CN115525998B - Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method - Google Patents

Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method Download PDF

Info

Publication number
CN115525998B
CN115525998B CN202211163511.6A CN202211163511A CN115525998B CN 115525998 B CN115525998 B CN 115525998B CN 202211163511 A CN202211163511 A CN 202211163511A CN 115525998 B CN115525998 B CN 115525998B
Authority
CN
China
Prior art keywords
sub
channel
fuel assembly
spiral cross
subchannel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202211163511.6A
Other languages
Chinese (zh)
Other versions
CN115525998A (en
Inventor
张大林
姜殿强
李新宇
周星光
贺亚男
田文喜
秋穗正
苏光辉
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xian Jiaotong University
Original Assignee
Xian Jiaotong University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xian Jiaotong University filed Critical Xian Jiaotong University
Priority to CN202211163511.6A priority Critical patent/CN115525998B/en
Publication of CN115525998A publication Critical patent/CN115525998A/en
Application granted granted Critical
Publication of CN115525998B publication Critical patent/CN115525998B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/17—Mechanical parametric or variational design
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/28—Design optimisation, verification or simulation using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2111/00—Details relating to CAD techniques
    • G06F2111/10—Numerical modelling
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2113/00—Details relating to the application field
    • G06F2113/08—Fluids
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/08—Thermal analysis or thermal optimisation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Geometry (AREA)
  • Theoretical Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Pure & Applied Mathematics (AREA)
  • Mathematical Optimization (AREA)
  • Mathematical Analysis (AREA)
  • Evolutionary Computation (AREA)
  • General Engineering & Computer Science (AREA)
  • Computational Mathematics (AREA)
  • Algebra (AREA)
  • Computing Systems (AREA)
  • Fluid Mechanics (AREA)
  • Mathematical Physics (AREA)
  • Management, Administration, Business Operations System, And Electronic Commerce (AREA)

Abstract

The invention discloses a calculation method of thermal parameters of a sub-channel of a spiral cross-shaped fuel assembly, which comprises the following seven steps: 1. dividing sub-channels of the spiral cross-shaped fuel assembly; 2. defining basic geometric parameters; 3. fitting a relation between the dimensionless gap width and the torsion angle between adjacent spiral cross bars; 4. calculating the values of the flow sweepback mixing parameters in different dimensionless gap widths by a computational fluid dynamics method; 5. fitting a relation between a flow sweepback cross-mixing parameter and a dimensionless gap width; 6. substituting the relation fitted in the step 5 into the improved subchannel conservation equation for dispersion; 7. the spiral cross fuel assembly sub-channel thermal parameters are calculated using a sub-channel program. The method can be used for more accurately calculating the thermodynamic and hydraulic characteristics of the spiral cross-shaped fuel assembly.

