CN111753473A - Method, system, medium and apparatus for assessing critical heat flux of pressure vessel - Google Patents
Method, system, medium and apparatus for assessing critical heat flux of pressure vessel Download PDFInfo
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Abstract
The invention discloses a method, a system, a medium and an electronic device for evaluating critical heat flux of a pressure vessel, wherein the evaluation method comprises the steps of obtaining evaluation parameters, wherein the evaluation parameters comprise physical property parameters at an evaluation position and structural parameters of the pressure vessel; wherein the evaluation position is a preset position on a wall surface of the pressure vessel; respectively calculating the tangential heat flux and the radial heat flux of the pressure vessel according to the evaluation parameters; evaluating a critical heat flux of the pressure vessel based on the tangential heat flux and the radial heat flux. The technical scheme of the invention can accurately evaluate the critical heat flux of the pressure vessel, and has higher calculation accuracy. In addition, when the critical heat flux is calculated, the key two-phase flow parameters at the evaluation position can be obtained, and the safety and the reliability of the operation of the pressure container are effectively improved.
Description
Technical Field
The invention relates to the field of nuclear reactor thermodynamic and hydraulic calculation, in particular to a method, a system, a medium and electronic equipment for evaluating critical heat flux of a pressure vessel under a severe accident condition of a large advanced pressurized water reactor.
Background
The national development planning on nuclear energy indicates that the nuclear power industry of China enters a new stage of rapid development. However, the nuclear energy is a double-edged sword, which can bring clean and efficient energy to human beings and also can bring serious disasters to human beings. Particularly, the accidents in the united states of america in 1979, the accidents in soviet chernobiles in 1986 and the accidents in japanese fukushima nuclear in 2011 all cause serious disasters to the natural and social environments and severe physical and psychological injuries to the public, so that the enthusiasm and confidence of the public in developing nuclear power are greatly hit, and the nuclear power is developed into the low ebb valley period. In the 21 st century today, nuclear power safety is improved to an unprecedented level, and research on serious accidents and mitigation measures thereof become the first problems that must be considered in nuclear power development.
The purpose of the in-pile melt retention strategy is to effectively cool down the in-pile melt in a direct or indirect mode when a serious accident occurs, so that the integrity of the outer wall of the pressure vessel is guaranteed, radioactive substances are prevented from leaking into the external environment, and the in-pile melt retention strategy is one of important serious accident mitigation measures.
At present, the research of serious accidents focuses on maintaining the integrity of a pressure vessel, and the most widely applied method is that water is injected into a reactor cavity to cool the outer wall (particularly a lower end socket) of the pressure vessel so as to realize the retention of a molten material in a reactor during the serious accidents.
Through theoretical research of critical heat flux of the outer wall of the pressure vessel under the severe accident condition, corresponding two-phase natural circulation flow parameters can be provided for scientific research personnel to analyze, the cooling capacity of the outer wall of the pressure vessel during reactor cavity water injection can be better evaluated, and powerful guidance is provided for selecting proper design of the lower seal head of the pressure vessel. In addition, for a given pressure vessel, it can be predicted whether the local heat flow of melt decay will exceed the critical heat flux at the bottom of the lower head in the event of a severe accident.
Therefore, how to provide a method capable of accurately estimating the heat flux of the pressure vessel is a problem to be solved.
Disclosure of Invention
The invention aims to overcome the defect that substances in a pressure container are easy to leak when the pressure container has a serious accident because the critical heat flux of the pressure container cannot be accurately evaluated in the prior art, and provides a method, a system, a medium and electronic equipment for evaluating the critical heat flux of the pressure container.
The invention solves the technical problems through the following technical scheme:
a method of assessing critical heat flux of a pressure vessel, the method comprising:
acquiring evaluation parameters including physical property parameters at an evaluation position and structural parameters of the pressure vessel; wherein the evaluation position is a preset position on a wall surface of the pressure vessel;
respectively calculating the tangential heat flux and the radial heat flux of the pressure vessel according to the evaluation parameters;
evaluating a critical heat flux of the pressure vessel based on the tangential heat flux and the radial heat flux.
Preferably, the step of calculating the tangential heat flux and the radial heat flux of the pressure vessel from the evaluation parameters, respectively, comprises:
calculating a macro liquid film thickness, a bubble length, and a liquid phase flow rate within the macro liquid film at the evaluation position according to the evaluation parameters, and calculating the tangential heat flux using the macro liquid film thickness, the bubble length, and the liquid phase flow rate within the macro liquid film;
calculating bubble adherence residence time, two-phase boundary layer thickness and a void fraction according to the evaluation parameters, and calculating the radial heat flux by using the bubble adherence residence time, the two-phase boundary layer thickness and the void fraction;
and/or the presence of a gas in the gas,
said step of estimating a critical heat flux of said pressure vessel based on said tangential heat flux and said radial heat flux comprises:
summing the tangential heat flux and the radial heat flux to obtain a critical heat flux for the pressure vessel.
Preferably, the pressure vessel comprises a lower seal head, and the evaluation position is positioned on an arc-shaped wall surface of the lower seal head of the pressure vessel;
the tangential heat flux is a heat flux in a direction perpendicular to a line connecting the evaluation position and the center point; the center point is the center of the arc-shaped wall surface of the lower end enclosure;
the radial heat flux is a heat flux in a direction coinciding with a line connecting the evaluation position and the center point.
