Experimental system and method for ultra-high temperature convective heat transfer of actively cooled sandwich structures

Abstract

The present invention discloses an ultra-high temperature convective heat transfer experimental system and method for an actively cooled sandwich structure. The system includes a spray gun heating test piece, at both ends of which are a spray gun heating inlet module and a spray gun heating outlet module; a spray gun heating system, a test system, a cooling system, and a control computer; the method includes executing the initial position of the spray gun and igniting it; adjusting the distance between the spray gun and the target point; judging whether the outlet temperature of the heating flow channel has reached a maximum value, and judging whether the inlet and outlet temperatures of the heating flow channel are equal. When the temperature still does not meet the requirements, adjusting the ratio of fuel and oxygen. The present invention uses a high-temperature flame spray gun as a heat source for the first time, thereby increasing the upper temperature limit of the high-temperature convective heat transfer experimental environment. The high-temperature flame airflow provides a constant temperature boundary condition for realizing the complex heating flow channel surface. The sandwich structure convective heat transfer experiment is promoted from a substructure experiment to an overall structure experiment, which accelerates the progress of engineering design.

Description

Technical Field

[0001] The present invention belongs to the field of aerospace thermal structure and thermal protection technology, and in particular relates to an ultra-high temperature convection heat transfer experimental system and an experimental method for an actively cooled sandwich structure. Background Art

[0002] In engineering fields like aerospace, thermal structures are subject to the combined effects of extreme heat, force, vibration, and noise throughout their lifecycle. For example, the combustion chamber of a rocket engine with a thrust-to-weight ratio of 10 must withstand temperatures of 1600°C and pressures of 3 MPa; the combustion chamber of a scramjet engine must withstand temperatures of 1400°C.

[0003] In order to meet the force and heat requirements of the combustion chamber structure of hypersonic aircraft, an active cooling sandwich structure design can be adopted, and the materials and structural forms of each layer can be designed separately to meet the corresponding functional requirements.

[0004] Thermal protection systems with actively cooled sandwich structures are the first choice for long-term service under high temperatures and high heat flux densities. They also place stringent demands on the integrated actively cooled sandwich structures to provide an ultra-high temperature convective heat transfer experimental environment.

[0005] The existing convective heat transfer experimental device for sandwich structures has the following shortcomings:

[0006] 1. The sandwich structure convective heat transfer experimental device under the existing technology uses resistance wire or quartz lamp, which has limited heating temperature and applicable heating space. It cannot provide high temperature above 1500℃ and is not convenient to be installed in complex geometric flow channels.

[0007] 2. Existing sandwich structure convective heat transfer experimental equipment is not designed for high-temperature environments. Although resistance wires, carbon rods, and quartz lamps can provide temperatures up to 1500°C, they are not actually designed for such conditions. Existing equipment and technology can only be used for experiments with heating temperatures below 600°C. For example, only the periodic structure within the sandwich structure is studied for the heat transfer characteristics of the cooling medium within the normal physical range, without including the sandwich structure of the outer substrate. For the scramjet engine combustion chamber, the inner substrate of the entire sandwich structure, which serves as the main structure of the combustion chamber, must be heated to a temperature of over 1400°C. If only the periodic structure is studied, it cannot reflect the impact of the complex temperature environment that may exist under actual operating conditions on the actual performance of the thermal protection structure, and ignores the important role of the outer substrate temperature in the thermal protection target. Summary of the Invention

[0008] In response to the problems existing in the prior art, the present invention proposes an ultra-high temperature convective heat transfer experimental system and experimental method for an actively cooled sandwich structure. The first purpose is to solve the problem that the prior art heating uses resistance wires and quartz lamps with limited temperature and geometric shape, cannot provide a high temperature of 1500°C, and is inconvenient to install in complex geometric flow channels; the second purpose is to solve the problem that the experiments in the prior art are not designed for high temperature environments. Although resistance wires and quartz lamps can provide a high temperature of 1500°C, due to the limitations of experimental equipment and experimental objects, only actual high temperature experiments below 600°C can be carried out, and only unit heat transfer characteristics of the cooling medium within the range of normal physical properties can be studied; the third purpose is to solve the problem that the prior art can only conduct basic heat transfer characteristic experiments on the periodic change structure of the middle layer of the sandwich structure, but cannot conduct heat transfer characteristic experiments on the entire sandwich structure.

[0009] The present invention adopts the following technical solutions to solve the technical problems:

[0010] A high-temperature convection heat transfer experimental device comprises a spray gun heating test piece (4-2), at both ends of the spray gun heating test piece (4-2), one end is a spray gun heating inlet module (4-1), and the other end is a spray gun heating outlet module (4-3); at both ends of the spray gun heating inlet module (4-1), one end is connected to the spray gun heating test piece (4-2), and the other end is connected to a flame spray gun-based heating system (1) for providing heating temperature for the spray gun heating test piece (4-2); a measuring system (3) is provided around the spray gun heating test piece (4-2); the spray gun heating test piece (4-2) and the spray gun heating inlet module (4-1), and the spray gun heating test piece (4-2) and the spray gun heating outlet module (4-3) are sealed; the spray gun heating inlet module, the spray gun heating outlet module, and the spray gun heating test piece (4-2) are cooled by a test piece cooling system respectively; the device is characterized in that:

[0011] The flame spray gun-based heating system (1) comprises an oxygen supply device (1-1), a kerosene supply device (1-2), a high-temperature flame spray gun (1-3), a spray gun distance control module (1-4), and an external system control computer (7); the oxygen supply device (1-1) and the kerosene supply device (1-2) are respectively connected to the spray gun distance control module (1-4) at one end and to the system control computer (7) at the other end; the spray gun distance control module (1-4) is connected to the high-temperature flame spray gun (1-3) at one end and to the system control computer (7) at the other end. computer (7); the oxygen supply device (1-1) and the kerosene supply device (1-2) change the flame temperature by changing the mass flow of oxygen and kerosene under the control of the system control computer (7), so that the actual flame temperature can reach 2000°C; the spray gun distance control module (1-4) adjusts the distance between the flame spray gun and the straight channel section of the spray gun heating flow channel inlet (1-5) of the spray gun heating inlet module through a stepping motor under the control of the system control computer (7), so that the high-temperature airflow generated by combustion enters the heating flow channel at a higher speed;

[0012] The cross section of the heating flow channel (1-7) of the spray gun heating test piece (4-2) includes a regular cross section and an irregular geometric cross section with a complex shape to meet the actual needs of different working conditions.

