Compressor disc flow thermal coupling temperature calculation method

Abstract

The invention aims to provide a compressor disc flow thermal coupling temperature calculation method. The compressor disc flow thermal coupling temperature calculation method comprises the following steps: acquiring a flow analysis result of fluid in a compressor disc cavity; the compressor disc cavity is divided into a first cavity body and a second cavity body according to the analysis result; simplifying the temperature in the first cavity into a cavity temperature node, and obtaining the temperature of the cavity temperature node and the temperature of a wall surface node of the first cavity; and the temperature in the second cavity is simplified into a heat flow line which exchanges heat with the wall face of the compressor disc cavity, a heat balance equation of the heat flow line is constructed, and the temperature of a node of the wall face of the second cavity is obtained according to the heat balance equation. The method can improve the heat analysis precision of the compressor disc.

Description

Technical Field

[0001] The invention relates to the field of gas turbine engines, and in particular to a compressor disk flow-heat coupling temperature calculation method. Background Art

[0002] With the development of aero-engine technology, the working environment of compressors is becoming increasingly harsh, and it is very important to accurately predict their temperature distribution. Accurate thermal analysis of parts can not only provide reliable part temperature data for strength and life design, but also is an important basis for determining the life of airworthy engine life-limited parts.

[0003] The compressor rotating disc cavity is the main part of the flow path through which the cooling air passes in an aero-engine, and has typical aerodynamic and heat transfer coupling characteristics. The traditional thermal analysis of the compressor disc is based on solving the heat conduction differential equation based on the third-order heat exchange boundary to obtain the compressor rotor temperature field. The heat exchange temperature is generally given by experience, and the fluid air temperature and solid temperature on the metal surface are usually decoupled. However, due to the significant swirl in the compressor rotor disc cavity, the rotor disc surface feels the relative total temperature, and the heat exchange between the fluid and the solid will affect the heat exchange temperature on the rotor disc surface. Therefore, the decoupling solution between the air and the rotating disc may bring large calculation errors to the compressor rotor temperature calculation. In order to solve this problem, the current main method is the fluid-heat coupling calculation method of CFD software, which couples the heat exchange boundary and solid temperature on the fluid-solid interface. However, this method also has some problems, such as a large number of grids, a long time for pre-processing and calculation, etc. The total calculation cost is high, which is not suitable for the rapid evaluation of multiple schemes in engineering.

[0004] There is an urgent need to provide a compressor disk flow-heat coupling temperature calculation method to improve the accuracy of compressor disk thermal analysis. Summary of the invention

[0005] The object of the present invention is to provide a compressor disk flow-heat coupling temperature calculation method, which can improve the accuracy of compressor disk thermal analysis.

[0006] A compressor disk flow-heat coupling temperature calculation method for achieving the above-mentioned purpose comprises the following steps:

[0007] Obtain the fluid flow analysis results in the compressor disc cavity;

[0008] According to the analysis result, the compressor disc cavity is divided into a first cavity and a second cavity, the first cavity is located radially outside the second cavity, and the fluid flow state in the first cavity is different from the fluid flow state in the second cavity;

[0009] Simplifying the temperature inside the first cavity into a cavity temperature node, considering the heat exchange between the cavity temperature node and the wall of the compressor disc cavity, and obtaining the temperature of the cavity temperature node and the first cavity wall node;

[0010] The temperature inside the second cavity is simplified to a heat flow line that exchanges heat with the wall of the compressor disc cavity, and a heat balance equation of the heat flow line is constructed. The temperature of the second cavity wall node is obtained according to the heat balance equation.

[0011] In one or more embodiments, the fluid flow in the first cavity is dominated by centrifugal force, and the fluid flow in the second cavity is dominated by inertial force.

[0012] In one or more embodiments, the heat exchange between the cavity temperature node and the compressor disc cavity wall is considered to obtain a group of heat balance equations in the first cavity, and the temperatures of the cavity temperature node and the first cavity wall node are obtained by jointly solving the group of heat balance equations.

