Rotary equal-wall-temperature convective heat transfer coefficient measurement experiment system

Abstract

The invention provides a rotary equal-wall-temperature convective heat transfer coefficient measurement experiment system, and belongs to the technical field of rotary heat transfer experiments. The rotating arm is fixedly mounted on the rotating shaft; the test piece comprises a framework and a plurality of copper blocks, the framework is fixed on the rotating arm, the plurality of copper blocks are fixed on the framework, the plurality of copper blocks are spliced to form a cooling channel, a heating assembly is arranged on the outer wall surface, corresponding to the cooling channel, of each copper block, the heating assemblies are used for heating the copper blocks, and the heating assemblies on the copper blocks are arranged independently; and the plurality of temperature detection assemblies are in one-to-one correspondence with the plurality of copper blocks. By means of the treatment scheme, an equal-wall-temperature system with the same temperature of all copper blocks can be achieved, and any temperature distribution can also be achieved.

Description

Technical Field

[0001] The present application relates to the field of rotary heat transfer experiments, and in particular to a rotary constant wall temperature convective heat transfer coefficient measurement experimental system. Background Art

[0002] In order to improve the performance of aircraft engines and gas turbines, increasing the temperature before the turbine and improving the compressor pressure ratio on this basis is an important technical path. However, the temperature before the turbine has reached 2000K, which is far beyond the allowable temperature of high-temperature alloys. Therefore, in order to ensure the normal operation of the turbine blades, various advanced cooling measures are adopted. Thermal barrier coatings and film cooling are used on the outside of the turbine blades to cool the turbine blades. The inside of the turbine blades uses enhanced heat exchange to use cold air to take away the heat of the blades. The internal cooling technology of the turbine blades includes impingement cooling at the leading edge, ribbed serpentine channels in the middle, and wedge-shaped rib column channels at the trailing edge.

[0003] For turbine rotor blades, the blades rotate at a speed of tens of thousands of revolutions per minute. The rotation not only affects the strength of the blades, but the additional force induced by the rotation also affects the flow of cold air in the blade cooling channel, thereby affecting the cooling of the blade wall. In order to study the effect of rotation on the flow and heat transfer of the cooling channel, relevant experiments are needed. The copper block method is a mature method for studying such problems. It uses a series of copper block units to form a cooling channel. However, in previous research processes, the heating films on the back of the copper blocks are generally connected in series in sequence, and the thermal boundary conditions formed are close to the equal heat flux boundary. Due to the different convective heat transfer coefficients on the surface of the copper blocks, there must be heat conduction caused by the temperature difference between the copper blocks, and this part of the heat transfer cannot be quantified through the heat loss experiment. Therefore, the accuracy of the experiment is low, and the actual temperature distribution on the blade surface is closer to the equal wall temperature thermal boundary condition, so this experimental method cannot simulate the true physical boundary of the blade. Summary of the invention

[0004] In view of this, the present application provides a rotating isotropic convection heat transfer coefficient measurement experimental system, which solves the problems in the prior art, realizes an isotropic system in which all copper blocks have the same temperature, and can also achieve arbitrary temperature distribution.

[0005] The present application provides a rotating constant wall temperature convective heat transfer coefficient measurement experimental system using the following technical solutions: A rotating constant wall temperature convection heat transfer coefficient measurement experimental system, comprising: Test bench; A shaft, rotatably mounted on a test bench; A driving assembly is fixedly arranged relative to the test bench, and the driving assembly is used to drive the rotating shaft to rotate, and the rotating axis of the rotating shaft is parallel to the length direction of the rotating shaft; A rotating arm, fixedly mounted on the rotating shaft; The test piece comprises a skeleton and a plurality of copper blocks, wherein the skeleton is fixed on a rotating arm, the plurality of copper blocks are fixed on the skeleton, the plurality of copper blocks are spliced ​​to form a cooling channel, one side of the copper block serves as an inner wall surface of the cooling channel, and the other side of the copper block serves as an outer wall surface of the cooling channel, each of the copper blocks is provided with a heating component on the outer wall surface of the cooling channel corresponding to the copper block, the heating component is used to heat the copper block, and the heating components on each copper block are independently arranged; A plurality of temperature detection components corresponding to a plurality of copper blocks, wherein the temperature detection components are used to detect the temperature of the copper blocks; A cooling medium delivery pipeline is fixed on the rotating shaft and the rotating arm, one end of the cooling medium delivery pipeline is connected to a cooling medium source, and the other end of the cooling medium delivery pipeline is used to communicate with a cooling channel of the test piece.