[0013] Furthermore, the spray gun heating inlet module has an inner and outer three-layer structure: the inner layer is the spray gun heating inlet flow channel (1-5), the middle layer is the specimen inlet insulation flow channel (2-1), and the specimen coolant inlet flow channel (2-3) is located between the middle layer and the outer layer; the spray gun heating test piece (4-2) has a sandwich structure, with inner and outer double-layer flow channels: the inner layer is the specimen heating flow channel (1-7), and the specimen cooling flow channel (2-4) is located between the outer layer and the inner layer; the spray gun heating outlet module has an inner and outer double-layer structure: the inner layer is the spray gun heating outlet flow channel (1-6), and the specimen coolant outlet flow channel (2-5) is located between the inner layer and the outer layer;

[0014] The spray gun heating inlet flow channel (1-5), the specimen heating flow channel (1-7), and the spray gun heating outlet flow channel (1-6) are connected; the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4), and the specimen coolant outlet flow channel (2-5) are connected; the specimen inlet heat insulation flow channel (2-1) and the specimen coolant inlet flow channel (2-3) are sealed at the heating inlet of the spray gun heating test piece (4-2);

[0015] A heat conduction blocking channel (2-2) is also provided on the outer wall of the spray gun heating outlet module near the outlet. The heat conduction blocking channel (2-2) is used to cool the connection area between the inner and outer double layers near the tail of the spray gun heating outlet module, thereby blocking heat conduction from the spray gun heating outlet channel (1-6) to the outer wall of the specimen cooling channel (2-4) through the channel support component.

[0016] Furthermore, the spray gun heating flow channel inlet (1-5) is a bell mouth to better guide the heating flame airflow into the heating flow channel and reduce the turbulence of the heating airflow; the spray gun heating flow channel inlet (1-5) and the spray gun heating flow channel outlet (1-6) are made of high-temperature alloy, and are arranged with a high-temperature thermal insulation coating to reduce heat loss and protect the high-temperature alloy.

[0017] Furthermore, since the flame enters the specimen heating flow channel (1-7) at a subsonic speed, the high-speed and high-temperature airflow generated by the flame combustion has a very short flow time in the specimen heating flow channel (1-7), and the heat exchange with the tube wall is approximately zero. Therefore, it is believed that it provides a constant temperature boundary condition for the inner wall surface of the specimen heating flow channel (1-7).

[0018] Furthermore, the geometric cross-section with a complex shape includes a closed structure enclosed by irregular curves and a closed structure formed by microporous flow channels.

[0019] Furthermore, the experimental device also includes a support module, which includes a spray gun heating inlet module fixing device (4-4), a test piece limiting plate (4-5), a test piece gasket (4-6), a connecting rod (4-7), a front test section (4-8), a rear test section (4-9), a module support platform (4-10), and bolts (4-11);

[0020] The spray gun heating inlet module fixing device (4-1) is connected to the spray gun heating inlet module (1-5) via bolts, provides support and fixation for the module, and ensures that the center lines of the high-temperature flame spray gun (1-3) and the spray gun heating flow channel inlet (1-5) are aligned;

[0021] The front test section (4-8), the rear test section (4-9), and the connecting rod (4-7) are connected together by bolts, and have a tightening effect on the spray gun heating test piece (4-2); the front test section (4-8) and the rear test section (4-9) are respectively fixed to the test piece limit plates (4-5) at both ends of the spray gun heating test piece (4-2).

[0022] There are four connecting rods (4-7) uniformly distributed along the axial direction on the periphery of the spray gun heating test piece (4-2), and both ends of the four connecting rods (4-7) are fixedly connected to their respective connecting rod support plates;

[0023] The test piece limiting plates (4-5) are two ring-shaped structures, which are respectively mounted on the outer surfaces of both ends of the spray gun heating test piece (4-2) and connected to the spray gun heating test piece (4-2) in a line contact manner to reduce the heat conduction area of ​​the outer surface of the spray gun heating test piece (4-2);

[0024] The test piece gasket (4-6) is respectively arranged on both sides of the spray gun heating test piece (4-2), that is, between the spray gun heating test piece (4-2) and the spray gun heating inlet module (4-1), and between the spray gun heating test piece (4-2) and the spray gun heating outlet module (4-3), and is used for sealing the connection between the front test section (4-8) and the spray gun heating inlet module (4-1) and the rear test section (4-9) and the spray gun heating outlet module (4-3), and reducing the heat flux density between the outer surface and the test section.

[0025] The test piece limit plate (4-5) is made of high-temperature resistant heat-insulating material, and the test piece gasket (4-6) is made of high-temperature resistant heat-insulating asbestos material.

[0026] Furthermore, the specimen cooling system comprises a specimen water-cooling coolant source (5) and an air-cooling coolant source (6); the water-cooling coolant source (5) supplies cooling to the specimen inlet heat-insulating flow channel (2-1), the heat-conducting blocking flow channel (2-2), and the spray gun cooling flow channel respectively; the air-cooling coolant source (6) supplies cooling to the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4), and the specimen coolant outlet flow channel (2-5) respectively; the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4) ), the specimen coolant outlet flow channel (2-5) is the same flow channel that runs through the front and back, and they are connected to each other by high-temperature sealing gaskets; the specimen inlet insulation flow channel (2-1), the heat conduction blocking flow channel (2-2), and the spray gun cooling flow channel are three independent flow channels; the water-cooled coolant source (5) and the air-cooled coolant source (6) are both monitored and controlled by the system control computer (7); the system control computer (7) monitors the flow rate, pressure, inlet and outlet temperatures and other parameters of the cooling medium to ensure the normal operation of the cooling system.

