Platform and test method suitable for testing heat transfer performance of different cell structures

Abstract

The platform and test method are suitable for testing the heat transfer performance of different cell structures, which belong to the technical field of heat exchange equipment. The test platform provides air source through a centrifugal fan. The air flowing out of the centrifugal fan enters the duct heater and is heated. The hot fluid then enters the cell heat exchange structure for heat exchange, is cooled by the cold fluid, and is then discharged through the air flow channel pipeline. The final exhaust nozzle is used to stabilize the airflow in the pipeline. Measurement points are arranged on the air flow channel pipeline before and after the test section to measure the pressure and temperature of the air flow inlet and outlet for analyzing the flow and heat transfer performance of the cell heat exchange structure. The flow and heat transfer performance of the cell heat exchange structure is tested under different cell configurations, different structural parameters, and different surface roughness to analyze and evaluate the influence of structural type, structural parameters, and surface roughness on the flow and heat transfer performance of the cell heat exchange structure.

Description

Technical Field

[0001] The present invention relates to a device for testing cellular heat exchange structures in the field of heat exchange equipment, and in particular to a platform and a test method suitable for testing the heat exchange performance of different cellular structures. Background Art

[0002] In the aerospace sector, new propulsion systems are constantly being proposed to achieve more economical and higher Mach numbers in the development of aerospace transport equipment. As a key component of pre-cooled air intake engines, high-performance heat exchangers can quickly cool the high-temperature air flowing into the engine intake, thereby increasing the compressor pressure ratio and playing a significant role in improving aircraft performance.

[0003] As metal additive manufacturing processes mature, cellular heat exchange structures with high compactness and excellent heat transfer performance are gradually being used in aerospace and other fields. The cellular heat exchange structure is composed of periodic cells to fill the volume or surface. While having high space utilization, it also has low weight and high stiffness, and can provide good heat transfer capacity. Therefore, designing and manufacturing cellular heat exchange structures with better flow heat transfer performance is of great significance to improving the performance of aerospace vehicle power equipment. When designing and studying cellular heat exchange structures, it is also urgent to conduct experimental research, analysis and verification of the flow heat transfer performance of cellular heat exchange structures under different cell configurations, different structural parameters and different surface roughness, to provide a reference for the optimization of the cellular heat exchange structure, so as to further optimize the flow heat transfer performance of the cellular heat exchange structure. Summary of the Invention

[0004] The present invention aims to address the need for research on the flow and heat transfer performance of cellular heat exchange structures by providing a platform suitable for testing the heat transfer performance of different cellular structures. The test platform is constructed using a centrifugal fan, a ducted heater, a test section, an airflow channel piping system, a cooling system, and an exhaust nozzle. A blower provides the air source. Air flowing out of the blower enters the ducted heater through the airflow channel piping, where it is heated. The hot air then enters the cellular heat exchange structure for heat exchange, where it is cooled by a coolant before being discharged through the airflow channel piping. The exhaust nozzle stabilizes the airflow within the piping. Measurement points are placed on the airflow channel piping before and after the test section to measure the pressure and temperature at the inlet and outlet of the airflow for analysis of the flow and heat transfer performance of the cellular heat exchange structure. By selecting test pieces with different cell configurations and structural parameters and treating the surface roughness of the test pieces, the flow and heat transfer performance of cellular heat exchange structures with different cell configurations, structural parameters, and surface roughness can be tested. This allows for analysis and evaluation of the effects of structural type, structural parameters, and surface roughness on the flow and heat transfer performance of the cellular heat exchange structure.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A platform suitable for testing the heat transfer performance of different cell structures, comprising a centrifugal fan, a duct heater, a test section, a cooling system, and an exhaust nozzle;

[0007] The centrifugal fan is connected to the inlet of the duct heater through an air intake pipe. The outlet of the duct heater is connected in sequence to the flow stabilization pipe, the pre-heat exchange test square pipe, the test section, the post-heat exchange test square pipe, the exhaust channel and the exhaust nozzle. The adjacent sections of the pipe are connected by flanges. The flow stabilization pipe and the exhaust channel are supported by brackets respectively.

