CN-121997585-A - Method for calculating turbine cooling gas demand

CN121997585ACN 121997585 ACN121997585 ACN 121997585ACN-121997585-A

Abstract

The disclosure provides a method for calculating the turbine cooling gas demand, which can be applied to the technical field of turbine cooling. The method comprises the steps of constructing a heat transfer geometric model based on structural parameters of a turbine, constructing a first initial condition based on basic rotating speed of a turbine rotor, initial temperature of a turbine solid part and basic parameters of cooling gas, calculating a steady-state temperature field of a solid region and a fluid region under a working condition of the cooling gas in turbine operation by using a first algorithm based on the first initial condition, constructing a second initial condition based on the adjusting rotating speed of the turbine rotor and the temperature of a corresponding turbine solid part in the steady-state temperature field, calculating a basic transient temperature field of the solid region and the fluid region under the working condition of stopping cooling gas after turbine shutdown by using a second algorithm based on the second initial condition, wherein the value of the adjusting rotating speed is zero, and outputting a calculation result of the cooling gas after turbine shutdown without continuously under the condition that the temperature of a target region in the basic transient temperature field does not exceed a preset threshold value.

Inventors

GUO CHAOHONG
XU XIANG
LIN MINGXIANG
TIAN JIAHAO
LI ZHIGANG
REN HAIKUN
GONG XINYU
ZHANG HAISONG
TIAN YONG
WANG BO

Assignees

中国科学院工程热物理研究所

Dates

Publication Date: 20260508
Application Date: 20260122

Claims (13)

