Design of a comprehensive cooling efficiency test bench for turbine blades and cooling verification method

Abstract

The present invention discloses a method for designing and cooling verification of a comprehensive cooling efficiency test bench for turbine blades, comprising the following steps: constructing a test bench geometric model, meshing the test bench geometric model and performing numerical calculations of flow and heat exchange; optimizing the internal cooling channels of the test bench geometric model based on the numerical calculation results; performing numerical calculations of flow and heat exchange on the high-temperature heat exchange concentration area of ​​the test bench geometric model again, and continuing to optimize the test bench geometric model based on the latest numerical calculation results; constructing the test bench based on the optimized test bench geometric model, and performing physical experiments on the constructed test bench to complete cooling verification. The calculation and experimental methods of the present invention can effectively solve the problem of overheating of the test bench in the comprehensive cooling efficiency experiment of turbine blades, and the designed test bench has strong adaptability to turbine blade test pieces with various geometric shapes and cooling structures, and can provide effective assistance for the comprehensive cooling efficiency experiment of turbine blades.

Description

Technical Field

[0001] The invention belongs to the technical field of turbine blade comprehensive cooling effect experimental measurement, and in particular relates to a turbine blade comprehensive cooling effect experimental platform design and a cooling verification method. Background Art

[0002] As one of the main working parts in a gas turbine engine, the turbine is located downstream of the combustion chamber. The working fluid accelerates and expands in the convergent channels of the stationary blades and the moving blades, converting the internal energy into mechanical energy. In the moving blade channel, the high-temperature and high-speed airflow impacts the blades and outputs shaft work. The turbine blades of modern aircraft engines need to work continuously at a speed of more than 10,000 revolutions per minute in a mainstream gas environment of about 1700K. The inertial centrifugal force and aerodynamic load brought by the high transmission speed pose a great challenge to the mechanical properties of the material. In order to ensure the smooth and efficient operation of the engine and a long service life, thermal protection and testing of gas turbine engine turbine blades are particularly important.

[0003] The turbine blade comprehensive cooling efficiency test bench is currently the preferred technology for evaluating the comprehensive cooling efficiency of turbine blades. Its basic principle is to place the turbine blade test piece in the test bench, introduce high-temperature combustion gas into the flow channel of the test bench, and make the high-temperature combustion gas impact the turbine blade test piece at a temperature, pressure, and speed close to the actual operating conditions. The temperature of each position in the turbine blade is measured using a temperature measuring device embedded in the test piece, so as to approximately obtain the temperature distribution of the metal area of ​​the blade under actual operating conditions and evaluate the comprehensive cooling efficiency.

[0004] At present, various high-efficiency cooling methods are widely used in aircraft engine turbine blades. Designing a turbine blade comprehensive cooling efficiency test bench for experimental research and comprehensive cooling efficiency evaluation of blade models with different cooling designs is of great significance for optimizing the cooling structure.

[0005] At present, due to the continuous increase in the actual operating temperature of aircraft engine turbine blades, in order to simulate the actual working conditions, the gas temperature in the test bench is also continuously increased. However, due to the limited high temperature resistance of the test bench material, the test bench components may be damaged due to the decrease in the mechanical properties of the material at high temperature and the vibration accompanying the experiment during the experiment, which will have an adverse effect on the experiment. This problem also has a great obstacle to the comprehensive cooling effect experiment of turbine blades under actual working conditions. Therefore, it is urgent to propose a turbine blade comprehensive cooling effect test bench design and cooling verification method to solve the problem that the test bench is difficult to withstand high temperature test conditions in high temperature and high pressure tests. Summary of the invention

[0006] The purpose of the present invention is to provide a turbine blade comprehensive cooling efficiency test bench design and cooling verification method to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides a turbine blade comprehensive cooling efficiency test bench design and cooling verification method, comprising the following steps:

[0008] Constructing a test bench geometric model, and performing mesh generation and flow and heat transfer numerical calculations on the test bench geometric model;

[0009] Optimizing the internal cooling channel of the test bench geometric model based on the numerical calculation results;

[0010] Performing flow heat transfer numerical calculation again on the high-temperature heat transfer concentrated area of ​​the test bench geometric model, and continuing to optimize the test bench geometric model based on the latest numerical calculation results;

[0011] The test bench is built based on the optimized test bench geometric model, and the cooling verification is completed through physical experiments on the built test bench.

[0012] Optionally, the constructed test bench includes: a front transition section, an air intake section, a test section and an exhaust section; the front end of the front transition section is connected to a high-temperature gas source, the rear end of the front transition section is connected to the front end of the air intake section via a flange, the rear end of the air intake section is connected to the front end of the test section via a flange, the rear end of the test section is connected to the front end of the exhaust section via a flange, and the rear end of the exhaust section is connected to a gas collection and circulation device.

[0013] Optionally, a turbine blade test piece is fixed in a middle slot of the test section by a tenon, and a lower portion of the turbine blade test piece is connected to a cold air source.

[0014] Optionally, the test section is provided with a foil blade, a cooling water jacket, a thermal insulation ceramic and a turbine blade test piece base and a slot.

