CN116611181A - Flow thermal coupling analysis method, system, equipment and medium for turbine casing structure - Google Patents

Flow thermal coupling analysis method, system, equipment and medium for turbine casing structure Download PDF

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CN116611181A
CN116611181A CN202310495280.7A CN202310495280A CN116611181A CN 116611181 A CN116611181 A CN 116611181A CN 202310495280 A CN202310495280 A CN 202310495280A CN 116611181 A CN116611181 A CN 116611181A
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邓维
赵尊盛
赵丹
董奇
王旭
周志翔
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Hunan Aviation Powerplant Research Institute AECC
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Hunan Aviation Powerplant Research Institute AECC
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Abstract

The application discloses a method, a system, equipment and a medium for analyzing the flow-heat coupling of a turbine casing structure. And then, based on the coupling construction of the air flow path finite element model and the solid finite element model, a coupling heat transfer model is obtained, the heat exchange coupling of fluid and solid in the model on the boundary is realized, and then the air flow of each flow path, the convective heat transfer coefficient of the fixed surface and the inlet air temperature are loaded into the coupling heat transfer model as known quantities. Finally, carrying out flow thermal coupling iterative analysis and solving to obtain a fluid temperature field and a solid temperature field after coupling iteration, wherein the heat exchange boundary of one-dimensional fluid and two-dimensional solid is completed in an internal automatic coupling mode, so that the heat exchange condition between cold air and the surface of the turbine casing structure can be considered more finely, and more real fluid and fixed temperature distribution can be obtained.

Description

Flow thermal coupling analysis method, system, equipment and medium for turbine casing structure
Technical Field
The present application relates to the field of temperature simulation analysis of a turbine casing structure, and in particular, to a method and a system for flow thermal coupling analysis of a turbine casing structure, an electronic device, and a computer readable storage medium.
Background
As a most typical high-temperature heat engine, the gas turbine engine has heat transfer characteristics of high temperature gradient inevitably, cold air flow of an air system and solid heat conduction are mutually coupled to influence, heat transfer data transmission inevitably exists between the gas turbine engine and surrounding cooling air in an analysis model, heat exchange exists between a solid wall surface and the surrounding cooling air at any moment, the solid temperature can be influenced by heat exchange of surrounding fluid, and in turn, the solid temperature also directly influences the temperature rise of the surrounding cooling air. Therefore, when the air system and the hot end component are subjected to heat transfer coupling analysis, the influence of heat exchange on the temperature distribution of cold air and solid is considered, and particularly, the temperature distribution of the solid is predicted more truly at the position where the coupling heat exchange effect is strong.
At present, a conventional analysis method generally adopts a method of calculating a fluid domain and a solid domain respectively, an air system performs one-dimensional network analysis, the solid domain performs two-dimensional/three-dimensional analysis, the two are boundary conditions, and a conventional analysis logic flow chart is shown in fig. 1 through a manual sequential iterative solution method. The common practice is as follows: firstly, calculating parameters of each flow path of an air system, wherein the wall surface temperature of the solid is preliminarily assumed, so that the flow and heat exchange of the fluid are calculated; then, extracting the temperature of the fluid and the convection heat transfer coefficient of the fluid and the solid surface as boundary conditions for solid temperature analysis; and finally, calculating the solid component, and obtaining the temperature field of the component by adopting thermal analysis commercial software through the heat exchange boundary of the loading surface. Since the calculated solid temperature is inconsistent with the preliminarily assumed temperature during the flow path analysis of the air system, it is obvious that the accuracy is difficult to be ensured without performing iterative calculation, and therefore, the temperature field of the solid component is also required to be substituted into the air system again, and the calculation process is repeated until the fluctuation value of the obtained solid temperature result is within an acceptable range.
Therefore, in the conventional analysis method, since the calculation analysis of the air system and the thermal analysis of the solid are performed independently, two different sets of software are adopted, and finally, the convergence is achieved by manually processing the boundary iteration. The method can achieve an approximate result with certain precision through few steps of iteration in steady state calculation with smaller edge Cheng Wensheng, but can not obtain accurate boundary conditions under the conditions of quicker gas path parameter change and higher edge Cheng Wensheng, and particularly for complex and huge systems such as turbine cases and the like, the data transmission of the calculation method is too complex, the calculation amount is large, the accuracy is difficult to ensure, and the requirement of temperature field analysis in the engineering design process can not be obviously met far. Meanwhile, the temperature of the solid body is continuously changed along with time during transient thermal analysis, so that a real transient temperature result cannot be obtained for manual iteration, and transient coupling calculation cannot be performed by a conventional analysis method.
Disclosure of Invention
The application provides a method and a system for analyzing the flow thermal coupling of a turbine casing structure, electronic equipment and a computer readable storage medium, which are used for solving the technical problems that the existing analysis method cannot accurately analyze the temperature field of the turbine casing structure and cannot perform transient coupling calculation.