[0013] In one or more embodiments, the heat balance equations include the following equations (1) to (6):

[0014] ∑h i A i (T wi -T f )+H in -H out =0 (1);

[0015]

[0016]

[0017]

[0018] T out =T f (5);

[0019]

[0020] Among them, T wi is the first cavity wall node temperature, T f is the temperature of the first cavity temperature node, H in is the enthalpy of the axial throughflow into the first cavity, H out is the enthalpy of the axial throughflow leaving the first cavity and entering the disk core, is the flow rate entering the first cavity, is the constant pressure specific heat capacity of the gas entering the first cavity, T in is the temperature of the gas entering the first cavity, is the flow leaving the first chamber, is the specific heat capacity of the gas leaving the first chamber at constant pressure, T out is the temperature of the gas leaving the first chamber, h i is the local heat transfer coefficient, A i is the local heat exchange area, T ni is the internal temperature of the first cavity wall, λ is the thermal conductivity, q λ is the heat flux density parallel to the wall of the first cavity.

[0021] In one or more embodiments, the heat balance equation of the heat flow line is as follows (7):

[0022]

[0023] Among them, T w is the wall temperature of the second cavity, T fn is the local air flow temperature, h is the local heat transfer coefficient, A is the local heat transfer area, is the air mass flow rate, C p is the specific heat of the gas at constant pressure.

[0024] In one or more embodiments, the temperature of the second cavity wall node is obtained according to the heat balance equation and the heat balance equation of the metal surface node, and the heat balance equation of the metal surface node is the following formula (8):

[0025]

[0026] Among them, T ni is the internal temperature of the second cavity wall, T wi is the second cavity wall node temperature, λ is the thermal conductivity, q λ is the heat flux density parallel to the wall of the first cavity.

[0027] In one or more embodiments, computational fluid dynamics simulation software is used to analyze the fluid flow in the compressor disc cavity to obtain analysis results of the fluid flow in the compressor disc cavity.

[0028] On the other hand, according to some embodiments of the present application, a readable storage medium is provided, on which computer instructions are stored. When the computer instructions are executed by a processor, the steps of the compressor disk flow thermal coupling temperature calculation method as described above are implemented.

[0029] The beneficial effects of the present invention are:

[0030] This method uses the CFD flow analysis results to obtain the flow structure in the compressor axial through-flow disk cavity, and then divides it into several regions according to the flow characteristics in the disk cavity. The energy conservation equation is used to simplify the model for these regions, simplifying the fluid into a one-dimensional flow, and considering the thermal balance between the one-dimensional fluid and the surface of the two-dimensional solid finite element thermal analysis model. A compressor disk thermal analysis model based on thermal cavities and thermal streamlines is established to simulate the energy exchange in the compressor disk cavity. The fluid-heat coupling effect is considered in the solid finite element calculation, thereby improving the accuracy of the compressor disk temperature calculation. Through this method, on the one hand, the solution speed is accelerated, and on the other hand, the fluid-heat coupling can be considered to reflect the physical reality as much as possible, thereby improving the accuracy of the thermal analysis of the compressor disk in engineering and meeting the needs of rapid temperature evaluation on the model.

[0031] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0033] Figure 1 A schematic diagram of the CFD flow analysis results of the compressor disc cavity is shown;

[0034] Figure 2 A schematic diagram of partitioning different positions of the compressor disc cavity according to the compressor disc flow-heat coupling temperature calculation method is shown;

[0035] Figure 3 A schematic diagram of the thermal balance of the thermal cavity in the compressor disc cavity is shown;

[0036] Figure 4 The heat flow balance diagram according to the compressor disk flow heat coupling temperature calculation method is shown;

[0037] Figure 5 A schematic diagram showing the thermal flow lines and thermal cavity layout of a typical compressor disc cavity finite element model. DETAILED DESCRIPTION

[0038] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0040] The traditional compressor disk temperature calculation uses the method of fluid-heat decoupling, which cannot reflect the physical reality and leads to the problem of low temperature accuracy. Although the CFD calculation method can consider fluid-heat coupling and reflect more detailed flow and heat transfer conditions, its solution is time-consuming and the pre-processing workload is relatively large, which cannot meet the needs of rapid temperature evaluation in engineering. How to speed up the solution while considering fluid-heat coupling and reflect the physical reality as much as possible is an urgent problem to be solved in the thermal analysis of the current model compressor disk.