[0027] Furthermore, the measurement system includes a stepper motor module (3-1), a static pressure conduit (3-2), a total pressure conduit (3-3), a pressure sensor (3-4), a temperature meter (3-5), a specimen cooling channel thermocouple (3-6), a heating channel thermocouple (3-7), an infrared thermal imager (3-8), and a data recording computer (8); the stepper motor module (3-1) is fixed to the module support (4-10) by bolts, and is used to simultaneously adjust the positions of the static pressure conduit (3-2), the total pressure conduit (3-3), and the specimen cooling channel thermocouple (3-6) in the vertical direction of the specimen cooling channel to obtain the physical quantity P 静 、P 总 and T fChanges in the vertical direction; the specimen cooling channel thermocouple (3-6) is inserted into the specimen coolant inlet channel (2-3) and the straight channel of the specimen cooling channel (2-4) in the front test section (4-8) and the rear test section (4-9) through the measuring hole; the heating channel thermocouple (3-7) is a platinum-rhodium thermocouple with a corundum protective sheath, and is inserted into the inlet and outlet positions of the specimen heating channel (1-7) through the measuring hole. The static pressure conduit (3-2) and the total pressure conduit (3-3) are connected to the pressure sensor (3-4) through a hose, and the thermocouple (3-6) is connected to the thermometer (3-5) through a wire; the pressure sensor (3-4) and the thermometer (3-5) transmit the temperature, static pressure and total pressure data of the inlet and outlet of the specimen cooling channel (2-4) to the data recording computer (7), and the computer calculates the inlet and outlet flow rate of the specimen cooling channel (2-4) based on the static pressure and total pressure, and simultaneously monitors the inlet and outlet temperature of the specimen heating channel (1-7). Thermometers (3-5) are used to record the temperature data of the outer surface of the test piece and monitor the thermal insulation effect of the connection between the test piece and the front and rear test sections.

[0028] A high-temperature convection heat transfer experimental control method is characterized in that it includes the following steps:

[0029] Step 1: Initialize parameter settings;

[0030] Step 2: Open each cooling channel;

[0031] Step 3: Monitor the flow of each cooling channel and check the equipment condition;

[0032] Step 4: Check whether the flow rate meets the requirements. If not, return to step 3. If yes, continue to step 4.

[0033] Step 5: Execute the initial position of the spray gun and ignite;

[0034] Step 6. Adjust the distance between the spray gun and the target point;

[0035] Step 7: Check whether the outlet temperature of the heating channel reaches the maximum value. If not, return to step 6. If yes, proceed to step 8.

[0036] Step 8: Check whether the inlet and outlet temperatures of the heating channel are equal. If not, proceed to step 9. If yes, proceed to step 10.

[0037] Step 9: Increase the distance between the spray gun and the target point and return to step 8;

[0038] Step 10: Does the current temperature reach the expected temperature? If not, proceed to step 11; if yes, proceed to step 12;

[0039] Step 11: Adjust the ratio of fuel and oxygen, and return to step 9;

[0040] Step 12: End.

[0041] The initialization parameter setting includes:

[0042] Initialize the flow parameters of the heat-insulating flow channel (2-1) and the heat-conducting flow channel (2-2) at the inlet of the specimen;

[0043] Initialize the flow parameters of the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4), and the specimen coolant outlet flow channel (2-5);

[0044] Initialize the distance between the spray gun and the target point; the target point is the distance between the high-temperature flame spray gun (1-3) and the starting point of the straight flow section of the spray gun heating flow channel inlet (1-5);

[0045] Initialize the temperature parameters of the inlet and outlet points of the spray gun heating test piece (4-2).

[0046] Advantages and effects of the present invention

[0047] 1. In this patent solution, a high-temperature flame spray gun is used as a heat source for the first time, which increases the temperature limit of the high-temperature convection heat transfer experimental environment.

[0048] 2. In this patent solution, the high-temperature flame airflow can provide constant temperature boundary conditions for the heating flow channel surface with complex cross-section.

[0049] 3. This patent solution adopts a modular design to provide solutions for convective heat transfer experiments of samples with different closed flow channel cross-sections, gas and liquid cooling media, thereby improving the utilization rate of the device to reduce design and manufacturing costs, thereby realizing scaled convective heat transfer experiments of integrated structures with multiple material sandwiches.

[0050] 4. The existing sandwich structure convective heat transfer experiment is promoted from substructure experiment to overall structure experiment, which greatly accelerates the progress from basic research on the heat transfer performance of sandwich structures to engineering design, and provides convective heat transfer reduction experimental conditions for the active cooling TPS of sandwich structures with annular heating walls such as scramjet engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1a Schematic diagram of the high-temperature convection heat transfer experimental device of the present invention;

[0052] Figure 1b For the present invention Figure 1a A partial enlarged view of

[0053] Figure 2 This is an exploded view of the experimental device of the present invention;

[0054] Figure 3a This is the first perspective of the flow channel cross section of the experimental device of the present invention;

[0055] Figure 3bThis is the second viewing angle of the flow channel cross section of the experimental device of the present invention;

[0056] Figure 3c This is the third perspective of the flow channel cross section of the experimental device of the present invention;

[0057] Figure 4a This is the first perspective of the axonometric drawing of the experimental device of the present invention;

[0058] Figure 4b This is the second perspective of the axonometric drawing of the experimental device of the present invention;

[0059] Figure 5 A schematic diagram of a geometric cross-section of a complex shape of a heating test piece of the present invention;

[0060] Figure 6 This is a schematic diagram showing the principle of regulating temperature by adjusting the spray gun distance in the present invention;

[0061] Figure 7 This is a flow chart of the high-temperature convection heat exchange spray gun heating method of the present invention;

[0062] 1-1: Oxygen supply device; 1-2: Kerosene supply device; 1-3: High-temperature flame spray gun; 1-4: Spray gun support module; 1-5: Spray gun heating flow channel inlet; 1-6: Spray gun heating flow channel outlet; 1-7: Specimen heating flow channel; 1-8: Drainage baffle;

[0063] 2-1: Specimen inlet insulation channel; 2-2: Heat conduction blocking channel; 2-3: Specimen coolant inlet channel; 2-4: Specimen cooling channel; 2-5: Specimen coolant outlet channel; 2-6: Grille; 2-7: Filter;

[0064] 3: Test system; 3-1: Stepper motor module; 3-2: Static pressure conduit; 3-3: Total pressure conduit; 3-4: Pressure sensor;