According to one aspect of the present application, there is provided a method for analyzing a flow thermal coupling of a turbine casing structure, including:
carrying out one-dimensional flow calculation on the air system to obtain the air flow of each flow path and the convection heat exchange coefficient of the surface of the turbine casing structure;
establishing a solid finite element model and an air flow path finite element model of a turbine casing structure, establishing a coupling heat transfer model according to the corresponding relation between one-dimensional fluid and two-dimensional solid surfaces, and loading the convection heat transfer coefficient of the turbine casing structure surface, the air flow rate of each flow path and the inlet air temperature in the coupling heat transfer model;
and carrying out fluid thermal coupling iterative analysis and solving based on the loaded coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration.
Further, the process of carrying out fluid thermal coupling iterative analysis and solving based on the loaded coupling heat transfer model to obtain the fluid temperature field and the solid temperature field after coupling iteration specifically comprises the following steps:
splitting the coupling heat transfer model into a plurality of heat transfer coupling units along the air flow direction, wherein each heat transfer coupling unit comprises an air one-dimensional fluid unit formed by two air nodes and a solid two-dimensional unit formed by two solid nodes;
constructing a node heat transfer coupling equation between the air one-dimensional fluid unit and the solid two-dimensional unit based on a finite element method;
and carrying out flow thermal coupling analysis and solving based on a node heat transfer coupling equation to obtain the temperatures of two air nodes and two solid nodes in each heat transfer coupling unit, thereby obtaining a fluid temperature field and a solid temperature field.
Further, the node heat transfer coupling equation is:
wherein A and l respectively represent the cross-sectional area and the length of the air one-dimensional fluid unit along the flow direction, lambda, cp andrespectively representing the heat conductivity coefficient, specific heat and mass flow rate of air, h K And h L The convective heat transfer coefficients of the fixed nodes K and L are respectively represented, A K And A L Respectively represent the heat exchange areas of the fixed nodes K and L, T i And T j Respectively representing the temperatures of air nodes i and j, T K And T L Respectively represent the temperatures of fixed nodes K and L, Q i And Q j Representing the heat flows of air nodes i and j, respectively, Q K And Q L The heat flows of the fixed nodes K and L are shown, respectively.
Further, the finite element model construction and the flow thermal coupling iterative analysis are both performed in ANSYS software.
In addition, the application also provides a flow thermal coupling analysis system of the turbine casing structure, which comprises:
the one-dimensional flow calculation module is used for carrying out one-dimensional flow calculation on the air system to obtain the air flow of each flow path and the convection heat exchange coefficient of the surface of the turbine casing structure;
the coupling model construction module is used for establishing a solid finite element model and an air flow path finite element model of the turbine casing structure, constructing a coupling heat transfer model according to the corresponding relation between one-dimensional fluid and two-dimensional solid surfaces, and loading the convection heat transfer coefficient of the turbine casing structure surface, the air flow rate of each flow path and the inlet air temperature in the coupling heat transfer model;
and the flow thermal coupling analysis module is used for carrying out flow thermal coupling iterative analysis and solving based on the loaded coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration.
Further, the flow thermal coupling analysis module includes:
the splitting unit is used for splitting the coupling heat transfer model into a plurality of heat transfer coupling units along the air flow direction, and each heat transfer coupling unit comprises an air one-dimensional fluid unit formed by two air nodes and a solid two-dimensional unit formed by two solid nodes;
the coupling unit is used for constructing a node heat transfer coupling equation between the air one-dimensional fluid unit and the solid two-dimensional unit based on a finite element method;
and the calculation unit is used for carrying out fluid thermal coupling analysis and solving based on a node heat transfer coupling equation to obtain the temperatures of two air nodes and two solid nodes in each heat transfer coupling unit, thereby obtaining a fluid temperature field and a solid temperature field.
Further, the node heat transfer coupling equation is:
wherein A and l respectively represent the cross-sectional area and the length of the air one-dimensional fluid unit along the flow direction, lambda, cp andrespectively representing the heat conductivity coefficient, specific heat and mass flow rate of air, h K And h L The convective heat transfer coefficients of the fixed nodes K and L are respectively represented, A K And A L Respectively represent the heat exchange areas of the fixed nodes K and L, T i And T j Respectively representing the temperatures of air nodes i and j, T K And T L Respectively represent the temperatures of fixed nodes K and L, Q i And Q j Representing the heat flows of air nodes i and j, respectively, Q K And Q L The heat flows of the fixed nodes K and L are shown, respectively.
In addition, the application also provides an electronic device comprising a processor and a memory, wherein the memory stores a computer program, and the processor is used for executing the steps of the method by calling the computer program stored in the memory.
In addition, the application also provides a computer-readable storage medium for storing a computer program for carrying out a flow thermal coupling analysis on a turbine casing structure, which computer program, when run on a computer, carries out the steps of the method as described above.