Description

Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method
Technical Field
The invention relates to the technical field of hydrodynamic simulation and analysis of reactor fuel assemblies, in particular to a method for calculating thermal parameters of a spiral cross-shaped fuel assembly sub-channel.
Background
The spiral cross-shaped fuel assembly consists of spiral cross-shaped fuel rods, and the fuel rods can be mutually supported and positioned without arranging a positioning grid structure. The spiral cross fuel assembly has larger heat exchange area with the same nuclear fuel loading volume, and the spiral structure can enhance transverse mixing, so that heat and mass transfer between the sub-channels is enhanced. Compared with the traditional cylindrical fuel assembly, the power density can be improved by more than 20%.
The transverse mixing of the spiral cross-shaped fuel assembly is mainly flow backswept, the transverse mixing is forced mixing, compared with natural mixing, the mixing degree is obviously enhanced, and turbulent mixing is negligible compared with flow backswept. In addition, the geometry of the helical cross rod results in a gap width that is not a constant, the magnitude of which is related to the twist angle, and constant blending parameters do not allow for accurate calculation of the lateral blending of the helical cross fuel assembly, thereby resulting in the inability of conventional subchannel programs to accurately calculate the thermotechnical parameters of the helical cross fuel assembly subchannels.
Disclosure of Invention
In order to overcome the problems of the prior art, the invention aims to provide a method for calculating the thermal parameters of a spiral cross-shaped fuel assembly sub-channel, and the method can provide more accurate calculation results of the thermal parameters for the spiral cross-shaped fuel assembly sub-channel.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a thermal parameter calculation method for a spiral cross-shaped fuel assembly sub-channel comprises the following steps:
step 1: dividing the coolant flow passage of the spiral cross-shaped fuel assembly into a plurality of sub-passages;
step 2: determining basic geometric parameters of the spiral cross-shaped fuel assembly, including reference coordinates, the pitch of the spiral cross-shaped rod, the flow areas of various types of sub-channels, namely an inner sub-channel, an edge sub-channel and an angle sub-channel, and the maximum value of the gap width of the adjacent spiral cross-shaped rod;
step 3: determining a functional relation between the torsion angle of the spiral cross rod and the Z coordinate of the reference coordinate, and fitting a relation between the dimensionless gap width and the torsion angle between adjacent spiral cross rods;
step 4: calculating the values of the flow sweepback mixing parameters in different dimensionless gap widths by a computational fluid dynamics method;
step 5: fitting a relation between a flow sweepback cross-mixing parameter and a dimensionless gap width;
step 6: substituting the relation fitted in the step 5 into an improved subchannel conservation equation for dispersion;
step 7: the spiral cross fuel assembly sub-channel thermal parameters are calculated using a sub-channel program.
The sub-channel dividing method in the step 1 is as follows: on the same cross section, adjacent spiral cross-shaped rod center points are connected, a perpendicular line is drawn from the spiral cross-shaped rod center point of the edge of the fuel assembly to the outer wall of the edge, a sub-channel adjacent to the outer wall angle of the fuel assembly is an angle sub-channel, a sub-channel adjacent to the outer wall edge of the fuel assembly is an edge sub-channel, and the rest sub-channels are inner sub-channels.
The basic geometric parameters in the step 2 are fixed constants.
The torsion angle in said step 3 is related to the vertical and ranges from 0 to 360 ° at each pitch of the helical cross bar.
And in the step 4, respectively extracting detailed numerical calculation results at interfaces of at least one group of inner sub-channels, side sub-channels and corner sub-channels, wherein the detailed numerical calculation results comprise: x, Y, Z coordinate values of the plurality of groups of data extraction points, fluid temperatures of the plurality of groups of data extraction points, fluid densities of the plurality of groups of data extraction points, fluid combination speeds of the plurality of groups of data extraction points, and components of the fluid combination speeds of the plurality of groups of data extraction points in an x axis and a y axis; and after the treatment result, obtaining flow sweepback mixing parameters under different dimensionless gap widths.
And (5) fitting the flow sweepback mixing parameter in the step by adopting a quadratic polynomial or a cubic polynomial.
The improved subchannel conservation equation in step 6 is as follows:
mass conservation equation:
Figure GDA0004238378200000031
axial momentum conservation equation:
Figure GDA0004238378200000032
lateral momentum conservation equation:
Figure GDA0004238378200000033
energy conservation equation:
Figure GDA0004238378200000034
wherein:
A i fluid area, m, of subchannel i 2 ；
C，C s ，C t Is a constant factor;
D h the hydraulic diameter of the subchannel, m;
h g ,h i ,h j the fluid flow enthalpy values of the gap g, the sub-channel i and the sub-channel J, J/kg;
H r w/(m) is the heat transfer coefficient 2 ·K)；
k f W/(mK) is the transverse heat conductivity;
K f ,K g ,K l friction coefficients respectively;
l ij the center distance, m, of the sub-channel i and the sub-channel j;
p i ,p j the pressures Pa of sub-channel i and sub-channel j, respectively;
P r is the wet perimeter, m, of the subchannel;
T f is the subchannel fluid temperature, K;
T i ,T j the fluid temperatures, K, of sub-channel i and sub-channel j, respectively;
u i ,u j respectively sub-channel i and sub-channelFluid axial velocity, m/s, of lane j;
u' k the axial speed of the equivalent sub-channel control body is m/s;
v i ' j the transverse flow velocity of the fluid in the subchannel i entering the subchannel j is m/s;
v' k the transverse speed of the equivalent subchannel control body is m/s;
Figure GDA0004238378200000041
is the dimensionless gap width of the interface between subchannel i and subchannel j at torsion angle θ;
S max is the maximum value of the interface gap width between the sub-channel i and the sub-channel j, m;
W θ,ij kg/m.s for the mass flow per unit length of fluid entering subchannel j in subchannel i at torsion angle θ;
ρ i ,ρ g fluid density at sub-channel i and gap g, kg/m respectively 3 ；
The length of the Δz subchannel study region, m;
Δβ k is the difference in reference angle between adjacent gaps.
The calculation flow of the sub-channel program adopted in the step 7 is as follows:
step 1: reading in fluid physical parameters, flow sweepback mixing parameters, constant factors of conservation equations and size parameters;
step 2: setting an initial value and boundary conditions of a fluid calculation domain;
step 3: solving an axial momentum conservation equation to obtain an axial pressure gradient of the sub-channel;
step 4: solving a transverse momentum conservation equation to obtain the transverse speed of the subchannel control body;
step 5: solving an energy conservation equation to obtain the enthalpy value and the temperature of the fluid;
step 6: solving a mass conservation equation to obtain the axial velocity of the fluid;
step 7: judging the solving knot of the step 3-6If yes, the convergence condition is satisfied:
Figure GDA0004238378200000051
where ε is the pressure drop convergence constant, Δpi is the total pressure drop/Pa for sub-channel i, Δpav is the average pressure drop/Pa for the component channels; if the convergence condition is not satisfied, starting the next step; if the convergence condition is met, returning to the step 3;
step 8: outputting the calculation result of the thermal parameters of the sub-channels of the spiral cross-shaped fuel assembly;
step 9: judging whether the set calculation time step is reached, and if the set calculation time step is reached, starting the next step; if the set time step is not reached, returning to the step 2, and taking the output thermal parameter calculation result as an initial value and a boundary condition of the next time step;
step 10: and (5) ending the calculation.
Compared with the prior art, the invention has the following advantages:
1. the calculation result is accurate. Considering the sizes of flow sweepback mixing parameters at different gap widths of interfaces between the sub-channels, the calculated thermodynamic hydraulic parameters are more accurate than the solving results of the parameters of the traditional sub-channels.
2. The application range is wide. The method can calculate the fuel assemblies in hexagonal arrangement and square arrangement, and the fuel assemblies formed by the spiral cross-shaped fuel rods with different geometric parameters are still applicable.
3. The calculation is simple and convenient. The flow sweepback mixing parameters are obtained by adopting a computational fluid dynamics method, and the applied computational fluid dynamics software is convenient to operate and simple to calculate.
Drawings
FIG. 1 is a flow chart of a method of analyzing transverse cross-mixing characteristics of a spiral cross-shaped fuel assembly of the present invention.
Fig. 2 is a sub-channel division of a spiral cross-type nineteen-bundle channel.
Fig. 3 shows the flow sweep mixing parameters corresponding to the gap 1, i.e. the different dimensionless gap widths of the inner sub-channel interface.
Detailed Description
The invention provides a thermal parameter calculation method for a spiral cross-shaped fuel assembly sub-channel, which takes a spiral cross-shaped nineteenth bar bundle channel as an example to describe the specific implementation mode of the method.
As shown in fig. 1, the method for calculating the thermal parameters of the sub-channels of the spiral cross-shaped fuel assembly comprises the following steps:
step 1: dividing the coolant flow passage of the spiral cross-shaped fuel assembly into a plurality of sub-passages;
