Aero-engine nacelle accessory thermal environment equivalent test regulation method

Abstract

The application discloses an aero-engine nacelle component thermal environment equivalent test regulation method and belongs to the technical field of aero-engine nacelle thermal management. In view of the problems of high test cost of a full-ring nacelle test and simulation distortion of a thermal environment of a simulation simplified test device, the application establishes an equivalent mapping relationship between a real ring-shaped test device and a simulation test device, selects a nacelle temperature skin temperature, an air inlet flow rate and air temperature under a full-ring working condition as key influence variables, takes a nacelle temperature of the equivalent test device as a compensation variable, regulates the nacelle temperature when the variable conditions are consistent, compensates for the flow field and temperature field deviation caused by geometric differences, guarantees the equivalent effect of the component surface temperature, and fits to obtain a regulation relationship for guiding the regulation of a temperature control boundary of the equivalent test. The application greatly reduces test energy consumption and manufacturing cost, improves the simulation precision of the equivalent test, and provides a scientific and reliable regulation method for aero-engine nacelle component heat exchange performance evaluation and regulation.

Description

Technical Field

[0001] This invention relates to thermal management of aero-engine nacelles, specifically to a method for equivalent test control of thermal environment of aero-engine nacelle components. Background Technology

[0002] With the continuous improvement of the thrust-to-weight ratio of aero engines, the thermal load on the engine core is increasing, and the thermal environment inside the nacelle is becoming extremely harsh. The nacelle houses a large number of components, which are subjected not only to convective heat transfer from the high-temperature airflow during operation, but also to significant thermal radiation from the high-temperature casing and skin. The temperature distribution of these components directly affects their operational reliability and service life, necessitating experimental research to study their heat transfer performance and the effectiveness of their thermal protection design.

[0003] Currently, the industry commonly uses full-ring cabin testing, which offers high reliability. However, full-ring test specimens are geometrically enormous, resulting in high manufacturing costs and long lead times. The required air supply flow and heating power also lead to high energy consumption. Existing simplified equivalent test specimens directly apply full-ring operating condition boundary conditions, ignoring the heat transfer coefficient shift caused by geometric differences. This results in significant deviations between the temperature distribution of components and actual operating conditions, making it difficult for test data to effectively guide real-world environmental simulations.

[0004] Therefore, finding a scientific method to dynamically control the thermal boundary of the equivalent simulation tester and make it more accurately simulate the real thermal environment of the entire ring is a key technical problem that urgently needs to be solved in the field of aero-engine thermal management. Summary of the Invention

[0005] The purpose of this invention is to provide a method for controlling the temperature field of an equivalent tester. By establishing a compensation mathematical model, the simulation tester can achieve equivalence to the real working conditions of the entire ring. This solves the technical problem that the cost of full-ring model testing is too high in the thermal testing of existing aero-engine nacelle accessories, while conventional rectangular simplified models suffer from distortion of thermal environment simulation and poor equivalence due to geometric differences.

[0006] The specific technical solution of this invention is as follows:

[0007] A method for controlling the equivalent thermal environment of aircraft engine nacelles and accessories during testing includes the following steps:

[0008] S1. Construct an equivalent feature model: Design a simulation tester based on the full-ring tester, keeping the geometric shape, feature size, relative distance to the cabin wall, and relative distance between the components consistent in both models;

[0009] S2. Determine the key influencing variables of the thermal environment: Select the casing temperature, skin temperature, air inlet velocity, and air inlet temperature under the full-ring working condition as key influencing variables, and select the casing temperature of the equivalent test apparatus as the equivalent compensation variable;

[0010] S3. Multi-condition sampling: Perform variable-condition tests on the full-ring model to obtain the temperature distribution of each surface of the corresponding components, and test the equivalent tester under the same conditions.

[0011] S4. Equivalent control based on the control variable method: In the simulation tester, keep the key influencing variables of the temperature field consistent, and monitor the average temperature of each surface of the components by adjusting the casing temperature of the simulation tester.