The application has the following effects:
according to the flow thermal coupling analysis method of the turbine casing structure, one-dimensional flow calculation is firstly carried out on an air system, and air flow of each flow path and a convection heat exchange coefficient of the surface of the turbine casing structure are obtained. Then, an air flow path finite element model for expressing air along-path flowing heat exchange and a solid finite element model for expressing heat conduction inside the casing are simultaneously constructed in an ANSYS software platform, and the two finite element models are coupled to construct a coupling heat transfer model, so that heat exchange coupling between fluid and solid inside the model on the boundary is realized, manual iterative processing of two sets of model complex boundaries is replaced, and the calculation efficiency is improved. And loading the air flow of each flow path obtained by one-dimensional flow calculation, the convective heat transfer coefficient of the fixed surface and the inlet air temperature into a coupling heat transfer model as known quantities. Finally, carrying out flow thermal coupling iterative analysis and solving based on a coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration, wherein the air flow of each flow path and the convection heat transfer coefficient of a fixed surface do not participate in finite element solving, but are used as known quantity input, the heat transfer boundary of one-dimensional fluid and two-dimensional solid is completed in an internal automatic coupling mode, the heat transfer condition between cold air and the surface of a turbine casing structure can be considered more finely in the internal automatic coupling mode, more real fluid and fixed temperature distribution is obtained, the difficulty of cooling air along-path temperature rise calculation is solved, meanwhile, the air fluid parameters and the temperature distribution of solid components after the flow thermal coupling are considered can be obtained, and the transient thermal analysis of the turbine casing structure can be realized.
In addition, the flow thermal coupling analysis system of the turbine casing structure also has the advantages.
In addition to the objects, features and advantages described above, the present application has other objects, features and advantages. The present application will be described in further detail with reference to the drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 is a schematic logic flow diagram of a prior art heat transfer coupling analysis method.
Fig. 2 is a flow chart of a flow thermal coupling analysis method of a turbine casing structure according to a preferred embodiment of the present application.
Fig. 3 is a schematic diagram of a solid geometry model constructed in accordance with a preferred embodiment of the present application.
FIG. 4 is a schematic diagram of a coupled heat transfer model constructed in accordance with a preferred embodiment of the present application.
Fig. 5 is a schematic view showing cooling of the air flow path inside the casing in the preferred embodiment of the present application.
Fig. 6 is a schematic view of the sub-flow of step S3 in fig. 2.
Fig. 7 is a schematic diagram of an air one-dimensional fluidic unit according to a preferred embodiment of the present application.
FIG. 8 is a schematic illustration of wall temperature side points at various locations of a turbine case as experimentally verified in a preferred embodiment of the present application.
FIG. 9 is a schematic illustration of turbine casing wall temperature measurements taken during experimental verification in a preferred embodiment of the present application.
FIG. 10 is a schematic illustration of a turbine case temperature field calculated using conventional methods in a preferred embodiment of the present application.
FIG. 11 is a schematic illustration of a turbine case temperature field calculated using the method of the present application in a preferred embodiment of the present application.
Fig. 12 is a schematic block diagram of a flow thermal coupling analysis system of a turbine casing structure according to another embodiment of the present application.
Detailed Description
Embodiments of the application are described in detail below with reference to the attached drawing figures, but the application can be practiced in a number of different ways, as defined and covered below.
It will be appreciated that as shown in fig. 2, a preferred embodiment of the present application provides a method for analyzing a flow thermal coupling of a turbine casing structure, for performing a temperature simulation analysis on the turbine casing structure of a gas turbine engine, comprising the following specific steps:
step S1: carrying out one-dimensional flow calculation on the air system to obtain the air flow of each flow path and the convection heat exchange coefficient of the surface of the turbine casing structure;
step S2: establishing a solid finite element model and an air flow path finite element model of a turbine casing structure, establishing a coupling heat transfer model according to the corresponding relation between one-dimensional fluid and two-dimensional solid surfaces, and loading the convection heat transfer coefficient of the turbine casing structure surface, the air flow rate of each flow path and the inlet air temperature in the coupling heat transfer model;
step S3: and carrying out fluid thermal coupling iterative analysis and solving based on the loaded coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration.