[0008] The flow stabilization pipeline adopts a flow stabilization round straight pipe and a round-to-square tapered channel. A front static pressure test hole, a front total pressure test hole and a temperature test hole are sequentially arranged on the front heat exchange test square pipe along the flow direction of the airflow. The front test square pipe outlet flange of the front heat exchange test square pipe is connected to the heat flow inlet flange of the test section;

[0009] The test section includes a cellular heat exchange structure test piece, a test piece assembly flange and a cold fluid inlet and outlet assembly. The cellular heat exchange structure test piece is provided with a cold flow inlet, a cold flow outlet, a hot flow inlet and a hot flow outlet; the hot flow inlet flange of the test piece assembly flange is arranged at the hot flow inlet, and the hot flow outlet flange is arranged at the hot flow outlet; the cold fluid inlet and outlet assembly parts are respectively connected to the test assembly parts using a cold flow inlet part and a cold flow outlet part, and are arranged on the outside of the cellular heat exchange structure test piece; the cold flow inlet part adopts a cold flow inlet circular tube to be connected with a circular-to-square gradually expanding inlet, and the circular-to-square gradually expanding inlet cooperates with the cold flow inlet; the cold flow outlet part adopts a square-to-circular gradually shrinking outlet to be connected with a cold flow outlet circular tube, and the square-to-circular gradually shrinking outlet cooperates with the cold flow outlet;

[0010] The heat flow outlet flange of the test section is connected to the rear test square tube inlet flange of the heat exchange rear test square tube, and the heat exchange rear test square tube is sequentially provided with a rear temperature test hole, a rear total pressure test hole and a rear static pressure test hole along the flow direction of the airflow;

[0011] The cooling system is connected to the cold flow inlet piece and the cold flow outlet piece respectively.

[0012] The air intake pipeline adopts a square-to-circular tapered channel and a curved circular pipe.

[0013] The distance between the front total pressure test hole and the outlet flange of the front test square tube is more than 5 times the cross-sectional width of the front heat exchange test square tube.

[0014] The distance between the rear total pressure test hole and the inlet flange of the rear test square tube is more than 5 times the cross-sectional width of the rear heat exchange test square tube.

[0015] The cellular heat exchange structure test piece converts the TPMS and honeycomb-like cellular heat exchange micro-element adaptability into a rectangular heat exchange structure channel, and the cold and hot fluids exchange heat through the inner wall of the cellular heat exchange structure test piece.

[0016] The centrifugal fan provides an air source, which is heated in a duct heater and flows through a cellular heat exchange structure test piece in the test section to exchange heat with a cooling medium. The exhaust gas is then discharged through a steady-flow exhaust nozzle. At the same time, the temperature and pressure of the air flow are measured before and after the test section. Based on this, the flow heat transfer performance parameters of the hot air after passing through the cellular heat exchange structure test piece, including the surface heat transfer coefficient, Nu number, and friction resistance coefficient, are calculated.

[0017] The ratio of the cross-sectional width of the test piece to the length of the test piece is 1:3.

[0018] A test method for a platform suitable for testing heat transfer performance of different cell structures comprises the following steps:

[0019] S1. Start the test by starting the centrifugal fan and adjusting the fan frequency; start the cooling system and pass the cold fluid into the cellular heat exchange structure test piece to cool the hot fluid; set the heating temperature of the duct heater to the specified operating temperature and turn on the heating switch to heat the intake air;

[0020] S2. Observe the results displayed by the pressure acquisition system and check the temperature detector readings. After the pressure and temperature values ​​stabilize, record the temperature and pressure values ​​of the test square tube before and after the heat exchange, and repeat the test data acquisition at equal intervals.

[0021] S3. After collecting the temperature and pressure data on the test square tubes before and after the heat exchange under the test condition, adjust the centrifugal fan frequency and the heating temperature of the duct heater to the next test condition, repeat the test process of the above steps, and collect and record the test data under each condition until all test conditions are tested.

[0022] S4. End the test and turn off the duct heater, centrifugal fan, and cooling system in sequence. Disconnect the power supply to the control cabinet and turn off the temperature and pressure acquisition system. Remove the cellular heat exchange structure test piece, replace it with the next test piece, reassemble the test pieces, seal them with sealant, and repeat the above test section air tightness and cold fluid tightness inspection process.

[0023] S5. Repeat the above test process until the flow heat transfer test experiments of all cellular heat transfer structure test pieces are completed.