step 2: determining basic geometric parameters of the spiral cross-shaped fuel assembly, including reference coordinates, the pitch of the spiral cross-shaped rod, the flow areas of various types of sub-channels (inner sub-channel, side sub-channel and corner sub-channel), and the maximum value of the gap width of adjacent spiral cross-shaped rods;
step 3: determining a functional relation between the torsion angle of the spiral cross rod and the Z coordinate of the reference coordinate, and fitting a relation between the dimensionless gap width and the torsion angle between adjacent spiral cross rods;
step 4: calculating the values of the flow sweepback mixing parameters in different dimensionless gap widths by a computational fluid dynamics method;
step 5: fitting a relation between a flow sweepback cross-mixing parameter and a dimensionless gap width;
step 6: substituting the relation fitted in the step 5 into an improved subchannel conservation equation for dispersion;
step 7: calculating a thermal parameter of a sub-channel of the spiral cross-shaped fuel assembly by using a sub-channel program;
the sub-channel dividing method in step 1 is as follows: on the same cross section, connecting adjacent spiral cross-shaped rod center points, taking the spiral cross-shaped rod center points of the edges of the spiral cross-shaped nineteenth rod bundle channels as an origin to make a vertical line to the outer wall of the edge, taking sub-channels adjacent to the outer wall angles of the rod bundle channels as corner sub-channels, taking sub-channels adjacent to the outer wall edges of the rod bundle channels as side sub-channels, and taking the rest sub-channels as inner sub-channels as shown in figure 2;
the basic geometric parameters in the step 2 are fixed constants;
in the step 3, the torsion angle is related to the vertical coordinate, and the torsion angle ranges from 0 to 360 degrees under each screw pitch of the spiral cross-shaped rod, and the torsion angle is related to the vertical coordinate as follows:
Figure GDA0004238378200000071
wherein:
k is a positive integer, k=0, 1,2,3;
n is a positive integer, and the number of n is a positive integer,
Figure GDA0004238378200000072
p is the pitch, m;
z is a vertical height direction coordinate, m;
z 0 m is the reference vertical coordinate;
θ is the torsion angle, degree;
alpha is the equivalent torsion angle, 0< alpha <90 degrees;
and 4, respectively extracting detailed numerical calculation results at interfaces of at least one group of inner sub-channels, side sub-channels and corner sub-channels, wherein the detailed numerical calculation results comprise: x, Y, Z coordinate values of the plurality of groups of data extraction points, fluid temperatures of the plurality of groups of data extraction points, fluid densities of the plurality of groups of data extraction points, fluid combination speeds of the plurality of groups of data extraction points, and components of the fluid combination speeds of the plurality of groups of data extraction points in an x axis and a y axis; obtaining the average mass flow rate per unit length between adjacent sub-channel interfaces by adopting a calculation result:
Figure GDA0004238378200000081
Figure GDA0004238378200000082
Figure GDA0004238378200000083
wherein:
S θ,ij a gap width m at a torsion angle theta of an interface between the sub-channel i and the sub-channel j;
v' θ,ij for the lateral flow velocity of the fluid in subchannel i entering subchannel j at torsion angle θ, m/s;
u θ,g is the axial velocity of the fluid at gap g, m/s;
u is the speed, m/s;
Figure GDA0004238378200000084
the mass flow rate per unit length in the forward direction and the reverse direction of the interface between the sub-channel i and the sub-channel j at the torsion angle theta are kg/m.s respectively;
W θ,ij kg/m.s for the mass flow per unit length of fluid entering subchannel j in subchannel i at torsion angle θ;
ρ g for density at gap g, kg/m 3 ；
The dimensionless gap width is defined as follows:
Figure GDA0004238378200000085
wherein:
S max is the maximum value of the interface gap width between the sub-channel i and the sub-channel j, m;
Figure GDA0004238378200000091
is the dimensionless gap width of the interface between subchannel i and subchannel j at torsion angle θ;
the flow sweep blending parameters were calculated using the following:
Figure GDA0004238378200000092
wherein:
Figure GDA0004238378200000093
for average mass flow rate of sub-channel i and sub-channel j kg/m 2 ·s；
Figure GDA0004238378200000094
A flow sweep back mixing parameter at the torsion angle theta for the interface between subchannel i and subchannel j;
as shown in fig. 3, the values of the flow sweep mixing parameters for gap 1 in fig. 2 at different dimensionless gap widths are shown;
the spiral cross nineteen-rod-bundle channel takes a Reynolds number 3000 as a boundary between a laminar flow region and a turbulent flow region, wherein the Reynolds number is less than 3000 and is a laminar flow region, and the Reynolds number is more than 3000 and is a turbulent flow region;
in the step 5, the sweepback mixing parameters of the flow of the inner sub-channel adopt a quadratic polynomial, and the fitting relation of the laminar flow area of the inner sub-channel is as follows:
Figure GDA0004238378200000095
the fit relation for the inner sub-channel turbulence zone is as follows:
Figure GDA0004238378200000096
the laminar flow areas of the side sub-channels and the corner sub-channels are fitted by adopting a cubic polynomial, and fitting relation formulas are respectively as follows:
Figure GDA0004238378200000097
Figure GDA0004238378200000098
the flow sweepback mixing parameters of the turbulent flow areas of the side sub-channels and the corner sub-channels are fitted by adopting a quadratic polynomial, and the fitting relation is as follows:
Figure GDA0004238378200000101
Figure GDA0004238378200000102
wherein:
Figure GDA0004238378200000103
is the dimensionless gap width of the interface between sub-channel 1 and sub-channel 2 at torsion angle θ;
Figure GDA0004238378200000104
is the dimensionless gap width of the interface between sub-channel 3 and sub-channel 4 at torsion angle θ;
Figure GDA0004238378200000105
is the dimensionless gap width of the interface between sub-channel 4 and sub-channel 5 at torsion angle θ;
Figure GDA0004238378200000106
a sweepback mixing parameter for laminar flow region flow at torsion angle theta at the interface between subchannel 1 and subchannel 2;
Figure GDA0004238378200000107
a sweepback mixing parameter for a turbulent flow zone flow at a torsion angle θ for the interface between sub-channel 1 and sub-channel 2;
Figure GDA0004238378200000108
a sweepback mixing parameter for laminar flow region flow at torsion angle θ for the interface between sub-channel 3 and sub-channel 4;
Figure GDA0004238378200000109
a sweepback mixing parameter for the turbulent flow zone flow at the torsion angle θ of the interface between sub-channel 3 and sub-channel 4;
Figure GDA00042383782000001010
a sweepback mixing parameter for laminar flow region flow at torsion angle θ for the interface between sub-channel 4 and sub-channel 5;
Figure GDA00042383782000001011
a sweepback mixing parameter for the turbulent flow zone flow at the torsion angle θ of the interface between sub-channel 4 and sub-channel 5;
the improved subchannel conservation equation in step 6 is as follows:
mass conservation equation:
Figure GDA0004238378200000111
axial momentum conservation equation:
Figure GDA0004238378200000112
lateral momentum conservation equation:
Figure GDA0004238378200000113
energy conservation equation:
Figure GDA0004238378200000114
wherein:
A i fluid area, m, of subchannel i 2 ；
C，C s ，C t Is a constant factor;
D h the hydraulic diameter of the subchannel, m;
h g ,h i ,h j the fluid flow enthalpy values of the gap g, the sub-channel i and the sub-channel J, J/kg;
H r w/(m) is the heat transfer coefficient 2 ·K)；
k f W/(mK) is the transverse heat conductivity;
K f ,K g ,K l friction coefficients respectively;
l ij the center distance, m, of the sub-channel i and the sub-channel j;
p i ,p j the pressures Pa of sub-channel i and sub-channel j, respectively;
P r is the wet perimeter, m, of the subchannel;
T f is the subchannel fluid temperature, K;
T i ,T j the fluid temperatures, K, of sub-channel i and sub-channel j, respectively;
u i ,u j the fluid axial speeds of the sub-channel i and the sub-channel j are m/s respectively;
u' k the axial speed of the equivalent sub-channel control body is m/s;
v i ' j the transverse flow velocity of the fluid in the subchannel i entering the subchannel j is m/s;
v' k the transverse speed of the equivalent subchannel control body is m/s;
ρ i for fluid density in subchannel i, kg/m 3 ；
The length of the Δz subchannel study region, m;
Δβ k is the difference between the reference angles of adjacent gaps;
the sub-channel program adopted in the step 7 is based on the original sub-channel program
The calculation flow is as follows:
step 1: reading in fluid physical parameters, flow sweepback mixing parameters, constant factors of conservation equations and size parameters;
step 2: setting an initial value and boundary conditions of a fluid calculation domain;
step 3: solving an axial momentum conservation equation to obtain an axial pressure gradient of the sub-channel;
step 4: solving a transverse momentum conservation equation to obtain the transverse speed of the subchannel control body;
step 5: solving an energy conservation equation to obtain the enthalpy value and the temperature of the fluid;
step 6: solving a mass conservation equation to obtain the axial velocity of the fluid;
step 7: judging whether the solving result in the step 3-6 meets the convergence condition:
Figure GDA0004238378200000121
where ε is the pressure drop convergence constant, Δp i Is the total pressure drop/Pa, Δp of sub-channel i av Mean pressure drop/Pa for the component channels; if the convergence condition is not satisfied, starting the next step; if the convergence condition is met, returning to the step 3;
step 8: outputting the calculation result of the thermal parameters of the sub-channels of the spiral cross-shaped fuel assembly;
step 9: judging whether the set calculation time step is reached, and if the set calculation time step is reached, starting the next step; if the set time step is not reached, returning to the step 2, and taking the output thermal parameter calculation result as an initial value and a boundary condition of the next time step;
step 10: and (5) ending the calculation.

