；

Method C) utilize at least four class fitting experimental datas and institute of the collected various mixing grillworks under different operating modes Momentum source term universal correlation function and energy source item universal correlation function that the various mixing grillworks collected match, then by be analyzed Experimental data of the mixing grillwork of reactor core under different operating modes tries to achieve momentum source term universal correlation function and energy source item is logical It is final to obtain the momentum source term relational expression and energy source for reflecting that the mixing grillwork critical component mixes performance with the coefficient of relational expression N-th-trem relation n formula；The critical component includes mixing the wing, just band, convex, spring and solder joint；

Method C) in fitting momentum source term relational expression and energy source n-th-trem relation n formula method it is specific as follows：

C1) the same class experimental data of collection is contrasted, is found out that mix performance to screen work related according to physical phenomenon Geometrical structure parameter and local thermal-hydraulic parameter, the parameter to finding out carries out sensitivity analysis, or rule of thumb lists weight Spend sequencing table；It is described with mix performance-relevant screen work geometrical structure parameter and include but is not limited to mix wing area, mix the wing Bent angle, wing torsional angle is mixed, chord degree is mixed, is mixed wing width；With mix performance-relevant local thermal technology's hydraulic parameters include but It is not limited to axial flow velocity, transverse flow speed, temperature, pressure, CHF values, CHF positions；

C2) according to sensitivity analysis result or importance sorting table, multiple geometrical structure parameters of mixing grillwork are selected With local thermal-hydraulic parameter as momentum source term universal correlation function and the variable of energy source item universal correlation function；Momentum source term leads to Variable with relational expression and energy source item universal correlation function is incomplete same；The variable number depends on collected experiment number According to number, collected experimental data is more, and variable number is more；Variable number is more, momentum source term universal correlation function and Energy source item universal correlation function more can more accurately reflect actual mixes performance；

C3 the variable of the experimental data and selection collected) is combined, using least square fitting momentum source term total relation Formula and energy source item universal correlation function；

The momentum source term universal correlation function being fitted includes axial momentum source item universal correlation function Φ_AWith transverse momentum source item Universal correlation function Φ_L, they are all closely related with the variable of selection, specific as follows：

In formula：

A″_WWetted perimeter when being comprising screen work, unit is m；

ρ is fluid density, and unit is kg/m³；

V_totalIt is flow field local velocity, unit is m/s；

A_RWetted perimeter when being not comprising screen work, unit is m；

θ is the angle of flow field local velocity and cluster direction, and unit is degree；It is the local axial velocity and part in flow field The function of lateral velocity, its calculating formula can be expressed as follows：

D″_VSubchannel equivalent diameter when being comprising screen work, unit is m；

P is the wetted perimeter of subchannel, and unit is m；

U is cluster axial direction component velocity, and unit is m/s；

V is cluster cross stream velocity component, and unit is m/s；

u₁It is to mix wing tangential-velocity component, unit is m/s；

v₁It is to mix wing normal direction component velocity, unit is m/s；

α is the angle for mixing the wing and cluster direction, and unit is degree；

K in formula_u, K_v, K_u1And K_v1It is that correspondence reactor core to be analyzed mixes lattice in momentum source term universal correlation function The coefficient of frame.Above-mentioned axial momentum source item universal correlation function and transverse momentum source item universal correlation function be applied to gas phase, liquid phase and/ Or drop phase, for specific each phase, every expression formula can make further refinement in formula.

With reference to the experimental data and the variable of selection collected, using with fitting momentum source term universal correlation function identical method Fitting energy source item universal correlation function；Interfacial area, liquid phase ratio of the energy source item universal correlation function being fitted with gas-liquid two-phase Enthalpy, gas phase specific enthalpy, liquid velocity, gas phase velocity, pressure are closely related, specific as follows：

In formula：

Subscript l represents liquid phase, and subscript g represents gas phase；

ρ_lAnd ρ_gIt is respectively density of liquid phase and density of gas phase, unit is kg/m³；

h_lAnd h_gIt is respectively liquid phase specific enthalpy gentle compared to enthalpy, unit is kJ/kg；

V_lAnd V_gIt is respectively liquid velocity and gas phase velocity, unit is m/s；

L is to mix chord degree, and unit is m；

E₁, E₂And E₃It is the coefficient of the mixing grillwork of corresponding reactor core to be analyzed in energy source item universal correlation function.

E₁, E₂And E₃Value it is related to the flow pattern in flow field with the geometry of the mixing grillwork of reactor core to be analyzed, Including bubble flow, slug flow, Dispersed Flows and annular flow.

C4)K_u, K_v, K_u1And K_v1Need the experimental data with reference to the mixing grillwork to determine, finally obtain the mixing grillwork Momentum source term relational expression.K_u, K_v, K_u1And K_v1Value it is closely related with the geometry of mixing grillwork, including mix wing-like And size, the size and arrangement mode of spring, just convex, band and solder joint.