Preferably, the evaluation method further comprises:
dividing different cooling levels for different positions of the outer wall of the pressure vessel according to the critical heat flux so that the local heat flow of the decayed melt in the pressure vessel does not exceed the critical heat flux;
and/or the presence of a gas in the gas,
and adjusting the structural design parameters of the pressure vessel according to the critical heat flux so that the local heat flow of the melt decay in the pressure vessel does not exceed the critical heat flux.
Preferably, the thickness of the macro liquid film is positively correlated with the liquid phase supercooling degree at the evaluation position;
and/or the liquid phase velocities at different distances from the wall surface of the pressure vessel are different in a direction in which the evaluation position coincides with a line connecting the center point.
An evaluation system of critical heat flux of a pressure vessel, the evaluation system comprising:
an evaluation parameter acquisition module for acquiring evaluation parameters including physical property parameters at an evaluation position and structural parameters of the pressure vessel; wherein the evaluation position is a preset position on a wall surface of the pressure vessel;
a heat flux component calculation module for calculating a tangential heat flux and a radial heat flux of the pressure vessel, respectively, based on the evaluation parameters;
a critical heat flux assessment module to assess a critical heat flux of the pressure vessel as a function of the tangential heat flux and the radial heat flux.
Preferably, the heat flux component calculation module is configured to calculate a macro liquid film thickness, a bubble length, and a liquid phase flow rate within the macro liquid film at the evaluation position according to the evaluation parameter, and calculate the tangential heat flux using the macro liquid film thickness, the bubble length, and the liquid phase flow rate within the macro liquid film;
the heat flux component calculation module is further used for calculating bubble adherence residence time, two-phase boundary layer thickness and a void fraction according to the evaluation parameters, and calculating the radial heat flux by using the bubble adherence residence time, the two-phase boundary layer thickness and the void fraction;
and/or the presence of a gas in the gas,
the critical heat flux evaluation module is configured to sum the tangential heat flux and the radial heat flux to obtain a critical heat flux for the pressure vessel.
Preferably, the pressure vessel comprises a lower seal head, and the evaluation position is positioned on an arc-shaped wall surface of the lower seal head of the pressure vessel;
the tangential heat flux is a heat flux in a direction perpendicular to a line connecting the evaluation position and the center point; the center point is the center of the arc-shaped wall surface of the lower end enclosure; the radial heat flux is a heat flux in a direction coinciding with a line connecting the evaluation position and the center point.
Preferably, the evaluation system further comprises a cooling level classification module and a structural parameter adjustment module:
the cooling grade dividing module is used for dividing different cooling grades for different positions of the outer wall of the pressure vessel according to the critical heat flux so that the local heat flow of the decayed melt in the pressure vessel does not exceed the critical heat flux;
and/or the presence of a gas in the gas,
the structural parameter adjusting module is used for adjusting the structural design parameters of the pressure vessel according to the critical heat flux so that the local heat flow of the melt decay in the pressure vessel does not exceed the critical heat flux.
Preferably, the thickness of the macro liquid film is positively correlated with the liquid phase supercooling degree at the evaluation position;
and/or the presence of a gas in the gas,
the liquid phase velocities at different distances from the wall surface of the pressure vessel are different in a direction in which the evaluation position coincides with the line connecting the center point.
An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the method for assessing a critical heat flux of a pressure vessel as described above when executing the computer program.
A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the aforementioned steps of the method for assessing the critical heat flux of a pressure vessel
The positive progress effects of the invention are as follows: according to the method and the system for evaluating the critical heat flux of the pressure container, the influence of the supercooling degree, the channel geometric dimension and the radius of the pressure container on the critical heat flux is considered in the evaluation process, and meanwhile, the influence of two-phase flow layering is considered in the calculation method, so that the calculation accuracy is high. In addition, while the critical heat flux is calculated, some key two-phase flow parameters (such as liquid phase speed, gas phase speed, adherent bubble suspension time and the like) at the evaluation position can be obtained, and the safety and the reliability of the operation of the pressure container are effectively improved.
Furthermore, theoretical support and technical support can be provided for further improving the structural parameters of the pressure vessel or further accurately determining the cooling grade in the advanced pressurized water reactor design process according to the critical heat flux values at different inclination angles of the arc-shaped wall surface.
Drawings
Fig. 1 is a flowchart of a method for evaluating a critical heat flux of a pressure vessel according to example 1 of the present invention.
Fig. 2 is a flowchart illustrating the step S11 in the method for evaluating the critical heat flux of the pressure vessel according to embodiment 1 of the present invention.
Fig. 3 is a schematic view of a macro liquid film evaporation model in embodiment 1 of the present invention.
FIG. 4 is a schematic representation of the flow stratification of the outer wall of the pressure vessel under severe accident conditions according to example 1 of the present invention.
Fig. 5 is a flowchart of a method for evaluating the critical heat flux of the pressure vessel according to example 2 of the present invention.
Fig. 6 is a block diagram showing a system for evaluating a critical heat flux of a pressure vessel according to embodiment 3 of the present invention.
Fig. 7 is a block diagram of a system for evaluating a critical heat flux of a pressure vessel according to embodiment 4 of the present invention.
Fig. 8 is a block diagram of an electronic device according to embodiment 5 of the present invention.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
Example 1
The present embodiment provides a method for evaluating a critical heat flux of a pressure vessel, and when evaluating the critical heat flux, the method considers the following heat exchange conditions: firstly, under the influence of the actual water level height, the inlet water temperature of the pressure container is generally lower than the saturated water temperature of an evaluation position; a flow channel formed between the outer wall surface of the pressure container and the heat insulating layer can also cause certain influence on critical heat flux; and thirdly, unlike the heat exchange of the upward surface, the force of the bubbles on the downward surface and the influence on the critical heat flux need to be considered. Therefore, the critical heat flux evaluation method in this embodiment combines hydrodynamic instability and macroliquid film evaporation to develop a critical heat flux calculation method suitable for severe accident conditions.