[0041] According to some embodiments of the present application, a method for calculating compressor disk flow-heat coupling temperature is provided, which comprises the following steps:

[0042] The fluid flow analysis result in the compressor disc cavity is obtained. Specifically, the fluid flow in the compressor disc cavity is analyzed using computational fluid dynamics simulation software (CFD) to obtain the fluid flow analysis result in the compressor disc cavity.

[0043] According to the analysis results, the compressor disc cavity is divided into a first cavity 1 and a second cavity 2 along the radial direction a of the compressor disc cavity. Figure 1 The schematic diagram of the CFD flow analysis results of the compressor disc cavity is shown. Figure 2 A schematic diagram of the partitioning of different positions of the compressor disc cavity is shown, where the first cavity 1 is located radially outside the second cavity 2, and the fluid flow state in the first cavity 1 is different from the fluid flow state in the second cavity 2.

[0044] In a specific embodiment, Figure 1As shown in the figure, the flow structures in the disc cavities at each level are similar. There is a rigid vortex with a rotation speed close to the wall of the disc cavity in the first cavity 1 of the middle and high radius in the disc cavity, and the rigid vortex is mainly dominated by centrifugal force. In the second cavity 2 at the low radius position, after the axial flow b reaches the entrance of the disc cavity, a part of the airflow will invade the disc cavity. After the invading airflow exchanges heat with the airflow in the disc cavity and the wall of the compressor disc, it will finally leave the disc cavity and merge into the mainstream, then flow downstream and enter the next disc cavity, and so on. Therefore, after the compressor disc cavity is divided into the first cavity 1 and the second cavity 2, the fluid flow in the first cavity 1 is dominated by centrifugal force, and the fluid flow in the second cavity 2 is dominated by inertial force. Since the heat exchange of the disc cavity wall is mainly affected by the flow state of the nearby airflow, the axial through-flow disc cavity can be roughly divided into two upper and lower regions when processing the finite element thermal analysis model, and the thermal model can be established separately to improve the calculation efficiency.

[0045] Then, the cavity temperature of the first cavity is simplified to a cavity temperature node, such as Figure 2 As shown in the figure, a part of the airflow on the left side of the disk cavity inlet enters the disk cavity due to the centrifugal force. In the second cavity 2, the airflow exchanges heat with the wall of the compressor disk while flowing into the first cavity 1 with a high radius; the other part of the airflow still flows backward along the axial direction b. This part of the invading airflow entering the first cavity 1 brings in a part of the enthalpy. In addition, due to the conservation of mass, after the heat exchange between this part of the airflow and the airflow in the rigid vortex of the first cavity 1, it will take away a part of the enthalpy and leave the first cavity 1, enter the second cavity 2, and finally merge with the axial flow in the center area of ​​the disk, and then flow axially to the next level of disk cavity. Since the airflow in the first cavity 1 is a rigid vortex, the heat transfer coefficient is small, and the heat transfer temperature is relatively uniform. Therefore, when processing the finite element temperature heat transfer boundary, it can be assumed that the heat exchange temperature in the first cavity 1 is uniform, and the cavity temperature is simplified to a node. The temperature of this node is used to express the cavity temperature of the first cavity 1. This node is the cavity temperature node. Considering the heat exchange between the cavity temperature node and the wall of the compressor disc cavity in the first cavity 1, the temperature of the cavity temperature node of the first cavity 1 and the temperature of the wall node of the compressor disc cavity in the first cavity 1 can be obtained. Among them, the wall node is the position of the point on the compressor wall where the temperature needs to be obtained.

[0046] Then, the temperature inside the second cavity 2 is simplified to a heat flow line 3 that exchanges heat with the wall of the compressor disc cavity, such as Figure 4 As shown, the temperature of the airflow near the center of the second cavity 2 will change along the way. It cannot be simplified into a point like a hot cavity, but is simplified into a line that exchanges heat with the wall, namely, the heat flow line 3. By constructing the heat balance equation of the heat flow line, the temperature of the compressor wall node of the second cavity 2 is obtained according to the heat balance equation.