It can be understood that in the flow thermal coupling analysis method of the turbine casing structure of this embodiment, first, one-dimensional flow calculation is performed on the air system to obtain the air flow of each flow path and the convective heat transfer coefficient of the surface of the turbine casing structure. Then, an air flow path finite element model for expressing air along-path flowing heat exchange and a solid finite element model for expressing heat conduction inside the casing are simultaneously constructed in an ANSYS software platform, and the two finite element models are coupled to construct a coupling heat transfer model, so that heat exchange coupling between fluid and solid inside the model on the boundary is realized, manual iterative processing of two sets of model complex boundaries is replaced, and the calculation efficiency is improved. And loading the air flow of each flow path obtained by one-dimensional flow calculation, the convective heat transfer coefficient of the fixed surface and the inlet air temperature into a coupling heat transfer model as known quantities. Finally, carrying out flow thermal coupling iterative analysis and solving based on a coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration, wherein the air flow of each flow path and the convection heat transfer coefficient of a fixed surface do not participate in finite element solving, but are used as known quantity input, the heat transfer boundary of one-dimensional fluid and two-dimensional solid is completed in an internal automatic coupling mode, the heat transfer condition between cold air and the surface of a turbine casing structure can be considered more finely in the internal automatic coupling mode, more real fluid and fixed temperature distribution is obtained, the difficulty of cooling air along-path temperature rise calculation is solved, meanwhile, the air fluid parameters and the temperature distribution of solid components after the flow thermal coupling are considered can be obtained, and the transient thermal analysis of the turbine casing structure can be realized.
It can be understood that in the step S1, one-dimensional flow calculation is performed on the air system to obtain the air flow rate of each flow path and the convective heat transfer coefficient of the turbine casing structure surface, and the air flow rate and the convective heat transfer coefficient are used as the known quantities in the flow thermal coupling analysis, and do not participate in finite element solution. The one-dimensional flow calculation process for the air system specifically comprises the following steps: firstly, building a one-dimensional flow calculation network element model according to an air system flow path structure, wherein the network element model of an air system consists of an inlet, an outlet, a volume element, a resistance element or a resistance-volume combination element, the whole flow network mainly consists of staggered connection of the volume element and the resistance element, the adjacent position of the resistance element is the volume element, the adjacent position of the volume element is the resistance element, and each branch is formed by connecting a plurality of elements in series; then, according to the actual structural size of the engine part, the geometric parameters and the flow resistance characteristics of each element are given; giving the pressure and temperature of the network inlet and outlet nodes; and then, during calculation, firstly setting initial values of pressure and temperature in the volume element, calculating to obtain the flow of each resistance element, then calculating time derivatives of the pressure and the temperature according to the total flow entering the volume element, integrating along the time step to obtain the pressure and the temperature in the volume element at the next moment, recalculating the flow passing through each resistance element according to the newly obtained pressure and the newly obtained temperature, and gradually integrating along the time direction to obtain the change of gas parameters of inlets and outlets of each element in the network along the time. When the integration is carried out for a certain time, the gas parameters in the network are not changed with time, and the flow reaches a stable state. It can be understood that the whole flow path network system adopts transient one-dimensional flow calculation, namely, a computer analysis program is established according to a one-dimensional flow continuous equation, a flow equation and an energy equation, the established flow network is solved, and output values of all elements of the whole network, namely, the distribution of flow, pressure, temperature and the like along the air system, are obtained. The input parameters of the software comprise total inlet pressure and total temperature of the air network, static pressure of an outlet of the air network, geometric parameters of all elements in the air network, heat exchange boundary conditions of heat exchange elements, initial pressure and initial temperature values of volume elements, time steps, convergence accuracy and the like, and the output parameters comprise mass flow, pressure, temperature, flow coefficient, outlet Ma number, convection heat exchange coefficient and the like of all the elements. Although a heat exchange element considering the heat exchange influence between air and parts can be built in the one-dimensional flow calculation network of the air system, and the temperature calculation result of the air and the solid is obtained through energy equation solving, the heat exchange characteristics and the complexity of the real part structure are various, and the part structure can only be approximately simplified into a flat plate or a tube shape with fixed thickness in the one-dimensional flow calculation of the air system, so that the calculation precision is necessarily low. Therefore, in the conventional method, to obtain the solid temperature and the fluid temperature with higher precision, it is necessary to calculate the more precise two-dimensional or three-dimensional solid temperature by other software, and re-substitute the two-dimensional or three-dimensional fixed temperature into the air system, and repeat the above calculation process until the obtained fluctuation value of the solid temperature result is within an acceptable range. In summary, the accuracy of fluid temperature and fixed temperature results obtained by one-dimensional flow calculations of an air system is not high, and must be obtained through complex manual iterations in order to improve accuracy.