Wherein the severe accident may include a core melting accident of a nuclear island part of the nuclear power plant.
The critical heat flux model of the outer wall of the pressure vessel under the condition of serious accidents needs to be developed, and factors such as the supercooling degree, the geometric shape of a flow channel, the periodic behavior of a bubble layer, the stress condition of bubbles on the downward surface and the like need to be considered.
Aiming at the heat exchange condition of the outer wall of the pressure container under the condition of serious accident, a macro liquid film evaporation model and a hydrodynamic instability model are combined to further develop a critical heat flux evaluation method suitable for the downward surface.
As shown in fig. 1, the evaluation method may include the steps of:
step S10: acquiring evaluation parameters including physical property parameters at an evaluation position and structural parameters of the pressure vessel; wherein the evaluation position is a preset position on a wall surface of the pressure vessel;
step S11: respectively calculating the tangential heat flux and the radial heat flux of the pressure vessel according to the evaluation parameters;
step S12: evaluating a critical heat flux of the pressure vessel based on the tangential heat flux and the radial heat flux.
In this embodiment, the physical property parameters may include, but are not limited to: saturation temperature, liquid phase constant pressure specific heat capacity, bubble surface tension, liquid phase dynamic viscosity, steam density and liquid density.
The structural parameters may include, but are not limited to: the area of the heating wall under the bubble, the width of the heating surface, and the width of the rectangular channel on the heating wall surface.
Further, referring to fig. 2, the step S11 may specifically include the following steps:
step S110: calculating a macro liquid film thickness, a bubble length, and a liquid phase flow rate within the macro liquid film at the evaluation position according to the evaluation parameters, and calculating the tangential heat flux using the macro liquid film thickness, the bubble length, and the liquid phase flow rate within the macro liquid film;
step S111: calculating bubble adherence residence time, two-phase boundary layer thickness and a void fraction according to the evaluation parameters, and calculating the radial heat flux by using the bubble adherence residence time, the two-phase boundary layer thickness and the void fraction;
in this embodiment, the tangential heat flux and the radial heat flux may be summed to obtain a critical heat flux for the pressure vessel.
In this embodiment, the pressure vessel may include a lower head having an arcuate hemispherical wall. The evaluation location may be located on an arcuate wall of a bottom head of the pressure vessel.
Based on this, the tangential heat flux is a heat flux in a direction perpendicular to a line connecting the evaluation position and the center point; the center point is the center of the arc-shaped wall surface of the lower end enclosure; the radial heat flux is a heat flux in a direction coinciding with a line connecting the evaluation position and the center point.
In this embodiment, the thickness of the macro-liquid film is positively correlated with the degree of supercooling of the liquid phase at the evaluation position. The supercooling degree refers to the difference between the temperature of condensed water under a certain pressure and the saturation temperature under the corresponding pressure.
The liquid phase velocities at different distances from the wall surface of the pressure vessel are different in a direction in which the evaluation position coincides with the line connecting the center point.
In order to make the calculation principle of the present technical solution clearer, the calculation principle of the critical heat flux is described in detail below with reference to fig. 3-4.
Referring to fig. 2, a layer of macroliquid film is provided beneath the elongated bubble adjacent the heated wall. The macro-liquid film is composed of a series of liquid films, and the liquid films contain steam columns. Under steady saturated boiling conditions, the mass flow rate of the gas column is equal to the nucleate boiling amount.
Referring to fig. 3, the flow field may be divided into four parts: the macro-liquid film area near the heating wall surface, the bubble layer where the bubbles are located, the two-phase area in the middle of the bubbles and the single-phase area far away from the wall, and the macro-liquid film, the bubble layer and the two-phase area jointly form a two-phase boundary layer.
In this embodiment, the tangential heat flux can be calculated in the following preferred manner.
The mass flow in the macro-liquid film can be expressed as:
equation 1: m iss＝ρlulmAm；
Wherein m issIs the rate of replenishment of liquid from upstream of the evaluation location, which is upstream of the source of cooling liquid for a predetermined evaluation location on the wall of the pressure vessel. RholIs the liquid density, ulmIs the effective velocity of the liquid phase in the macroliquid membrane, AmIs the cross-sectional area between the heated wall and the bubble.
The evaporation mass rate in the macroscopic liquid film under the bubble can be expressed as:
equation 2:
wherein m isdIs the mass evaporation rate, qθIs the tangential component of the nucleate boiling heat flux (i.e., the aforementioned tangential heat flux), AwIs the area of the heating wall under the bubble, hfgIs the latent heat of vaporization.
At critical heat flux, ms＝mdThus, combining equation 1 and equation 2, one can obtain:
equation 3:
defining the thickness of the macro-liquid film asmThe length of the elongated bubbles is LbWall width of wbThus, AmAnd AwCan be respectively expressed as:
equation 4: a. them≈mwb
Equation 5: a. thew≈Lbwb
Substituting equation 4 and equation 5 into equation 3, equation 3 becomes the following form:
equation 6:
as can be seen from equation 6, the independent variables that affect the tangential heat flux are the liquid phase flow rate within the macroliquid membrane, the thickness of the macroliquid membrane and the bubble length.
In this embodiment, the radial heat flux can be calculated in the following preferred manner.