E₁, E₂And E₃Need the experimental data with reference to the mixing grillwork to determine, finally obtain the energy source of the mixing grillwork N-th-trem relation n formula.E₁, E₂And E₃Value except with geometry mutually outside the Pass, it is also relevant with flow pattern, including bubble flow, slug flow, disperse Stream and annular flow, under different flow pattern operating modes, E₁, E₂And E₃Value difference, it is necessary to according to the experiment number under different flow pattern operating modes According to determining.

The determination of coefficient is needed according to the mixing grillwork in momentum source term universal correlation function and energy source item universal correlation function Experimental data determine its pressure limit, flow field temperature range, flow field velocity scope and heating power scope, and utilize a most young waiter in a wineshop or an inn Multiplication determines each undetermined coefficient.It is determined that after coefficient be only applicable to the mixing grillwork, and be only applicable to the reality of the mixing grillwork Test in parameter area determined by data.

4) in channel program add step 3) obtain momentum source term relational expression and energy source n-th-trem relation n formula, then use this Channel program calculates the thermal-hydraulic parameter of reactor core to be analyzed, therefrom obtains under reactor core difference operating mode CHF values and the predicted value of CHF positions；

Concretely comprise the following steps：

4.1) in channel program add step 3) obtain momentum source term relational expression and energy source n-th-trem relation n formula；Together When, determine the geometrical condition of reactor core to be analyzed and calculate the residual error to be met requirement；The geometrical condition includes Fuel rod number, fuel rod diameter, fuel rod center spacing, cluster length and cluster circulation area, screen work spacing；The residual error Require to include and solve the residual error to be met when mass-conservation equation, momentum conservation equation or energy conservation equation requirement；

4.2) in the channel program that with the addition of momentum source term relational expression and energy source n-th-trem relation n formula, by reactor core Flow field according to its axial power distribution, lateral direction power distribution and geometrical condition be divided into it is many with subchannel as flow area Individual axial control volume；The subchannel is by the line of centres of adjacent fuel rod surface and consecutive fuel rod as shown in Figure 2 The minimum circulation passage A for surrounding, or the line of centres by adjacent fuel rod surface, wall and consecutive fuel rod extension line The minimum circulation passage B or C for surrounding；

4.3) the fuel model for solving the reactor core obtains thermal boundary condition, or according to the hot-fluid of the reactor core Density obtains thermal boundary condition；The fuel model of reactor core is module industrially using comparative maturity, is not the present invention Content, therefore be not described here in detail；Heat flow density is according to the customized parameter of actual conditions by user；

4.4) energy conservation equation, momentum conservation equation and mass-conservation equation are solved, the institute of residual error requirement is met There is the thermal-hydraulic parameter in axial control volume；The solution of wherein momentum conservation equation is needed the momentum source term of the mixing grillwork Relational expression is added in the momentum conservation equation of corresponding fluid gas-phase, liquid phase and/or drop phase, the solution of energy conservation equation Need to keep the energy source n-th-trem relation n formula of the mixing grillwork added to the energy of corresponding fluid gas-phase, liquid phase and/or drop phase In permanent equation；

4.5) local thermal technology's hydraulic parameters are extracted from the thermal-hydraulic parameter in all axial control volume for obtaining is solved, Therefrom obtain the reactor core difference operating mode under CHF values and CHF positions predicted value.Thermal technology's water in all axial control volumes Predicted value comprising heat flow density in force parameter, comprising the heat flow density of heating in all axial control volumes in thermal boundary condition； When in certain axial control volume the predicted value of heat flow density with the corresponding axial control volume heat heat flow density ratio For 1 when, the predicted value of the heat flow density of the corresponding axial control volume is exactly the predicted value of CHF values, it is corresponding this axially control The position of body is exactly the predicted value of CHF positions.

Step 4.4) specifically there are various solutions；Although the specific solution of different subchannel analyses is different, this Invention momentum source term universal correlation function and energy source item universal correlation function according to fitting experimental data, and lattice are mixed according to this The experimental data of frame, momentum source term universal correlation function and energy source item universal correlation function to mixing grillwork of different shapes are assigned Different coefficients, therefore can be widely applied to various types of subchannel analyses；The present invention show in particular two kinds of solutions.

The first solution：

4.4.1) with each axial control volume as unit, the energy of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the energy source n-th-trem relation n formula of the mixing grillwork in reactor core is added in the energy conservation equation, show Under for example：

In formula：

I and j are subchannel numberings, and wherein i represents the subchannel of required solution, and the son that j represents adjacent with subchannel i leads to Road；

A_iIt is the circulation area of subchannel i, unit is m²；

ρ_iIt is the fluid density in subchannel i, unit is kg/m³；

h_iAnd h_jIt is respectively the specific enthalpy in subchannel i and subchannel j, unit is kJ/kg；

T is the time, and unit is s；

m_iIt is the axial flow in subchannel i, unit is kg/s；

Z is the axial height of single axial control volume, and unit is m；

w_ijIt is the horizontal flow from subchannel i to subchannel j, unit is kg/ (m*s)；w_ijBe on the occasion of when represent horizontal stream Amount flows to subchannel j, w from subchannel i_ijRepresent that horizontal flow flows to subchannel i from subchannel j during for negative value；

h^*It is the specific enthalpy in donor unit control volume, unit is kJ/kg；Its expression of significance such as following formula：

w′_ijIt is the turbulent flow amount of mixing from subchannel i to subchannel j, unit is kg/ (m*s)；

w′_jiIt is the turbulent flow amount of mixing from subchannel j to subchannel i, unit is kg/ (m*s)；