In the present application, it is considered that in the one-dimensional flow calculation of the air system, the calculation result of the element flow is generally affected by the air pressure in the upstream and downstream, the resistance characteristic of the element and the air temperature, for example, a typical calculation formula of the aperture element flow can be expressed as follows:
wherein, the liquid crystal display device comprises a liquid crystal display device,represents mass flow, C d Represents the pore flow coefficient, A represents the pore area, P 1 * Represents the total inlet pressure, T 1 * Represents total temperature, k represents adiabatic index, R represents gas constant, P 2 Representing the outlet static pressure. From the above equation, the temperature of the air affects the flow only through the air density, and is relatively smaller than the influence of the pressure difference and the resistance characteristic of the element on the flow, so that even if the air temperature calculation result has a certain error, the flow result can meet the precision requirement in engineering application. The results of the element heat exchange coefficient calculations in the one-dimensional flow calculations of an air system are generally affected by the air flow and air temperature, and for forced turbulent convective heat transfer in a typical smooth duct,the most commonly used correlation at present is the Dittus-Boelter formula, which can be expressed as: nu=0.023 Re f 0.8 Pr f n And the formula for calculating the heat convection coefficient is as follows:wherein d represents hydraulic diameter, A represents flow area, h represents heat exchange coefficient, lambda represents air heat conduction coefficient, mu represents dynamic viscosity, pr f Represents Plantt number, re f Representing the reynolds number. Under a definite structure, namely the hydraulic diameter d and the flow area A are unchanged, the heat exchange coefficient h is influenced by the air heat conduction coefficient lambda, the dynamic viscosity mu and the Planet number Pr f And air flowAnd air thermal conductivity lambda, dynamic viscosity mu, pr f The thermal physical properties of air are determined by the temperature of air, but in general, even if there is a certain error in the calculation result of the temperature of air, the thermal physical properties do not change much, so that it can be considered approximately that the convective heat transfer coefficient h and the air flow rate->To the power of 0.8. In the one-dimensional flow calculation result of the air system, the accuracy of the flow calculation result is relatively high, so that the calculation accuracy of the heat exchange coefficient is also high.
Therefore, in one-dimensional flow calculation of the air system, the accuracy of the air temperature result and the solid temperature result is not high, but the calculation accuracy of the air flow and the convective heat transfer coefficient is high, and the traditional method has to adopt the air temperature result with lower accuracy to calculate the solid temperature, so that repeated manual iteration is needed, and the application takes the air flow result and the convective heat transfer coefficient result as the known quantity in the process of the fluid-heat coupling analysis, thereby effectively avoiding the problems existing in the prior art and having higher calculation accuracy.
It will be appreciated that in step S2, an air flow path geometric model is built in the ANSYS software platform, and the physical properties of air, unit types, and the like are defined and meshed, thereby building an air flow path finite element model representing the air flow along the path heat exchange. Meanwhile, a solid geometric model of the turbine casing structure is built in an ANSYS software platform, as shown in fig. 3, unit types, materials and other attributes are defined, fixed grids are divided, and therefore a solid finite element model representing heat conduction inside the casing is built. And then, coupling the two finite element models according to the corresponding relation between the one-dimensional fluid and the two-dimensional solid surface in an ANSYS software platform, and establishing a coupling heat transfer model for transferring heat exchange data between the two finite element models, as shown in fig. 4.
It can be understood that, as shown in fig. 5, the heat exchange process of the air flow path inside the casing is: the high-temperature fuel gas transfers heat to the inside of the casing, cooling air flows from left to right to take away heat in the casing and is used for cooling the casing, the heat released by the casing is absorbed in the flowing process of the cold air in the casing, the temperature of the cold air is continuously increased along the way, so that the temperature of the cold air in the casing is changed, the degree of temperature change depends on the heat exchange amount of the casing, the higher the temperature of the casing is, the higher the temperature of the cold air is, the cold air temperature and the temperature of the casing are in a coupling relation, and a heat transfer coupling model is required to be established for solving. Specifically, the formula for calculating the heat exchange between the air flow and the casing can be expressed as: q=h g A(T g -T w )＝h c A(T w -T c ) Wherein T is g 、T w And T c Respectively representing the gas temperature, the casing wall temperature and the cold air local temperature, h g The heat exchange coefficient of the fuel gas and the surface of the casing is expressed, h c The heat exchange coefficient of the cold air and the surface of the casing is shown, and Q and A respectively show the heat exchange quantity and the heat exchange area. And the heat dissipation capacity of the casing is absorbed by the cold air to form cold air temperature rise, and the cold air temperature rise calculation formula is as follows:wherein (1)>And c p Respectively represent the mass flow rate and specific heat of cold air, T ci Indicating coldGas inlet temperature.
In the coupling analysis between the cold air temperature and the casing temperature, the heat exchange process between the high-temperature fuel gas and the casing needs to be given boundary conditions in advance, namely T g 、h g Is a known quantity. Thus, the solution can be achieved by establishing a thermal equilibrium equation from the two formulas above, except T w And T c The remainder are known amounts for the unknown amounts. The traditional method needs to assume the wall temperature T firstly because the coupling method is not established w The cold air temperature T is obtained through calculation of an air system flow heat exchange calculation model c Then cool air temperature T c Loading the temperature to a heat transfer finite element model of the casing, and calculating to obtain updated wall temperature T w Generally, no less than 3 manual iterations are required until no obvious change is obtained in the two calculation results of the mild cold air temperature of the casing wall. And the traditional method calculates the air flow path and the casing model by adopting different software respectively, the coupling heat balance of the node level cannot be realized on the heat exchange boundary, and the calculation efficiency and the precision are greatly limited. In the application, the analysis model of one-dimensional fluid and two-dimensional solid is simultaneously constructed in the ANSYS software platform, so that the heat exchange coupling of the fluid and the solid in the model on the boundary is realized, the manual iterative processing of two sets of complex boundaries of the model is replaced, and the calculation efficiency is improved.