[0047] This method uses the CFD flow analysis results to obtain the flow structure in the compressor axial through-flow disk cavity, and then divides it into several regions according to the flow characteristics in the disk cavity. The energy conservation equation is used to simplify the model for these regions, simplifying the fluid into a one-dimensional flow, and considering the thermal balance between the one-dimensional fluid and the surface of the two-dimensional solid finite element thermal analysis model. A compressor disk thermal analysis model based on thermal cavities and thermal streamlines is established to simulate the energy exchange in the compressor disk cavity. The fluid-heat coupling effect is considered in the solid finite element calculation, thereby improving the accuracy of the compressor disk temperature calculation. Through this method, on the one hand, the solution speed is accelerated, and on the other hand, the fluid-heat coupling can be considered to reflect the physical reality as much as possible, thereby improving the accuracy of the thermal analysis of the compressor disk in engineering and meeting the needs of rapid temperature evaluation on the model.

[0048] In the description of the embodiments of the present application, the technical terms "first" and "second", such as "first cavity", "second cavity", etc., are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0049] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0050] In some embodiments of the compressor disk flow thermal coupling temperature calculation method, the temperatures of the cavity temperature nodes of the first cavity 1 and the first cavity wall nodes are obtained by considering the heat exchange between the cavity temperature nodes and the compressor disk cavity wall, and the heat balance equations in the first cavity are obtained by solving the heat balance equations jointly.

[0051] Specifically, the heat balance equations include the following formulas (1) to (6):

[0052] ∑h i A i (T wi -T f )+H in -H out =0 (1);

[0053]

[0054]

[0055] According to the law of conservation of mass:

[0056] According to the flow characteristics of the compressor disc cavity, the temperature of the gas flowing out of the hot cavity should be approximately equal to the gas temperature of the hot cavity itself, so: T out =T f (5);

[0057] Combination Figure 3 As shown, for the compressor disk cavity metal surface temperature node i, the heat balance equation can be listed as follows:

[0058] Among them, T wi is the first cavity wall node temperature, T f is the temperature of the first cavity temperature node, H in is the enthalpy of the axial throughflow into the first cavity, H out is the enthalpy of the axial throughflow leaving the first cavity and entering the disk core, is the flow rate into the first cavity, is the constant pressure specific heat capacity of the gas entering the first cavity, T in is the temperature of the gas entering the first cavity, is the flow leaving the first chamber, is the specific heat capacity of the gas leaving the first chamber at constant pressure, T out is the temperature of the gas leaving the first chamber, h i is the local heat transfer coefficient, A i is the local heat exchange area, T ni is the internal temperature of the first cavity wall, λ is the thermal conductivity, q λ is the heat flux density parallel to the wall of the first cavity. By solving (1)-(6) simultaneously, the temperature of the nodes of the first cavity 1 and the nodes of the wall of the compressor disk of the first cavity 1 can be obtained.

[0059] Combination Figure 4 As shown, in some embodiments of the compressor disk flow thermal coupling temperature calculation method, the heat balance equation of the heat flow line is the following formula (7):

[0060]

[0061] Among them, T w is the wall temperature of the second cavity, T fn is the local air flow temperature, h is the local heat transfer coefficient, A is the local heat transfer area, is the air mass flow rate, C p is the specific heat of the gas at constant pressure.

[0062] In some embodiments of the compressor disk flow thermal coupling temperature calculation method, the temperature of the second cavity wall node is obtained according to the heat balance equation and the heat balance equation of the metal surface node. The heat balance equation of the metal surface node is the following formula (8), which is the aforementioned heat balance equation of the compressor disk cavity metal surface temperature node i:

[0063]

[0064] Among them, T ni is the internal temperature of the second cavity wall, T wi is the second cavity wall node temperature, λ is the thermal conductivity, q λ is the heat flux density parallel to the wall of the first cavity.

[0065] Figure 5 The arrangement of heat streamlines 101 and heat cavities 100 of a typical compressor disc cavity finite element model is given. When solving the temperature field, the solid heat conduction equation and the one-dimensional energy conservation equation of the fluid can be used to simultaneously obtain the solid temperature field and the one-dimensional fluid temperature field. This method combines the advantages of CFD and traditional finite element thermal analysis methods, which can improve the calculation accuracy of the compressor disc temperature while ensuring the calculation efficiency, thereby better supporting the design of model compressors.

[0066] The computer-readable storage medium provided by the present disclosure stores computer instructions thereon. When the computer instructions are executed by a processor, the compressor disk flow-thermal coupling temperature calculation method provided by any of the above embodiments can be implemented, thereby improving the accuracy of compressor disk thermal analysis.