λ_iIt is the flow thermal conductivity coefficient in subchannel i, unit is W/ (m*K)；

T_iAnd T_jRespectively the fluid temperature (F.T.) in subchannel i and subchannel j, unit for DEG C；

S_ijIt is the gap width between subchannel i and subchannel j, unit is m；

L_CIt is geometric corrections constant, unit is 1；

N is the heating wall number adjacent with subchannel i, and unit is 1；

It is the heating wall area adjacent with subchannel i, unit is m²；

q_nIt is the heat flow density of the heating wall adjacent with subchannel i, unit is J/ (m²*s)；

Θ is to reflect that the mixing grillwork mixes the energy source n-th-trem relation n formula of performance；When energy conservation equation represents the energy of gas phase During quantitative change law, the symbol before Θ is just, when energy conservation equation represents the energy variation rule of liquid phase, before Θ Symbol is negative.

Left side Section 1 is that subchannel i self-energys change with time rate on per unit axial length in formula；Section 2 is The spatial variations of subchannel i self-energys on per unit axial length；Section 3 is all connected in subchannel i on per unit axial length Transverse energy sum on gap, i.e., on per unit axial length from all adjacent subchannel j flow to subchannel i transverse energy it With；Section 4 is because turbulent flow mixes the energy between the subchannel i for causing and all adjacent subchannel j on per unit axial length Exchange；The right represents the gross energy change on per unit axial length in subchannel i in formula.

The energy conservation equation of fluid gas-phase, liquid phase and/or drop phase is solved according to thermal boundary condition, each axial direction is obtained The specific enthalpy of control volume, fuel rod surface temperature, fluid density and fluid temperature (F.T.)；

4.4.2) with each axial control volume as unit, the momentum of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the momentum source term relational expression of the mixing grillwork in reactor core is added in the momentum conservation equation；Cause It is directional for momentum is scalar, therefore momentum is typically decomposed into axial momentum and transverse momentum in subchannel analysis method Two parts, corresponding momentum conservation equation includes axial momentum conservation equation and transverse momentum conservation equation, corresponding momentum source N-th-trem relation n formula also includes axial momentum source item relational expression and transverse momentum source item relational expression；The momentum source term of the mixing grillwork is closed Be that formula is by step 3) any one of set up；The axial momentum conservation equation and transverse momentum conservation equation difference example It is as follows：

Axial momentum conservation equation：

In formula：

u^*It is the axial flow velocity in donor unit control volume, unit is m/s；Its expression of significance such as following formula：

f_TIt is that lateral turbulence mixes coefficient of friction, unit is 1；

u′_iWith u '_jIt is respectively the fluctuation velocity of subchannel i and subchannel road j, unit is m/s；

p_iIt is the pressure in subchannel i, unit is Pa；

G is acceleration of gravity, and unit is m/s²；

F is axial rub coefficient, and unit is 1；

D_hIt is the equivalent diameter of subchannel, unit is m；

Φ_AIt is the axial momentum source item relational expression for mixing performance for reflecting the mixing grillwork.

Left side Section 1 is that axial momentum changes with time on per unit axial length in formula, and Section 2 is unit axial direction The spatial variations of axial momentum in length, Section 3 is the tribute on whole joint gaps to axial momentum on per unit axial length Offer, Section 4 is that turbulent flow mixes contribution to axial momentum；The right Section 1 is respectively axial pressure gradient, gravity to Section 3 Influence with frictional resistance to axial momentum, last is the axial momentum source item pair for mixing performance for reflecting the mixing grillwork The influence of axial momentum.Above-mentioned axial momentum conservation equation is applied to gas phase, liquid phase and/or drop phase, for specific each phase, Every expression formula can make further refinement in formula.

Transverse momentum conservation equation：

In formula：

L is the equivalent length of transverse momentum control volume, and unit is m；

v^*It is the transverse flow speed in donor unit control volume, unit is m/s；Its expression of significance such as following formula：

K_GIt is lateral flow resistance coefficient, unit is 1；

Φ_LIt is the transverse momentum source item relational expression for mixing performance for reflecting the mixing grillwork.

Left side Section 1 is that transverse momentum changes with time on per unit axial length in formula, and Section 2 is unit axial direction The spatial variations of transverse momentum in length, Section 3 is the tribute on whole joint gaps to transverse momentum on per unit axial length Offer；The right Section 1 and Section 2 are respectively influence of the lateral resistance to lateral resistance and transverse-pressure gradient to transverse momentum, Section 3 is to reflect the influence of the transverse momentum source item for mixing performance to transverse momentum of the mixing grillwork.Above-mentioned transverse momentum is kept Permanent equation is applied to gas phase, liquid phase and/or drop phase, and for specific each phase, every expression formula can be made further thin in formula Change.

