Temperature control system and method for friction and wear testing machine of typical kinematic pairs of high-temperature aviation tail nozzle

Abstract

The present invention provides a temperature control system and method for a friction and wear testing machine for a typical kinematic pair of a high-temperature aviation tail nozzle, comprising a box-type insulation structure, a heating actuator, a heat dissipation actuator, a temperature sensor, a temperature controller, and a host computer. The temperature control process is divided into stages, and different control strategies are adopted in different stages. A self-tuning PID is used to control the heating actuator, and a traditional PID is used to control the heat dissipation actuator. Through fluid-heat transfer coupled finite element simulation, a spatiotemporal distribution model of the temperature field is established and analyzed, the characteristic temperature measurement points and the critical temperature of the heating process are determined, a multi-point temperature measurement temperature prediction method is developed, the power allocation weight is determined for each heating actuator, and the measurement and control accuracy of the temperature control module is improved. The present invention provides a stable 800-degree Celsius temperature condition for the test area of ​​the friction and wear testing machine, and can effectively avoid the influence of the high-temperature area on temperature-sensitive components such as sensors.

Description

Technical Field

[0001] The present invention relates to the technical field of friction and wear testing machines, and in particular to a temperature control system and method for a friction and wear testing machine for a typical kinematic pair of a high-temperature aviation tail nozzle. Background Art

[0002] The supersonic cruise and super maneuverability performance of the latest generation of advanced fighter jets require that the engine tail nozzle movement adjustment speed be greater than 30° / s. The movement adjustment mechanism is subjected to aerodynamic loads exceeding 10,000 Newtons and temperatures of nearly 1,000 degrees Celsius for a long time. In order to avoid the service performance degradation or even failure of key motion pairs of the movement adjustment mechanism during the design life cycle, thereby limiting the adjustment accuracy, response performance, life and reliability of the overall equipment system, and even causing major engineering disasters, it is urgent to clarify the tribological performance degradation mechanism of the moving parts and optimize the surface interface tribological design. However, there is no high-temperature and heavy-load simulated working condition tribological test system suitable for the research of aircraft tail nozzle movement adjustment mechanism at home and abroad, which cannot provide experimental support for the above research and restricts technological breakthroughs.

[0003] Among the existing friction and wear testing machines, the universal friction and wear testing machine is the most widely used. This type of testing machine can only test the friction and wear performance of the material level. It has limited loading forms, simple motion forms, and single temperature conditions. It is confined to a certain point, line, or surface of the material sample to perform specific reciprocating, rotational, and micro-motion movements. However, the actual motion mechanism has multiple components and moving pairs. A single part has multiple moving pairs, and multiple points of force are applied. In addition, the parts have tolerance matching characteristics, and the friction and heat generated by mutual movement are obvious. The material-level test and analysis conditions based on the universal friction and wear testing machine are too simplified, and the results obtained are significantly different from the friction and wear conditions of the moving pairs of the actual mechanism moving parts. It is only suitable for basic theoretical research and analysis.

[0004] To overcome the limitations of general-purpose material-grade friction and wear testing machines, a high-temperature, heavy-load friction and wear testing machine was designed for research on typical kinematic pairs in aircraft tail nozzle motion control mechanisms. Due to the harsh temperature conditions in the test area of ​​a high-temperature, heavy-load friction and wear testing machine, with extreme temperature gradients in some areas, the large number of sensors, and the significant impact of operating temperature on measurement accuracy, a high-precision, high-temperature control module was required for this machine, along with a corresponding temperature control method.

[0005] Patent document No. 200710052437 discloses a temperature control method for a high-temperature annular annealing furnace, which is achieved by configuring different furnace temperature regulator output parameters for different temperature conditions in combination with conventional PID control. However, the applicable scenarios are limited and the adaptive control capability is insufficient. Summary of the Invention

[0006] In view of the defects in the prior art, the purpose of the present invention is to provide a temperature control system and method for a friction and wear testing machine of a typical kinematic pair of a high-temperature aviation tail nozzle.

[0007] The temperature control system of the friction and wear testing machine for the typical kinematic pair of a high-temperature aviation tail nozzle provided by the present invention comprises: a box-type thermal insulation structure, a heating actuator, a heat dissipation actuator, a temperature sensor, a temperature controller and a host computer;

[0008] The heating actuator includes a U-shaped carbon silicon electric heating rod and a solid relay. The U-shaped carbon silicon electric heating rod is placed on one inner wall of the box-type thermal insulation structure, and the solid relay is placed on the opposite inner wall of the box-type thermal insulation structure, and is used to heat the interior of the box-type thermal insulation structure to a specified temperature.