[0024] Furthermore, the following steps are also included before the start of the experiment:

[0025] S1. Connect the thermocouple thermometer and pressure probe to the temperature and pressure acquisition system, and check the connection between the acquisition instrument and each pipeline. Turn on the power switch of the control cabinet, start the centrifugal fan, complete the air tightness of the air flow channel and pipeline system of the test platform at the rated flow rate, and calibrate and debug the temperature and pressure acquisition system.

[0026] S2. Under normal temperature conditions, the flow rate of the centrifugal fan is varied by adjusting the frequency to change the airflow velocity. Pressure probes installed at the front static pressure test port and the front total pressure test port of the heat exchanger test square tube are used to monitor and record the static pressure and total pressure at that frequency in real time. The measured data are combined with known information about gas density and pipe diameter to calculate the corresponding airflow velocity. The Reynolds number under the operating conditions is calculated based on the airflow velocity, characteristic pipe dimensions, and dynamic viscosity of the fluid, thereby calibrating the airflow Reynolds number before the test section at different fan frequencies.

[0027] S3. In a static state, turn on the cooling system to cool the hot fluid, check the flowability of the cold fluid and the sealing of the pipeline, especially the fitting connection between the cellular heat exchange structure test piece and the test piece assembly flange and the cold fluid inlet and outlet assembly parts, and re-seal the leaking parts.

[0028] The test equipment mainly includes centrifugal fans and duct heaters. The centrifugal fans provide air source for the test. By adjusting the fan frequency, the flow rate of the centrifugal fans is controlled to adjust the flow rate and velocity under the test conditions. The duct heaters are controlled by a thyristor control cabinet to adjust the heating temperature, so that the air temperature can be adjusted within the range of 20℃~300℃.

[0029] The airflow channel piping system refers to the channel piping that connects various devices in the test platform and transports flowing air, including the intake pipe, the steady flow channel pipe, the test pipe and the exhaust pipe. The various sections of the channel pipes are connected by flanges; the intake pipe is composed of a square-to-circular gradually contracting channel and a curved circular pipe, connecting the centrifugal fan and the inlet of the duct heater to send the centrifugal fan air into the duct heater; the steady flow channel pipe is composed of a circular straight pipe and a circular-to-square gradually contracting channel, connecting the outlet of the duct heater and the test pipe to stabilize the hot air flowing out of the duct heater; the test pipe has four static pressure test holes, one total pressure test hole and one temperature test hole. The two test pipes are installed in front and behind the test section respectively, and pressure probes and temperature probes are installed on them to measure the temperature and pressure of the inlet and outlet of the test section; the exhaust channel is composed of a square-to-circular gradually expanding channel and a circular straight pipe, connecting the test pipe and the exhaust nozzle, and discharging the test exhaust gas;

[0030] The cooling system provides cooling medium to cool the high-temperature gas for the heat exchange of the cellular heat exchange structure test piece, ensuring that the cooling fluid flow remains constant, maintaining a stable flow state of the cold fluid in the test piece, and maintaining a stable cold source for the flow heat exchange test of the test piece;

[0031] The test system includes thermocouple thermometers, pressure probes, and temperature and pressure collectors. The thermocouple thermometers and pressure probes are installed in front and behind the test piece, and transmit data signals to the temperature and pressure collectors respectively to monitor and collect temperature and pressure data during the test.

[0032] During the test, first turn on the power and adjust the frequency of the centrifugal fan to provide air source for the test platform. The air flows into the heater through the pipe. Then set the heating temperature, start the heater, heat the incoming air, and wait until it is heated to the set temperature and the air flow stabilizes for a certain period of time. At this time, the hot air flows out of the heater, flows into the test piece through the pipes, and exchanges heat with the cold fluid through the wall of the test piece. The air flow after heat exchange is then discharged through the pipes and reaches the critical state at the outlet through the exhaust nozzle. Static pressure, total pressure and temperature measuring holes are arranged on the pipes before and after the test piece, and the temperature and pressure of the test piece inlet and outlet are measured by temperature probes and pressure probes.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention is aimed at testing the flow and heat exchange performance of a complex cellular heat exchange structure. A centrifugal fan is used to provide an air source and a duct heater is used for heating. The hot air exchanges heat with a cooling medium in a test piece of the cellular heat exchange structure. By collecting and recording the temperature and pressure data at the inlet and outlet of the test piece, the flow and heat exchange performance of the cellular heat exchange structure is evaluated and analyzed. By selecting test pieces with different cell configurations and different structural parameters and processing the surface roughness of the test pieces, the flow and heat exchange performance of the cellular heat exchange structure can be tested under different cell configurations, different structural parameters and different surface roughness, and the influence of the configuration type, structural parameters and surface roughness on the flow and heat exchange performance of the cellular heat exchange structure can be evaluated and analyzed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of a heat exchange performance testing platform applicable to different cell structures of the present invention.