The conservation equation for the mass of the liquid and gas phases in the rectangular channel on the wall of the heating vessel is given by equation 7 below:
ρlulm(1-αm)mw+ρgugαm mw+ρlulb(1-αb)Dbw+ρgugαbDbw+ρluls(1-αtw)(-Db-m)w+ρgugαtw(-Db-m)w+ρluls(H-)w＝G*H*w
wherein u islm，ulbAnd ulsα are respectively the effective liquid phase velocity in the macro liquid film, the effective liquid phase velocity in the center of the bubble, and the effective liquid phase velocities in the two-phase region and the single-phase region, the velocity unit is m/sm，αbAnd αtwRespectively is the average void fraction in the macro liquid film, the void fraction in the bubble layer and the void fraction in the two-phase region; is the thickness of the two-phase boundary layer in m (meters); w is the width of the heating surface in m (meters); dbIs the bubble diameter; h is the height of the rectangular channel in m (meters); g is the average mass flow of the cross section at the evaluation position in the natural circulation flow process, and the unit is kg/(m)2S) (kg/(m)2Second)).
In this embodiment, the tangential heat flux is generated by the evaporation of the liquid phase that is diffused into the macroliquid film through the two-phase region and the single-phase region from the gas phase portion in the two-phase boundary layer.
In this example, the mass m of the liquid phase diffused into the macroliquid film per unit timekAs follows:
equation 8:
radial heat flux qrThe following relationship exists with respect to the thickness of the two-phase boundary layer:
equation 9: q. q.sr×τ＝E0ρlhfgα
Wherein tau is the bubble adherence residence time, the thickness of the two-phase boundary layer, α is the void fraction, and the tangential heat flux is the total phase transition heat (rho) in the two-phase boundary layerlhfgα) E0Multiple (0 ≤ E)0<1)。
In this embodiment, the void fraction may be calculated in the following preferred manner:
determining the distribution of void fraction at the evaluation position, with continuing reference to fig. 2, the wavy gas column inside the macro-liquid film can be approximately regarded as a cylinder, and the void fraction in the macro-liquid film can be approximately equal to the area A of the gas columngAnd heating wall surface area AwRatio of (b) in the macro liquid film, the fraction of the bubbles in the macro liquid film is αmThe calculation method is as follows:
equation 10:
since the void fraction is 0.915 when CHF (critical heat flux) occurs under the pool boiling saturation condition, the maximum value of the void fraction is 0.915 when CHF occurs, and the position is located in the area where the bubbles are located, namely, the position where the bubbles are locatedm≤y<m+Db。
In addition, the proportion of voids in the single-phase region is 0.
Therefore, the void fraction distribution boundary condition is shown in equation 11:
equation 11:
wherein y is the distance from the wall surface, and when y is equal tom+DbAnd when y is equal, α is equal to 0.
From macro liquid film boundariesmTo the center of the deformed bubble
The void fraction increases monotonically.
It can be considered that,m+Dbby the boundary of the two-phase boundary layer, the value of the void fraction decreases monotonically from 0.915 to 0.
From the above analysis, the proportion of the bubbles in the macro liquid film is αm＝0.013，
mTom+DbAverage value of void fraction αb＝0.915，
m+DbAverage void fraction α to the boundary of the two-phase boundary layertwComprises the following steps:
in this embodiment, equation 10 can be further explained:
the establishment condition of (1).
For an ideal infinite wall, the bubbles are generated from the peaks of the Taylor waves, the critical Taylor wavelength being the most dangerous wavelength and the critical Taylor wavelength λDThe calculation is performed using equation 12.
Equation 12:
wherein the individual parameter g is the gravity coefficient, ρgSubscript g in (1) denotes gas phase, plThe subscript l in (1) denotes the liquid phase, pgIs the vapor density, plFor liquid density, σ is the bubble surface tension.
Assuming that one bubble can be generated per heated wall per square wavelength, the volume of vapor provided to the bubble per unit time
Can be expressed by equation 13:
equation 13:
attachment time tau of air bubble and macro liquid filmdAnd volume of steam
The relationship between them is shown in equation 14:
equation 14:
where the factor 11/16 is the volume fraction of liquid carried by the bubble as it moves.
The bubbles impede contact of the liquid in the main flow area with the macro-liquid film. Therefore, the thickness of the macro liquid film is gradually reduced by evaporation. When critical heat flux occurs, the time for the macro liquid film to be completely dried is just equal to the time for the bubbles to be attached to the macro liquid film. That is, the macro-liquid film just dries out completely as the bubbles exit. From the viewpoint of energy balance, the amount of heat diffused into the heating wall surface during the time of bubble adhesion is equal to the latent heat of complete evaporation of the macro-liquid film.
Equation 15: tau isbqθAw＝ρl m(Aw-Ag)hfg
Will taudAndmsubstituting equation 15 results in equation 16 as follows:
equation 16:
this embodiment takes into account the critical heat flux in case of hydrodynamic instability, and
equation 17:
order to
Equaling the tangential heat flux in equation 16 yields equation 18:
equation 18:
and because of
So equation 19 can be obtained:
equation 19:
in the present embodiment, the macro liquid film thickness and the bubble diameter can be calculated in the following preferable manner.
As will be appreciated by those skilled in the art, the bubbles absorb increasing amounts of heat from the continuous vaporization of the macroliquid film. When the buoyancy of the bubble exceeds the resistance and surface tension of the surrounding fluid, the bubble begins to detach from the heated wall, and the cycle repeats itself at high heat flux. The time from the start of bubble generation to the departure is called the hover time. It is assumed that a critical heat flux occurs when the macro-liquid film is completely evaporated.