[0006] Optionally, the rotating constant wall temperature convection heat transfer coefficient measurement experimental system also includes a heating controller, a temperature acquisition module, a computer and a DC power supply; The heating controller is electrically connected to all the heating components, the temperature acquisition module is electrically connected to the temperature detection component, the heating controller and the temperature acquisition module are both electrically connected to a computer, and the heating controller is electrically connected to the DC power supply; Among them, the temperature acquisition module is used to convert the voltage analog signal of the temperature detection component into a digital signal, the computer receives the temperature data of each copper block sent by the temperature acquisition module, the computer calculates the heating power of the heating component to heat each copper block to a preset temperature based on the real-time temperature data of each copper block, and the heating controller controls the heating power output by each heating component based on the received heating power of each copper block.

[0007] Optionally, an electric slip ring is installed on the rotating shaft, the heating controller and the temperature acquisition module are installed on the rotating shaft, the heating controller is electrically connected to a computer via the electric slip ring, the heating controller is electrically connected to the DC power supply via the electric slip ring, and the temperature acquisition module is electrically connected to the computer via the electric slip ring.

[0008] Optionally, the heating controller adjusts the heating power of the heating component via a pulse width modulation generator.

[0009] Optionally, the heating component is a resistance film, which covers one side of the outer wall of the cooling channel of the copper block corresponding to the copper block, and an insulating cover plate is provided on the side of the resistance film facing away from the copper block. The insulating cover plate is fixed on the copper block and covers the resistance film.

[0010] Optionally, the temperature detection component is a thermocouple, and a detection probe of the thermocouple contacts one side of the outer wall surface of the cooling channel corresponding to the copper block.

[0011] Optionally, adjacent copper blocks are sealed by a sealing insulation structure.

[0012] Optionally, a rotating joint is installed at one end of the rotating shaft, one end of the rotating joint is a fixed end, the fixed end is fixedly arranged relative to the rotating shaft, and the other end of the rotating joint is a free end, the fixed end is connected to the cooling medium delivery pipeline, and the free end is connected to the cooling medium source.

[0013] In summary, this application includes the following beneficial technical effects: In this application, the temperature of each copper block is measured, controlled and heated separately, and can be set to the same wall temperature distribution or non-uniform wall temperature distribution as needed. It can realize an equal wall temperature system with equal temperature of all copper blocks, and can also realize arbitrary temperature distribution. It can also realize strict equal heat flow boundary conditions by adjusting the algorithm, which greatly facilitates the experimental study of various heat transfer boundary conditions. Moreover, since the constant wall temperature boundary condition can be achieved, there is no need to wait for the thermal equilibrium time when the flow changes, which can greatly shorten the experimental time and improve the experimental efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 This is a schematic diagram of the overall structure of the rotating constant wall temperature convection heat transfer coefficient measurement experimental system of this application; Figure 2 This is a schematic diagram of the assembly structure of the copper block, heating component and temperature detection component of this application; Figure 3 Circuit diagram of the experimental system for measuring the rotating constant wall temperature convection heat transfer coefficient for this application.

[0016] Explanation of the reference numerals: 1. test bench; 11. support frame; 2. rotating shaft; 21. rotary joint; 3. motor; 31. belt; 4. rotating arm; 5. test piece; 51. copper block; 52. heating component; 53. insulation cover; 54. temperature detection component; 6. heating controller; 61. pulse width modulation generator; 7. temperature acquisition module; 8. computer; 9. DC power supply; 10. electric slip ring. DETAILED DESCRIPTION

[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] The following describes the implementation methods of the present application through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0019] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0020] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0021] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0022] The embodiment of the present application provides a rotating constant wall temperature convection heat transfer coefficient measurement experimental system.

[0023] like Figure 1 , Figure 2 and Figure 3 As shown, a rotating constant wall temperature convection heat transfer coefficient measurement experimental system includes: The test bench 1 comprises two support frames 11 which are spaced apart from each other.

[0024] The rotating shaft 2 is rotatably mounted on the test bench 1 , and the two support frames 11 are both provided with bearing seats. At least two positions of the rotating shaft 2 are mounted on the two support frames 11 through bearings and bearing seats.

[0025] The driving assembly is fixedly arranged relative to the test bench 1, and is used to drive the rotating shaft 2 to rotate, and the rotation axis of the rotating shaft 2 is parallel to the length direction of the rotating shaft 2. In the embodiment of the present application, the driving assembly includes a motor 3, a belt 31 and a pulley, and the output shaft of the motor 3 and the outer periphery of the rotating shaft 2 are both fixed with pulleys, and the two pulleys are driven by the belt 31, and the motor 3 is fixed on the ground or fixed on the test bench 1.