[0036] Figure 2 It is a schematic diagram of the test section structure of the present invention, which is applicable to the heat exchange performance test platform of different cell structures.

[0037] Figure 3 It is a schematic diagram of the test section decomposition of the test platform of the present invention that is applicable to heat exchange performance testing platforms with different cell structures.

[0038] Figure 4 It is a schematic diagram of the square tube structure before heat exchange testing of the present invention, which is applicable to the heat exchange performance testing platform of different cell structures.

[0039] Figure 5 It is a schematic diagram of the square tube structure for testing after heat exchange, which is applicable to a heat exchange performance testing platform with different cell structures according to the present invention.

[0040] Figure 6 It is a structural schematic diagram of a cellular heat exchange structure test piece suitable for a heat exchange performance test platform of different cellular structures of the present invention.

[0041] In the figure: 1, centrifugal fan, 2, duct heater, 3, test section, 3a, cellular heat exchange structure test piece, 3a-1, cold flow inlet, 3a-2, cold flow outlet, 3a-3, hot flow inlet, 3a-4, hot flow outlet, 3b, test piece assembly flange, 3b-1, hot flow inlet flange, 3b-2, hot flow outlet flange, 3c, cold fluid inlet and outlet assembly parts, 3c-1, cold flow inlet part, 3c-11, cold flow inlet circular pipe, 3c-12, round to square gradually expanding inlet, 3c-2, cold flow outlet part, 3c-21, square to round gradually shrinking outlet, 3c-22, cold flow outlet circular pipe, 3c-3, test assembly parts;

[0042] 4a, intake pipe, 4a-1, square-to-circular convergent channel, 4a-2, curved circular pipe, 4b, steady flow pipe, 4b-1, steady flow circular straight pipe, 4b-2, circular-to-square convergent channel, 4c, square pipe for test before heat exchange, 4c-1, front static pressure test hole, 4c-2, front total pressure test hole, 4c-3, front temperature test hole, 4c-4, front test square pipe outlet flange, 4d, square pipe for test after heat exchange, 4d-1, rear static pressure test hole, 4d-2, rear total pressure test hole, 4d-3, rear temperature test hole, 4d-4, rear test square pipe inlet flange, 4e, exhaust channel, 4e-1, square-to-circular divergent channel, 4e-2, exhaust circular straight pipe, 5. Cooling system, 6. Exhaust nozzle, 7. Bracket. DETAILED DESCRIPTION

[0043] The microtube vibration wind tunnel test section of the present invention is described in detail below with reference to the accompanying drawings and specific implementation plans.

[0044] A platform suitable for testing the heat exchange performance of different cell structures includes a centrifugal fan 1, a ducted heater 2, a test section 3, an airflow channel piping system 4, a cooling system 5, an exhaust nozzle 6, and a bracket 7. Adjacent pipe sections are connected by flanges. The platform also includes test equipment such as the centrifugal fan and ducted heater, a cell heat exchange structure test piece, an airflow channel piping system, a cooling system, and a test system.

[0045] The centrifugal fan 1 provides an air source for the platform applicable to the heat exchange performance testing of different cell structures in this application, and delivers the airflow into the duct heater 2 through the air intake duct 4a of the airflow channel piping system 4. The duct heater 2 heats the intake air. The heater is controlled by a thyristor frequency converter, so that the air temperature is stable and adjustable within the range of 20°C to 300°C. The hot air then enters the test section 3 through the steady flow duct 4b of the airflow channel piping system. The steady flow duct 4b uses a steady flow straight circular pipe 4b-1 and a circular-to-square tapered channel 4b-2. The front static pressure test hole 4c-1, the front total pressure test hole 4c-2, and the temperature test hole 4c-3 are sequentially arranged on the front test square tube 4c along the flow direction of the airflow. The front test square tube outlet flange 4c-4 of the front test square tube 4c is connected to the heat flow inlet flange 3b-1 of the test section 3.