Specific enthalpy, fuel rod surface temperature, fluid density and fluid temperature (F.T.) according to each axial control volume, while simultaneous is asked The axial momentum conservation equation and transverse momentum conservation equation are solved, transverse flow speed and pressure is obtained；

4.4.3) with each axial control volume as unit, the quality of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, example is as follows：

Section 1 is that per unit axial length is improved quality and changed with time in formula, and Section 2 is axle on per unit axial length To the spatial variations of mass flow, Section 3 is that turbulent flow mixes the mass exchange for causing on per unit axial length.Above-mentioned energy is kept Permanent equation is applied to gas phase, liquid phase and/or drop phase, and for specific each phase, every expression formula can be made further thin in formula Change.

According to transverse flow speed and pressure in each axial control volume, the mass-conservation equation is solved, obtain axial flow velocity；

4.4.4) judge whether mass-conservation equation, momentum conservation equation and energy conservation equation meet residual error requirement, if Be unsatisfactory for, then according to step 4.4.1) to step 4.4.3) order iterated, if meeting, obtain each and axially control The internal thermal-hydraulic parameter of system；The thermal-hydraulic parameter includes fuel rod surface temperature, axial flow velocity, transverse flow speed, pressure Power, fluid density, fluid temperature (F.T.), specific enthalpy.

The second solution：

4.4.1) with each axial control volume as unit, the momentum of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the momentum source term relational expression of the mixing grillwork in the reactor core is added to corresponding fluid gas-phase, liquid Mutually and/or in the momentum conservation equation of drop phase；It is directional because momentum is scalar, therefore one in subchannel analysis method As momentum is decomposed into axial momentum and transverse momentum two parts, corresponding momentum conservation equation includes axial momentum conservation equation With transverse momentum conservation equation, corresponding momentum source term relational expression is also including axial momentum source item relational expression and transverse momentum source item Relational expression；The momentum source term relational expression of the mixing grillwork is by step 3) any one of set up；The axial momentum is kept Permanent equation and transverse momentum conservation equation difference example are as follows：

Axial momentum conservation equation：

Transverse momentum conservation equation：

Axial momentum conservation equation and transverse momentum conservation equation are solved according to thermal boundary condition, initial horizontal stream is obtained Speed and axial flow velocity；

4.4.2) with each axial control volume as unit, the quality of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, example is as follows：

According to the transverse flow speed and axial flow velocity of each axial control volume, the mass-conservation equation is solved, after being updated Transverse flow speed, axial flow velocity and pressure；

4.4.3) with each axial control volume as unit, the energy of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Conservation equation, and the energy source n-th-trem relation n formula of the mixing grillwork in reactor core is added in the energy conservation equation, show Under for example：

According to the transverse flow speed after being updated in each axial control volume, axial flow velocity and pressure, the conservation of energy side is solved Journey, obtains specific enthalpy；

4.4.4) judge whether momentum conservation equation, mass-conservation equation and energy conservation equation meet residual error requirement, if Be unsatisfactory for, then according to step 4.4.1) to step 4.4.3) order iterated, if meeting, obtain each and axially control The internal thermal-hydraulic parameter of system；The thermal-hydraulic parameter includes fuel rod surface temperature, axial flow velocity, transverse flow speed, pressure Power, fluid density, fluid temperature (F.T.), specific enthalpy.

5) judge the predicted value and step 2 of CHF values under reactor core difference operating mode respectively) in collected CHF values Between ratio, and under different operating mode CHF positions predicted value and step 2) in difference between collected CHF positions be It is no to meet step 1) in the default degree of accuracy；If any one is unsatisfactory for, channel program is optimized and/or right CHF relational expressions are improved, and repeat step 4) and 5)；

6) the CHF values of reactor core to be analyzed and the predicted value of CHF positions are exported.

Mentality of designing：

The present invention provides a kind of combination resistance and Energy distribution mixes the subchannel analysis method of effect comprising screen work.In view of Current channel program fails really to reflect the influence that mixing grillwork stream field is produced, of the invention by mixing grillwork stream field Influence is added separately to corresponding momentum conservation equation and energy by the form of momentum source term relational expression and energy source n-th-trem relation n formula In amount conservation equation, by solving new conservation equation, sub- in-passage pressure is dropped, is flow over and Temperature Distribution so as to obtain and mix the wing Influential effect, obtain more accurately local thermal technology's hydraulic parameters.

Technology Roadmap of the invention is as shown in Figure 3 and Figure 4.Collect first and include reactor core mixing grillwork to be analyzed It is many with collected according to the fitting experimental data being collected into experimental data of the interior various mixing grillworks under different operating modes Momentum source term universal correlation function and energy source item universal correlation function that mixing grillwork matches are planted, then to reactor to be analyzed The experimental data of the mixing grillwork of reactor core, obtains the coefficient in momentum source term universal correlation function and energy source item universal correlation function, The momentum source term relational expression and energy source n-th-trem relation n formula of the mixing grillwork are finally obtained, then lists mass-conservation equation, momentum and kept Permanent equation and energy conservation equation, momentum source term relational expression is added in corresponding momentum conservation equation, and energy source item is closed It is that formula is added in corresponding energy conservation equation, iterative quality, momentum and energy conservation equation are straight in sequence To residual error requirement is met, so as to obtain more accurately local thermal technology's hydraulic parameters, closed for more accurately CHF predictions or CHF It is the exploitation of formula.