[0012] S5. Establish equivalence judgment criteria: When the relative temperature difference between the internal temperature distribution of the simulated tester and the real ring tester is less than ±4%, the thermal environment of the simulated tester is determined to be equivalent to that of the full ring tester, and the corresponding casing temperature of the simulated tester is recorded.

[0013] S6. Construction of performance test relationship: Based on the casing temperature, skin temperature, air inlet flow rate, air inlet temperature and corresponding casing temperature of the simulation tester under full-ring operating conditions, a fitting dataset is established. Using the multivariate nonlinear regression method, the control relationship used to guide the test is fitted.

[0014] S7. Closed-loop control in real test: During the equivalent simulator test, the target full-loop operating condition parameters are input, and the casing control temperature value of the equivalent thermal environment of the simulator under the corresponding operating condition is automatically calculated through the control relationship. The test is carried out according to the casing control temperature.

[0015] Preferably, in step S1, the simulation tester is a rectangular tester. The inner cavity height of the rectangular tester is set to the difference between the inner and outer radii of the full-ring nacelle, and the width is set to a set ratio of the corresponding arc length of the full-ring nacelle, so as to eliminate the interference of the sidewall effect on the core flow field. The main body of the tester is made of high-temperature resistant stainless steel. The accessory to be tested is located at the center of the cavity, and its distance relative to the bottom casing wall and the top skin wall is strictly equivalent to the radial position in the actual full-ring working condition. The size of the accessory is consistent with that of the full-ring working condition.

[0016] Preferably, in step S3, a straight and stable flow section with an aspect ratio of not less than 10 is connected in front of the tester; the gas supply guarantee system adjusts the flow rate entering the test section through a mass flow controller, and at the same time, it provides real-time feedback and adjusts the inlet gas temperature through a pre-heating temperature acquisition device; all gas flow parameters are monitored in real time through a data acquisition system arranged in front of the inlet section.

[0017] Preferably, in step S3, patch or embedded thermocouples are arranged in all directions on the surface of the attachment model to monitor the surface temperature of each attachment under the influence of the windward stagnation zone, the side shear flow zone, the leeward recirculation zone, and the radiation-sensitive zone near the skin.

[0018] Both the casing and skin of the full-ring tester and the simulation tester are divided into multiple independent temperature control zones. Each zone is equipped with a thermocouple as a feedback sensor, and the heating power is adjusted by a power controller to control the wall temperature.

[0019] Preferably, in step S5, the selection rules for surface temperature measuring points of the attachments include: prioritizing the top surface of the attachments as the core monitoring area; avoiding areas where attachments block each other; and setting temperature measuring points in areas where the flow is fully developed or the streamlines are straight.

[0020] Preferably, in step S5, the specific process of temperature control is as follows:

[0021] Initially, the temperature of the rectangular simulation test chamber casing is set equal to the temperature of the ring test chamber casing, i.e. Record the temperature of each side wall of the attachment within the simulator at this time, and calculate the absolute temperature difference between the attachments in the two models. Relative temperature difference Local thermal sensitivity coefficient of casing-assembly accessories , The calculation is as follows:

[0022] Absolute temperature difference: ;

[0023] Relative temperature difference: ;

[0024] Local thermal sensitivity coefficient of casing-assemblies: ;

[0025] like Then record the temperature of the corresponding rectangular simulator housing and end the temperature control cycle;

[0026] like and ,but ;

[0027] like and ,but ;

[0028] In the formula, The preset temperature disturbance is set to 5-10K. At this time, the temperature of the simulator housing is set to 0. The temperature control cycle is entered again until the relative temperature difference between the components in the two models reaches ±4%. The corresponding simulator housing temperature is recorded, and the cycle ends.