[0065] 3-5: Thermometer; 3-6: Thermocouple of cooling channel of specimen; 3-7: Thermocouple of heating channel; 3-8: Infrared thermal imager;

[0066] 4-1: Spray gun heating inlet module; 4-2: Spray gun heating test piece; 4-3: Spray gun heating outlet module;

[0067] 4-4: Test bench fixture; 4-5: Test piece limit plate; 4-6: Test piece gasket; 4-7: Connecting rod; 4-7-1: Connecting rod support device; 4-8: Front test section; 4-9: Rear test section; 4-10: Module support platform; 4-11: Bolts;

[0068] 5: Water-cooled coolant source; 6: Air-cooled coolant source; 7: Control computer; 8: Data recording computer; DETAILED DESCRIPTION

[0069] Design principle of the present invention

[0070] 1. Innovation: The first domestic convective heat transfer experimental device that uses a flame spray gun to heat the inner flow channel. Most of the previous studies have focused on the characteristics of high-temperature flames, and there is no concept of using flame flow for high-temperature convective heat transfer experiments. The advantages of the convective heat transfer experimental device using the inner flow channel for heating in the present invention are: First, compared with the methods of resistance wire heat exchange and quartz lamp radiation heating, since the present invention uses high-temperature gas heating generated by a flame spray gun, gas heating does not need to consider whether the flow channel can reasonably arrange the quartz lamp group or resistance wire, and does not need to consider the geometric shape of the flow channel cross section. It is not limited to the shape of the cross section, and even very complex geometric structures can allow gas to pass through. Second, the maximum temperature of the flame spray gun can reach 2000°, which can be used for experiments such as convective heat transfer of scaled-down components of scramjet engine combustion chambers.

[0071] 2. Technical Difficulties: The difficulty lies in finding a balance between the three factors: the distance between the high-temperature flame spray gun 1-3 and the starting point of the straight flow section of the spray gun heating inlet flow channel 1-5, the ratio of fuel (e.g., acetylene) and oxygen, and the consistency of the inlet and outlet temperatures of the spray gun heating test piece 4-2. These three factors must be taken into account, and one cannot simply be emphasized while ignoring the other two. Figure 6 As shown in the figure, the horizontal axis is the effective length of the air-cooling channel, 400 mm (the effective length of the air-cooling channel: the total length of the straight flow section starting point of the spray gun heating channel inlet 1-5 → the specimen heating channel 1-7 → the spray gun heating channel outlet 1-6 constitutes the effective length of the air-cooling channel), the vertical axis is the temperature (K), and the four curves represent the distance d from the high-temperature flame spray gun 1-3 to the starting point of the straight flow section of the spray gun heating channel inlet 1-5. From far to near, d is 200 mm, 130 mm, 70 mm, and 20 mm, respectively.

[0072] from Figure 6 Three points can be seen. First, the closer the flame spray gun distance d is, the higher the starting point temperature of the straight flow section 1-5 of the spray gun heating inlet flow channel 1-5. When the distance d is less than 130mm, d is 70mm, or d is 20mm, the temperature actually decreases as the distance decreases. Second, when the oxidant and burner flow rates are given, the flame spray gun distance d is used to adjust the temperature. Assuming the target temperature is 2000K, Figure 6 The highest temperature in the test piece only reaches 1800 K. Third point: When regulating the temperature with the high-temperature flame spray gun 1-3 and the distance d between the starting point of the direct current section of the spray gun heating inlet flow channel 1-5, the positions of the direct current sections of the four curves must also be taken into account. That is, the inlet and outlet of the spray gun heating test piece 4-2 must be within the range of the direct current section.

[0073] 3. Key points of the present invention:

[0074] First, the order of adjusting d and adjusting the oxygen-fuel ratio: use the method of adjusting d, then use the method of adjusting the oxygen-fuel ratio. This order cannot be reversed.

[0075] Second, when using the method of adjusting the oxygen-fuel ratio, d cannot be adjusted. When using the method of adjusting d, if the temperature reaches the target temperature and the inlet and outlet temperatures are the same, the temperature can be maintained without increasing the distance d.

[0076] Third, the specimen coolant inlet channel 2-3 is the source of the entire specimen cooling channel. Its inner layer is the spray gun heating inlet channel 1-5. The temperature of the spray gun heating inlet channel 1-5 is very high. If no insulation treatment is performed between the spray gun heating inlet channel 1-5 and the specimen coolant inlet channel 2-3, the temperature of the coolant near the wall of the specimen coolant inlet channel 2-3 will rise, causing the temperature of the coolant to be uneven when entering the specimen cooling channel 2-4. Therefore, the present invention adds an insulation layer, namely, the specimen inlet insulation channel 2-1, between the spray gun heating inlet channel 1-5 and the specimen coolant inlet channel 2-3 to prevent the local temperature of the coolant in the specimen coolant inlet channel 2-3 from being affected by the temperature increase of the spray gun heating inlet channel 1-5. The entire gas flow channel only needs to add the specimen inlet insulation channel to the spray gun heating inlet channel 1-5.

[0077] Fourth, the heating outlet of the spray gun heating test piece 4-2 ensures the thermal insulation boundary condition at the connection between the outer wall of the test piece and the device. Figure 3c As shown, near the tail of the spray gun heating outlet flow channel 1-6, there is a dense connection between the inner and outer layers. As a result, the temperature of the inner layer will be transferred to the outer metal structure of the specimen coolant outlet flow channel 2-5, and ultimately destroy the adiabatic boundary condition of the outer wall of the spray gun heating test piece 4-2. In order to cut off the heat conduction route, the present invention adds a blocking heat conduction flow channel (2-2) to block the heat conduction from the spray gun heating outlet flow channel 1-6 to the outer wall of the specimen cooling flow channel 2-4 through the flow channel support component.

[0078] Fifth, the three layers of materials of the spray gun heating inlet module 4-1, the two layers of materials of the spray gun heating test piece 4-2 and the spray gun heating outlet module 4-3 are all made of metal materials, and the innermost layer of each is a high-temperature alloy with a thermal barrier coating.