[0009] The heat dissipation actuator is installed on the components of the motion mechanism outside the box-type thermal insulation structure, and uses the liquid cooling medium circulating inside to reduce the temperature of the components;

[0010] The temperature sensor includes a high-temperature area thermocouple and a low-temperature area thermocouple. The high-temperature area thermocouple is installed inside the box-type thermal insulation structure and is used to measure the temperature of a specific point. The low-temperature area thermocouple is installed on the sensor-containing component of the motion mechanism and is used to measure the temperature of the sensor area to compensate for sensor temperature drift.

[0011] The temperature controller is a memory-type PID controller that integrates signal input, signal output, and data panel display functions, and communicates with the host computer via RS485 protocol;

[0012] The host computer is an industrial control computer, which is used to connect the temperature controller to the test machine measurement and control software and control the heat dissipation actuator at the same time.

[0013] Preferably, the box-type thermal insulation structure comprises a box-type structure, thermal insulation material and an optical window;

[0014] The box-type structure is composed of 6 pieces of GH2747 high-temperature alloy steel, which are fixed to the test machine frame through the top and side surfaces. The box-type structure is embedded with thick zirconia ceramic fiberboard as an integrally installed thermal insulation material.

[0015] The front of the box-type insulation structure has a GH2747 high-temperature alloy steel plate embedded with a ceramic fiber composite insulation board. The overall design is a single door for installation and removal of test pieces.

[0016] Optical windows are installed on the GH2747 high-temperature alloy steel plate on the back of the box-type insulation structure and the embedded zirconia ceramic fiber plate. They are made of multiple layers of high-temperature resistant glass and serve to observe the working status of the fixture during the test and capture the motion image of the testing machine.

[0017] The bottom and sides of the box-type insulation structure are provided with slots for accommodating the motion mechanism of the testing machine. The outer surface of the box-type insulation structure is installed with high-temperature resistant guide rails and heat-insulating baffles. The heat-insulating baffles are fixedly connected to the motion mechanism of the testing machine. When the motion mechanism of the testing machine moves, the slots are shielded to reduce convection and radiation heat transfer.

[0018] Preferably, the number of the U-shaped carbon silicon electric heating rods is 8, which are connected to a solid relay in a star connection manner. The solid relay uses the weak current signal output by the temperature controller to control the on and off of the 380V power supply.

[0019] Preferably, the heat dissipation actuator includes a cooling water jacket, a liquid pipeline, a circulating pump, a radiator and a cooling fan, all of which are installed on the components of the motion mechanism outside the box-type insulation structure, and the internal circulating liquid cooling medium is used to lower the temperature of the components to reduce the temperature drift of the sensor in the motion mechanism.

[0020] Preferably, the high temperature area thermocouples are three S-type thermocouples installed inside the box-type insulation structure for measuring the temperature at specific points;

[0021] The low-temperature area thermocouples are three K-type thermocouples, which are respectively installed on the sensor-containing components in the motion mechanism and are used to measure the temperature of the sensor area to compensate for the sensor temperature drift.

[0022] According to the temperature control method for a typical kinematic pair friction and wear testing machine for a high-temperature aviation tail nozzle provided by the present invention, the average temperature of the internal environment of a box-type thermal insulation structure is used as the target temperature. Through fluid-heat transfer coupled finite element simulation, the temperature distribution at different target temperatures is analyzed, and a temperature distribution model of the box-type thermal insulation structure, the heating actuator, the heat dissipation actuator, and the test piece is established. The inner surface of the box-type thermal insulation structure is approximately divided into squares with a preset side length. The variation pattern of the average temperature in each square area with the target temperature is analyzed. The centroids of the three areas with the best linearity are taken as characteristic points to arrange thermocouples in the high-temperature area to measure the temperature of the characteristic points. The average temperature of the environment and the temperature of the test piece are predicted based on the summarized temperature variation pattern.

[0023] When obtaining the steady-state temperature field distribution of the box-type insulation structure, a U-shaped carbon-silicon electric heating rod was set as the volume heat source. A series of power combinations were set for the eight U-shaped carbon-silicon electric heating rods through the experimental design method, and steady-state heat transfer finite element calculations were performed. The power of the U-shaped carbon-silicon electric heating rod was used as input, and the average temperature of the test piece area in the calculation results was used as output. An approximate mapping relationship between the power of the eight U-shaped carbon-silicon electric heating rods and the average temperature of the test piece area in a specific power range was obtained, which served as the mathematical basis for temperature control.