Because the present invention reflects what mixing grillwork brought by adding momentum source term relational expression and energy source n-th-trem relation n formula Influence, the not solution flow of reprogramming, therefore the present invention is not limited by channel program structure and solution, can answered extensively In the calculating of various types of channel programs, the channel program of two-fluid model is mainly used in.

Fig. 6 and Fig. 7 are the result of calculation of the transverse flow speed in the 5x5 cluster subchannels gap with mixing grillwork.Wherein black Curve represents the result calculated by calibrated fluid dynamics software, and a reference value analyzed as a comparison, blue curve is represented The result calculated by atom channel program, red curve represents the knot that the channel program after being improved by the method for the present invention is calculated Really.The subchannel of 5x5 clusters is divided and numbered as shown in figure 5, Fig. 6 is the crossing current value in the gap between subchannel (2,8), Fig. 7 It is the crossing current value in the gap between subchannel (9,10).As seen from the figure, the channel program after being improved using the method for the present invention The predictive ability of local thermal technology's hydraulic parameters is significantly improved, can be used for opening for the more accurately prediction of CHF or CHF relational expressions Hair.

Claims (7)

1. the subchannel analysis method of effect is mixed with reference to resistance and Energy distribution comprising screen work, it is characterised in that including following Step：

1) degree of accuracy of the predicted value of the CHF values and CHF positions of reactor core to be analyzed is preset；

2) experimental data of the mixing grillwork under different operating modes is collected；

The mixing grillwork is the mixing grillwork of reactor core to be analyzed, or mixes lattice comprising reactor core to be analyzed Frame is in interior various mixing grillworks；

The experimental data includes at least four classes：The first kind and Equations of The Second Kind experimental data are cluster axially and radially non-uniform heating CHF values and CHF positions that CHF experiments under operating mode are obtained, remaining experimental data is in the distribution of cluster channel pressure, cluster passage Velocity flow profile, mix experiment obtain Exit temperature distribution and cluster channel flow field temperature in optionally at least two classes；

3) following either method is taken to set up the momentum source term relational expression and energy of the mixing grillwork of reactor core to be analyzed Source item relational expression：

Method A) utilize at least four class experimental datas of the mixing grillwork of reactor core to be analyzed under different operating modes direct Fitting momentum source term relational expression and energy source n-th-trem relation n formula；

Method B) utilize at least four class experimental datas of the mixing grillwork of reactor core to be analyzed under different operating modes to demarcate Computational fluid dynamics software, then local thermal technology's hydraulic parameters are calculated in the range of demarcation with the software, it is fitted momentum source term Relational expression and energy source n-th-trem relation n formula；

Method C) at least four class fitting experimental datas using collected various mixing grillworks under different operating modes with it is collected Various mixing grillworks the momentum source term universal correlation function and energy source item universal correlation function that match, then by reaction to be analyzed Experimental data of the mixing grillwork of heap reactor core under different operating modes tries to achieve momentum source term universal correlation function and the general pass of energy source item It is the coefficient of formula, it is final to obtain momentum source term relational expression and energy the source item pass for reflecting that the mixing grillwork critical component mixes performance It is formula；The critical component includes mixing the wing, just band, convex, spring and solder joint；

4) in channel program add step 3) obtain momentum source term relational expression and energy source n-th-trem relation n formula, then with the son lead to Road program calculates the thermal-hydraulic parameter of reactor core to be analyzed, therefrom obtains CHF under reactor core difference operating mode Value and the predicted value of CHF positions；

5) judge the predicted value and step 2 of CHF values under reactor core difference operating mode respectively) between collected CHF values Ratio, and under different operating mode CHF positions predicted value and step 2) in difference between collected CHF positions whether expire Sufficient step 1) in the default degree of accuracy；If any one is unsatisfactory for, channel program is optimized and/or CHF is closed It is that formula is improved, repeats step 4) and 5)；

6) the CHF values of reactor core to be analyzed and the predicted value of CHF positions are exported.

2. combination resistance according to claim 1 and Energy distribution mix the subchannel analysis method of effect comprising screen work, It is characterized in that：The step 3) method C) in fitting momentum source term relational expression and energy source n-th-trem relation n formula method it is specific such as Under：

C1) the same class experimental data of collection is contrasted, find out with screen work mix performance-relevant geometrical structure parameter and Local thermal technology's hydraulic parameters；

C2) multiple geometrical structure parameters of selection mixing grillwork and local thermal-hydraulic parameter are respectively as the general pass of momentum source term It is the variable of formula and energy source item universal correlation function；

C3) combine the variable of the experimental data and selection collected, using least square fitting momentum source term universal correlation function and Energy source item universal correlation function；

C4) experimental data for reactor core mixing grillwork to be analyzed determines momentum source term universal correlation function and energy source Coefficient in item universal correlation function, finally gives momentum source term relational expression and energy source n-th-trem relation n formula.