[0079] Based on the above invention principle, the present invention designs an active cooling sandwich structure ultra-high temperature convection heat transfer experimental system, such as Figure 1b 、 Figure 2As shown, the device includes a spray gun heating test piece 4-2, at both ends of which are a spray gun heating inlet module 4-1 and a spray gun heating outlet module 4-3. At both ends of the spray gun heating inlet module 4-1, one end is connected to the spray gun heating test piece 4-2, and the other end is connected to a flame spray gun-based heating system 1 that provides heating temperature for it. A measurement system 3 is provided outside and inside the spray gun heating inlet module 4-1, the spray gun heating test piece 4-2, and the spray gun heating outlet module 4-3. The spray gun heating test piece 4-2 and the spray gun heating inlet module 4-1, as well as the spray gun heating test piece 4-2 and the spray gun heating outlet module 4-3, are sealed. The spray gun heating inlet module 4-1, the spray gun heating outlet module 4-3, and the spray gun heating test piece 4-2 are cooled by a specimen cooling system respectively. The device is characterized in that:

[0080] like Figure 1a As shown, the flame spray gun-based heating system 1 includes an oxygen supply device 1-1, a fuel supply device 1-2, a high-temperature flame spray gun 1-3, and a spray gun distance control module 1-4, which is externally connected to a system control computer 7; the oxygen supply device 1-1 and the kerosene supply device 1-2 are respectively connected to the spray gun distance control module 1-4 at one end and to the system control computer 7 at the other end; the spray gun distance control module 1-4 is connected to the high-temperature flame spray gun 1-3 at one end and to the system control computer 7 at the other end; under the control of the system control computer 7, the oxygen supply device 1-1 and the kerosene supply device 1-2 enable the actual flame temperature to reach 2000°C; under the control of the system control computer 7, the spray gun distance control module 1-4 adjusts the distance between the flame spray gun and the spray gun heating flow channel inlet straight flow section 1-5 of the spray gun heating inlet module through a stepping motor, so that the high-temperature airflow generated by combustion enters the heating flow channel at a higher speed;

[0081] The cross section of the heating flow channel (1-7) of the spray gun heating test piece 4-2 includes a regular cross section and an irregular geometric cross section with a complex shape to meet the actual needs of different working conditions.

[0082] like Figure 3a As shown, the spray gun heating inlet module 4-1 is a three-layer structure: the inner layer is the spray gun heating inlet flow channel 1-5, the middle layer is the specimen inlet insulation flow channel 2-1, and the specimen coolant inlet flow channel 2-3 is between the middle layer and the outer layer; the spray gun heating test piece 4-2 is a sandwich structure, with inner and outer double-layer flow channels: the inner layer is the specimen heating flow channel 1-7, and the specimen cooling flow channel 2-4 is between the outer layer and the inner layer; the spray gun heating outlet module 4-3 is a double-layer structure: the inner layer is the spray gun heating outlet flow channel 1-6, and the specimen coolant outlet flow channel 2-5 is between the inner layer and the outer layer;

[0083] like Figure 2As shown, the inner side of the heating inlet cooling channel 2-1 is the spray gun heating inlet channel 1-5, and the outer side is the specimen coolant inlet channel 2-3. Water-cooled coolant 5 enters from the bottom end and flows out from the top end to the specimen inlet insulation channel 2-1. Within this channel, the channel surface is fully cooled by the diversion baffle 1-8, which acts as a thermal resistor to prevent heat conduction between the spray gun heating inlet channel 1-5 and the specimen coolant, thereby ensuring a uniform and stable temperature of the coolant in the specimen coolant inlet channel 2-3. This spray gun cooling system (not shown) is used to prevent the high-temperature flame spray gun 1-3 from overheating.

[0084] like Figure 3a As shown, the spray gun heating inlet flow channel 1-5, the specimen heating flow channel 1-7, and the spray gun heating outlet flow channel 1-6 are connected; the specimen coolant inlet flow channel 2-3, the specimen cooling flow channel 2-4, and the specimen coolant outlet flow channel 2-5 are connected; the specimen inlet insulation flow channel 2-1 and the specimen coolant inlet flow channel 2-3 are sealed at the heating inlet of the spray gun heating test piece 4-2;

[0085] like Figure 3a As shown, a blocking heat conduction channel 2-2 is also provided on the outer wall of the spray gun heating outlet module 4-3 near the outlet. The blocking heat conduction channel 2-2 is used to cool the connection area between the inner and outer double layers near the tail of the spray gun heating outlet module, thereby blocking the heat conduction from the spray gun heating outlet channel 1-6 through the channel support component to the outer wall of the specimen cooling channel 2-4.

[0086] like Figure 3a As shown, the spray gun heating flow channel inlet 1-5 is a bell mouth to better guide the heating flame airflow into the heating flow channel and reduce the turbulence of the heating airflow; the spray gun heating flow channel inlet 1-5 and the spray gun heating flow channel outlet 1-6 are made of high-temperature alloy, and a high-temperature thermal insulation coating is arranged to reduce heat loss and protect the high-temperature alloy.

[0087] like Figure 3a As shown in the figure, since the flame-heated airflow enters the specimen heating channel 1-7 at a high speed, the airflow flows through the specimen heating channel 1-7 for a very short time, and the heat exchange with the tube wall is approximately zero. Therefore, it is considered that it provides a constant temperature boundary condition for the inner wall surface of the specimen heating channel 1-7.

[0088] like Figure 6 As shown, the geometric cross-section with a complex shape includes a closed structure enclosed by irregular curves and a closed structure formed by microporous flow channels.

[0089] like Figure 1a 、 Figure 2 、 Figure 3a 、 Figure 4aAs shown, the experimental device also includes a support module, which includes a spray gun heating inlet module fixing device 4-4, a test piece limiting plate 4-5, a test piece gasket 4-6, a connecting rod 4-7, a front test section 4-8, a rear test section 4-9, a module support 4-10, and a bolt 4-11;

[0090] The spray gun heating inlet module fixing device 4-4 is connected to the spray gun heating inlet module 4-1 by bolts, and provides support and fixation for it, while ensuring that the center line of the high-temperature flame spray gun 1-3 and the spray gun heating flow channel inlet 1-5 is aligned;

[0091] like Figure 2 As shown, the front test section 4-8, the rear test section 4-9, and the connecting rod 4-7 are connected together by bolts to fasten the spray gun heating test piece 4-2; the front test section 4-8 and the rear test section 4-9 are respectively fixed to the test piece limit plates 4-5 at both ends of the spray gun heating test piece 4-2.