[0024] Perform the following steps:

[0025] In the first working stage, the heating actuator works at full power and the heat dissipation actuator does not work, so that the internal ambient temperature of the box-type insulation structure quickly approaches the target value;

[0026] In the second working stage, the heating actuator and the heat dissipation actuator work simultaneously to make the internal ambient temperature of the box-type insulation structure reach the target value and converge;

[0027] In the third working stage, the heating actuator and the heat dissipation actuator work simultaneously to maintain a stable ambient temperature inside the box-type insulation structure, providing a stable working condition for the friction and wear test;

[0028] In the fourth working stage, the heat dissipation actuator works at full power and the heating actuator does not work, quickly reducing the internal temperature of the box-type insulation structure.

[0029] Preferably, a thermocouple in the high-temperature area is used to measure the temperature of the characteristic point. Based on the fluid-heat transfer coupled transient simulation, the spatiotemporal distribution of the temperature of the box-type insulation structure, the heating actuator, the heat dissipation actuator and the test piece in the first working stage is calculated, and the temperature of the characteristic temperature measurement point when the temperature sensitive area reaches the temperature threshold is determined, which is used as the starting temperature of the second heating stage.

[0030] Preferably, a multi-point temperature measurement and temperature prediction method is used to obtain the temperature distribution of the box-type insulation structure, heating actuator, heat dissipation actuator and test piece, and the correspondence between the thermocouple readings in the three high-temperature areas and the average temperature of the internal environment of the box-type insulation structure is obtained according to the temperature distribution law; the temperature controller uses the calculated average temperature of the internal environment of the box-type insulation structure as the control target, and uses low-frequency PWM to periodically control the on and off of the solid-state relay to control the average heating power of the U-shaped carbon silicon electric heating rod; in the second working stage and the third working stage, the temperature controller runs the self-tuning PID to control the PWM duty cycle to adjust the average heating power of the U-shaped carbon silicon electric heating rod, so as to control the internal environment temperature of the box-type insulation structure.

[0031] Preferably, in the third working stage, the temperature controller runs the self-tuning PID control PWM duty cycle to adjust the average heating power of the U-shaped carbon silicon electric heating rod. On this basis, the working power is weightedly distributed to the 8 U-shaped carbon silicon electric heating rods according to the approximate mapping relationship between the power of the U-shaped carbon silicon electric heating rod in a specific power range and the average temperature of the test piece area, so as to compensate for the uneven temperature distribution caused by the uneven thermal resistance distribution of the box-type insulation structure, reduce the temperature gradient inside the test area, and optimize the test conditions.

[0032] Preferably, in the second and third working stages, the host computer measures the temperature of the sensor installation area through the low-temperature area thermocouple, uses this as the target quantity of PID control, and uses traditional PID to control the speed of the circulation pump and the cooling fan in the heat dissipation actuator to ensure that the temperature of the motion mechanism sensor is stable at the set working temperature; in the fourth working stage, the circulation pump and the cooling fan in the heat dissipation actuator run at the high speed set by the system to quickly reduce the internal temperature of the box-type insulation structure;

[0033] The measurement values ​​of the motion mechanism sensor at different working temperatures were experimentally calibrated, and a cubic polynomial relationship was obtained by fitting. When recording the experimental data, the thermocouple readings in the low temperature area were used as the measured temperature data to correct the temperature drift of the motion mechanism sensor.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The present invention establishes and analyzes the spatiotemporal distribution model of the temperature field through fluid-heat transfer coupled finite element simulation, determines the characteristic temperature measurement points and the critical temperature of the heating process, develops a multi-point temperature measurement temperature prediction method, determines the power allocation weight for each heating actuator, and improves the measurement and control accuracy of the temperature control module;

[0036] (2) The present invention provides a stable temperature condition of 800 degrees Celsius for the test area of ​​the friction and wear testing machine, and can effectively avoid the influence of the high temperature area on temperature sensitive components such as sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0038] Figure 1a and Figure 1b Schematic diagram of the box-type insulation structure of the temperature control module;

[0039] Figure 2 This is the hardware architecture diagram of the temperature control module;

[0040] Figure 3 This is the control flow chart of the temperature control module;