It may be understood that, as shown in fig. 6, in the step S3, the process of obtaining the fluid temperature field and the solid temperature field after the coupling iteration by performing the iterative analysis and solution of the fluid thermal coupling based on the loaded coupling heat transfer model specifically includes:
step S31: splitting the coupling heat transfer model into a plurality of heat transfer coupling units along the air flow direction, wherein each heat transfer coupling unit comprises an air one-dimensional fluid unit formed by two air nodes and a solid two-dimensional unit formed by two solid nodes;
step S32: constructing a node heat transfer coupling equation between the air one-dimensional fluid unit and the solid two-dimensional unit based on a finite element method;
step S33: and carrying out flow thermal coupling analysis and solving based on a node heat transfer coupling equation to obtain the temperatures of two air nodes and two solid nodes in each heat transfer coupling unit, thereby obtaining a fluid temperature field and a solid temperature field.
Specifically, the coupling heat transfer model is firstly split into a plurality of heat transfer coupling units along the flow direction of fluid, and each coupling unit comprises an air one-dimensional fluid unit formed by two air nodes and a solid two-dimensional unit formed by two solid nodes. Wherein, as shown in fig. 7, the air one-dimensional fluid unit comprises air nodes i and j with a length of L, air flows from node i to node j, and node K, L respectively represents fixed nodes, and heat conduction exists between air nodes i and j, and heat conduction also exists between node i and node K, and similarly, heat conduction also exists between node j and node L.
Then, according to a finite element method, a node heat transfer coupling equation between the air one-dimensional fluid unit and the solid two-dimensional unit is constructed: [ R ] { T } = { Q }, wherein [ R ] represents a heat conduction matrix, { T } represents a set of temperatures of each node in the heat transfer coupling unit, and { Q } represents a set of heat flows of each node in the heat transfer coupling unit. Substituting the relevant physical quantity to obtain the node heat transfer coupling equation:
wherein A and l respectively represent the cross-sectional area and the length of the air one-dimensional fluid unit along the flow direction, lambda, cp andrespectively representing the heat conductivity coefficient, specific heat and mass flow rate of air, h K And h L The convective heat transfer coefficients of the fixed nodes K and L are respectively represented, A K And A L Respectively represent the heat exchange areas of the fixed nodes K and L, T i And T j Respectively representing the temperatures of air nodes i and j, T K And T L Respectively represent the temperatures of fixed nodes K and L, Q i And Q j Representing the heat flows of air nodes i and j, respectively, Q K And Q L The heat flows of the fixed nodes K and L are shown, respectively. For the heat flow set { Q }, inWhen in calculation, the temperature value T of four nodes in each heat transfer coupling unit can be obtained by giving in advance, establishing a heat balance equation of the air flow path and the surface of the casing through the equation, realizing a heat transfer coupling solving function i 、T j 、T K And T L . And then, constructing the node heat transfer coupling equation for all the heat transfer coupling units in the coupling heat transfer model, and solving the node heat transfer coupling equation, so that a circulation temperature field and a casing surface temperature field can be obtained.
It is understood that, in order to verify the effectiveness and accuracy of the flow thermal coupling analysis method of the present application, the present inventors also performed thermal analysis tests and calculations for the turbine casing of a certain engine, and compared the test results with the calculation results. As shown in fig. 8, a plurality of casing wall temperature measuring points are respectively arranged at the front part, the middle part and the rear part of the turbine casing, the wall temperature measuring results are shown in fig. 9, the turbine casing temperature results obtained by calculation by the conventional method and the method of the application are shown in fig. 10 and 11, and the turbine casing temperature calculation result pairs in three modes are shown in table 1:
table 1, turbine casing temperature calculation result comparison Table (Unit K)
Therefore, as can be seen from table 1, the wall temperature of the casing obtained by the conventional thermal analysis method is generally low, and the wall temperature calculated by the analysis method of the application greatly improves the accuracy of calculation, and the deviation from the test value is within 10 ℃.
In addition, as shown in fig. 12, another embodiment of the present application further provides a flow thermal coupling analysis system of a turbine casing structure, preferably adopting the flow thermal coupling analysis method as described above, the system comprising:
the one-dimensional flow calculation module is used for carrying out one-dimensional flow calculation on the air system to obtain the air flow of each flow path and the convection heat exchange coefficient of the surface of the turbine casing structure;
the coupling model construction module is used for establishing a solid finite element model and an air flow path finite element model of the turbine casing structure, constructing a coupling heat transfer model according to the corresponding relation between one-dimensional fluid and two-dimensional solid surfaces, and loading the convection heat transfer coefficient of the turbine casing structure surface, the air flow rate of each flow path and the inlet air temperature in the coupling heat transfer model;
and the flow thermal coupling analysis module is used for carrying out flow thermal coupling iterative analysis and solving based on the loaded coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration.