[0046] The test section 3 is composed of a cellular heat exchange structure test piece 3a, a test piece assembly flange 3b, and a cold fluid inlet and outlet assembly part 3c. The two test piece assembly flanges 3b are connected with the two ends of the cellular heat exchange structure test piece 3a; and the cold fluid inlet and outlet assembly parts 3c are fixed on the cellular heat exchange structure test piece 3a by fitting and bolt connection. The cold fluid inlet and outlet circular pipes on the cellular heat exchange structure test piece 3a can be connected with the inlet and outlet pipes to provide cooling medium for the test section 3; the fitting connection between the cellular heat exchange structure test piece 3a and the test piece assembly flange 3b and the cold fluid inlet and outlet assembly parts 3c is sealed by applying sealant to ensure that the hot air and cold fluid of the test section 3 do not leak during the test; the cellular heat exchange structure test piece 3a is provided with a cold flow inlet 3a-1, a cold flow outlet 3a-2, and a hot flow inlet 3a-3. a-3 and hot flow outlet 3a-4; the hot flow inlet flange 3b-1 in the test piece assembly flange 3b is set at the hot flow inlet 3a-3, and the hot flow outlet flange 3b-2 is set at the hot flow outlet 3a-4; the cold fluid inlet and outlet assembly parts 3c adopt cold flow inlet parts 3c-1 and cold flow outlet parts 3c-2 to be connected with the test assembly parts 3c-3 respectively, and are set on the outside of the cellular heat exchange structure test piece 3a; the cold flow inlet part 3c-1 adopts a cold flow inlet circular tube 3c-11 to be connected with the round-to-square gradually expanding inlet 3c-12, and the round-to-square gradually expanding inlet 3c-12 cooperates with the cold flow inlet 3a-1; the cold flow outlet part 3c-2 adopts a square-to-round gradually shrinking outlet 3c-21 to be connected with the cold flow outlet circular tube 3c-22, and the square-to-round gradually shrinking outlet 3c-21 cooperates with the cold flow outlet 3a-2.

[0047] The hot flow outlet flange 3b-2 of test section 3 is connected to the rear test square tube inlet flange 4d-4 of the post-heat exchange test square tube 4d. The post-heat exchange test square tube 4d is provided with a rear temperature test hole 4d-3, a rear total pressure test hole 4d-2, and a rear static pressure test hole 4d-1, sequentially along the airflow direction. The cooling system 5 is connected to the cold flow inlet and outlet pieces 3c-1 and 3c-2, respectively. The exhaust duct 4e, consisting of a square-to-circular diverging channel 4e-1 and a straight exhaust pipe 4e-2, connects to the post-heat exchange test square tube 4d and the exhaust nozzle 6, discharging the test exhaust gas.

[0048] Two test pipes are installed at the front and rear of test section 3, with pressure and temperature probes mounted on them to measure the temperature and pressure at the inlet and outlet of test section 3. The average of the four static pressure test values ​​is used as the static pressure of the mainstream airflow to reduce errors. Combined with the total pressure value, the airflow velocity can be calculated. Furthermore, the distance between the front total pressure test hole 4c-2 and the front test square pipe outlet flange 4c-4 is at least five times the cross-sectional width of the test square pipe 4c before the heat exchange. The distance between the rear total pressure test hole 4d-2 and the rear test square pipe inlet flange 4d-4 is at least five times the cross-sectional width of the test square pipe 4d after the heat exchange. This ensures the stability of the measured pressure.

[0049] The cooling system 5 provides a cold fluid with stable flow and temperature to the cellular heat exchange structure test piece 3a to exchange heat with the high-temperature gas in the cellular heat exchange structure test piece 3a. The cold fluid can be a cooling medium such as low-temperature helium, cold water, etc.

[0050] The exhaust nozzle 6 controls the airflow exhaust outlet to a critical state to avoid the outlet back pressure from affecting the test pressure, thereby ensuring the accuracy of the test results.

[0051] The bottom of the bracket 7 is fixed to the bottom surface and connected by anchor bolts. The top is a semicircular support platform, which is connected to the pipe of the air flow channel pipeline system 4 to support the test pipeline.