[0092] like Figure 2 As shown, there are four connecting rods 4-7, which are evenly distributed along the axial direction on the periphery of the spray gun heating test piece 4-2, and the two ends of the four connecting rods 4-7 are fixedly connected to their respective connecting rod support plates 4-7-1;

[0093] like Figure 3c As shown, the test piece limit plates 4-5 are two ring-shaped structures, which are respectively mounted on the outer surfaces of both ends of the spray gun heating test piece 4-2 and connected to the spray gun heating test piece 4-2 in a line contact manner to reduce the heat conduction area of ​​the outer surface of the spray gun heating test piece 4-2;

[0094] like Figure 3c As shown, the test piece gasket 4-6 is respectively arranged on both sides of the spray gun heating test piece 4-2, that is, between the spray gun heating test piece 4-2 and the spray gun heating inlet module 4-1, and between the spray gun heating test piece 4-2 and the spray gun heating outlet module 4-3, and is used for sealing the connection between the front test section 4-8 and the spray gun heating inlet module 4-1 and the rear test section 4-9 and the spray gun heating outlet module 4-3, and reducing the heat flux density between the outer surface and the test section.

[0095] The test piece limit plate 4-5 is made of high temperature resistant heat insulating material, and the test piece gasket 4-6 is made of high temperature resistant heat insulating asbestos material.

[0096] like Figure 1a 、 Figure 3aAs shown, the specimen cooling system includes a specimen water-cooled coolant source 5 and an air-cooled coolant source 6; the water-cooled coolant source 5 supplies cooling to the specimen inlet insulation flow channel 2-1, the heat conduction blocking flow channel 2-2, and the spray gun cooling flow channel respectively; the air-cooled coolant source 6 supplies cooling to the specimen coolant inlet flow channel 2-3, the specimen cooling flow channel 2-4, and the specimen coolant outlet flow channel 2-5 respectively; the specimen coolant inlet flow channel 2-3, the specimen cooling flow channel 2-4, and the specimen coolant outlet flow channel 2-5 are the same flow channel that runs through the front and back, and they are connected to each other by high-temperature sealing gaskets; the specimen inlet insulation flow channel 2-1, the heat conduction blocking flow channel 2-2, and the spray gun cooling flow channel are three independent flow channels; the water-cooled coolant source 5 and the air-cooled coolant source 6 are both monitored and regulated by the system control computer 7; the system control computer 7 monitors the flow rate, pressure, inlet and outlet temperatures and other parameters of the cooling medium to ensure the normal operation of the cooling system.

[0097] like Figure 1a 、 Figure 1b 、 Figure 2 As shown, the measurement system includes a stepper motor module 3-1, a static pressure conduit 3-2, a total pressure conduit 3-3, a pressure sensor 3-4, a temperature meter 3-5, a specimen cooling channel thermocouple 3-6, a heating channel thermocouple 3-7, an infrared thermal imager 3-8, and a data recording computer 8; the stepper motor module 3-1 is fixed to the module support 4-10 by bolts, and is used to simultaneously adjust the positions of the static pressure conduit 3-2, the total pressure conduit 3-3, and the specimen cooling channel thermocouple 3-6 in the vertical direction of the specimen cooling channel to obtain the physical quantity P 静 、P 总 and T f Changes in the vertical direction; the specimen cooling channel thermocouple 3-6 is inserted through the measurement hole into the specimen coolant inlet channel 2-3 and the straight channel of the specimen cooling channel 2-4 within the front test section 4-8 and the rear test section 4-9; the heating channel thermocouple is inserted through the measurement hole into the inlet and outlet of the specimen heating channel 1-7. The static pressure conduit 3-2 and the total pressure conduit 3-3 are connected to the pressure sensor 3-4 via a hose, and the thermocouple 3-6 is connected to the thermometer 3-5 via a wire. The pressure sensor 3-4 and the thermometer 3-5 transmit the temperature, static pressure, and total pressure data of the inlet and outlet of the specimen cooling channel 2-4 to the data recording computer 7. The computer program uses Bernoulli's principle to calculate the inlet and outlet flow velocity v of the specimen cooling channel 2-4 through the static pressure and total pressure, and simultaneously monitors the inlet and outlet temperature of the specimen heating channel 1-7. The thermometer 3-5 is used to record the temperature data of the specimen's external surface and monitor the thermal insulation effect of the connection between the specimen and the front and rear test sections.

[0098] The Bernoulli principle is as follows:

[0099]

[0100] A high-temperature convection heat transfer experiment control method is characterized by comprising the following steps:

[0101] Step 1: Initialize parameter settings;

[0102] Step 2: Open each cooling channel;

[0103] Step 3: Monitor the flow of each cooling channel and check the equipment condition;

[0104] Step 4: Check whether the flow rate meets the requirements. If not, return to step 3. If yes, continue to step 4.

[0105] Step 5: Execute the initial position of the spray gun and ignite;

[0106] Step 6. Adjust the distance between the spray gun and the target point;

[0107] Step 7: Check whether the outlet temperature of the heating channel reaches the maximum value. If not, return to step 6. If yes, proceed to step 8.

[0108] Step 8: Check whether the inlet and outlet temperatures of the heating channel are equal. If not, proceed to step 9. If yes, proceed to step 10.

[0109] Step 9: Increase the distance between the spray gun and the target point and return to step 8;

[0110] Step 10: Does the current temperature reach the expected temperature? If not, proceed to step 11; if yes, proceed to step 12;

[0111] Step 11: Adjust the ratio of fuel and oxygen, and return to step 10;

[0112] Step 12: End.