[0029] Preferably, in step S6, the fitted regulation relationship is as follows:

[0030] ;

[0031] in, The equivalent test chamber temperature, The temperature of the ring tester casing. The temperature of the ring tester skin is Re, and Re is the Reynolds number at the air inlet. The air inlet temperature. , , This is a correction factor.

[0032] Preferably, the correction coefficient The value is 0.0246. The value is 3.10. The value is 4.15.

[0033] The beneficial effects of this invention are as follows:

[0034] The present invention discloses an equivalent test control method for thermal environment of aircraft engine nacelle accessories. It decouples the complex temperature field compensation mechanism. Unlike traditional methods that pursue complete physical boundary equivalence, it acknowledges the difference in heat transfer coefficient caused by geometric differences. It uses the idea of ​​temperature compensation for flow field loss and uses the casing temperature for thermal regulation to reduce the heat flow deviation caused by geometric differences.

[0035] This invention transforms the differences in the actual accessory temperature field and flow field environment into quantifiable temperature control by using a highly accurate equivalent temperature difference criterion. It establishes a multivariate function model covering heat conduction, convection, and radiation, and uses the simulated test chamber temperature as the core adjustment factor to help researchers conduct equivalent accessory heat transfer performance test studies in a simple and operable manner.

[0036] Meanwhile, this invention significantly reduces the manufacturing cost and cycle time of the test apparatus, and greatly reduces the airflow requirements and heating energy requirements for simulating the real thermal environment during the test research, thus greatly improving the economy and flexibility of the test. Furthermore, the relational fitting process established by this method has universality and can be extended to equivalent studies of cabins with different models and accessory layouts.

[0037] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the experimental system on which the present invention is based;

[0039] Figure 2 This is a schematic diagram of the ring test apparatus on which the present invention is based;

[0040] Figure 3This is a cloud map showing the flow field and temperature field distribution at the central cross-section of the annular tester of the present invention;

[0041] Figure 4 This is a cloud map showing the flow field and temperature field distribution at the central section of the rectangular tester of the present invention.

[0042] Figure 5 This is a schematic diagram of the rectangular simulation test apparatus on which the present invention is based;

[0043] Figure 6 This is a schematic diagram of the equivalent simulator casing temperature control process of the present invention.

[0044] Figure descriptions: 1. Casing wall; 2. Skin wall; 3. Accessory assembly; 4. Heating lamp; 5. Equivalent tester skin wall; 6. Equivalent tester controlled casing wall. Detailed Implementation

[0045] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] like Figures 1-6 As shown in the figure, this embodiment provides a method for controlling the equivalent test of the thermal environment of aircraft engine nacelle accessories. First, an equivalent characteristic model is constructed. During the design process, factors such as airflow velocity, flow distribution uniformity, local pressure drop, structural strength, sealing reliability and processing feasibility are comprehensively considered to ensure that the equivalent test device has stable, uniform and safe test performance under working conditions.

[0047] In this embodiment, a rectangular tester is used as the simulation tester. Its internal cavity size is strictly determined according to the size of the full-ring tester. The height of the simulation tester is set to the difference between the inner and outer radii of the full-ring nacelle, and the width is set to a certain proportion of the corresponding arc length of the full-ring nacelle, so as to eliminate the interference of the sidewall effect on the core flow field.

[0048] The main body of the test apparatus is made of high-temperature resistant stainless steel. The component to be tested is arranged in the center of the cavity. Its distance relative to the bottom casing wall and the top skin wall is strictly equivalent to the radial position in the actual working condition of the full ring. At the same time, the geometric shape, characteristic dimensions, and relative distance between the components are consistent with the working condition of the full ring.

[0049] After completing the construction of the equivalent characteristic model, the key influencing variables of the thermal environment were determined. The casing temperature, skin temperature, air inlet velocity, and air inlet temperature under the full-ring working condition were selected as the key influencing variables of the thermal environment. At the same time, the casing temperature of the equivalent test device was selected as the equivalent compensation variable. The deviation of flow field and heat transfer characteristics caused by the difference in geometric structure was compensated by adjusting the variables.