[0052] The cellular heat exchange structure test piece 3a converts the cellular heat exchange micro-elements such as TPMS and honeycomb into a rectangular heat exchange structure channel. In addition to the hot fluid inlet and outlet, there are two cold fluid inlets and outlets on the side of the test piece. The hot and cold fluids exchange heat through the internal wall of the cellular heat exchange structure test piece 3a. In order to ensure that the flow and heat exchange of the hot and cold fluids are sufficient as much as possible, the ratio of the length and width of the test piece channel section to the length of the test piece is 1:3.

[0053] The cellular heat exchange structure test piece 3a is not limited to one type of cellular heat exchange structure, but is applicable to heat exchange structures composed of cellular heat exchange micro-elements such as various types of TPMS and honeycomb-like structures. By performing surface treatment on the inner surface of the channel to obtain cellular heat exchange structure test pieces 3a with different surface roughness, the flow and heat exchange of the cellular heat exchange structure under different surface roughness can be carried out to evaluate the influence of surface roughness on the flow and heat exchange performance of the cellular heat exchange structure.

[0054] The centrifugal fan 1 provides an air source, which is heated in the duct heater 2 and flows through the cellular heat exchange structure test piece 3a in the test section 3 to exchange heat with the cooling medium. The exhaust gas is then discharged through the steady-flow exhaust nozzle 6. At the same time, the temperature and pressure of the airflow are measured before the test section 3. Based on this, the flow heat transfer performance parameters such as the surface heat transfer coefficient, Nu number, and friction resistance coefficient after the hot air passes through the cellular heat exchange structure test piece 3a are calculated to evaluate the flow heat transfer performance of the cellular heat exchange structure test piece 3a.

[0055] A test method for a platform suitable for testing heat transfer performance of different cell structures comprises the following steps:

[0056] S1. Build a test platform for testing the flow and heat transfer performance of a cellular heat exchange structure. Assemble all components according to the test plan. Connect the thermocouple thermometer and pressure probe to the temperature and pressure acquisition system. Check the connections between the acquisition instruments and each pipeline. After ensuring that everything is correct, turn on the power switch of the control cabinet, start the centrifugal fan 1, and complete the air tightness test of the airflow channel pipeline system 4 of the test platform at the rated flow rate. At the same time, calibrate and debug the temperature and pressure acquisition system.

[0057] S2. Under normal operating conditions, adjust the frequency of centrifugal fan 1 to change the flow rate and thus the airflow velocity. Using an inlet pressure probe installed on the test pipeline, monitor and record the static and total pressures at a specific frequency in real time. Using this measured data, combined with known information such as gas density and pipeline diameter, calculate the corresponding airflow velocity. Furthermore, based on the airflow velocity, characteristic pipeline dimensions, and dynamic viscosity of the fluid, calculate the Reynolds number for the specific operating conditions, thereby calibrating the airflow Reynolds number before test section 3 at different fan frequencies.

[0058] S3. In a static state, turn on the cooling system 5 to cool the hot air and check the flowability of the cold fluid and the tightness of the pipelines, especially the joints between the cellular heat exchange structure test piece 3a, the test piece assembly flange 3b, and the cold fluid inlet and outlet fittings 3c. Reseal any leaks with glue.

[0059] S4. The test officially begins by turning on the power switch of the control cabinet, starting the centrifugal fan 1, and adjusting the fan frequency to the specified Reynolds number; turning on the cooling system 5, passing the cold fluid into the cellular heat exchange structure test piece 3a to cool the hot air; setting the heating temperature of the duct heater 2 to the specified operating temperature, and turning on the heating switch to heat the intake air;

[0060] S5. Observe the results displayed by the pressure acquisition system and check the temperature detector readings. After the pressure and temperature values ​​stabilize, record the inlet and outlet temperatures and inlet and outlet pressure values, and repeat the test data acquisition at equal intervals.

[0061] S6. After collecting the inlet and outlet temperature and inlet and outlet pressure data of the test condition, adjust the frequency of the centrifugal fan 1 and the heating temperature of the duct heater 2 to the next test condition, repeat the test process of the above steps, and collect and record the test data under each condition until all test conditions are tested;

[0062] S7. End the test. Turn off the duct heater 2, centrifugal fan 1, and cooling system 5 in sequence. Disconnect the power to the control cabinet and shut down the temperature and pressure acquisition systems. Remove the cellular heat exchange structure test piece 3a, replace it with the next type of test piece, reassemble it, and seal it with sealant. Repeat the air tightness and cold fluid tightness inspection process in test section 3 above.