The energy and mass balance on the macro-liquid film has the following relationship:
equation 20:
where ρ isgIs the vapor density, plIs the density of the liquid, vgIs the steam jet velocity, vlThe velocity of the liquid flowing vertically into the heating surface, AwFor heating area under the whole bubble, AgArea occupied by the steam column, hfgFor latent heat of vaporization, q ″)NBTo evaluate nucleate boiling heat flux at the site. Q' at the onset of CHFNB＝qθThe lower index l indicates the liquid phase and the lower index g indicates the gas phase.
And in the time t, the macro liquid film is completely evaporated to dryness, and the condition under the critical heat flux density condition is t ═ tau,m0. Where τ is the bubble hover time and t is the time required for the macro liquid film to completely evaporate.
Equation 21:
in this embodiment, the steam velocity v is shown in formula 21gThe Helmholtz instability can be related to the initial thickness of the macro liquid filminitial，CHFAre linked together. Relative to the velocity v of the gas phasegThe velocity v of the liquid can be ignoredlAnd assuming that the macro-liquid film thickness is one-quarter of the Helmholtz instability wavelength, i.e.
The Helmholtz instability wavelength may be expressed as:
equation 22:
velocity v of steamgCan be expressed as:
equation 23:
based on this, the initial thickness of the macro-liquid filminitial，CHFCan be expressed as:
equation 24:
it can be seen from equation 19 that the ratio of the vapor column area to the heating surface is a function of the ratio of the gas phase to the liquid phase densities.
Substituting equation 19 into equation 24 yields the following equation 25:
where τ is the bubble hover time.
When the supercooled liquid will contact the upper part of the bubbles, this causes some gas to condense inside the bubbles, thereby increasing the attachment time between bubbles.
Equation 26:
wherein the content of the first and second substances,
wherein the value of k can be defined as 1. In addition, CpIs the specific heat capacity at constant pressure, and the unit is J/(Kg. degree
K) (Joule/(kg. Kelvin)); tau issubIs the hover time of a bubble under fluid supercooling in units of s (seconds); ja is the Jacobian number, which is a dimensionless number for measuring the supercooling degree of a liquid film in the heat transfer science; delta TsubIs the degree of supercooling, equal to the saturation temperature of the fluid minus the actual temperature of the fluid, i.e. Δ Tsub＝Tsat-T。
In equation 25 we can see that bubble hover time increases with increasing subcooling level.
Next, the bubble velocity and the bubble diameter near the wall surface can be calculated. At high heat flux, the bubbles absorb some of the bubbles sliding from upstream to coalesce into larger, elongated, bulk bubbles.
Considering the tangential force balance, the liquid phase velocity and the gas phase velocity will be determined by the balance of drag and buoyancy.
Equation 27: fd＝Fb；
Equation 28:
equation 29:
wherein D isbIs the bubble thickness (which may also be referred to as the diameter of the bubble), in m (meters);
Cdis the coefficient of resistance, theta is the angle of inclination of the curved wall surface, ugIs the gas phase velocity ulIs the liquid phase velocity, FdIs the resistance to the bubbles, FbIs the bubble buoyancy force.
Coefficient of resistance CdIs DbAnd is defined as:
equation 30:
the simultaneous equations 27-30 can be derived:
equation 31:
the liquid phase velocity at the center of the bubble can be calculated in one non-limiting manner as follows:
equation 32:
where Re is the Reynolds number, which is a dimensionless number that characterizes viscous fluid flow.
Since equation 32 is the result of the calculation from the single phase turbulence equation, the actual experimental process is a two-phase flow process, and the use of the empirical constant of 0.758 is not accurate, another non-limiting and more preferred calculation method after modification can be selected:
equation 33:
wherein C is an empirical constant. In a natural two-phase flow process, buoyancy is one of the main driving forces, and bubbles generated by boiling drag the surrounding liquid phase flow. Therefore, the liquid phase velocity is highest at the center of the bubble, and the inside of the bubbleThe void fraction is higher and the liquid phase velocity within the bubble can be considered to be equivalent to the liquid phase velocity at the center of the bubble. Then gradually decreases towards both sides, and the effective velocity u of the liquid phase in the macroliquid film is reduced because the air bubble is close to the macroliquid filmlmAnd the liquid phase velocity u at the center of the bubbleblIs in positive correlation. Namely:
equation 34: u. oflm＝C1ubl
The effective velocities of the liquid phases in the two-phase region and the single-phase region are also equal to ublAnd (4) positively correlating. Namely:
equation 35: u. ofls＝C2ubl
Wherein, C1And C2Is an empirical constant.
During flow boiling, bubbles form on the heated surface, detach from the wall, and then form again, with changing shape and size. This embodiment may use the average size of the bubbles as the bubble detachment diameter and assuming that the average diameter of the bubbles near the wall is the same as the bubble detachment diameter, a balanced relationship between the fluid forces and the surface forces on the bubbles may be obtained.
The calculation of the bubble thickness (i.e., bubble diameter) uses the relationship:
equation 36:
wherein D isbFor bubble thickness, σ is surface tension, CplIs liquid phase specific heat capacity, TsatTo estimate the saturation temperature at the location.
Preferably, the evaluation method in the present embodiment may perform data processing and calculation by MATLAB (matrix laboratory) software.
The method for evaluating the critical heat flux of the pressure vessel provided by the embodiment considers the influence of the supercooling degree, the geometric dimension of the flow channel and the radius of the pressure vessel on the critical heat flux in the evaluation process, and simultaneously considers the influence of two-phase flow layering, so that the calculation accuracy is high. In addition, while the critical heat flux is calculated, some key two-phase flow parameters (such as liquid phase speed, gas phase speed, adherent bubble suspension time and the like) at the evaluation position can be obtained, and the safety and the reliability of the operation of the pressure container are effectively improved.