[0050] Subsequently, multi-condition sampling tests were conducted, and variable-condition tests were performed on the full-ring tester to obtain the temperature distribution of each surface of the components under corresponding conditions. Simultaneous tests were then carried out on the equivalent tester under the same conditions. During the tests, a straight, stable flow section with a length-to-diameter ratio of not less than 10 was connected in front of the tester to reduce the flow influence from the upstream pipeline and ensure a uniform velocity distribution of the airflow entering the test area. The air supply guarantee system adjusted the flow velocity entering the test section through a mass flow controller, and simultaneously provided real-time feedback and adjusted the inlet airflow temperature through a pre-mounted temperature acquisition device. All airflow parameters were monitored in real-time by a data acquisition system located in front of the inlet section.

[0051] Patches or embedded thermocouples are arranged on the surfaces of the assembly model in all directions to monitor the temperature of each surface of the assembly under the influence of the stagnant zone on the windward side, the shear flow zone on the side, the recirculation zone on the leeward side, and the radiation-sensitive zone near the skin. To achieve precise control and acquisition of the test equipment temperature, a wall heating system with independent control in different zones is designed. A multi-segment independent electric heating method is adopted, and the casing and skin walls of the full-ring test equipment and the simulation test equipment are divided into 4 independent temperature control zones. Multiple sets of K-type armored thermocouples are embedded in each zone as feedback sensors. The heating power is adjusted by a power controller to ensure that the wall temperature can quickly reach the required temperature.

[0052] After completing multi-condition sampling, equivalent regulation is carried out based on the control variable method. In the simulation tester, the key temperature field variables such as skin temperature, air inlet velocity, and air inlet temperature are kept consistent with the full-ring condition. Only the casing temperature of the simulation tester is adjusted, and the average temperature of each surface of the components is continuously monitored to offset the deviation of flow field and heat transfer characteristics caused by geometric differences.

[0053] During the control process, the equivalent effect of the thermal environment is judged according to the equivalence judgment criterion. When setting the surface temperature measurement point of the attachment, the top surface of the attachment is selected as the core monitoring area. Taking advantage of its characteristics of being directly facing the high temperature wall and being the most affected by thermal radiation impact and being in the heat plume gathering area, the response to changes in the boundary environment is captured to the maximum extent.

[0054] Secondly, the selection of temperature measurement points avoids areas where components block each other, in order to eliminate atypical interferences caused by local backflow and radiation shielding. Simultaneously, temperature measurement points are placed in areas where flow is sufficiently developed or streamlines are as straight as possible to improve the repeatability and accuracy of the test with relatively stable heat transfer characteristics. When the relative temperature difference between the component temperature distribution in the simulated test chamber and the actual toroidal test chamber is less than ±4%, the thermal environment of the simulated test chamber is deemed equivalent to that of the toroidal test chamber, and the casing temperature of the corresponding simulated test chamber is recorded.

[0055] The specific temperature control process is as follows: First, set the temperature of the rectangular simulator housing to be equal to the temperature of the ring tester housing, i.e. Record the temperature of each side wall of the attachment within the simulator at this time, and calculate the absolute temperature difference between the attachments in the two models. Relative temperature difference Local thermal sensitivity coefficient of casing-assembly accessories The initial sensitivity coefficient .

[0056] The formulas for calculating each parameter are as follows:

[0057] Absolute temperature difference: ;

[0058] Relative temperature difference: ;

[0059] Local thermal sensitivity coefficient of casing-assemblies: ;

[0060] If the calculated relative temperature difference Then, record the temperature of the corresponding rectangular simulator housing and end the temperature control cycle.

[0061] like >±4% and >0, then ;

[0062] like >±4% and <0, then ,

[0063] In the formula, The preset temperature disturbance is set to 5-10K. At this time, the temperature of the simulator housing is set to 0. The temperature control cycle is entered again until the relative temperature difference between the components in the two models reaches ±4%. The corresponding simulator housing temperature is recorded, and the cycle ends.