[0041] Figure 4 Schematic diagram of heat transfer simulation results;

[0042] in:

[0043] Box-type insulation structure 1 Host computer 6 High temperature resistant guide rails 1-4 High temperature area thermocouple 4-1

[0044] Heating actuator 2 Box structure 1-1 Heat insulation baffle 1-5 Low temperature area thermocouple 4-2

[0045] Heat dissipation actuator 3 Insulation material 1-2 U-shaped carbon silicon electric heating rod 2-1

[0046] Temperature controller 5 Optical window 1-3 Cooling water jacket 3-1 DETAILED DESCRIPTION

[0047] The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several changes and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0048] Example

[0049] like Figure 2 The present invention provides a temperature control system for a typical motion pair friction and wear testing machine of a high-temperature aviation tail nozzle, comprising: a box-type insulation structure 1, a heating actuator 2, a heat dissipation actuator 3, a temperature sensor, a temperature controller 5 and a host computer 6.

[0050] like Figure 1a and Figure 1b The box-type insulation structure 1 consists of a box-type structure 1-1, insulation material 1-2, and an optical window 1-3. The box-type structure 1-1 is composed of six pieces of GH2747 high-temperature alloy steel and is fixed to the test machine frame via the top and side surfaces. The box-type structure 1-1 is embedded with thick, integrated zirconia ceramic fiberboard as insulation material 1-2. The GH2747 high-temperature alloy steel plate on the front of the box-type insulation structure 1 has a characteristic thickness of 14mm, and the embedded ceramic fiber composite insulation board has a characteristic thickness of 53mm. The overall design is a single-door for installing and removing test pieces. The GH2747 high-temperature alloy steel plate and the embedded zirconia ceramic fiberboard on the back of the box-type insulation structure 1 contain an optical window 1-3. The optical window 1-3 is constructed of multiple layers of high-temperature resistant glass with a characteristic total thickness of 50mm. The single layer of high-temperature resistant glass is 4mm thick, and there are five layers in total. Four layers of vacuum interlayer, 7.5mm thick, are used between the glass to observe the working status of the fixture during the test and capture images of the test machine's motion. The bottom and sides of the box-type insulation structure 1 are provided with slots for accommodating the moving mechanism of the testing machine. The outer surface of the box-type insulation structure is installed with high-temperature resistant guide rails 1-4 and heat-insulating baffles 1-5. The heat-insulating baffles 1-5 are fixedly connected to the moving mechanism of the testing machine. When the moving mechanism of the testing machine moves, the slots are shielded to reduce convection and radiation heat transfer.

[0051] The heating actuator 2 consists of eight U-shaped carbon silicon electric heating rods 2-1 and a solid-state relay, rated at 380V and 4kW. The U-shaped carbon silicon electric heating rods 2-1 are placed on one inner wall of the box-type insulation structure 1, and the solid-state relay is placed on the opposite inner wall of the box-type insulation structure 1. They heat the interior of the box-type insulation structure 1 to a specified temperature, providing extreme temperature conditions for friction and wear testing of typical moving pairs of aircraft tail nozzles. The eight U-shaped carbon silicon electric heating rods are connected to the solid-state relay in a star configuration. The solid-state relay uses the weak current signal output by the temperature controller 5 to control the on / off of the 380V power supply.

[0052] The heat dissipation actuator 3 consists of a cooling water jacket 3-1, liquid piping, a circulating pump, a radiator, and a cooling fan. The cooling water jacket 3-1 is mounted on the components of the motion mechanism outside the box-type insulation structure 1. The liquid cooling medium circulating within the jacket cools the components and reduces temperature drift of the sensors in the motion mechanism.

[0053] The temperature sensor consists of a high-temperature thermocouple 4-1 and a low-temperature thermocouple 4-2. The high-temperature thermocouples 4-1 are three S-type thermocouples installed inside the box-type insulation structure 1 to measure the temperature of specific points. The low-temperature thermocouples 4-2 are three K-type thermocouples installed on the sensor-containing components of the motion mechanism to measure the temperature of the sensor area to compensate for sensor temperature drift.

[0054] The temperature controller 5 is a memory-type PID regulator that integrates signal input, signal output, and data panel display functions, and communicates with the host computer via the RS485 protocol.

[0055] The host computer 6 is an industrial control computer, which is used to connect the temperature controller to the test machine measurement and control software and control the heat dissipation actuator.