3. combination resistance according to claim 2 and Energy distribution mix the subchannel analysis method of effect comprising screen work, It is characterized in that：The step C3) in the momentum source term universal correlation function that is fitted include axial momentum source item universal correlation function Φ_AWith transverse momentum source item universal correlation function Φ_L, it is specific as follows：

${\mathrm{\Φ}}_A=K_u\frac{A_W^{\′\′}}{8}{\mathrm{\ρV}}_{total}^2\left(\frac{A_R}{A_W^{\′\′}}\right)\cos \mathrm{\θ}+K_{u1}\frac{A_W^{\′\′}}{8}{\mathrm{\ρV}}_{total}^2(1-\frac{A_R}{A_W^{\′\′}})\cos (\mathrm{\α}-\mathrm{\θ})\cos \mathrm{\α}+K_{v1}\frac{A_W^{\′\′}}{2}{{\mathrm{\ρv}}_1}^2\sin \mathrm{\α}---\left(1\right)$

${\mathrm{\Φ}}_L=K_v\frac{A_W^{\′\′}}{8}{\mathrm{\ρv}}^2{\left(\frac{D_V^{\′\′}}{P}\right)}^{0.4}+K_{u1}\frac{A_W^{\′\′}}{8}{\mathrm{\ρV}}_{total}^2(1-\frac{A_R}{A_W^{\′\′}})\cos (\mathrm{\α}-\mathrm{\θ})\sin \mathrm{\α}-K_{v1}\frac{A_W^{\′\′}}{2}{{\mathrm{\ρv}}_1}^2\cos \mathrm{\α}---\left(2\right)$

In formula：

A″_WWetted perimeter when being comprising screen work, unit is m；

ρ is fluid density, and unit is kg/m³；

V_totalIt is flow field local velocity, unit is m/s；

A_RWetted perimeter when being not comprising screen work, unit is m；

θ is the angle of flow field local velocity and cluster direction, and unit is degree；It is the local axial velocity and partial lateral in flow field The function of speed, its calculating formula can be expressed as follows：

$\mathrm{\θ}=arctan\left(\frac{v}{u}\right)---\left(3\right)$

D″_VSubchannel equivalent diameter when being comprising screen work, unit is m；

P is the wetted perimeter of subchannel, and unit is m；

U is cluster axial direction component velocity, and unit is m/s；

V is cluster cross stream velocity component, and unit is m/s；

u₁It is to mix wing tangential-velocity component, unit is m/s；

v₁It is to mix wing normal direction component velocity, unit is m/s；

α is the angle for mixing the wing and cluster direction, and unit is degree；

K_u, K_v, K_u1And K_v1It is the coefficient of the mixing grillwork of corresponding reactor core to be analyzed in momentum source term universal correlation function； K_u, K_v, K_u1And K_v1Value it is closely related with the geometry of the mixing grillwork, determined by the experimental data of the mixing grillwork；

The step C3) in the energy source item universal correlation function that is fitted with gas-liquid two-phase interfacial area, liquid phase specific enthalpy, gas phase Specific enthalpy, liquid velocity, gas phase velocity, pressure are closely related, specific as follows：

$\mathrm{\Θ}=E_1{\mathrm{\ρ}}_l{h}_l{V}_l\left(\frac{A_R}{A_W^{\′\′}}L\right)+E_2{\mathrm{\ρ}}_g{h}_g{v}_g(L-\frac{A_R}{A_W^{\′\′}}L)cos(\mathrm{\α}-\mathrm{\θ})+E_{3}L(V_l-V_g)({\mathrm{\ρ}}_l{h}_l-{\mathrm{\ρ}}_g{h}_g)---\left(4\right)$

In formula：

Subscript l represents liquid phase, and subscript g represents gas phase；

ρ_lAnd ρ_gIt is respectively density of liquid phase and density of gas phase, unit is kg/m³；

h_lAnd h_gIt is respectively liquid phase specific enthalpy gentle compared to enthalpy, unit is kJ/kg；

V_lAnd V_gIt is respectively liquid velocity and gas phase velocity, unit is m/s；

L is to mix chord degree, and unit is m；

E₁, E₂And E₃It is the coefficient of the mixing grillwork of corresponding reactor core to be analyzed in energy source item universal correlation function；E₁, E₂ And E₃Value it is related with the geometry of the mixing grillwork and the flow pattern in flow field, including bubble flow, slug flow, Dispersed Flows and ring-type Stream, under different flow pattern operating modes, E₁, E₂And E₃Value it is different, it is necessary to come true according to the experimental data under different flow pattern operating modes It is fixed.