[0113] The initialization parameter setting includes:

[0114] Initialize the flow parameters of the specimen inlet insulation channel 2-1 and the heat conduction blocking channel 2-2;

[0115] Initialize the flow parameters of the specimen coolant inlet flow channel 2-3, the specimen cooling flow channel 2-4, and the specimen coolant outlet flow channel 2-5;

[0116] Initialize the distance between the spray gun and the target point; the target point is the distance between the high-temperature flame spray gun 1-3 and the starting point of the straight flow section of the spray gun heating flow channel inlet 1-5;

[0117] Initialize the temperature parameters of the inlet and outlet points of the spray gun heating test piece 4-2.

[0118] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. An active cooling sandwich structure ultra-high temperature convection heat transfer experimental system, the device comprising a spray gun heating test piece (4-2), at both ends of the spray gun heating test piece (4-2), one end is a spray gun heating inlet module (4-1), and the other end is a spray gun heating outlet module (4-3); at both ends of the spray gun heating inlet module (4-1), one end is connected to the spray gun heating test piece (4-2), and the other end is connected to a flame spray gun-based heating system (1) for providing heating temperature for the spray gun heating test piece (4-2); a measurement system (3) is provided around the spray gun heating test piece (4-2); the spray gun heating test piece (4-2) and the spray gun heating inlet module (4-1) are sealed, and the spray gun heating test piece (4-2) and the spray gun heating outlet module (4-3) are sealed; the spray gun heating inlet module, the spray gun heating outlet module, and the spray gun heating test piece (4-2) are cooled by the test piece cooling system respectively; the characteristics are: The flame spray gun-based heating system (1) comprises an oxygen supply device (1-1), a kerosene supply device (1-2), a high-temperature flame spray gun (1-3), a spray gun distance control module (1-4), and an external system control computer (7); the oxygen supply device (1-1) and the kerosene supply device (1-2) are respectively connected to the spray gun distance control module (1-4) at one end and to the system control computer (7) at the other end; the spray gun distance control module (1-4) is connected to the high-temperature flame spray gun (1-3) at one end and to the system control computer (7) at the other end. computer (7); the oxygen supply device (1-1) and the kerosene supply device (1-2) change the flame temperature by changing the mass flow of oxygen and kerosene under the control of the system control computer (7), so that the actual flame temperature can reach 2000°C; the spray gun distance control module (1-4) adjusts the distance between the flame spray gun and the straight channel section of the spray gun heating flow channel inlet (1-5) of the spray gun heating inlet module through a stepping motor under the control of the system control computer (7), so that the high-temperature airflow generated by combustion enters the heating flow channel at a higher speed; The cross section of the heating flow channel (1-7) of the spray gun heating test piece (4-2) includes a regular cross section and an irregular geometric cross section with a complex shape to meet the actual needs of different working conditions.

2. The active cooling sandwich structure ultra-high temperature convection heat transfer experimental system according to claim 1, characterized in that: The spray gun heating inlet module has an inner and outer three-layer structure: the inner layer is the spray gun heating inlet flow channel (1-5), the middle layer is the specimen inlet heat insulation flow channel (2-1), and the specimen coolant inlet flow channel (2-3) is located between the middle layer and the outer layer; the spray gun heating test piece (4-2) has a sandwich structure, with inner and outer double-layer flow channels: the inner layer is the specimen heating flow channel (1-7), and the specimen cooling flow channel (2-4) is located between the outer layer and the inner layer; the spray gun heating outlet module has an inner and outer double-layer structure: the inner layer is the spray gun heating outlet flow channel (1-6), and the specimen coolant outlet flow channel (2-5) is located between the inner layer and the outer layer; The spray gun heating inlet flow channel (1-5), the specimen heating flow channel (1-7), and the spray gun heating outlet flow channel (1-6) are connected; the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4), and the specimen coolant outlet flow channel (2-5) are connected; the specimen inlet heat insulation flow channel (2-1) and the specimen coolant inlet flow channel (2-3) are sealed at the heating inlet of the spray gun heating test piece (4-2); A heat conduction blocking channel (2-2) is also provided on the outer wall of the spray gun heating outlet module near the outlet. The heat conduction blocking channel (2-2) is used to cool the connection area between the inner and outer double layers near the tail of the spray gun heating outlet module, thereby blocking heat conduction from the spray gun heating outlet channel (1-6) to the outer wall of the specimen cooling channel (2-4) through the channel support component.

3. The active cooling sandwich structure ultra-high temperature convection heat transfer experimental system according to claim 2, characterized in that: The spray gun heating flow channel inlet (1-5) is a bell mouth to better guide the heating flame airflow into the heating flow channel and reduce the turbulence of the heating airflow; the spray gun heating flow channel inlet (1-5) and the spray gun heating flow channel outlet (1-6) are made of high-temperature alloy and are provided with a high-temperature thermal insulation coating to reduce heat loss and protect the high-temperature alloy.

4. The active cooling sandwich structure ultra-high temperature convection heat transfer experimental system according to claim 2, characterized in that: Since the flame enters the specimen heating channel (1-7) at a subsonic speed, the high-speed and high-temperature airflow generated by the flame combustion has a very short flow time in the specimen heating channel (1-7), and the heat exchange with the tube wall is approximately zero. Therefore, the temperature change of the airflow is negligible. It is therefore believed that it provides a constant temperature boundary condition for the inner wall of the specimen heating channel (1-7).

5. The active cooling sandwich structure ultra-high temperature convection heat transfer experimental system according to claim 1, characterized in that: The geometric cross section with a complex shape includes a closed structure enclosed by irregular curves and a closed structure formed by microporous flow channels.