Claims (7)

1. A thermal parameter calculation method for a spiral cross-shaped fuel assembly sub-channel is characterized by comprising the following steps of: the method comprises the following steps:
step 1: dividing the coolant flow passage of the spiral cross-shaped fuel assembly into a plurality of sub-passages;
step 2: determining basic geometric parameters of the spiral cross-shaped fuel assembly, including reference coordinates, the pitch of the spiral cross-shaped rod, the flow areas of the inner sub-channel, the side sub-channel and the corner sub-channel, and the maximum value of the gap width of the adjacent spiral cross-shaped rod;
step 3: determining a functional relation between the torsion angle of the spiral cross rod and the Z coordinate of the reference coordinate, and fitting a relation between the dimensionless gap width and the torsion angle between adjacent spiral cross rods;
step 4: calculating the values of the flow sweepback mixing parameters in different dimensionless gap widths by a computational fluid dynamics method;
step 5: fitting a relation between a flow sweepback cross-mixing parameter and a dimensionless gap width;
step 6: substituting the relation fitted in the step 5 into an improved subchannel conservation equation for dispersion;
step 7: calculating a thermal parameter of a sub-channel of the spiral cross-shaped fuel assembly by using a sub-channel program;
the improved subchannel conservation equation in step 6 is as follows:
mass conservation equation:
Figure FDA0004238378190000011
axial momentum conservation equation:
Figure FDA0004238378190000012
lateral momentum conservation equation:
Figure FDA0004238378190000021
energy conservation equation:
Figure FDA0004238378190000022
wherein:
A i fluid area, m, of subchannel i 2 ；
C，C s ，C t Is a constant factor;
D h the hydraulic diameter of the subchannel, m;
h g ,h i ,h j the fluid flow enthalpy values of the gap g, the sub-channel i and the sub-channel J, J/kg;
H r w/(m) is the heat transfer coefficient 2 ·K)；
k f W/(mK) is the transverse heat conductivity;
K f ,K g ,K l friction coefficients respectively;
l ij the center distance, m, of the sub-channel i and the sub-channel j;
p i ,p j the pressures Pa of sub-channel i and sub-channel j, respectively;
P r is the wet perimeter, m, of the subchannel;
T f is the subchannel fluid temperature, K;
T i ,T j the fluid temperatures, K, of sub-channel i and sub-channel j, respectively;
u i ,u j the fluid axial speeds of the sub-channel i and the sub-channel j are m/s respectively;
u' k the axial speed of the equivalent sub-channel control body is m/s;
v′ ij the transverse flow velocity of the fluid in the subchannel i entering the subchannel j is m/s;
v' k the transverse speed of the equivalent subchannel control body is m/s;
Figure FDA0004238378190000031
is the dimensionless gap width of the interface between subchannel i and subchannel j at torsion angle θ;
S max is the maximum value of the interface gap width between the sub-channel i and the sub-channel j, m;
W θ,ij kg/m.s for the mass flow per unit length of fluid entering subchannel j in subchannel i at torsion angle θ;
ρ i ,ρ g fluid density at sub-channel i and gap g, kg/m respectively 3 ；
The length of the Δz subchannel study region, m;
Δβ k is the difference in reference angle between adjacent gaps.
2. A method of calculating thermal parameters for a spiral cross fuel assembly sub-channel as defined in claim 1, wherein: the sub-channel dividing method in the step 1 is as follows: on the same cross section, adjacent spiral cross-shaped rod center points are connected, a perpendicular line is drawn from the spiral cross-shaped rod center point of the edge of the fuel assembly to the outer wall of the edge, a sub-channel adjacent to the outer wall angle of the fuel assembly is an angle sub-channel, a sub-channel adjacent to the outer wall edge of the fuel assembly is an edge sub-channel, and the rest sub-channels are inner sub-channels.