1. A method of calculating turbine cooling gas demand by an electronic device, comprising: Constructing a heat transfer geometric model based on structural parameters of a turbine, wherein the heat transfer geometric model comprises a solid area for simulating temperature change of a solid part of the turbine and a fluid area for simulating temperature change of a cooling air flowing through a cooling flow passage; Constructing a first initial condition based on the basic rotating speed of the turbine rotor, the initial temperature of the turbine solid part and the basic parameters of the cooling gas, and calculating a steady-state temperature field of a solid area and a fluid area under the working condition of introducing the cooling gas in the turbine operation by using a first algorithm based on the first initial condition; constructing a second initial condition based on the adjustment rotating speed of the turbine rotor and the temperature of a corresponding turbine solid part in the steady-state temperature field, and calculating to obtain a basic transient temperature field of a solid region and a fluid region under the working condition of stopping introducing cooling gas after turbine shutdown by using a second algorithm based on the second initial condition, wherein the value of the adjustment rotating speed is zero; And outputting a calculation result that cooling gas does not need to be continuously introduced after turbine shutdown under the condition that the temperature of a target area in the basic transient temperature field does not exceed a preset threshold value.
2. The method of claim 1, wherein the method further comprises: Under the condition that the temperature of a target area in the basic transient temperature field exceeds a preset threshold value, constructing a plurality of groups of third initial conditions based on the adjusting rotating speed of the turbine rotor, the temperature of a corresponding turbine solid part in the steady-state temperature field and a plurality of groups of cooling gas adjusting parameters, and calculating a plurality of groups of reference transient temperature fields of a solid area and a fluid area under the working condition of continuously introducing cooling gas after turbine shutdown by utilizing a third algorithm based on the plurality of groups of third initial conditions, wherein the plurality of groups of reference transient temperature fields correspond to a plurality of groups of cooling gas adjusting parameters; And determining a cooling gas adjustment parameter with the minimum flow rate for enabling the temperature of the target area not to exceed a preset threshold value based on the calculation results of the multiple groups of reference transient temperature fields, and outputting a cooling gas demand quantity calculation result after turbine shutdown based on the cooling gas adjustment parameter.
3. The method according to claim 1 or 2, wherein, Constructing a heat transfer geometric model based on structural parameters of a rotor, a casing and a wheel disc of the turbine; The heat transfer geometric model comprises a plurality of solid areas respectively used for simulating temperature changes of a rotor, a casing and a wheel disc wall surface, and a plurality of fluid areas respectively used for simulating temperature changes of cooling air flow in the process of passing through a rotor gap and a wheel back gap, wherein the rotor gap is a gap between the bottom of the casing and the rotor, and the wheel back gap is a gap between the side surface of the casing and the wheel disc.
4. The method of claim 3, wherein, Constructing a first initial condition based on the basic rotating speed of a turbine rotor, the wall temperature of a basic wheel disc, the initial temperatures of the rotor and a casing, the first cooling gas inlet temperature, the first cooling gas inlet pressure and the first cooling gas mass flow, wherein the wall temperature of the basic wheel disc is equal to the temperature of a working medium in the turbine; Constructing a second initial condition based on the adjusted rotating speed of the turbine rotor and temperatures of the wheel disc wall surface, the rotor and the casing in the steady-state temperature field; Constructing a plurality of sets of third initial conditions includes constructing a plurality of sets of third initial conditions corresponding to a plurality of second cooling gas mass flows based on the adjusted rotational speed of the turbine rotor, temperatures at the wheel disc wall, the rotor, and the casing in the steady-state temperature field, a second cooling gas inlet temperature, a second cooling gas inlet pressure, and the plurality of incremental second cooling gas mass flows.
5. The method of claim 3, wherein, The calculating the steady-state temperature field, the basic transient temperature field and the reference transient temperature field of the solid area and the fluid area all comprise a plurality of iterative calculations, wherein for any algorithm of a first algorithm, a second algorithm and a third algorithm, the arbitrary k+1 time calculation comprises: and calculating a k+1 time temperature calculation result of the solid region and the fluid region based on the k time temperature calculation result of the solid region and the fluid region, wherein k is a positive integer.
6. The method of claim 5, wherein the method further comprises meshing the solid region and the fluid region; Calculating the temperature calculation result at the (k+1) th time of the solid region and the fluid region based on the temperature calculation result at the (k+1) th time includes calculating the temperature of any one of the target grids having two-dimensional coordinates i, j in the solid region and the fluid region at the (k+1) th time The method comprises the following steps: ; wherein A, B, C, D, E, F is the calculation coefficient, 、、、、 Respectively refer to the temperatures of the target grid with two-dimensional coordinates i, j and a plurality of adjacent grids around the target grid at the kth time.
7. The method of claim 6, wherein, The fluid region includes a cooling gas axial flow region corresponding to the rotor gap and a cooling gas radial flow region corresponding to the wheel back gap; The solid region comprises a rotor solid region and a casing solid region, wherein the rotor solid region comprises a rotor central region and a plurality of rotor boundary surfaces, and the casing solid region comprises a casing central region and a plurality of casing boundary surfaces; In any one of the first algorithm, the second algorithm and the third algorithm, the calculation methods of the calculation coefficients A, B, C, D, E, F are different for the cooling gas axial flow region, the cooling gas radial flow region, the rotor center region, the plurality of rotor boundary surfaces, the casing center region and the plurality of casing boundary surfaces.
8. The method of claim 7, wherein, in the first algorithm: the calculation coefficient A, B, C, D, E, F is calculated based on the following parameters of a first rotor surface heat exchange coefficient, a first casing axial heat exchange coefficient, a cooling gas mass flow, a cooling gas constant pressure heat capacity, a cooling gas density, a rotor radius and a rotor gap size, wherein the first rotor surface heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between cooling gas and a rotor surface in turbine operation, and the first casing axial heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between the cooling gas and a casing bottom in turbine operation; the calculation coefficient A, B, C, D, E, F is calculated based on the following parameters of a first casing radial heat exchange coefficient, a first wheel disc surface convection heat exchange coefficient, cooling gas mass flow, cooling gas constant pressure heat capacity, cooling gas density and wheel back gap size, wherein the first casing radial heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between cooling gas and a casing side surface in turbine operation, and the first wheel disc surface convection heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between the cooling gas and a wheel disc surface in turbine operation; The calculation coefficient A, B, C, D, E, F is calculated according to the following parameters of a first rotor surface convection heat exchange coefficient, a rotor thermal diffusivity