[0056] The temperature prediction method for the high-precision temperature control module of the friction and wear testing machine for typical kinematic pairs of high-temperature aircraft tail nozzles is as follows: Taking the average temperature of the internal environment of the box-type insulation structure 1 as the target temperature, the temperature distribution at different target temperatures is analyzed through fluid-heat transfer coupled finite element simulation, and a temperature distribution model of the box-type insulation structure 1, heating actuator 2, heat dissipation actuator 3, and test piece is established. The inner surface of the box-type insulation structure 1 is approximately divided into squares with a side length of 100 mm. The variation of the average temperature in each square area with the target temperature is analyzed. The centroids of the three areas with the best linearity are used as characteristic points to arrange the high-temperature area thermocouple 4-1 to measure the temperature of the characteristic points. Based on the summarized temperature variation pattern, the average temperature of the environment and the test piece temperature are predicted.

[0057] In order to study the steady-state temperature field distribution of the box-type insulation structure 1, a U-shaped carbon silicon electric heating rod 2-1 was set as the volume heat source. A series of power combinations were set for the eight U-shaped carbon silicon electric heating rods 2-1 through the experimental design method, and steady-state heat transfer finite element calculations were performed. The power of the U-shaped carbon silicon electric heating rod 2-1 was used as input, and the average temperature of the test piece area in the calculation results was used as output. The approximate mapping relationship between the power of the eight U-shaped carbon silicon electric heating rods 2-1 and the average temperature of the test piece area in a specific power range was obtained.

[0058] like Figure 3 The present invention provides a high-precision temperature control method for a friction and wear testing machine of a typical kinematic pair of a high-temperature aviation tail nozzle. In order to save test preparation time, a temperature control strategy of segmented operation is implemented. The specific implementation is as follows: in the first working stage, the heating actuator 2 works at full power, and the heat dissipation actuator does not work, so that the internal ambient temperature of the box-type thermal insulation structure 1 quickly approaches the target value; in the second working stage, the heating actuator 2 and the heat dissipation actuator 3 work simultaneously, so that the internal ambient temperature of the box-type thermal insulation structure 1 reaches the target value and converges; in the third working stage, the heating actuator 2 and the heat dissipation actuator 3 work simultaneously, so that the internal ambient temperature of the box-type thermal insulation structure 1 remains stable, providing a stable working condition for the friction and wear test; in the fourth working stage, the heat dissipation actuator 3 works at full power, and the heating actuator 2 does not work, so as to quickly reduce the internal temperature of the box-type thermal insulation structure 1.

[0059] The temperature of the characteristic point is measured using the high-temperature area thermocouple 4-1. Based on the fluid-heat transfer coupled transient simulation, the spatiotemporal distribution of the temperature of the box-type insulation structure 1, the heating actuator 2, the heat dissipation actuator 3 and the test piece in the first working stage is calculated. The temperature of the characteristic temperature measurement point when the temperature-sensitive area reaches the temperature threshold is determined, and this is used as the starting temperature of the second heating stage.

[0060] A multi-point temperature measurement and prediction method was used to determine the temperature distribution of the box-type insulation structure 1, heating actuator 2, heat dissipation actuator 3, and the test piece. Based on the temperature distribution pattern, the corresponding relationship between the readings of the three high-temperature thermocouples 4-1 and the average ambient temperature within the box-type insulation structure 1 was determined. The temperature controller 5 used the calculated average ambient temperature within the box-type insulation structure 1 as the control target and used low-frequency PWM to periodically control the on-off switching of the solid-state relay, thereby controlling the average heating power of the U-shaped carbon-silicon electric heating rod 2-1. During the second and third operating stages, the temperature controller 5 used a self-tuning PID control PWM duty cycle to adjust the average heating power of the U-shaped carbon-silicon electric heating rod 2-1, thereby controlling the ambient temperature within the box-type insulation structure 1.

[0061] In the third working stage, the temperature controller 5 runs the self-tuning PID control PWM duty cycle to adjust the average heating power of the U-shaped carbon silicon electric heating rod 2-1. On this basis, the working power is weightedly distributed to the 8 U-shaped carbon silicon electric heating rods 2-1 according to the approximate mapping relationship between the power of the U-shaped carbon silicon electric heating rod 2-1 in a specific power range and the average temperature of the test piece area, so as to compensate for the uneven temperature distribution caused by the uneven thermal resistance distribution of the box-type insulation structure 1, reduce the temperature gradient inside the test area, and optimize the test conditions.