3. A method of calculating thermal parameters for a spiral cross fuel assembly sub-channel as defined in claim 1, wherein: the basic geometric parameters in the step 2 are fixed constants.
4. A method of calculating thermal parameters for a spiral cross fuel assembly sub-channel as defined in claim 1, wherein: the torsion angle in said step 3 is related to the vertical and ranges from 0 to 360 ° at each pitch of the helical cross bar.
5. A method of calculating thermal parameters for a spiral cross fuel assembly sub-channel as defined in claim 1, wherein: and in the step 4, respectively extracting detailed numerical calculation results at interfaces of at least one group of inner sub-channels, side sub-channels and corner sub-channels, wherein the detailed numerical calculation results comprise: x, Y, Z coordinate values of the plurality of groups of data extraction points, fluid temperatures of the plurality of groups of data extraction points, fluid densities of the plurality of groups of data extraction points, fluid combination speeds of the plurality of groups of data extraction points, and components of the fluid combination speeds of the plurality of groups of data extraction points in an x axis and a y axis; and after the treatment result, obtaining flow sweepback mixing parameters under different dimensionless gap widths.
6. A method of calculating thermal parameters for a spiral cross fuel assembly sub-channel as defined in claim 1, wherein: and (5) fitting the flow sweepback mixing parameter in the step by adopting a quadratic polynomial or a cubic polynomial.
7. A method of calculating thermal parameters for a spiral cross fuel assembly sub-channel as defined in claim 1, wherein: the calculation flow of the sub-channel program adopted in the step 7 is as follows:
step 1: reading in fluid physical parameters, flow sweepback mixing parameters, constant factors of conservation equations and size parameters;
step 2: setting an initial value and boundary conditions of a fluid calculation domain;
step 3: solving an axial momentum conservation equation to obtain an axial pressure gradient of the sub-channel;
step 4: solving a transverse momentum conservation equation to obtain the transverse speed of the subchannel control body;
step 5: solving an energy conservation equation to obtain the enthalpy value and the temperature of the fluid;
step 6: solving a mass conservation equation to obtain the axial velocity of the fluid;
step 7: judging whether the solving result in the step 3-6 meets the convergence condition:
Figure FDA0004238378190000041
where ε is the pressure drop convergence constant, Δp i Is the total pressure drop/Pa, Δp of sub-channel i av Mean pressure drop/Pa for the component channels; if the convergence condition is not satisfied, starting the next step; if the convergence condition is met, returning to the step 3;
step 8: outputting the calculation result of the thermal parameters of the sub-channels of the spiral cross-shaped fuel assembly;
step 9: judging whether the set calculation time step is reached, and if the set calculation time step is reached, starting the next step; if the set time step is not reached, returning to the step 2, and taking the output thermal parameter calculation result as an initial value and a boundary condition of the next time step;
step 10: and (5) ending the calculation.
CN202211163511.6A 2022-09-23 2022-09-23 Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method Active CN115525998B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211163511.6A CN115525998B (en) 2022-09-23 2022-09-23 Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211163511.6A CN115525998B (en) 2022-09-23 2022-09-23 Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method