and a rotor heat conduction coefficient aiming at a target rotor boundary surface in a plurality of rotor boundary surfaces, wherein the target rotor boundary surface is a region where the rotor surface is in direct contact with cooling gas; For the rotor center region and the rest rotor boundary surfaces except the target rotor boundary surface, the calculation coefficient A, B, C, D, E, F is calculated based on rotor thermal diffusivity; The calculation coefficient A, B, C, D, E, F is calculated based on the following parameters of a first casing radial heat exchange coefficient, a first casing axial heat exchange coefficient, a casing thermal diffusivity and a casing heat conduction coefficient, wherein the two first target casing boundary surfaces are respectively areas of the casing side surface and the casing bottom which are in direct contact with cooling gas; For a second target casing boundary surface, of the plurality of casing boundary surfaces, in which the casing side surface is in direct contact with the turbine internal working medium, a=d=1, b=c=e=f=0, wherein the temperature of the second target casing boundary surface is equal to the temperature of the turbine internal working medium; The calculation coefficient A, B, C, D, E, F is calculated based on the case thermal diffusivity for the case center region and the rest of the case boundary surfaces except the first target case boundary surface and the second target case boundary surface; The temperature at the interface between the rotor and the disk, and the interface between the cooling gas and the disk, are equal to the temperature of the working medium in the turbine.
9. The method according to claim 8, wherein: the first rotor surface convection heat exchange coefficient and the first casing axial heat exchange coefficient are calculated based on a first Knoop number, a cooling gas heat conduction coefficient and a rotor length, wherein the first Knoop number is calculated based on a rotor gap rotation Reynolds number, a rotor gap axial Reynolds number, a rotor length, a rotor radius, a rotor gap size, a cooling gas dynamic viscosity, a cooling gas constant pressure heat capacity and a cooling gas heat conduction coefficient; The radial heat exchange coefficient of the first casing and the surface convection heat exchange coefficient of the first wheel disc are calculated based on a second Knoop number, a cooling gas heat conduction coefficient and a wheel disc radius, and the second Knoop number is calculated based on a rotating Reynolds number at the turbine wheel disc, a radial Reynolds number at the turbine wheel disc, a wheel back gap size and a wheel disc radius.
10. The method of claim 7, wherein, in a third algorithm: The calculation coefficient A, B, C, D, E, F is calculated based on the parameters of a second rotor surface convection heat exchange coefficient, a second casing axial heat exchange coefficient, a cooling gas mass flow, a cooling gas constant pressure heat capacity, a cooling gas density, a rotor radius and a rotor gap size, wherein the second rotor surface convection heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between the cooling gas and the rotor surface after turbine shutdown, and the second casing axial heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between the cooling gas and the casing bottom after turbine shutdown; The calculation coefficient A, B, C, D, E, F is calculated based on the following parameters of a second casing radial heat exchange coefficient, a second wheel disc surface convection heat exchange coefficient, cooling gas mass flow, cooling gas constant pressure heat capacity, cooling gas density and wheel back gap size, wherein the second casing radial heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between cooling gas and a casing side after turbine shutdown, and the second wheel disc surface convection heat exchange coefficient represents a heat exchange coefficient for carrying out convection heat exchange between cooling gas and a wheel disc surface after turbine shutdown; the calculation coefficient A, B, C, D, E, F is calculated according to the following parameters of a second rotor surface convection heat exchange coefficient, a rotor thermal diffusivity and a rotor heat conduction coefficient aiming at a target rotor boundary surface in a plurality of rotor boundary surfaces, wherein the target rotor boundary surface is a region where the rotor surface is in direct contact with cooling gas; For the rotor center region and the rest rotor boundary surfaces except the target rotor boundary surface, the calculation coefficient A, B, C, D, E, F is calculated based on rotor thermal diffusivity; The calculation coefficient A, B, C, D, E, F is calculated based on the following parameters of a second casing radial heat exchange coefficient, a second casing axial heat exchange coefficient, a casing thermal diffusivity and a casing heat conduction coefficient for two first target casing boundary surfaces in the plurality of casing boundary surfaces, wherein the two first target casing boundary surfaces are respectively areas where the side surface of the casing and the bottom of the casing are in direct contact with cooling gas; Setting a second target casing boundary surface, which is in direct contact with the working medium inside the turbine, of the casing boundary surfaces as an adiabatic boundary, wherein the calculation coefficient A, B, C, D, E, F is calculated based on the heat diffusivity of the casing; The calculation coefficient A, B, C, D, E, F is calculated based on the case thermal diffusivity for the case center region and the rest of the case boundary surfaces except the first target case boundary surface and the second target case boundary surface; The calculated coefficient A, B, C, D, E, F is calculated based on the rotor thermal diffusivity for the boundary surface where the rotor and the disk contact and the boundary surface where the cooling gas and the disk contact are set as adiabatic boundaries.
11. The method according to claim 10, wherein: The second rotor surface convection heat exchange coefficient and the second casing axial heat exchange coefficient are calculated based on a third Knoop number, a cooling gas heat conduction coefficient and a rotor length, wherein the third Knoop number is calculated based on an axial Reynolds number at a rotor gap, a cooling aerodynamic viscosity, a cooling gas constant pressure heat capacity and a cooling gas heat conduction coefficient; The radial heat exchange coefficient of the second casing and the surface convection heat exchange coefficient of the second wheel disc are calculated based on a fourth Knoop number, a cooling gas heat conduction coefficient and a wheel back gap size, and the fourth Knoop number is calculated based on a radial Reynolds number, cooling aerodynamic viscosity, cooling gas constant pressure heat capacity and cooling gas heat conduction coefficient at the turbine wheel disc.
12. The method of claim 7, wherein, in the second algorithm: For the cooling gas axial flow region and the cooling gas radial flow region, the calculation coefficient A, B, C, D, E, F is calculated based on the following parameters of cooling gas heat conductivity coefficient, cooling gas constant pressure heat capacity and cooling gas density; The calculation coefficient A, B, C, D, E, F is calculated based on rotor thermal diffusivity for a rotor center region, a target rotor boundary surface of a plurality of rotor boundary surfaces, and the remaining rotor boundary surfaces other than the target rotor boundary surface; The calculation coefficient A, B, C, D, E, F is calculated based on the case thermal diffusivity aiming at a case center area, two first target case boundary surfaces in a plurality of case boundary surfaces, a second target case boundary surface with the case side surface in direct contact with the working medium inside the turbine, and other case boundary surfaces except the first target case boundary surface and the second target case boundary surface; The calculated coefficient A, B, C, D, E, F is calculated based on the rotor thermal diffusivity for the boundary surface where the rotor and the disk contact and the boundary surface where the cooling gas and the disk contact are set as adiabatic boundaries.
13. The method according to claim 1, wherein: the target area is a solid wall surface at the inlet of the cooling flow channel.