Example 2
The present embodiment provides a method for evaluating a critical heat flux of a pressure vessel, which is a further improvement based on the embodiment, specifically, referring to fig. 5, the method may further include:
step S20: dividing different cooling levels for different positions of the outer wall of the pressure vessel according to the critical heat flux so that the local heat flow of the decayed melt in the pressure vessel does not exceed the critical heat flux;
and/or the presence of a gas in the gas,
step S21: and adjusting the structural design parameters of the pressure vessel according to the critical heat flux so that the local heat flow of the melt decay in the pressure vessel does not exceed the critical heat flux.
The method for evaluating the critical heat flux of the pressure vessel provided by the embodiment can provide theoretical support and technical support for further improving the structural parameters of the pressure vessel or further accurately determining the cooling level in the advanced pressurized water reactor design process according to the critical heat flux values at different inclination angles of the arc-shaped wall surface.
Example 3
The present embodiment provides an evaluation system for critical heat flux of a pressure vessel, as shown in fig. 6, where the evaluation system 1 may include:
an evaluation parameter obtaining module 11, configured to obtain an evaluation parameter, where the evaluation parameter includes a physical property parameter at an evaluation position and a structural parameter of the pressure vessel; wherein the evaluation position is a preset position on a wall surface of the pressure vessel;
a heat flux component calculation module 12 for calculating a tangential heat flux and a radial heat flux of the pressure vessel, respectively, based on the evaluation parameters;
a critical heat flux assessment module 13 for assessing a critical heat flux of the pressure vessel based on the tangential heat flux and the radial heat flux.
Specifically, the heat flux component calculation module 12 is configured to calculate a macro liquid film thickness, a bubble length, and a liquid phase flow rate within the macro liquid film at the evaluation position according to the evaluation parameter, and calculate the tangential heat flux using the macro liquid film thickness, the bubble length, and the liquid phase flow rate within the macro liquid film;
the heat flux component calculation module 12 is further configured to calculate a bubble adherence residence time, a two-phase boundary layer thickness, and a void fraction according to the evaluation parameter, and calculate the radial heat flux by using the bubble adherence residence time, the two-phase boundary layer thickness, and the void fraction.
The critical heat flux evaluation module 13 is configured to sum the tangential heat flux and the radial heat flux to obtain a critical heat flux of the pressure vessel.
Preferably, the pressure vessel comprises a lower seal head, and the evaluation position is positioned on an arc-shaped wall surface of the lower seal head of the pressure vessel;
the tangential heat flux is a heat flux in a direction perpendicular to a line connecting the evaluation position and the center point; the center point is the center of the arc-shaped wall surface of the lower end enclosure; the radial heat flux is a heat flux in a direction coinciding with a line connecting the evaluation position and the center point.
In the embodiment, the thickness of the macro liquid film is positively correlated with the supercooling degree of the liquid phase at the evaluation position;
the liquid phase velocities at different distances from the wall surface of the pressure vessel are different in a direction in which the evaluation position coincides with the line connecting the center point.
For the detailed calculation principle of the critical heat flux in embodiment 3, the calculation formula in embodiment 1 may be referred to, and this embodiment is not described again.
The system for evaluating the critical heat flux of the pressure vessel provided by the embodiment considers the influence of the supercooling degree, the geometric dimension of the channel and the radius of the pressure vessel on the critical heat flux in the evaluation process, and simultaneously, the calculation method considers the influence of two-phase flow layering, so that the calculation accuracy is high. In addition, while the critical heat flux is calculated, some key two-phase flow parameters (such as liquid phase speed, gas phase speed, adherent bubble suspension time and the like) at the evaluation position can be obtained, and the safety and the reliability of the operation of the pressure container are effectively improved.
Example 4
The present embodiment provides an evaluation system of critical heat flux of a pressure vessel, which is a further improvement on the basis of embodiment 6.
Specifically, referring to fig. 7, the evaluation system 1 may further include a cooling level classification module 14 and a structural parameter adjustment module 15:
the cooling grade dividing module 14 is used for dividing different cooling grades for different positions of the outer wall of the pressure vessel according to the critical heat flux so that the local heat flow of the decaying melt in the pressure vessel does not exceed the critical heat flux;
and/or the presence of a gas in the gas,
the structural parameter adjusting module 15 is configured to adjust the structural design parameters of the pressure vessel according to the critical heat flux, so that the local heat flow of the melt decay in the pressure vessel does not exceed the critical heat flux.
The system for evaluating the critical heat flux of the pressure vessel provided by the embodiment can provide theoretical support and technical support for further improving the structural parameters of the pressure vessel or further accurately determining the cooling level in the advanced pressurized water reactor design process according to the critical heat flux values at different inclination angles of the arc-shaped wall surface.
Example 5
The present invention also provides an electronic device, as shown in fig. 8, which may include a memory, a processor and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of the method for estimating the critical heat flux of the pressure vessel in the foregoing embodiment 1 or 2.
It should be understood that the electronic device shown in fig. 8 is only an example, and should not bring any limitation to the functions and the scope of the application of the embodiments of the present invention.
As shown in fig. 8, the electronic device 2 may be embodied in the form of a general purpose computing device, such as: which may be a server device. The components of the electronic device 2 may include, but are not limited to: the at least one processor 3, the at least one memory 4, and a bus 5 connecting the various system components (including the memory 4 and the processor 3).