4. combination resistance according to claim 1 and Energy distribution mix the subchannel analysis method of effect comprising screen work, It is characterized in that：The step 4) it is specific as follows：

4.1) in channel program add step 3) obtain momentum source term relational expression and energy source n-th-trem relation n formula；Meanwhile, really The geometrical condition of fixed reactor core to be analyzed and the calculating residual error to be met requirement；The geometrical condition includes fuel rod Number, fuel rod diameter, fuel rod center spacing, cluster length and cluster circulation area, screen work spacing；The residual error requirement bag Include and solve the residual error to be met when mass-conservation equation, momentum conservation equation or energy conservation equation requirement；

4.2) in the channel program that with the addition of momentum source term relational expression and energy source n-th-trem relation n formula, by the stream of reactor core Field is divided into the multiple axles with subchannel as flow area according to the distribution of its axial power, lateral direction power distribution and geometrical condition To control volume；The subchannel is as shown in Fig. 2 surrounded by the line of centres of adjacent fuel rod surface and consecutive fuel rod Minimum circulation passage A, or surrounded by the extension line of the line of centres of adjacent fuel rod surface, wall and consecutive fuel rod Minimum circulation passage B or C；

4.3) the fuel model for solving the reactor core obtains thermal boundary condition, or according to the heat flow density of the reactor core Obtain thermal boundary condition；

4.4) energy conservation equation, momentum conservation equation and mass-conservation equation are solved, all axles of residual error requirement are met To the thermal-hydraulic parameter in control volume；The solution of wherein momentum conservation equation is needed the momentum source term relation of the mixing grillwork Formula is added in the momentum conservation equation of corresponding fluid gas-phase, liquid phase and/or drop phase, and the solution of energy conservation equation needs By the energy source n-th-trem relation n formula of the mixing grillwork added to the conservation of energy side of corresponding fluid gas-phase, liquid phase and/or drop phase Cheng Zhong；

4.5) local thermal technology's hydraulic parameters are extracted from the thermal-hydraulic parameter in all axial control volume for obtaining is solved, therefrom Obtain the reactor core difference operating mode under CHF values and CHF positions predicted value.

5. combination resistance according to claim 4 and Energy distribution mix the subchannel analysis method of effect comprising screen work, It is characterized in that：The step 4.4) it is specific as follows：

4.4.1) with each axial control volume as unit, the conservation of energy of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Equation, and by the energy source n-th-trem relation n formula of the mixing grillwork in the reactor core added to corresponding fluid gas-phase, liquid phase and/ Or in the energy conservation equation of drop phase；The energy conservation equation is solved further according to thermal boundary condition, each is obtained and is axially controlled The specific enthalpy of body, fuel rod surface temperature, fluid density and fluid temperature (F.T.)；

4.4.2) with each axial control volume as unit, the conservation of momentum of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Equation, and by the momentum source term relational expression of the mixing grillwork in the reactor core added to corresponding fluid gas-phase, liquid phase and/ Or in the momentum conservation equation of drop phase；Specific enthalpy, fuel rod surface temperature, fluid density further according to each axial control volume and Fluid temperature (F.T.), solves the momentum conservation equation, obtains transverse flow speed and pressure；

4.4.3) with each axial control volume as unit, the conservation of mass of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Equation；According to transverse flow speed and pressure in each axial control volume, the mass-conservation equation is solved, obtain axial flow velocity；

4.4.4) judge whether mass-conservation equation, momentum conservation equation and energy conservation equation meet residual error requirement, if discontented Foot, then according to step 4.4.1) to step 4.4.3) order iterated, if meeting, obtain each axial control volume Interior thermal-hydraulic parameter；The thermal-hydraulic parameter includes fuel rod surface temperature, axial flow velocity, transverse flow speed, pressure, stream Volume density, fluid temperature (F.T.), specific enthalpy.

6. combination resistance according to claim 4 and Energy distribution mix the subchannel analysis method of effect comprising screen work, It is characterized in that：The step 4.4) it is specific as follows：

4.4.1) with each axial control volume as unit, the conservation of momentum of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Equation, and by the momentum source term relational expression of the mixing grillwork in the reactor core added to corresponding fluid gas-phase, liquid phase and/ Or in the momentum conservation equation of drop phase；The momentum conservation equation is solved further according to thermal boundary condition, initial horizontal stream is obtained Speed and axial flow velocity；

4.4.2) with each axial control volume as unit, the conservation of mass of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Equation, according to the transverse flow speed and axial flow velocity of each axial control volume, solves the mass-conservation equation, the horizontal stroke after being updated To flow velocity, axial flow velocity and pressure；

4.4.3) with each axial control volume as unit, the conservation of energy of corresponding fluid gas-phase, liquid phase and/or drop phase is listed Equation, and by the energy source n-th-trem relation n formula of the mixing grillwork in the reactor core added to corresponding fluid gas-phase, liquid phase and/ Or in the energy conservation equation of drop phase；Further according to the transverse flow speed after being updated in each axial control volume, axial flow velocity and pressure Power, solves the energy conservation equation, obtains specific enthalpy；

4.4.4) judge whether momentum conservation equation, mass-conservation equation and energy conservation equation meet residual error requirement, if discontented Foot, then according to step 4.4.1) to step 4.4.3) order iterated, if meeting, obtain each axial control volume Interior thermal-hydraulic parameter；The thermal-hydraulic parameter includes axial flow velocity, transverse flow speed, pressure, fluid density, fluid temperature Degree, specific enthalpy.