It can be understood that in the flow thermal coupling analysis system of the turbine casing structure of this embodiment, first, one-dimensional flow calculation is performed on the air system to obtain the air flow rate of each flow path and the convective heat transfer coefficient of the surface of the turbine casing structure. Then, an air flow path finite element model for expressing air along-path flowing heat exchange and a solid finite element model for expressing heat conduction inside the casing are simultaneously constructed in an ANSYS software platform, and the two finite element models are coupled to construct a coupling heat transfer model, so that heat exchange coupling between fluid and solid inside the model on the boundary is realized, manual iterative processing of two sets of model complex boundaries is replaced, and the calculation efficiency is improved. And loading the air flow of each flow path obtained by one-dimensional flow calculation, the convective heat transfer coefficient of the fixed surface and the inlet air temperature into a coupling heat transfer model as known quantities. Finally, carrying out flow thermal coupling iterative analysis and solving based on a coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration, wherein the air flow of each flow path and the convection heat transfer coefficient of a fixed surface do not participate in finite element solving, but are used as known quantity input, the heat transfer boundary of one-dimensional fluid and two-dimensional solid is completed in an internal automatic coupling mode, the heat transfer condition between cold air and the surface of a turbine casing structure can be considered more finely in the internal automatic coupling mode, more real fluid and fixed temperature distribution is obtained, the difficulty of cooling air along-path temperature rise calculation is solved, meanwhile, the air fluid parameters and the temperature distribution of solid components after the flow thermal coupling are considered can be obtained, and the transient thermal analysis of the turbine casing structure can be realized.
Wherein the flow thermocouple analysis module comprises:
the splitting unit is used for splitting the coupling heat transfer model into a plurality of heat transfer coupling units along the air flow direction, and each heat transfer coupling unit comprises an air one-dimensional fluid unit formed by two air nodes and a solid two-dimensional unit formed by two solid nodes;
the coupling unit is used for constructing a node heat transfer coupling equation between the air one-dimensional fluid unit and the solid two-dimensional unit based on a finite element method;
and the calculation unit is used for carrying out fluid thermal coupling analysis and solving based on a node heat transfer coupling equation to obtain the temperatures of two air nodes and two solid nodes in each heat transfer coupling unit, thereby obtaining a fluid temperature field and a solid temperature field.
Wherein, the node heat transfer coupling equation is:
wherein A and l respectively represent the cross-sectional area and the length of the air one-dimensional fluid unit along the flow direction, lambda, cp andrespectively representing the heat conductivity coefficient, specific heat and mass flow rate of air, h K And h L The convective heat transfer coefficients of the fixed nodes K and L are respectively represented, A K And A L Respectively represent the heat exchange areas of the fixed nodes K and L, T i And T j Respectively representing the temperatures of air nodes i and j, T K And T L Respectively represent the temperatures of fixed nodes K and L, Q i And Q j Representing the heat flows of air nodes i and j, respectively, Q K And Q L The heat flows of the fixed nodes K and L are shown, respectively.
In addition, another embodiment of the present application also provides an electronic device, including a processor and a memory, where the memory stores a computer program, and the processor is configured to execute the steps of the method described above by calling the computer program stored in the memory.
In addition, another embodiment of the present application also provides a computer-readable storage medium storing a computer program for performing a flow thermal coupling analysis of a turbine casing structure, the computer program executing the steps of the method as described above when run on a computer.
Forms of general computer-readable storage media include: a floppy disk (floppy disk), a flexible disk (flexible disk), hard disk, magnetic tape, any other magnetic medium, a CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a Random Access Memory (RAM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), a FLASH erasable programmable read-only memory (FLASH-EPROM), any other memory chip or cartridge, or any other medium from which a computer can read. The instructions may further be transmitted or received over a transmission medium. The term transmission medium may include any tangible or intangible medium that may be used to store, encode, or carry instructions for execution by a machine, and includes digital or analog communications signals or their communications with intangible medium that facilitate communication of such instructions. Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise a bus for transmitting a computer data signal.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The scheme in the embodiment of the application can be realized by adopting various computer languages, such as object-oriented programming language Java, an transliteration script language JavaScript and the like.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the application.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims (9)

1. The flow thermal coupling analysis method of the turbine casing structure is characterized by comprising the following steps of:
carrying out one-dimensional flow calculation on the air system to obtain the air flow of each flow path and the convection heat exchange coefficient of the surface of the turbine casing structure;
establishing a solid finite element model and an air flow path finite element model of a turbine casing structure, establishing a coupling heat transfer model according to the corresponding relation between one-dimensional fluid and two-dimensional solid surfaces, and loading the convection heat transfer coefficient of the turbine casing structure surface, the air flow rate of each flow path and the inlet air temperature in the coupling heat transfer model;
and carrying out fluid thermal coupling iterative analysis and solving based on the loaded coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration.