6. The active cooling sandwich structure ultra-high temperature convection heat transfer experimental system according to claim 1, characterized in that: The experimental device also includes a support module, which includes a spray gun heating inlet module fixing device (4-4), a test piece limit plate (4-5), a test piece gasket (4-6), a connecting rod (4-7), a front test section (4-8), a rear test section (4-9), a module support platform (4-10), and bolts (4-11); The spray gun heating inlet module fixing device (4-1) is connected to the spray gun heating inlet module (1-5) via bolts, provides support and fixation for the module, and ensures that the center lines of the high-temperature flame spray gun (1-3) and the spray gun heating flow channel inlet (1-5) are aligned; The front test section (4-8), the rear test section (4-9), and the connecting rod (4-7) are connected together by bolts, and have a tightening effect on the spray gun heating test piece (4-2); the front test section (4-8) and the rear test section (4-9) are respectively fixed to the test piece limit plates (4-5) at both ends of the spray gun heating test piece (4-2); There are four connecting rods (4-7) uniformly distributed along the axial direction on the periphery of the spray gun heating test piece (4-2), and the two ends of the four connecting rods (4-7) are respectively fixedly connected to their respective connecting rod support plates; The test piece limiting plate (4-5) is a ring-shaped structure, which is respectively mounted on the outer surfaces of both ends of the spray gun heating test piece (4-2), and is connected to the spray gun heating test piece (4-2) in a line contact manner to reduce the heat conduction area of ​​the outer surface of the spray gun heating test piece (4-2); The test piece gasket (4-6) is respectively arranged on both sides of the spray gun heating test piece (4-2), that is, between the spray gun heating test piece (4-2) and the spray gun heating inlet module (4-1), and between the spray gun heating test piece (4-2) and the spray gun heating outlet module (4-3), and is used for sealing the connection between the front test section (4-8) and the spray gun heating inlet module (4-1) and the rear test section (4-9) and the spray gun heating outlet module (4-3), and reducing the heat flux density between the outer surface and the test section; The test piece limit plate (4-5) is made of high-temperature resistant heat-insulating material, and the test piece gasket (4-6) is made of high-temperature resistant heat-insulating asbestos material.

7. The active cooling sandwich structure ultra-high temperature convection heat transfer experimental system according to claim 2, characterized in that: The specimen cooling system comprises a specimen water-cooling coolant source (5) and an air-cooling coolant source (6); the water-cooling coolant source (5) supplies cooling to the specimen inlet heat-insulating flow channel (2-1), the heat-conducting blocking flow channel (2-2), and the spray gun cooling flow channel respectively; The air-cooled coolant source (6) supplies cooling to the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4), and the specimen coolant outlet flow channel (2-5) respectively; the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4), and the specimen coolant outlet flow channel (2-5) are the same flow channel that is connected from front to back and are connected to each other using high-temperature sealing gaskets; the specimen inlet heat insulation flow channel (2-1), the heat conduction blocking flow channel (2-2), and the spray gun cooling flow channel are three independent flow channels; the water-cooled coolant source (5) and the air-cooled coolant source (6) are both monitored and controlled by the system control computer (7); the system control computer (7) monitors parameters such as the flow rate, pressure, inlet and outlet temperatures of the cooling medium to ensure the normal operation of the cooling system.

8. The active cooling sandwich structure ultra-high temperature convection heat transfer experimental system according to claim 1, characterized in that: The measuring system includes a stepper motor module (3-1), a static pressure conduit (3-2), a total pressure conduit (3-3), a pressure sensor (3-4), a temperature measuring instrument (3-5), a specimen cooling channel thermocouple (3-6), a heating channel thermocouple (3-7), an infrared thermal imager (3-8), and a data recording computer (8); the stepper motor module (3-1) is fixed to a module support (4-10) by bolts and is used to simultaneously adjust the positions of the static pressure conduit (3-2), the total pressure conduit (3-3), and the specimen cooling channel thermocouple (3-6) in the vertical direction of the specimen cooling channel to obtain the physical quantity P 静 、P 总 and T f Changes in the vertical direction; the specimen cooling channel thermocouple (3-6) is probed into the specimen coolant inlet channel (2-3) and the straight channel of the specimen cooling channel (2-4) in the front test section (4-8) and the rear test section (4-9) through the measuring hole; the heating channel thermocouple (3-7) is a platinum-rhodium thermocouple with corundum as a protective sheath, and is probed into the inlet and outlet positions of the specimen heating channel (1-7) through the measuring hole; the static pressure conduit (3-2) and the total pressure conduit (3-3) are connected to the pressure sensor (3-4) through a hose, The thermocouple (3-6) is connected to the thermometer (3-5) through a wire; the pressure sensor (3-4) and the thermometer (3-5) transmit the temperature, static pressure and total pressure data of the inlet and outlet of the specimen cooling channel (2-4) to the data recording computer (7), and the computer calculates the inlet and outlet flow rate of the specimen cooling channel (2-4) through the static pressure and total pressure, and monitors the inlet and outlet temperature of the specimen heating channel (1-7); the thermometer (3-5) is used to record the outer surface temperature data of the specimen and monitor the thermal insulation effect of the connection between the specimen and the front and rear test sections.

9. A high-temperature convection heat transfer experiment control method for an ultra-high-temperature convection heat transfer experiment system with an active cooling sandwich structure according to any one of claims 1 to 8, characterized in that , including the following steps: Step 1: Initialize parameter settings; Step 2: Open each cooling channel; Step 3: Monitor the flow of each cooling channel and check the equipment condition; Step 4: Check whether the flow rate meets the requirements. If not, return to step 3. If yes, proceed to step 5. Step 5: Execute the initial position of the spray gun and ignite; Step 6. Adjust the distance between the spray gun and the target point; Step 7: Check whether the outlet temperature of the heating channel reaches the maximum value. If not, return to step 6. If yes, proceed to step 8. Step 8: Check whether the inlet and outlet temperatures of the heating channel are equal. If not, proceed to step 9. If yes, proceed to step 10. Step 9: Increase the distance between the spray gun and the target point and return to step 8; Step 10: Does the current temperature reach the expected temperature? If not, proceed to step 11; if yes, proceed to step 12; Step 11: Adjust the ratio of fuel and oxygen, and return to step 9; Step 12: End.

10. A high temperature convection heat transfer experimental control method according to claim 9, characterized in that ,The initialization parameter settings include: Initialize the flow parameters of the heat-insulating flow channel (2-1) and the heat-conducting flow channel (2-2) at the inlet of the specimen; Initialize the flow parameters of the specimen coolant inlet flow channel (2-3), the specimen cooling flow channel (2-4), and the specimen coolant outlet flow channel (2-5); Initialize the distance between the spray gun and the target point; the target point is the distance between the high-temperature flame spray gun (1-3) and the starting point of the straight flow section of the spray gun heating flow channel inlet (1-5); Initialize the temperature parameters of the inlet and outlet points of the spray gun heating test piece (4-2).

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