Description

Method for calculating turbine cooling gas demand Technical Field The disclosure relates to the technical field of turbine cooling, in particular to a method for calculating turbine cooling gas demand. Background In a supercritical carbon dioxide radial turbine, in order to meet the cooling requirement of the turbine shaft end, dry gas sealing gas is required to be introduced into a rotor-stator gap of the turbine as cooling gas to cool a rotor. For the calculation of the cold air demand after turbine shutdown, a three-dimensional simulation method can be adopted to perform transient simulation on the change of the temperature fields of the rotor and the casing along with the standing time, and whether the cold air needs to be injected is judged. The three-dimensional numerical simulation method has the advantages of high calculation requirement, long time consumption and poor numerical convergence, and particularly when the physical properties of the supercritical carbon dioxide working medium are processed, local non-physical solution or solution failure easily occurs, so that the turbine cooling gas requirement quantity result has low reliability and overlong calculation period, and the actual working condition requirement cannot be met. Disclosure of Invention In view of the foregoing, the present disclosure provides a method of calculating a turbine cooling gas demand amount performed by an electronic apparatus. According to a first aspect of the disclosure, a calculation method of a turbine cooling gas demand amount executed by electronic equipment is provided, and the calculation method comprises the steps of constructing a heat transfer geometric model based on structural parameters of a turbine, wherein the heat transfer geometric model comprises a solid area used for simulating temperature change of the solid area of the turbine and a fluid area used for simulating temperature change of cooling gas flowing through a cooling flow passage, constructing a first initial condition based on a basic rotating speed of a turbine rotor, an initial temperature of the solid area of the turbine and the basic parameters of the cooling gas, calculating to obtain a steady-state temperature field of the solid area and the fluid area under a condition of passing cooling gas in operation of the turbine by using a first algorithm based on the first initial condition, constructing a second initial condition based on an adjusted rotating speed of the turbine rotor and the temperature of the corresponding solid area of the turbine in the steady-state temperature field, calculating to obtain a basic transient temperature field of the solid area and the fluid area under the condition of stopping passing cooling gas after the turbine shutdown by using a second algorithm, wherein the adjusted rotating speed value is zero, and a calculation result of continuing cooling gas after the turbine shutdown is output under the condition that the temperature of the target area in the basic transient temperature field does not exceed a preset threshold. According to the embodiment of the disclosure, the method for calculating the turbine cooling gas demand, which is executed by the electronic equipment, further comprises the steps of constructing a plurality of groups of third initial conditions based on the adjustment rotating speed of the turbine rotor, the temperature of the corresponding turbine solid component in the steady-state temperature field and a plurality of groups of cooling gas adjustment parameters under the condition that the temperature of a target area in a basic transient temperature field exceeds a preset threshold value, calculating a plurality of groups of reference transient temperature fields of the solid area and the fluid area under the condition that the cooling gas is continuously introduced after the turbine is stopped by utilizing a third algorithm based on the plurality of groups of third initial conditions, wherein the plurality of groups of reference transient temperature fields correspond to the plurality of groups of cooling gas adjustment parameters, determining the cooling gas adjustment parameters which enable the flow rate of the temperature of the target area not to exceed the preset threshold value to be minimum based on the calculation result of the plurality of groups of reference transient temperature fields, and outputting the calculation result of the cooling gas demand after the turbine is stopped based on the minimum cooling gas adjustment parameters. According to the embodiment of the disclosure, the construction of the heat transfer geometric model based on the structural parameters of the turbine comprises the construction of the heat transfer geometric model based on the structural parameters of a rotor, a casing and a wheel disc of the turbine, wherein the heat transfer geometric model comprises a plurality of solid areas respectively used for simulating temperature changes of the