[0015] Optionally, an observation window structure, a cooling water jacket and thermal insulation ceramics are provided at the rear end of the air intake section.

[0016] Optionally, flanges in the front transition section, the air intake section, the test section and the exhaust section are provided with water cooling channels, and the water cooling channels are connected to an external water supply device.

[0017] Optionally, the process of conducting a physical experiment on the constructed test bench includes: the high-temperature combustion gas generated by the high-temperature gas source enters the test bench from the front transfer section, flows through the air intake section and then enters the test section, and exchanges heat with the turbine blade test piece fixed on the test section, and then the high-temperature combustion gas flows through the exhaust section and enters the combustion gas collection and circulation device; a temperature sensor is set in the test bench to collect the temperature signal of the high-temperature combustion gas during the circulation process of the test bench, and transmits it to the computer for verification.

[0018] The technical effects of the present invention are:

[0019] The calculation and experimental methods of the present invention can effectively solve the problem of overheating of the test bench in the comprehensive cooling efficiency experiment of turbine blades, and the designed test bench has strong adaptability to turbine blade test pieces with various geometric shapes and cooling structures, which can provide effective assistance for the comprehensive cooling efficiency experiment of turbine blades, and then the comprehensive cooling efficiency of the blades in actual working conditions can be more accurately evaluated through the test results of the test bench. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0021] Figure 1 A flow chart of a method for designing a comprehensive cooling efficiency test bench for turbine blades and for cooling verification in an embodiment of the present invention;

[0022] Figure 2 It is a schematic diagram of numerical calculation results of key heat exchange area verification in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of a complete experimental platform structure in an embodiment of the present invention;

[0024] Figure 4 It is an isometric view of the test bench in the embodiment of the present invention;

[0025] Among them, 1-high temperature gas source, 2-front transfer section, 3-air intake section, 4-test section, 5-turbine blade test piece, 6-cold air source, 7-exhaust section, 8-gas collection and circulation device, 9-external water supply equipment. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0027] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0028] Embodiment 1

[0029] like Figure 1-4 As shown, this embodiment provides a turbine blade comprehensive cooling efficiency test bench design and cooling verification method, including the following steps:

[0030] Step 1: Use 3D mechanical modeling software to perform preliminary design and geometric modeling of the test bench. In the modeling, first consider the segmentation of the test bench in the design, and determine the length of the test section and the flow channel size according to the size of the test piece. After determining the size of the test section, further determine the flow channel size and geometric parameters of the intake section and exhaust section according to the flow channel size, so that the flow channels of the test bench before and after the test section match the flow channel size of the test section, and ensure that the airflow is fully developed before entering the test section. After designing and modeling the main channel, model and design other areas of the test bench. The test section considers the arrangement of the turbine blade test pieces and the blade cooling air supply channel in the cooling efficiency experiment, the front transition section considers the interface connection with the air supply device, and the intake section and the exhaust section consider the geometric configuration of the internal gas channel and the arrangement of the observation window;

[0031] Step 2: Use commercial software to mesh the established test bench geometry model and perform numerical calculations on the flow and heat transfer. First, mesh the geometry model of the test bench, and perform mesh quality inspection and mesh independence verification on the computational mesh. Then, import the computational mesh into the numerical calculation software, input boundary conditions and perform calculation settings according to the design conditions of the test bench, and obtain the numerical simulation results of the test bench.

[0032] Step 3: Optimize the internal cooling channels of the test bench based on the numerical calculation results. Post-process the numerical simulation calculation results of the test bench to analyze the internal flow characteristics and the temperature distribution of the test bench. Improve the layout of the water cooling channels and increase the cooling water flow in areas with high temperature risks; improve the flow channel layout and optimize the flow field in areas where flow is congested;

[0033] Step 4: Perform numerical simulation calculations on the high-temperature heat exchange concentrated area found in step 3, establish an improved test bench model after iterative optimization, and perform numerical calculation verification. The process is the same as that described in step 2 until the numerical calculation results of the test bench model meet the design requirements and material properties;

[0034] Step 5: Build the test bench according to the results of numerical calculation and verification, arrange temperature sensors in key areas, connect the high-temperature gas source and cooling water circulation system to conduct physical experiment verification on the test bench, and continuously increase the gas flow and temperature in the process until the comprehensive cooling effect achieves the maximum test condition and no thermal damage occurs. The test bench completes the thermal design and verification;

[0035] In this embodiment, the test bench is firstly designed and geometrically modeled; secondly, the flow and heat transfer numerical calculations are performed on the established test bench geometric model, and the internal cooling channels of the test bench are optimized according to the numerical calculation results, and the numerical calculations are re-checked for the high-temperature heat exchange concentrated area; finally, the test bench is built according to the numerical calculation optimization results, and physical experiments are carried out for verification to meet the test bench design requirements.

[0036] To further optimize the plan, in step one, it is necessary to consider that the flanges and flow channel walls in the air intake section, test section, and exhaust section are all equipped with water cooling channels to cool the metal materials during the experiment, so that the test bench has the characteristics of high temperature resistance and high strength. At the same time, cooling water jackets and thermal insulation ceramics are installed at the end of the air intake section and the test section to reduce the metal temperature in the heat exchange concentrated area.