[0062] During the second and third operating phases, host computer 6 measures the temperature of the sensor installation area using low-temperature thermocouple 4-2. This temperature is used as the target variable for PID control, and conventional PID control is used to control the speeds of the circulation pump and cooling fan in cooling actuator 3. This ensures that the temperature of the motion mechanism sensor remains stable at the set operating temperature. During the fourth operating phase, the circulation pump and cooling fan in cooling actuator 3 operate at the system's set high speed, rapidly reducing the temperature within box-type insulation structure 1.

[0063] The measurement values ​​of the motion mechanism sensor at different working temperatures were experimentally calibrated, and a cubic polynomial relationship was obtained by fitting. When recording the experimental data, the reading of the thermocouple 4-2 in the low temperature area was used as the measured temperature data to correct the temperature drift of the motion mechanism sensor to improve the measurement accuracy of the sensor.

[0064] The fluid-heat transfer coupling simulation analysis method for the box-type thermal insulation structure is as follows: simplify the modeling of the box-type thermal insulation structure 1 and remove geometric features that have little effect on the temperature field distribution. Pre-process the simplified three-dimensional model of the box-type thermal insulation structure 1, and finely control the mesh size and distribution of the U-shaped carbon silicon electric heating rod 2-1, the cooling water jacket 3-1 and the inner surface of the box-type thermal insulation structure 1 according to the heat conduction characteristics. Select appropriate parameters to generate surface meshes according to the model characteristics and analysis needs, and then generate volume meshes based on the surface meshes and create matching meshes by setting them to have common nodes, thus completing the mesh division. Figure 4 , which is a schematic diagram of the heat transfer simulation results.

[0065] The material properties of each component in the box-type insulation structure 1 are configured based on the material characteristics. An equivalent calculation is performed for the integrally installed GH2747 and ceramic fiber composite insulation board. The characteristic thickness of the GH2747 is 14 mm, and the characteristic thickness of the ceramic fiber composite insulation board is 53 mm. The thermal conductivity of the GH2747 is 50 W / (m·K), and the thermal conductivity of the ceramic fiber composite insulation board is 0.025 W / (m·K). The calculation is based on the thermal resistance per unit area formula for a flat plate:

[0066] GH2747 thermal resistance per unit area calculation:

[0067]

[0068] Calculation of thermal resistance per unit area of ​​ceramic fiber composite insulation board:

[0069]

[0070] Calculation of equivalent thermal resistance per unit area:

[0071] r total =r steel +r c =2.1203553m 2 K / W

[0072] Calculation of equivalent thermal conductivity:

[0073]

[0074] The calculated equivalent thermal conductivity is 0.03160 W / (m·K).

[0075] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0076] Those skilled in the art will appreciate that, in addition to implementing the system, device, and various modules provided by the present invention in purely computer-readable program code, it is entirely possible to implement the same program in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, and the like by logically programming the method steps. Therefore, the system, device, and various modules provided by the present invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; the modules for implementing various functions can also be considered both software programs for implementing the method and structures within the hardware component.

[0077] The above describes specific embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art may make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. The embodiments of this application and the features in the embodiments may be combined with each other in any manner unless there is a conflict.