[0067] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. The software module may reside in a RAM memory, a flash memory, a ROM memory, an EPROM memory, an EEPROM memory, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to a processor so that the processor can read and write information from / to the storage medium. In an alternative, a storage medium may be integrated into a processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In an alternative, the processor and the storage medium may reside in a user terminal as discrete components.

[0068] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented as a computer program product in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. Disk and disc as used herein include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0069] It should be understood that "along" a certain direction mentioned in the text means that there is at least a component in the direction, preferably, the angle with the direction is within 10°, and more preferably, the angle is within 5°.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for calculating the compressor disk flow thermal coupling temperature, characterized in that: The steps include: Obtain the fluid flow analysis results in the compressor disc cavity; According to the analysis result, the compressor disc cavity is divided into a first cavity and a second cavity, the first cavity is located radially outside the second cavity, and the fluid flow state in the first cavity is different from the fluid flow state in the second cavity; Simplifying the temperature inside the first cavity into a cavity temperature node, considering the heat exchange between the cavity temperature node and the wall of the compressor disc cavity, and obtaining the temperature of the cavity temperature node and the first cavity wall node; The temperature inside the second cavity is simplified to a heat flow line that exchanges heat with the wall of the compressor disc cavity, and a heat balance equation of the heat flow line is constructed. The temperature of the second cavity wall node is obtained according to the heat balance equation.

2. The compressor disk flow thermal coupling temperature calculation method according to claim 1, characterized in that: The flow of fluid in the first cavity is dominated by centrifugal force, and the flow of fluid in the second cavity is dominated by inertial force.

3. The compressor disk flow thermal coupling temperature calculation method according to claim 1, characterized in that: Considering the heat exchange between the cavity temperature node and the wall of the compressor disc cavity, a group of heat balance equations in the first cavity is obtained, and the temperatures of the cavity temperature node and the first cavity wall node are obtained by jointly solving the group of heat balance equations.

4. The compressor disk flow thermal coupling temperature calculation method according to claim 3, characterized in that: The heat balance equations include the following formulas (1) to (6): ∑h i A i (T wi -T f )+H in -H out =0 (1); T out =T f (5); Among them, T wi is the first cavity wall node temperature, T f is the temperature of the first cavity temperature node, H in is the enthalpy of the axial throughflow into the first cavity, H out is the enthalpy of the axial throughflow leaving the first cavity and entering the disk core, is the flow rate entering the first cavity, is the constant pressure specific heat capacity of the gas entering the first cavity, T in is the temperature of the gas entering the first cavity, is the flow leaving the first chamber, is the specific heat capacity of the gas leaving the first chamber at constant pressure, T out is the temperature of the gas leaving the first chamber, h i is the local heat transfer coefficient, A i is the local heat exchange area, T ni is the internal temperature of the first cavity wall, λ is the thermal conductivity, q λ is the heat flux density parallel to the wall of the first cavity.

5. The compressor disk flow thermal coupling temperature calculation method according to claim 1, characterized in that: The heat balance equation of the heat flow line is as follows (7): Among them, T w is the second cavity wall temperature, T fn is the local air flow temperature, h is the local heat transfer coefficient, A is the local heat transfer area, is the air mass flow rate, C p is the specific heat of the gas at constant pressure.

6. The compressor disk flow-heat coupling temperature calculation method according to claim 5, characterized in that: The temperature of the second cavity wall node is obtained according to the heat balance equation and the heat balance equation of the metal surface node. The heat balance equation of the metal surface node is as follows (8): Among them, T ni is the internal temperature of the second cavity wall, T wi is the second cavity wall node temperature, λ is the thermal conductivity, q λ is the heat flux density parallel to the wall of the first cavity.

7. The compressor disk flow thermal coupling temperature calculation method according to claim 1, characterized in that: Computational fluid dynamics simulation software is used to analyze the fluid flow in the compressor disc cavity to obtain the analysis results of the fluid flow in the compressor disc cavity.

8. A readable storage medium, characterized in that: Computer instructions are stored thereon, and when the computer instructions are executed by a processor, the steps of the compressor disk flow-heat coupling temperature calculation method according to any one of claims 1 to 7 are implemented.

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