[0026] The rotating arm 4 is fixedly mounted on the rotating shaft 2 ; the rotating arm 4 is located between two supporting frames 11 , and the space between the two supporting frames 11 provides space for the rotating arm 4 to rotate.

[0027] The test piece 5 includes a skeleton and a plurality of copper blocks 51, wherein the skeleton is fixed on the rotating arm 4, and the plurality of copper blocks 51 are fixed on the skeleton. Adjacent copper blocks 51 are sealed by sealing and heat-insulating structural parts. The plurality of copper blocks 51 are spliced ​​to form a cooling channel, and one side of the copper block 51 serves as the inner wall surface of the cooling channel, and the other side of the copper block 51 serves as the outer wall surface of the cooling channel. A heating component 52 is provided on the outer wall surface of the cooling channel corresponding to each copper block 51, and the heating component 52 is used to heat the copper block 51, and the heating components 52 on each copper block 51 are independently arranged. The skeleton is made of nylon, and the sealing and heat-insulating structural parts are nylon and sealant.

[0028] A plurality of temperature detection components 54 correspond to a plurality of copper blocks 51 one by one, and the temperature detection components 54 are used to detect the temperature of the copper blocks 51 .

[0029] A cooling medium delivery pipeline is fixed on the rotating shaft 2 and the rotating arm 4 , one end of the cooling medium delivery pipeline is connected to a cooling medium source, and the other end of the cooling medium delivery pipeline is used to communicate with a cooling channel of the test piece 5 .

[0030] The method of using the rotating constant wall temperature convection heat transfer coefficient measurement experimental system in this application is as follows: Step 1, start the motor 3, the rotating shaft 2 drives the rotating arm 4 to rotate, and the test piece 5 on the rotating arm 4 simulates the working condition of the internal cooling channel when the turbine rotor blades rotate.

[0031] Step 2: Detect the temperature T on each copper block 51 through the temperature detection component 54. 0 , calculate the current temperature T of each copper block 51 0 and preset temperature T WThe difference between the two is calculated by using the PID algorithm to calculate the heating power of the heating components 52 on each copper block 51, so that the temperature of each copper block 51 is finally stabilized at T W .

[0032] Step 3: A cooling medium is introduced into the cooling channel through a cooling medium delivery pipeline. In the embodiment of the present application, the cooling medium is high-pressure cold air, and the pressure of the high-pressure cold air is 0.1-0.5 MPa and the flow rate is 0-150 kg / h. At this time, the cold air exchanges heat with the wall of the cooling channel composed of the copper block 51, so the power of the heating component 52 will change to stabilize the temperature of the copper block 51 at T W , at this time, the heating power of the heating component 52 is Q t .

[0033] Step 4: Fill the cold air passage with insulation material, repeat steps 1 and 2, and the copper block 51 is heated to a preset temperature T W After that, the heating assembly 52 stabilizes the temperature of each copper block 51 at T W The heating power is the heat loss power Q l .

[0034] Step 5, calculating and obtaining the local average convection heat transfer coefficient h at each copper block 51;

[0035] Where h is the convective heat transfer coefficient, Q t is the heating power, Q l is the heat loss power, A is the contact area between the copper block 51 and the cold air, T W is the temperature of copper block 51, T in The air conditioning temperature.

[0036] In other embodiments, the rotational speed of the rotating shaft 2, the flow rate of the cold air and the preset temperature of the copper block 51 can be adjusted to obtain the rotational heat exchange characteristics of the turbine rotor blade cooling channel.

[0037] In other embodiments, by setting the speed of the motor 3 to zero, the heat transfer characteristics of the cooling channel under static conditions can be obtained, and the heat transfer effect of rotation on the cooling channel can be obtained by comparing the heat transfer difference between rotation and static. By setting the speed of the motor 3 to zero, the heat transfer characteristics of the cooling channel in the turbine guide vane can be measured. In the present application, the temperature of each copper block 51 is measured, controlled and heated separately, and can be set to the same wall temperature distribution or non-uniform wall temperature distribution as needed. It can not only realize an equal wall temperature system with equal temperature of all copper blocks 51, but also realize arbitrary temperature distribution, and can also realize strict equal heat flow boundary conditions by adjusting the algorithm, which greatly facilitates the experimental study of various heat transfer boundary conditions. Moreover, since the temperature of the copper block 51 can be kept constant, there is no need to wait for the thermal equilibrium time when the flow changes, which can greatly shorten the experimental time and improve the experimental efficiency.