2. The method for analyzing the flow thermal coupling of the turbine casing structure according to claim 1, wherein the flow thermal coupling iterative analysis and solution is performed based on the loaded coupling heat transfer model, and the process of obtaining the fluid temperature field and the solid temperature field after the coupling iteration specifically comprises the following steps:
splitting the coupling heat transfer model into a plurality of heat transfer coupling units along the air flow direction, wherein each heat transfer coupling unit comprises an air one-dimensional fluid unit formed by two air nodes and a solid two-dimensional unit formed by two solid nodes;
constructing a node heat transfer coupling equation between the air one-dimensional fluid unit and the solid two-dimensional unit based on a finite element method;
and carrying out flow thermal coupling analysis and solving based on a node heat transfer coupling equation to obtain the temperatures of two air nodes and two solid nodes in each heat transfer coupling unit, thereby obtaining a fluid temperature field and a solid temperature field.
3. The method for analyzing the flow thermal coupling of the turbine casing structure according to claim 2, wherein the node heat transfer coupling equation is:
wherein A and l respectively represent the cross-sectional area and the length of the air one-dimensional fluid unit along the flow direction, lambda, cp andrespectively representing the heat conductivity coefficient, specific heat and mass flow rate of air, h K And h L The convective heat transfer coefficients of the fixed nodes K and L are respectively represented, A K And A L Respectively represent the heat exchange areas of the fixed nodes K and L, T i And T j Respectively representing the temperatures of air nodes i and j, T K And T L Respectively represent the temperatures of fixed nodes K and L, Q i And Q j Representing the heat flows of air nodes i and j, respectively, Q K And Q L The heat flows of the fixed nodes K and L are shown, respectively.
4. The method for analyzing the flow thermal coupling of the turbine casing structure according to claim 1, wherein the construction of the finite element model and the iterative analysis of the flow thermal coupling are performed in ANSYS software.
5. A flow thermal coupling analysis system of a turbine casing structure, comprising:
the one-dimensional flow calculation module is used for carrying out one-dimensional flow calculation on the air system to obtain the air flow of each flow path and the convection heat exchange coefficient of the surface of the turbine casing structure;
the coupling model construction module is used for establishing a solid finite element model and an air flow path finite element model of the turbine casing structure, constructing a coupling heat transfer model according to the corresponding relation between one-dimensional fluid and two-dimensional solid surfaces, and loading the convection heat transfer coefficient of the turbine casing structure surface, the air flow rate of each flow path and the inlet air temperature in the coupling heat transfer model;
and the flow thermal coupling analysis module is used for carrying out flow thermal coupling iterative analysis and solving based on the loaded coupling heat transfer model to obtain a fluid temperature field and a solid temperature field after coupling iteration.
6. The turbine casing structure flow thermocouple analysis system of claim 5, wherein the flow thermocouple analysis module comprises:
the splitting unit is used for splitting the coupling heat transfer model into a plurality of heat transfer coupling units along the air flow direction, and each heat transfer coupling unit comprises an air one-dimensional fluid unit formed by two air nodes and a solid two-dimensional unit formed by two solid nodes;
the coupling unit is used for constructing a node heat transfer coupling equation between the air one-dimensional fluid unit and the solid two-dimensional unit based on a finite element method;
and the calculation unit is used for carrying out fluid thermal coupling analysis and solving based on a node heat transfer coupling equation to obtain the temperatures of two air nodes and two solid nodes in each heat transfer coupling unit, thereby obtaining a fluid temperature field and a solid temperature field.
7. The turbine casing structure flow thermal coupling analysis system of claim 6, wherein the node heat transfer coupling equation is:
wherein A and l respectively represent the cross-sectional area and the length of the air one-dimensional fluid unit along the flow direction, lambda, cp andrespectively representing the heat conductivity coefficient, specific heat and mass flow rate of air, h K And h L The convective heat transfer coefficients of the fixed nodes K and L are respectively represented, A K And A L Respectively represent the heat exchange areas of the fixed nodes K and L, T i And T j Respectively representing the temperatures of air nodes i and j, T K And T L Respectively represent the temperatures of fixed nodes K and L, Q i And Q j Representing the heat flows of air nodes i and j, respectively, Q K And Q L The heat flows of the fixed nodes K and L are shown, respectively.
8. An electronic device comprising a processor and a memory, said memory having stored therein a computer program for executing the steps of the method according to any of claims 1-4 by invoking said computer program stored in said memory.
9. A computer-readable storage medium for storing a computer program for performing a flow-thermal coupling analysis of a turbine casing structure, characterized in that the computer program when run on a computer performs the steps of the method according to any one of claims 1-4.
CN202310495280.7A 2023-05-04 2023-05-04 Flow thermal coupling analysis method, system, equipment and medium for turbine casing structure Pending CN116611181A (en)

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