[0064] After obtaining the equivalent casing temperature under multiple operating conditions, a performance test relationship is constructed. The core control strategy of this method is to take the full-loop operating conditions as input and the equivalent test chamber control temperature value as output, and realize the equivalent control of the thermal environment of the accessories through the output equivalent test chamber temperature.

[0065] Based on the experimentally obtained full-ring casing temperature, skin temperature, air inlet Reynolds number, air inlet temperature, and corresponding casing temperature of the simulation test apparatus, a fitting dataset was established. Using a multivariate nonlinear regression method, the control relationship guiding the experiment was fitted and obtained. The control relationship is as follows:

[0066] ;

[0067] For the experimental simulator on which this invention is based, this control relationship can be written as:

[0068] ;

[0069] in, The equivalent test chamber temperature, The temperature of the ring tester casing. The temperature of the ring tester skin is Re, and Re is the Reynolds number at the air inlet. The air inlet temperature. , , The correction factor is used for the testing apparatus employed in this embodiment. The value is 0.0246. The value is 3.10. The value is 4.15.

[0070] After the relationship fitting is completed, the closed-loop control of the real test can be carried out. During the equivalent simulator test, the target full-loop operating condition parameters are input, and the casing control temperature value of the equivalent thermal environment of the aero-engine nacelle and accessories is automatically calculated through the equivalent test control relationship of the thermal environment of the aero-engine nacelle and accessories.

[0071] Based on the target operating conditions of the aero-engine, the original boundary parameters under the full-ring model are determined, including the target casing temperature, skin temperature, intake temperature, and intake Reynolds number. The above parameters are input into the control relationship, and the compensation temperature T' that should be set on the equivalent test chamber casing wall under the current operating conditions is automatically calculated through the control relationship of the equivalent thermal environment of the attachment. The test is carried out under the target operating conditions according to the calculated simulator casing temperature.

[0072] When the system reaches a stable thermal equilibrium state, the temperature of the accessory surface is recorded. The temperature data obtained at this time can be reliably regarded as the real temperature value in the entire nacelle environment, and its relative temperature difference with the real operating conditions in the entire nacelle can be guaranteed to be within ±4%.

[0073] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for controlling the equivalent thermal environment of aircraft engine nacelle accessories during testing, characterized in that, Includes the following steps: S1. Construct an equivalent feature model: Design a simulation tester based on the full-ring tester, keeping the geometric shape, feature size, relative distance to the cabin wall, and relative distance between the components consistent in both models; S2. Determine the key influencing variables of the thermal environment: Select the casing temperature, skin temperature, air inlet velocity, and air inlet temperature under the full-ring working condition as key influencing variables, and select the casing temperature of the equivalent test apparatus as the equivalent compensation variable; S3. Multi-condition sampling: Perform variable-condition tests on the full-ring model to obtain the temperature distribution of each surface of the corresponding components, and test the equivalent tester under the same conditions. S4. Equivalent control based on the control variable method: In the simulation tester, keep the key influencing variables of the temperature field consistent, and monitor the average temperature of each surface of the components by adjusting the casing temperature of the simulation tester. S5. Establish equivalence judgment criteria: When the relative temperature difference between the internal temperature distribution of the simulated tester and the real ring tester is less than ±4%, the thermal environment of the simulated tester is determined to be equivalent to that of the full ring tester, and the corresponding casing temperature of the simulated tester is recorded. S6. Construction of performance test relationship: Based on the casing temperature, skin temperature, air inlet flow rate, air inlet temperature and corresponding casing temperature of the simulation tester under full-ring operating conditions, a fitting dataset is established. Using the multivariate nonlinear regression method, the control relationship used to guide the test is fitted. S7. Closed-loop control in real test: During the equivalent simulator test, the target full-loop operating condition parameters are input, and the casing control temperature value of the equivalent thermal environment of the simulator under the corresponding operating condition is automatically calculated through the control relationship. The test is carried out according to the casing control temperature.