[0038] For heating, temperature measurement and control of the copper block 51, the present application provides the following embodiments: The rotating constant wall temperature convective heat transfer coefficient measurement experimental system also includes a heating controller 6, a temperature acquisition module 7, a computer 8 and a DC power supply 9; the heating controller 6 is electrically connected to all the heating components 52, the temperature acquisition module 7 is electrically connected to the temperature detection component 54, the heating controller 6 and the temperature acquisition module 7 are both electrically connected to the computer 8, and the heating controller 6 is electrically connected to the DC power supply 9.

[0039] The temperature acquisition module 7 is used to convert the voltage analog signal of the temperature detection component 54 into a digital signal. The computer 8 receives the temperature data of each copper block 51 sent by the temperature acquisition module 7. The computer 8 calculates the heating power of the heating component 52 for heating each copper block 51 to a preset temperature by using the PID algorithm according to the real-time temperature data of each copper block 51. The heating controller 6 controls the heating power output by each heating component 52 according to the received heating power of each copper block 51. The local average convection heat transfer coefficient h at each copper block 51 is also calculated by the computer 8. The heating controller 6 adjusts the heating power of the heating component 52 through the pulse width modulation generator 61. The full name of pulse width modulation in English is Pulse-Width Modulation, or PWM for short. The heating controller 6 adjusts the pulse frequency of the pulse width modulation generator 61 according to the received heating power of each copper block 51 to change the average heating power output by the heating component 52.

[0040] The present application can automatically adjust the heating power according to the set temperature through the feedback control algorithm of computer 8, thereby ensuring the adjustment speed and accuracy; the signal transmission between the rotating system and the stationary computer is carried out through digital signals.

[0041] The heating component 52 is a resistance film, which covers the side of the outer wall of the cooling channel corresponding to the copper block 51, and a heat-insulating cover plate 53 is provided on the side of the resistance film facing away from the copper block 51, and the heat-insulating cover plate 53 is fixed on the copper block 51 and covers the resistance film. The specific installation method of the resistance film is as follows: a groove is provided on the side of the outer wall of the cooling channel corresponding to the copper block 51, and the resistance film is placed in the groove, and a lead groove is provided on the side of the groove for the power supply cable of the resistance film to pass through, and the heat-insulating cover plate 53 closes the opening of the groove.

[0042] The temperature detection component 54 is a thermocouple, and the detection probe of the thermocouple contacts one side of the outer wall surface of the cooling channel corresponding to the copper block 51 .

[0043] An electric slip ring 10 is installed on the rotating shaft 2, the heating controller 6 and the temperature acquisition module 7 are installed on the rotating shaft 2, the heating controller 6 is electrically connected to the computer 8 through the electric slip ring 10, the heating controller 6 is electrically connected to the DC power supply 9 through the electric slip ring 10, and the temperature acquisition module 7 is electrically connected to the computer 8 through the electric slip ring 10. There are multiple copper blocks 51, and the copper blocks 51, the heating components 52 and the temperature detection components 54 correspond to each other. Therefore, there are multiple heating components 52 and temperature detection components 54. The heating controller 6 controls all the heating components 52, and the temperature acquisition module 7 collects multiple temperature signals. In this application, the heating controller 6 and the temperature acquisition module 7 are installed on the rotating shaft 2. The signal transmission between the heating controller 6 and the computer 8, the power transmission between the heating controller 6 and the DC power supply 9, and the signal transmission between the temperature acquisition module 7 and the computer 8 are transmitted in rotation and in a stationary manner through the electric slip ring 10, thereby reducing the number of channels that need to be converted between the rotating unit and the stationary unit, and reducing the number of channels of the electric slip ring 10.

[0044] A rotary joint 21 is installed at one end of the rotating shaft 2, one end of the rotary joint 21 is a fixed end, the fixed end is fixedly arranged relative to the rotating shaft 2, and the other end of the rotary joint 21 is a free end, the fixed end is connected to the cooling medium delivery pipeline, and the free end is connected to the cooling medium source. In the embodiment of the present application, the rotating shaft 2 and the rotating arm 4 are hollow, and the cooling medium delivery pipeline is laid inside the rotating shaft 2 and the rotating arm 4, and the cooling medium delivery pipeline is a polyurethane tube.

[0045] The above is only a 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 shall be based on the protection scope of the claims.