[0063] S8. Repeat the above test process until the flow heat transfer test experiments of all cellular heat transfer structure test pieces 3a are completed.

[0064] The above description is only a description of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any changes or modifications made by any person skilled in the art based on the above disclosed technical content should be regarded as equivalent valid embodiments and fall within the scope of protection of the technical solution of the present invention.

Claims

1. A platform suitable for testing the heat transfer performance of different cell structures, characterized by: It includes a centrifugal fan (1), a duct heater (2), a test section (3), a cooling system (5), and an exhaust nozzle (6); The centrifugal fan (1) is connected to the inlet of the duct heater (2) via an air inlet pipe (4a); the outlet of the duct heater (2) is sequentially connected to a flow stabilizing pipe (4b), a pre-heat exchange test square pipe (4c), a test section (3), a post-heat exchange test square pipe (4d), an exhaust channel (4e), and an exhaust nozzle (6); adjacent sections of the pipe are connected by flanges; the flow stabilizing pipe (4b) and the exhaust channel (4e) are supported by brackets (7), respectively; The flow stabilizing pipeline (4b) adopts a flow stabilizing circular straight pipe (4b-1) and a circular-to-square tapered channel (4b-2); a front static pressure test hole (4c-1), a front total pressure test hole (4c-2), and a temperature test hole (4c-3) are sequentially provided on the front heat exchange test square pipe (4c) along the flow direction of the airflow; and a front test square pipe outlet flange (4c-4) of the front heat exchange test square pipe (4c) is connected to a heat flow inlet flange (3b-1) of the test section (3); The test section (3) includes a cellular heat exchange structure test piece (3a), a test piece assembly flange (3b) and a cold fluid inlet and outlet assembly part (3c). The cellular heat exchange structure test piece (3a) is provided with a cold flow inlet (3a-1), a cold flow outlet (3a-2), a hot flow inlet (3a-3) and a hot flow outlet (3a-4); the hot flow inlet flange (3b-1) of the test piece assembly flange (3b) is provided at the hot flow inlet (3a-3), and the hot flow outlet flange (3b-2) is provided at the hot flow outlet (3a-4); the cold fluid inlet and outlet assembly part (3c) adopts a cold flow inlet part (3c-1) and the cold flow outlet piece (3c-2) are respectively connected to the test assembly part (3c-3) and are arranged on the outside of the cellular heat exchange structure test piece (3a); the cold flow inlet piece (3c-1) adopts a cold flow inlet circular tube (3c-11) to be connected with the circular-to-square gradually expanding inlet (3c-12), and the circular-to-square gradually expanding inlet (3c-12) is matched with the cold flow inlet (3a-1); the cold flow outlet piece (3c-2) adopts a square-to-circular gradually shrinking outlet (3c-21) to be connected with the cold flow outlet circular tube (3c-22), and the square-to-circular gradually shrinking outlet (3c-21) is matched with the cold flow outlet (3a-2); The cellular heat exchange structure test piece (3a) converts the TPMS and the honeycomb-like cellular heat exchange micro-element adaptability into a rectangular parallelepiped heat exchange structure channel, and the cold and hot fluids exchange heat through the inner wall surface of the cellular heat exchange structure test piece (3a); The heat flow outlet flange (3b-2) of the test section (3) is connected to the rear test square tube inlet flange (4d-4) of the heat exchange rear test square tube (4d), and the heat exchange rear test square tube (4d) is provided with a rear temperature test hole (4d-3), a rear total pressure test hole (4d-2) and a rear static pressure test hole (4d-1) in sequence along the flow direction of the airflow; The cooling system (5) is respectively connected to the cold flow inlet piece (3c-1) and the cold flow outlet piece (3c-2).

2. A platform suitable for testing heat transfer performance of different cell structures according to claim 1, characterized in that: The air intake pipeline (4a) adopts a square-to-circular gradually converging channel (4a-1) and a curved circular tube (4a-2).

3. A platform suitable for testing heat transfer performance of different cell structures according to claim 2, characterized in that: The distance between the front total pressure test hole (4c-2) and the front test square tube outlet flange (4c-4) is more than 5 times the cross-sectional width of the front heat exchange test square tube (4c).