Claims

1. A temperature control method for a typical motion pair friction and wear testing machine for a high-temperature aviation tail nozzle, characterized in that: The method is realized by a temperature control system of a high-temperature aviation tail nozzle typical motion pair friction and wear testing machine, wherein the temperature control system comprises: a box-type heat-insulating structure (1), a heating actuator (2), a heat dissipation actuator (3), a temperature sensor, a temperature controller (5) and a host computer (6); The heating actuator (2) comprises a U-shaped carbon silicon electric heating rod (2-1) and a solid relay, wherein the U-shaped carbon silicon electric heating rod (2-1) is placed on one inner wall of the box-type thermal insulation structure (1), and the solid relay is placed on the opposite inner wall of the box-type thermal insulation structure (1), and is used to heat the interior of the box-type thermal insulation structure (1) to a specified temperature; The heat dissipation actuator (3) is installed on a component of the outer movement mechanism of the box-type heat-insulating structure (1), and uses the liquid cooling medium circulating inside to reduce the temperature of the component; The temperature sensor comprises a high-temperature region thermocouple (4-1) and a low-temperature region thermocouple (4-2); the high-temperature region thermocouple (4-1) is installed inside the box-type thermal insulation structure (1) and is used to measure the temperature of a specific point; the low-temperature region thermocouple (4-2) is installed on a sensor-containing component in the motion mechanism and is used to measure the temperature of the sensor region to compensate for sensor temperature drift; The temperature controller (5) is a memory-type PID regulator, integrated with signal input, signal output, and data panel display functions, and communicates with the host computer (6) via the RS485 protocol; The host computer (6) is an industrial control computer, which is used to connect the temperature controller (5) to the test machine measurement and control software and control the heat dissipation actuator (3); The temperature control method of the high-temperature aviation tail nozzle typical motion pair friction and wear testing machine includes: taking the average temperature of the internal environment of the box-type thermal insulation structure (1) as the target temperature, analyzing the temperature distribution at different target temperatures through fluid-heat transfer coupled finite element simulation, establishing a temperature distribution model of the box-type thermal insulation structure (1), the heating actuator (2), the heat dissipation actuator (3) and the test piece, approximately dividing the inner surface of the box-type thermal insulation structure (1) into squares with a preset side length, analyzing the variation pattern of the average temperature in each square area with the target temperature, taking the centroids of the three areas with the best linearity as feature points, arranging high-temperature area thermocouples (4-1) to measure the temperature of the feature points, and predicting the average temperature of the environment and the temperature of the test piece based on the summarized temperature variation pattern; When obtaining the steady-state temperature field distribution of the box-type thermal insulation structure (1), a U-shaped carbon silicon electric heating rod (2-1) is set as a volume heat source, and a series of power combinations are set for the eight U-shaped carbon silicon electric heating rods (2-1) through the experimental design method, and a steady-state heat transfer finite element calculation is performed; the power of the U-shaped carbon silicon electric heating rod (2-1) is used as input, and the average temperature of the test piece area in the calculation result is used as output, and an approximate mapping relationship between the power of the eight U-shaped carbon silicon electric heating rods (2-1) and the average temperature of the test piece area in a specific power range is obtained, which is used as a mathematical basis for temperature control; Perform the following steps: In the first working stage, the heating actuator (2) works at full power and the heat dissipation actuator (3) does not work, so that the internal ambient temperature of the box-type thermal insulation structure (1) quickly approaches the target value; In the second working stage, the heating actuator (2) and the heat dissipation actuator (3) work simultaneously, so that the internal ambient temperature of the box-type thermal insulation structure (1) reaches the target value and converges; In the third working stage, the heating actuator (2) and the heat dissipation actuator (3) work simultaneously to keep the internal ambient temperature of the box-type thermal insulation structure (1) stable, thus providing a stable working condition for the friction and wear test; In the fourth working stage, the heat dissipation actuator (3) works at full power, the heating actuator (2) does not work, and the internal temperature of the box-type thermal insulation structure (1) is quickly reduced; The temperature of the characteristic point is measured using a thermocouple (4-1) in the high-temperature area. Based on the fluid-heat transfer coupled transient simulation, the temporal and spatial distribution of the temperature of the box-type insulation structure (1), the heating actuator (2), the heat dissipation actuator (3) and the test piece in the first working stage is calculated. The temperature of the characteristic temperature measurement point when the temperature sensitive area reaches the temperature threshold is determined, and this is used as the starting temperature of the second heating stage.

2. The temperature control method for a high-temperature aviation tail nozzle typical kinematic pair friction and wear testing machine according to claim 1, characterized in that: The box-type thermal insulation structure (1) comprises a box-type structure (1-1), a thermal insulation material (1-2) and an optical window (1-3); The box-type structure (1-1) is composed of 6 pieces of GH2747 high-temperature alloy steel, and is fixed to the testing machine frame through the top and side surfaces. The box-type structure (1-1) is embedded with an integrally installed thick zirconia ceramic fiberboard as a thermal insulation material (1-2); The front of the box-type insulation structure (1) is a GH2747 high-temperature alloy steel plate embedded with a ceramic fiber composite insulation board. The overall design is a single-door for installation and removal of test pieces. Optical windows (1-3) are provided on the GH2747 high-temperature alloy steel plate and the embedded zirconia ceramic fiber plate on the back of the box-type thermal insulation structure (1). The optical windows are made of multiple layers of high-temperature resistant glass and serve to observe the working status of the fixture during the test and to collect the motion images of the test machine. The bottom and side surfaces of the box-type thermal insulation structure (1) are both provided with slots for accommodating the motion mechanism of the testing machine. The outer surface of the box-type thermal insulation structure (1) is provided with high-temperature resistant guide rails (1-4) and heat-insulating baffles (1-5). The heat-insulating baffles (1-5) are fixedly connected to the motion mechanism of the testing machine, and the slots are shielded when the motion mechanism of the testing machine moves to reduce convection and radiation heat transfer.