7. combination resistance according to claim 1 and Energy distribution mix the subchannel analysis method of effect comprising screen work, It is characterized in that：The step 4) in the addition of momentum source term relational expression channel program momentum conservation equation it is specific such as Under：

Axial momentum conservation equation：

$\begin{array}{c}\frac{\∂m_i}{\∂t}+\frac{\∂}{\∂Z}\[m_i\left(\frac{m_i}{{\mathrm{\ρ}}_i{A}_i}\right)\]+\underset{j}{\Σ}{w}_{ij}{u}^{*}+\underset{j}{\Σ}{f}_T(W_{ij}^{\′}{u}_i^{\′}-W_{ji}^{\′}{u}_j^{\′})\\ =-A_i\frac{\∂p_i}{\∂Z}-A_i{\mathrm{\ρ}}_{i}g-\frac{1}{2}\frac{f}{D_h}\frac{m_i^2}{{\mathrm{\ρ}}_i{A}_i}-\frac{\∂{\mathrm{\Φ}}_A}{\∂Z}\end{array}---\left(5\right)$

In formula：

Subscript i and j are subchannel numberings, and wherein i represents the subchannel of required solution, and the son that j represents adjacent with subchannel i leads to Road；

m_iIt is the axial flow in subchannel i, unit is kg/s；

T is the time, and unit is s；

Z is the axial height of single axial control volume, and unit is m；

ρ_iIt is the fluid density in subchannel i, unit is kg/m³；

A_iIt is the circulation area of subchannel i, unit is m²；

w_ijIt is the horizontal flow from subchannel i to subchannel j, unit is kg/ (m*s)；w_ijBe on the occasion of when represent horizontal flow from Subchannel i flows to subchannel j, w_ijRepresent that horizontal flow flows to subchannel i from subchannel j during for negative value；

u^*It is the axial flow velocity in donor unit control volume, unit is m/s；Its expression of significance such as following formula：

f_TIt is that lateral turbulence mixes coefficient of friction, unit is 1；

w′_ijIt is the turbulent flow amount of mixing from subchannel i to subchannel j, unit is kg/ (m*s)；

w′_jiIt is the turbulent flow amount of mixing from subchannel j to subchannel i, unit is kg/ (m*s)；

u′_iIt is the fluctuation velocity of subchannel i, unit is m/s；

u′_jIt is the fluctuation velocity of subchannel j, unit is m/s；

p_iIt is the pressure in subchannel i, unit is Pa；

G is acceleration of gravity, and unit is m/s²；

F is axial rub coefficient, and unit is 1；

D_hIt is the equivalent diameter of subchannel, unit is m；

Φ_AIt is the axial momentum source item relational expression for mixing performance for reflecting the mixing grillwork；

Transverse momentum conservation equation：

$\frac{\∂w_{ij}}{\∂t}+\frac{\∂}{\∂Z}\[w_{ij}\left(\frac{m_i}{{\mathrm{\ρ}}_i{A}_i}\right)\]+\underset{j}{\Σ}\frac{1}{l}{w}_{ij}{v}^{*}=-\frac{1}{2l}{K}_G\frac{w_{ij}^2}{{\mathrm{\ρ}}_i{S}_{ij}}+\frac{S_{ij}}{l}(p_i-p_j)-\frac{1}{l}\frac{\∂{\mathrm{\Φ}}_L}{\∂Z}---\left(7\right)$

In formula：

L is the equivalent length of transverse momentum control volume, and unit is m；

v^*It is the transverse flow speed in donor unit control volume, unit is m/s；Its expression of significance such as following formula：

K_GIt is lateral flow resistance coefficient, unit is 1；

S_ijIt is the gap width between subchannel i and subchannel j, unit is m；

p_iAnd p_jIt is respectively the pressure in subchannel i and subchannel j, unit is Pa；

Φ_LIt is the transverse momentum source item relational expression for mixing performance for reflecting the mixing grillwork；

The step 4) in the addition of energy source n-th-trem relation n formula channel program energy conservation equation it is specific as follows：

In formula：

h_iAnd h_jIt is respectively the specific enthalpy in subchannel i and subchannel j, unit is kJ/kg；

h^*It is the specific enthalpy in donor unit control volume, unit is kJ/kg；Its expression of significance such as following formula：

λ_iIt is the flow thermal conductivity coefficient in subchannel i, unit is W/ (m*K)；

T_iAnd T_jRespectively the fluid temperature (F.T.) in subchannel i and subchannel j, unit for DEG C；

L_CIt is geometric corrections constant, unit is 1；

N is the heating wall number adjacent with subchannel i, and unit is 1；

It is the heating wall area adjacent with subchannel i, unit is m²；

q_nIt is the heat flow density of the heating wall adjacent with subchannel i, unit is J/ (m²*s)；

Θ is to reflect that the mixing grillwork mixes the energy source n-th-trem relation n formula of performance；When energy conservation equation represents the energy quantitative change of gas phase During law, symbol before Θ for just, when energy conservation equation represents the energy variation rule of liquid phase, the symbol before Θ It is negative.