Claims

1. A rotating constant wall temperature convection heat transfer coefficient measurement experimental system, characterized in that: include: Test bench (1); A rotating shaft (2) is rotatably mounted on the test bench (1); A driving assembly is fixedly arranged relative to the test bench (1), and is used to drive the rotating shaft (2) to rotate, wherein the rotation axis of the rotating shaft (2) is parallel to the length direction of the rotating shaft (2); A rotating arm (4) fixedly mounted on the rotating shaft (2); A test piece (5) comprises a frame and a plurality of copper blocks (51), wherein the frame is fixed on a rotating arm (4), the plurality of copper blocks (51) are fixed on the frame, the plurality of copper blocks (51) are spliced ​​to form a cooling channel, one side of the copper block (51) serves as an inner wall surface of the cooling channel, and the other side of the copper block (51) serves as an outer wall surface of the cooling channel, and each copper block (51) is provided with a heating component (52) on the outer wall surface of the cooling channel corresponding to the copper block (51), the heating component (52) is used to heat the copper block (51), and the heating components (52) on each copper block (51) are independently arranged; A plurality of temperature detection components (54) corresponding one to each of the plurality of copper blocks (51), wherein the temperature detection components (54) are used to detect the temperature of the copper blocks (51); A cooling medium delivery pipeline is fixed on the rotating shaft (2) and the rotating arm (4), one end of the cooling medium delivery pipeline is connected to a cooling medium source, and the other end of the cooling medium delivery pipeline is used to communicate with a cooling channel of the test piece (5).

2. The rotating constant wall temperature convection heat transfer coefficient measurement experimental system according to claim 1 is characterized in that: The rotating constant wall temperature convective heat transfer coefficient measurement experimental system also includes a heating controller (6), a temperature acquisition module (7), a computer (8) and a DC power supply (9); The heating controller (6) is electrically connected to all the heating components (52), the temperature acquisition module (7) is electrically connected to the temperature detection component (54), the heating controller (6) and the temperature acquisition module (7) are both electrically connected to a computer (8), and the heating controller (6) is electrically connected to the DC power supply (9); The temperature acquisition module (7) is used to convert the voltage analog signal of the temperature detection component (54) into a digital signal, the computer (8) receives the temperature data of each copper block (51) sent by the temperature acquisition module (7), the computer (8) calculates the heating power of the heating component (52) for heating each copper block (51) to a preset temperature according to the real-time temperature data of each copper block (51), and the heating controller (6) controls the heating power output by each heating component (52) according to the received heating power of each copper block (51).

3. The rotating constant wall temperature convection heat transfer coefficient measurement experimental system according to claim 2 is characterized in that: An electric slip ring (10) is installed on the rotating shaft (2); the heating controller (6) and the temperature acquisition module (7) are installed on the rotating shaft (2); the heating controller (6) is electrically connected to a computer (8) via the electric slip ring (10); the heating controller (6) is electrically connected to a DC power supply (9) via the electric slip ring (10); and the temperature acquisition module (7) is electrically connected to the computer (8) via the electric slip ring (10).

4. The rotating constant wall temperature convection heat transfer coefficient measurement experimental system according to claim 2 is characterized in that: The heating controller (6) adjusts the heating power of the heating component (52) via a pulse width modulation generator (61).

5. The rotating constant wall temperature convection heat transfer coefficient measurement experimental system according to claim 1 is characterized in that: The heating component (52) is a resistance film, and the resistance film covers one side of the outer wall surface of the copper block (51) corresponding to the cooling channel. A heat insulating cover plate (53) is provided on the side of the resistance film facing away from the copper block (51). The heat insulating cover plate (53) is fixed on the copper block (51) and covers the resistance film.

6. The rotating constant wall temperature convection heat transfer coefficient measurement experimental system according to claim 1 is characterized in that: The temperature detection component (54) is a thermocouple, and the detection probe of the thermocouple contacts one side of the outer wall surface of the copper block (51) corresponding to the cooling channel.

7. The rotating constant wall temperature convection heat transfer coefficient measurement experimental system according to claim 1 is characterized in that: Adjacent copper blocks (51) are sealed by a sealing heat-insulating structural member.

8. The rotating constant wall temperature convection heat transfer coefficient measurement experimental system according to claim 1 is characterized in that: A rotary joint (21) is installed at one end of the rotating shaft (2); one end of the rotary joint (21) is a fixed end, the fixed end is fixedly arranged relative to the rotating shaft (2); the other end of the rotary joint (21) is a free end, the fixed end is connected to the cooling medium delivery pipeline, and the free end is connected to the cooling medium source.

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