2. The method for controlling the equivalent thermal environment of aircraft engine nacelle components according to claim 1, characterized in that, In step S1, the simulation tester is a rectangular tester. The inner cavity height of the rectangular tester is set to the difference between the inner and outer radii of the full-ring nacelle, and the width is set to a set ratio of the corresponding arc length of the full-ring nacelle to eliminate the interference of the sidewall effect on the core flow field. The main body of the tester is made of high-temperature resistant stainless steel. The accessory to be tested is located at the center of the cavity, and its distance relative to the bottom casing wall and the top skin wall is strictly equivalent to the radial position in the actual full-ring working condition. The size of the accessory is consistent with that of the full-ring working condition.

3. The method for controlling the equivalent thermal environment of aircraft engine nacelle components according to claim 1, characterized in that, In step S3, a straight, stable flow section with an aspect ratio of not less than 10 is connected in front of the test apparatus; the gas supply guarantee system adjusts the flow rate entering the test section through a mass flow controller, and at the same time, it provides real-time feedback and adjusts the inlet gas temperature through a pre-heating temperature acquisition device; all gas flow parameters are monitored in real time through a data acquisition system arranged in front of the inlet section.

4. The method for controlling the equivalent thermal environment of aircraft engine nacelle components according to claim 1, characterized in that, In step S3, patch or embedded thermocouples are arranged on the surface of the attachment model in all directions to monitor the surface temperature of each attachment under the influence of the windward stagnation zone, the side shear flow zone, the leeward recirculation zone, and the radiation-sensitive zone near the skin. Both the casing and skin of the full-ring tester and the simulation tester are divided into multiple independent temperature control zones. Each zone is equipped with a thermocouple as a feedback sensor, and the heating power is adjusted by a power controller to control the wall temperature.

5. The method for controlling the equivalent thermal environment of aircraft engine nacelle components according to claim 1, characterized in that, In step S5, the selection rules for surface temperature measurement points of the attachments include: prioritizing the top surface of the attachments as the core monitoring area; avoiding areas where attachments block each other; and setting temperature measurement points in areas where the flow is fully developed or the streamlines are straight.

6. The method for controlling the equivalent thermal environment of aircraft engine nacelle components according to claim 1, characterized in that, In step S5, the specific process for temperature control is as follows: Initially, the temperature of the rectangular simulation test chamber casing is set equal to the temperature of the ring test chamber casing, i.e. Record the temperature of each side wall of the attachment within the simulator at this time, and calculate the absolute temperature difference between the attachments in the two models. Relative temperature difference Local thermal sensitivity coefficient of casing-assembly accessories , The calculation is as follows: Absolute temperature difference: ; Relative temperature difference: ; Local thermal sensitivity coefficient of casing-assemblies: ; like Then record the temperature of the corresponding rectangular simulator housing and end the temperature control cycle; like and ,but ; like and ,but ; In the formula, The preset temperature disturbance is set to 5-10K. At this time, the temperature of the simulator housing is set to 0. The temperature control cycle is entered again until the relative temperature difference between the components in the two models reaches ±4%. The corresponding simulator housing temperature is recorded, and the cycle ends.

7. The method for controlling the equivalent thermal environment of aircraft engine nacelle components according to claim 1, characterized in that, In step S6, the fitted regulation relationship is as follows: ； in, The equivalent test chamber temperature, The temperature of the ring tester casing. The temperature of the ring tester skin is Re, and Re is the Reynolds number at the air inlet. The air inlet temperature. , , This is a correction factor.

8. The method for controlling the equivalent thermal environment of aircraft engine nacelle components according to claim 7, characterized in that, The correction coefficient The value is 0.0246. The value is 3.

10. The value is 4.15.

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