The bus 5 may include a data bus, an address bus, and a control bus.
The memory 4 may include volatile memory, such as Random Access Memory (RAM)41 and/or cache memory 42, and may further include Read Only Memory (ROM) 43.
The memory 4 may also include a program tool 45 (or utility tool) having a set (at least one) of program modules 44, such program modules 44 including, but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which, or some combination thereof, may comprise an implementation of a network environment.
The processor 3 executes various functional applications and data processing, such as the steps of the method for evaluating the critical heat flux of the pressure vessel in the foregoing embodiment 1 or 2 of the present invention, by executing the computer program stored in the memory 4.
The electronic device 2 may also communicate with one or more external devices 6, such as a keyboard, pointing device, etc. Such communication may be via an input/output (I/O) interface 7. Also, the model-generated electronic device 2 may communicate with one or more networks (e.g., a Local Area Network (LAN), a Wide Area Network (WAN), and/or a public network) via the network adapter 8.
As shown in FIG. 8, the network adapter 8 may communicate with other modules of the model-generated electronic device 2 via a bus 5. It will be appreciated by those skilled in the art that although not shown in the figures, other hardware and/or software modules may be used in conjunction with the model-generated electronic device 2, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems, etc.
It should be noted that although in the above detailed description several units/modules or sub-units/modules of the electronic device are mentioned, such division is merely exemplary and not mandatory. Indeed, the features and functionality of two or more of the units/modules described above may be embodied in one unit/module according to embodiments of the invention. Conversely, the features and functions of one unit/module described above may be further divided into embodiments by a plurality of units/modules.
Example 6
The present embodiment provides a computer-readable storage medium on which a computer program is stored, which when executed by a processor, implements the steps of the method for evaluating the critical heat flux of a pressure vessel in the foregoing embodiment 1 or 2.
More specific ways in which the computer-readable storage medium may be employed may include, but are not limited to: a portable disk, a hard disk, random access memory, read only memory, erasable programmable read only memory, optical storage device, magnetic storage device, or any suitable combination of the foregoing.
In a possible implementation, the present invention may also be implemented in the form of a program product comprising program code for causing a terminal device to perform the steps of implementing the method for assessing the critical heat flux of a pressure vessel as described in embodiment 1 or 2 above, when the program product is run on the terminal device.
Where program code for carrying out the invention is written in any combination of one or more programming languages, the program code may execute entirely on the user device, partly on the user device, as a stand-alone software package, partly on the user device and partly on a remote device or entirely on the remote device.
While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that this is by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.
Claims (12)
1. A method of assessing critical heat flux of a pressure vessel, the method comprising:
acquiring evaluation parameters including physical property parameters at an evaluation position and structural parameters of the pressure vessel; wherein the evaluation position is a preset position on a wall surface of the pressure vessel;
respectively calculating the tangential heat flux and the radial heat flux of the pressure vessel according to the evaluation parameters;
evaluating a critical heat flux of the pressure vessel based on the tangential heat flux and the radial heat flux.
2. The method of assessing critical heat flux of a pressure vessel of claim 1,
the step of calculating the tangential heat flux and the radial heat flux of the pressure vessel from the evaluation parameters, respectively, comprises:
calculating a macro liquid film thickness, a bubble length, and a liquid phase flow rate within the macro liquid film at the evaluation position according to the evaluation parameters, and calculating the tangential heat flux using the macro liquid film thickness, the bubble length, and the liquid phase flow rate within the macro liquid film;
calculating bubble adherence residence time, two-phase boundary layer thickness and a void fraction according to the evaluation parameters, and calculating the radial heat flux by using the bubble adherence residence time, the two-phase boundary layer thickness and the void fraction;
and/or the presence of a gas in the gas,
said step of estimating a critical heat flux of said pressure vessel based on said tangential heat flux and said radial heat flux comprises:
summing the tangential heat flux and the radial heat flux to obtain a critical heat flux for the pressure vessel.
3. The method of claim 1, wherein the pressure vessel comprises a bottom head, and the evaluation location is located on an arc-shaped wall surface of the bottom head of the pressure vessel;
the tangential heat flux is a heat flux in a direction perpendicular to a line connecting the evaluation position and the center point; the center point is the center of the arc-shaped wall surface of the lower end enclosure;
the radial heat flux is a heat flux in a direction coinciding with a line connecting the evaluation position and the center point.
4. The method of assessing critical heat flux of a pressure vessel of claim 1, further comprising:
dividing different cooling levels for different positions of the outer wall of the pressure vessel according to the critical heat flux so that the local heat flow of the decayed melt in the pressure vessel does not exceed the critical heat flux;
and/or the presence of a gas in the gas,
and adjusting the structural design parameters of the pressure vessel according to the critical heat flux so that the local heat flow of the melt decay in the pressure vessel does not exceed the critical heat flux.
5. The method of assessing critical heat flux of a pressure vessel of claim 2, wherein the macroliquid film thickness is positively correlated with the degree of liquid phase subcooling at the assessment location;
and/or the presence of a gas in the gas,
the liquid phase velocities at different distances from the wall surface of the pressure vessel are different in a direction in which the evaluation position coincides with the line connecting the center point.
6. An assessment system of critical heat flux of a pressure vessel, the assessment system comprising:
an evaluation parameter acquisition module for acquiring evaluation parameters including physical property parameters at an evaluation position and structural parameters of the pressure vessel; wherein the evaluation position is a preset position on a wall surface of the pressure vessel;
a heat flux component calculation module for calculating a tangential heat flux and a radial heat flux of the pressure vessel, respectively, based on the evaluation parameters;
a critical heat flux assessment module to assess a critical heat flux of the pressure vessel as a function of the tangential heat flux and the radial heat flux.