4. A platform suitable for testing heat transfer performance of different cell structures according to claim 3, characterized in that: The distance between the rear total pressure test hole (4d-2) and the rear test square tube inlet flange (4d-4) is more than 5 times the cross-sectional width of the heat exchange rear test square tube (4d).

5. A platform suitable for testing heat transfer performance of different cell structures according to claim 4, characterized in that: The ratio of the channel cross-sectional width of the test section (3) to the length of the test piece is 1:

3.

6. A platform suitable for testing heat transfer performance of different cell structures according to claim 5, characterized in that: The centrifugal fan (1) provides an air source, which is heated in the duct heater (2) and flows through the cellular heat exchange structure test piece (3a) in the test section (3) to exchange heat with the cooling medium, and then the exhaust gas is discharged through the steady-flow exhaust nozzle (6); at the same time, the temperature and pressure of the air flow are measured before and after the test section (3), and based on this, the flow heat transfer performance parameters of the hot air after passing through the cellular heat exchange structure test piece (3a), such as the surface heat transfer coefficient, Nu number, and friction resistance coefficient, are calculated.

7. The test method of a platform suitable for testing the heat transfer performance of different cell structures according to claim 6, characterized in that: The following steps are involved: S1. Start the test, start the centrifugal fan (1), and adjust the fan frequency; start the cooling system (5), and pass the cold fluid into the cellular heat exchange structure test piece (3a) to cool the hot fluid; set the heating temperature of the duct heater (2) to the specified operating temperature, turn on the heating switch, and heat the intake air; S2. Observe the results displayed by the pressure acquisition system and check the readings of the temperature detector. After the pressure and temperature values ​​are stable, record the temperature and pressure values ​​on the test square tube (4c) before and after the heat exchange and the test square tube (4d) after the heat exchange before and after the test section (3), and repeat the test data acquisition at equal time intervals; S3. After collecting the temperature and pressure data on the test square tube (4c) before and after the heat exchange and the test square tube (4d) after the heat exchange before and after the test section (3) of the test condition, adjust the frequency of the centrifugal fan (1) and the heating temperature of the duct heater (2) to the next test condition, repeat the test process of the above steps, collect and record the test data under each condition, until all test conditions are completed; S4. End this test, turn off the duct heater (2), centrifugal fan (1), and cooling system (5) in sequence, disconnect the power supply of the control cabinet and turn off the temperature and pressure acquisition system; remove the cellular heat exchange structure test piece (3a), replace it with the next test piece, and re-join the test pieces, seal them with sealant, and repeat the air tightness and cold fluid sealing inspection process of the above test section (3); S5. Repeat the above test process until the flow heat transfer test experiments of all cellular heat transfer structure test pieces (3a) are completed.

8. The test method of a platform suitable for testing the heat transfer performance of different cell structures according to claim 7, characterized in that: The following steps are also included before the trial begins: S1. Connect the thermocouple thermometer and the pressure probe to the temperature and pressure acquisition system respectively, and check the connection between the acquisition instrument and each pipeline; turn on the power switch of the control cabinet, start the centrifugal fan (1), complete the air tightness of the air flow channel pipeline system (4) of the test platform at the rated flow rate, and at the same time calibrate and debug the temperature and pressure acquisition system; S2. Under normal temperature conditions, the flow rate of the centrifugal fan (1) is changed by adjusting the frequency to change the airflow velocity, and the static pressure and total pressure at the frequency are monitored and recorded in real time by means of pressure probes installed on the front static pressure test hole (4c-1) and the front total pressure test hole (4c-2) of the heat exchange front test square tube (4c). The measured data are combined with the known information of gas density and pipe diameter to calculate the corresponding airflow velocity; the Reynolds number under the working condition is solved according to the airflow velocity, the characteristic size of the pipe and the dynamic viscosity of the fluid, thereby calibrating the airflow Reynolds number before the test section (3) at different fan frequencies; S3. In a static state, open the cooling system (5) to cool the hot fluid, check the flowability of the cold fluid and the sealing of the pipeline, especially the fitting connection between the cellular heat exchange structure test piece (3a) and the test piece assembly flange (3b) and the cold fluid inlet and outlet assembly parts (3c), and re-seal the leaking parts.

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