[0037] To further optimize the solution, in step 2, it is necessary to focus on whether there is obvious temperature over-limit in the heat exchange concentrated area, and at the same time pay attention to whether the temperature distribution of the components is uniform, so as to avoid the situation where the uneven temperature distribution causes thermal stress to damage the components;

[0038] To further optimize the plan, in step four, in order to reduce the amount of calculation, separate models are established for different high-temperature concentrated areas and boundary conditions are given to simplify the calculation. Optimization and calculation are repeated based on the calculation results, and then numerical calculations are performed on the complete test bench model again to verify the thermal protection situation.

[0039] To further optimize the scheme, in step five, the complete test bench includes a high-temperature gas source 1, a front transfer section 2, an air intake section 3, a test section 4, a turbine blade test piece 5, a cold air source 6, an exhaust section 7, a gas collection and circulation device 8, and an external water supply device 9. Among them, the front end of the front transfer section 2 is connected to the high-temperature gas source 1, and the rear end is connected to the front end of the air intake section 3 through a flange; the front and rear ends of the test section 4 are respectively connected to the air intake section 3 and the exhaust section 7 through flanges; the turbine blade test piece 5 is fixed in the middle slot of the test section 4 through a tenon, and the lower part is connected to the cold air source 6; the rear end of the exhaust section 7 is connected to the gas collection and circulation device 8; each component of the test bench is provided with a water cooling structure, and the water cooling channel is connected to the external water supply device 9.

[0040] When the actual experiment is carried out, the high-temperature combustion gas generated by the high-temperature gas source 1 enters the test bench from the front transfer section 2, flows through the air intake section 3 and then enters the test section 4, deflects and expands in the blade grid, and exchanges heat with the turbine blade test piece 5 fixed on the test section 4, and then the high-temperature combustion gas flows through the exhaust section 7 and enters the combustion gas collection and circulation device 8; before the experiment, temperature sensors need to be pre-buried in the key monitoring area of ​​the test bench to obtain the temperature.

[0041] The wall geometry and flow field angles of the internal gas flow passage in the test bench that need to be considered in the design simulate the internal flow field of the aircraft engine, and foil blades are set in the test section 4 to make the high-temperature gas flow conditions in the test section 4 close to the flow conditions in the blade cascade in actual working conditions.

[0042] The design needs to consider that the end of the air inlet section 3 and the test section 4 are equipped with cooling water jackets and thermal insulation ceramics to reduce the metal temperature in the heat exchange concentrated area.

[0043] The design needs to consider setting up a turbine blade test piece base and slot in the test section 4, so that the turbine blade test piece can be replaced according to different experimental objects.

[0044] The design needs to consider that an observation window structure is provided at the end of the air intake section 3, and the test conditions in the test section can be observed through the glass observation window during the experiment.

[0045] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A turbine blade comprehensive cooling efficiency test bench design and cooling verification method, characterized in that: The following steps are involved: Constructing a test bench geometric model, and performing mesh generation and flow and heat transfer numerical calculations on the test bench geometric model; Optimizing the internal cooling channel of the test bench geometric model based on the numerical calculation results; Performing flow heat transfer numerical calculation again on the high-temperature heat transfer concentrated area of ​​the test bench geometric model, and continuing to optimize the test bench geometric model based on the latest numerical calculation results; The test bench is built based on the optimized test bench geometry model, and the cooling verification is completed by conducting physical experiments on the built test bench; The constructed test bench comprises: a front transfer section (2), an air intake section (3), a test section (4) and an exhaust section (7); the front end of the front transfer section (2) is connected to the high-temperature gas source (1), the rear end of the front transfer section (2) is connected to the front end of the air intake section (3) via a flange, the rear end of the air intake section (3) is connected to the front end of the test section (4) via a flange, the rear end of the test section (4) is connected to the front end of the exhaust section (7) via a flange, and the rear end of the exhaust section (7) is connected to a gas collection and circulation device (8); The test section (4) is provided with a foil blade, a cooling water jacket, a heat-insulating ceramic and a turbine blade test piece base and a slot; The flanges in the front transfer section (2), the air intake section (3), the test section (4) and the exhaust section (7) are provided with water cooling channels, and the water cooling channels are connected to an external water supply device (9); A turbine blade test piece (5) is fixed in a middle slot of the test section (4) by means of a tenon, and a lower portion of the turbine blade test piece (5) is connected to a cold air source (6); An observation window structure, a cooling water jacket and heat-insulating ceramics are arranged at the rear end of the air intake section (3); The process of conducting a physical experiment on the constructed test bench includes: the high-temperature combustion gas generated by the high-temperature gas source (1) enters the test bench from the front transfer section (2), flows through the air intake section (3) and then enters the test section (4), and exchanges heat with the turbine blade test piece (5) fixed on the test section (4), and then the high-temperature combustion gas flows through the exhaust section (7) and enters the combustion gas collection and circulation device (8); a temperature sensor is arranged in the test bench to collect the temperature signal of the high-temperature combustion gas during the circulation process of the test bench, and transmits it to a computer for verification.

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