3. The temperature control method for a high-temperature aviation tail nozzle typical kinematic pair friction and wear testing machine according to claim 1, characterized in that: The number of the U-shaped carbon silicon electric heating rods (2-1) is 8, which are connected to a solid relay in a star connection manner. The solid relay uses the weak current signal output by the temperature controller (5) to control the on and off of the 380V power supply.

4. The temperature control method for a high-temperature aviation tail nozzle typical kinematic pair friction and wear testing machine according to claim 1, characterized in that: The heat dissipation actuator (3) includes a cooling water jacket (3-1), a liquid pipeline, a circulation pump, a cold row and a heat dissipation fan, all of which are installed on the components of the motion mechanism outside the box-type thermal insulation structure (1). The liquid cooling medium circulating inside is used to lower the temperature of the components, thereby reducing the temperature drift of the sensor in the motion mechanism.

5. The temperature control method for a high-temperature aviation tail nozzle typical kinematic pair friction and wear testing machine according to claim 1, characterized in that: The high temperature area thermocouples (4-1) are three S-type thermocouples installed inside the box-type thermal insulation structure (1) and used to measure the temperature at a specific point; The low temperature area thermocouples (4-2) are three K-type thermocouples, which are respectively installed on the sensor-containing components in the motion mechanism and are used to measure the temperature of the sensor area to compensate for the sensor temperature drift.

6. The temperature control method for a high-temperature aviation tail nozzle typical kinematic pair friction and wear testing machine according to claim 1, characterized in that: The temperature distribution of the box-type thermal insulation structure (1), the heating actuator (2), the heat dissipation actuator (3) and the test piece is obtained by using a multi-point temperature measurement and temperature prediction method. The corresponding relationship between the readings of the three high-temperature area thermocouples (4-1) and the average temperature of the internal environment of the box-type thermal insulation structure (1) is obtained according to the temperature distribution law; the temperature controller (5) uses the calculated average temperature of the internal environment of the box-type thermal insulation structure (1) as the control target, and uses low-frequency PWM to periodically control the on and off of the solid-state relay to control the average heating power of the U-shaped carbon silicon electric heating rod (2-1); in the second working stage and the third working stage, the temperature controller (5) runs the self-tuning PID control PWM duty cycle to adjust the average heating power of the U-shaped carbon silicon electric heating rod (2-1), thereby realizing the control of the internal environment temperature of the box-type thermal insulation structure (1).

7. The temperature control method for a high-temperature aviation tail nozzle typical kinematic pair friction and wear testing machine according to claim 6, characterized in that: In the third working stage, the temperature controller (5) runs the self-tuning PID control PWM duty cycle to adjust the average heating power of the U-shaped carbon silicon electric heating rod (2-1). On this basis, the working power is weightedly distributed to the eight U-shaped carbon silicon electric heating rods (2-1) according to the approximate mapping relationship between the power of the U-shaped carbon silicon electric heating rod (2-1) in a specific power range and the average temperature of the test piece area, thereby compensating for the uneven temperature distribution caused by the uneven thermal resistance distribution of the box-type insulation structure (1), reducing the temperature gradient inside the test area, and optimizing the test conditions.

8. The temperature control method for a high-temperature aviation tail nozzle typical kinematic pair friction and wear testing machine according to claim 7, characterized in that: In the second and third working stages, the host computer (6) measures the temperature of the sensor installation area through the low-temperature area thermocouple (4-2), and uses this as the target quantity of PID control. The traditional PID is used to control the rotation speed of the circulation pump and the cooling fan in the heat dissipation actuator (3) to ensure that the temperature of the motion mechanism sensor is stable at the set working temperature. In the fourth working stage, the circulation pump and the cooling fan in the heat dissipation actuator (3) are operated at the high rotation speed set by the system to quickly reduce the internal temperature of the box-type insulation structure (1). The measurement values ​​of the motion mechanism sensor at different working temperatures were experimentally calibrated, and a cubic polynomial relationship was obtained by fitting. When recording the experimental data, the reading of the thermocouple (4-2) in the low temperature area was used as the measured temperature data to correct the temperature drift of the motion mechanism sensor.

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