7. The system for assessing critical heat flux of a pressure vessel of claim 6,
the heat flux component calculation module is used for calculating the thickness of a macro liquid film, the length of a bubble and the liquid phase flow rate in the macro liquid film at the evaluation position according to the evaluation parameters, and calculating the tangential heat flux by using the thickness of the macro liquid film, the length of the bubble and the liquid phase flow rate in the macro liquid film;
the heat flux component calculation module is further used for calculating bubble adherence residence time, two-phase boundary layer thickness and a void fraction according to the evaluation parameters, and calculating the radial heat flux by using the bubble adherence residence time, the two-phase boundary layer thickness and the void fraction;
and/or the presence of a gas in the gas,
the critical heat flux evaluation module is configured to sum the tangential heat flux and the radial heat flux to obtain a critical heat flux for the pressure vessel.
8. The system of claim 6, wherein the pressure vessel comprises a bottom head, and the evaluation location is located on an arcuate wall of the bottom head of the pressure vessel;
the tangential heat flux is a heat flux in a direction perpendicular to a line connecting the evaluation position and the center point; the center point is the center of the arc-shaped wall surface of the lower end enclosure; the radial heat flux is a heat flux in a direction coinciding with a line connecting the evaluation position and the center point.
9. The system for assessing critical heat flux of a pressure vessel of claim 6, further comprising a cooling level classification module and a structural parameter adjustment module:
the cooling grade dividing module is used for dividing different cooling grades for different positions of the outer wall of the pressure vessel according to the critical heat flux so that the local heat flow of the decayed melt in the pressure vessel does not exceed the critical heat flux;
and/or the presence of a gas in the gas,
the structural parameter adjusting module is used for adjusting the structural design parameters of the pressure vessel according to the critical heat flux so that the local heat flow of the melt decay in the pressure vessel does not exceed the critical heat flux.
10. The system for assessing critical heat flux of a pressure vessel of claim 7, wherein said macroliquid film thickness is positively correlated with liquid phase subcooling at said assessment location;
and/or the presence of a gas in the gas,
the liquid phase velocities at different distances from the wall surface of the pressure vessel are different in a direction in which the evaluation position coincides with the line connecting the center point.
11. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor, when executing the computer program, carries out the steps of the method for assessing a critical heat flux of a pressure vessel according to any of claims 1 to 5.
12. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method for assessing the critical heat flux of a pressure vessel according to any one of claims 1 to 5.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112597602A (en) * | 2020-11-02 | 2021-04-02 | 广西大学 | Method for evaluating corrosion life of pressure vessel |
| CN115859868A (en) * | 2023-02-27 | 2023-03-28 | 中国科学院合肥物质科学研究院 | Critical heat flow calculation method suitable for fusion reactor component under single-sided heating condition |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130156142A1 (en) * | 2010-09-03 | 2013-06-20 | Mitsubishi Heavy Industries, Ltd. | Critical heat flux prediction device, critical heat flux prediction method and safety evaluation system |
| CN103354102A (en) * | 2013-07-02 | 2013-10-16 | 中国核动力研究设计院 | Simulation apparatus and simulation method for heat flux density of lower head of pressure vessel |
| CN106055850A (en) * | 2016-07-18 | 2016-10-26 | 西安交通大学 | Method for acquiring departure from nucleate boiling type critical heat flux density |
-
2020
- 2020-06-24 CN CN202010591547.9A patent/CN111753473B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130156142A1 (en) * | 2010-09-03 | 2013-06-20 | Mitsubishi Heavy Industries, Ltd. | Critical heat flux prediction device, critical heat flux prediction method and safety evaluation system |
| CN103354102A (en) * | 2013-07-02 | 2013-10-16 | 中国核动力研究设计院 | Simulation apparatus and simulation method for heat flux density of lower head of pressure vessel |
| CN106055850A (en) * | 2016-07-18 | 2016-10-26 | 西安交通大学 | Method for acquiring departure from nucleate boiling type critical heat flux density |
Non-Patent Citations (5)
| Title |
|---|
| 何辉 等: "池沸腾下朝向曲面加热面临界热通量分析模型", 《化工学报》 * |
| 余红星 等: "严重事故条件下反应堆压力容器下封头CHF模型应用研究", 《核动力工程》 * |
| 张震 等: "严重事故条件下压力容器下封头外表面临界热流密度实验研究", 《核动力工程》 * |
| 杨磊 等: "海洋核动力平台严重事故下熔融物堆内滞留分析程序开发", 《原子能科学技术》 * |
| 郭涛: "严重事故熔融物滞留下反应堆压力容器下封头温度场研究", 《工程科技Ⅱ辑》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112597602A (en) * | 2020-11-02 | 2021-04-02 | 广西大学 | Method for evaluating corrosion life of pressure vessel |
| CN112597602B (en) * | 2020-11-02 | 2023-08-11 | 广西大学 | Pressure vessel corrosion life assessment method |
| CN115859868A (en) * | 2023-02-27 | 2023-03-28 | 中国科学院合肥物质科学研究院 | Critical heat flow calculation method suitable for fusion reactor component under single-sided heating condition |
| CN115859868B (en) * | 2023-02-27 | 2023-04-28 | 中国科学院合肥物质科学研究院 | Critical heat flow calculation method suitable for fusion reactor component under single-sided heating condition |
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