Publications (2)

Publication Number Publication Date
CN115525998A CN115525998A (en) 2022-12-27
CN115525998B true CN115525998B (en) 2023-07-04

Family

ID=84699160

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211163511.6A Active CN115525998B (en) 2022-09-23 2022-09-23 Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method

Country Status (1)

Country Link
CN (1) CN115525998B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118070363A (en) * 2024-02-20 2024-05-24 东北电力大学 Sub-channel dividing method for bar bundle channel with spiral structure

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109243640A (en) * 2018-09-17 2019-01-18 中国核动力研究设计院 A kind of isolating device for subchannel in cluster channel

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003075580A (en) * 2001-09-03 2003-03-12 Nuclear Fuel Ind Ltd Numerical evaluation method of tdc value of reactor fuel assembly
CN106897478B (en) * 2016-12-19 2020-04-10 杨保文 Sub-channel analysis method containing framework mixing effect based on resistance distribution
CN108304620B (en) * 2018-01-11 2020-07-24 西安交通大学 Calculation method for boron diffusion process in rod bundle channel of nuclear reactor core

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109243640A (en) * 2018-09-17 2019-01-18 中国核动力研究设计院 A kind of isolating device for subchannel in cluster channel

Also Published As

Publication number Publication date
CN115525998A (en) 2022-12-27

Similar Documents

Publication Publication Date Title
Webb et al. How structure in the louvered fin heat exchanger geometry
Sun et al. Evaluation of elliptical finned-tube heat exchanger performance using CFD and response surface methodology
He et al. Air-side heat-transfer enhancement by a new winglet-type vortex generator array in a plain-fin round-tube heat exchanger
Xinyi et al. Experimental and numerical study on heat transfer enhancement of a rectangular channel with discontinuous crossed ribs and grooves
Arora et al. Numerical optimization of location of ‘common flow up’delta winglets for inline aligned finned tube heat exchanger
CN115525998B (en) Spiral cross-shaped fuel assembly sub-channel thermal parameter calculation method
CN108304620B (en) Calculation method for boron diffusion process in rod bundle channel of nuclear reactor core
Khoshvaght-Aliabadi et al. Influence of Al2O3–H2O nanofluid on performance of twisted minichannels
Arora et al. Development of parametric space for the vortex generator location for improving thermal compactness of an existing inline fin and tube heat exchanger
Khoshvaght Aliabadi et al. 3D-CFD simulation and neural network model for the j and f factors of the wavy fin-and-flat tube heat exchangers
Bhuiyan et al. Plate fin and tube heat exchanger modeling: Effects of performance parameters for turbulent flow regime
Du et al. Experimental study of the effect of air inlet angle on the air-side performance for cross-flow finned oval-tube heat exchangers
Rao et al. Effect of power-law fluid behavior on momentum and heat transfer characteristics of an inclined square cylinder in steady flow regime
Hamid et al. Field synergy analysis for turbulent heat transfer on ribs roughened solar air heater
Abraham et al. Numerical analysis for thermo-hydraulic performance of staggered cross flow tube bank with longitudinal tapered fins
Kumar et al. A note on the comparative analysis between rectangular and modified duct heat exchanger
CN111027205A (en) Method for simulating core box interval flow value of liquid metal cooling fast reactor
Kuchkarov et al. Determining the optimal placement scheme and height of elements that accelerate heat exchange processes in solar air heater collectors through mathematical modeling
Abed et al. Experimental and CFD Analysis of two-phase forced convection flow in channels of various rib shapes
Kumar et al. Experimental assessment of thermohydraulic performance of a rectangular solar air heater duct using twisted v-shaped staggered ribs
Tian et al. Numerical study of flow and heat transfer enhancement by using delta winglets in a triangular wavy fin-and-tube heat exchanger
Sharma et al. Performance evaluation of a fin and tube heat exchanger based on different shapes of the winglets
Sharma et al. Numerical investigation of heat transfer characteristics in triangular channel in light water nuclear reactor by using CuO-water based nanofluids
Miao et al. Numerical investigation of heat transfer and flow resistance characteristics of interpenetrated flying-wing finned tubes
Zhou et al. A numerical investigation of turbulent flow and heat transfer in rectangular channels with elliptic scale-roughened walls

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant