A low-energy-consumption double-flow wide-working-condition heat transfer characteristic experiment system

Abstract

The present application belongs to the technical field of heat transfer characteristic analysis of gas turbine engine parts, and relates to a low-energy-consumption double-flow wide-condition heat transfer characteristic experiment system. The present application makes full use of the effect of turbojet engine, replaces multiple heating and pressurizing devices, simplifies the experiment system and reduces the experiment cost. The present application uses the gas generated by the turbojet engine as the main flow working medium, and the composition is closer to the real engine part working environment, so the experiment result is more reliable. The present application directly uses high-temperature gas as the main flow working medium, has high energy conversion efficiency, uses the secondary flow to heat the exhaust heat of the main flow, and reduces the energy consumption. The secondary flow temperature adjusting system of the present application has simple structure, large adjusting range and high safety. The present application flexibly and effectively realizes the matching of engine performance and various experiment conditions through the combined structure design of the switching pipeline and the adjusting orifice plate. The present application expands the applicable range of experiment conditions.

Description

Technical Field

[0001] This invention belongs to the technical field of heat transfer characteristic analysis of gas turbine engine components, and relates to a low-energy-consumption dual-flow-path wide-condition heat transfer characteristic experimental system. Background Technology

[0002] With the continuous improvement of gas turbine engine performance, the temperature of the gas inlet before the turbine is rising, far exceeding the temperature resistance limit of blade materials. In this extreme high-temperature environment, efficient cooling is essential to ensure the safe and long-term operation of turbine blades. Obtaining the heat transfer characteristics of turbine blades through scientific experimental methods is an indispensable part of blade cooling structure design, offering more intuitive and accurate advantages compared to methods such as numerical simulation and pipeline calculations.

[0003] In the field of heat transfer research, two-channel heat transfer experimental systems have a wide range of applications, with typical experimental schemes such as... Figure 1 As shown. This type of experimental scheme has two flow paths with different pressures, flow rates, and temperatures: a main flow and a secondary flow. In the main flow, air is drawn in by a main flow fan 1, and its pressure is increased. The mass flow rate of the main flow medium is then measured by a main flow meter 3. m g Then, the temperature is increased by the mainstream electric heater 6. Subsequently, the working fluid enters the mainstream stabilizing section 11, and after stabilization, it enters the mainstream measuring section 12. Here, the mainstream pressure sensor 13 and the mainstream thermocouple 14 measure the mainstream inlet pressure of the experimental section, respectively. P g1 and the mainstream inlet temperature of the experimental section T g1 The air then enters the main flow channel 15 of the double-sided blowing test section, flows through both sides of the double-sided blowing test piece 27 (typically a hollow turbine blade), and finally exits from the outlet of the test section pipe. The secondary flow path draws in the working air and increases its pressure through the secondary flow fan 16, and the secondary flow meter 17 measures the mass flow rate of the secondary working air. m c Then, the temperature is increased by the secondary flow electric heater 18. Subsequently, the working fluid enters the secondary flow stabilization section 23, and after stabilization, it enters the secondary flow measurement section 24. Here, the secondary flow pressure sensor 25 and the secondary flow thermocouple 26 measure the secondary flow inlet pressure of the experimental section, respectively. P c1 and the secondary flow inlet temperature of the experimental section T c1 The air then enters the internal channel of the double-sided blowing test piece 27, exchanges heat with it, and flows out from the outlet of the test piece, eventually merging into the mainstream and being discharged from the test section pipe. During the experiment, the flow rate, pressure, and temperature were continuously adjusted, and the surface temperature of the double-sided blowing test piece 27 was monitored. T wMeasurements (such as using calibrated thermocouples) are performed to calculate and evaluate the quality of the experimental component's cooling design. The pipes after heating the main and secondary flows are covered with a thermal insulation layer 28 to reduce heat loss from the experimental system and prevent personnel from being burned by the high-temperature pipes.

[0004] As mentioned above, background experimental schemes typically equip the main flow path and secondary flow path with fans and electric heaters respectively to meet the pressure and temperature requirements of the working fluid in both flow paths. These two devices are often quite large; for the electric heater, a large power supply and power control equipment are also required, further increasing the complexity and space required by the experimental system. Furthermore, from an energy utilization perspective, the process of converting electrical energy into heat energy and transferring it to the gaseous working fluid involves some energy loss. If the electrical energy comes from thermal power generation burning fuel, the final thermal efficiency transferred to the experimental working fluid is usually below 60%. From the perspective of energy loss, the heated high-temperature main flow path still retains significant heat after exiting the experimental section pipe outlet, but existing experimental schemes usually directly discharge it into the atmosphere without secondary energy utilization, resulting in complete energy loss. In summary, existing heat transfer experimental systems suffer from drawbacks such as complex design, large size, high cost, and high energy consumption, and urgently require improvement. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a low-energy-consumption dual-flow-path wide-condition heat transfer characteristic experimental system. In the main flow path, a turbojet engine serves as both the air and heat source, replacing the fan and electric heater in the background scheme with a relatively compact device. This satisfies the dual temperature and pressure requirements of the main flow path while reducing the overall space required for the experimental platform. Furthermore, the secondary flow temperature control system employed in this invention utilizes the waste heat from the main flow exhaust to raise and regulate the secondary flow temperature, eliminating the need for a secondary flow heating device and its energy input. This further simplifies the experimental system, saves experimental costs, and reduces energy consumption. Compared to the background heat transfer experimental scheme, the experimental system of this invention, while achieving the same operating conditions, reduces the experimental platform pipe length and floor space by more than 40% and energy consumption by approximately 30%.

[0006] The present invention adopts the following technical solution:

[0007] A low-energy-consumption dual-flow-path wide-condition heat transfer characteristic experimental system consists of two parts: a piping system and a measurement and control system. The piping system includes two flow paths: a main flow path and a secondary flow path. Figure 2 As shown. Unlike the previous scheme that used a fan and an electric heater, the main flow path of this invention uses a turbojet engine to provide a high-temperature, high-pressure gaseous working fluid. After the turbojet engine is ignited, air is drawn into the pipeline through the main flow inlet section, and its mass flow rate is measured after passing through the main flow meter. m aThe fuel then enters the turbojet engine through the engine inlet transition section. Simultaneously, the turbojet engine draws fuel from the fuel tank via a fuel pump, and its mass flow rate is measured by a fuel flow meter. m f Subsequently, the turbojet engine ejects high-temperature, high-pressure combustion gas, which serves as the mainstream working fluid entering the expansion engine outlet transition section. The pressure increases and the velocity decreases as the pipe cross-sectional area gradually expands along the flow path. The fluid then flows through a regulating orifice plate, where the pressure is reduced to approximately atmospheric pressure while maintaining the velocity, and the flow is rectified. Through the combined regulation of the transition pipe and orifice plate structure, the mainstream reaches the experimental operating conditions. The working fluid then enters the mainstream pressure stabilization section, and after flow stabilization, it enters the mainstream measurement section. Here, the mainstream pressure sensor and mainstream thermocouple measure the mainstream inlet pressure of the experimental section. P g1 and the mainstream inlet temperature of the experimental section T g1 Then it enters the main channel of the double-sided blowing test section, flows through both sides of the double-sided blowing test piece, and finally exits from the outlet of the test section pipe.

[0008] The secondary flow path draws in air working fluid through a secondary flow fan and increases its pressure, then flows through a secondary flow meter to measure its mass flow rate. m c The fluid then flows through a metal hose into the spiral heat exchanger tube. The spiral heat exchanger tube is positioned downstream of the main flow outlet of the double-sided blowing test section via a pipe clamping device and a displacement mechanism. It utilizes the waste heat of the main flow exhaust for heating, and the displacement mechanism controls the depth of the spiral heat exchanger tube's penetration into the main flow exhaust gas to regulate the secondary flow temperature. After passing through the spiral heat exchanger tube, the secondary flow working fluid flows through the metal hose into the secondary flow stabilization section. After stabilization, it enters the secondary flow measurement section, where a secondary flow pressure sensor and a secondary flow thermocouple measure the secondary flow inlet pressure of the test section. P c1 and the secondary flow inlet temperature of the experimental section T c1 It then enters the internal channel of the double-sided blowing test piece, exchanges heat with it, flows out from the outlet of the test piece, and finally merges into the mainstream and is discharged from the test section pipeline.

[0009] The pipelines after heating the main and secondary flows are covered with thermal insulation layers to reduce heat loss in the experimental system and prevent experimental personnel from being burned by the high-temperature pipelines.

[0010] The circuit connection scheme of the measurement and control system of the present invention is as follows: Figure 3 As shown. The main measurement scheme includes: using a main flow meter, a fuel flow meter, and a secondary flow meter to measure the main flow intake air mass flow rate. m a Engine fuel mass flow rate m fand the mass flow rate of the secondary working fluid m c Among them, the mainstream intake air mass flow rate m a With engine fuel mass flow rate m f The sum of these values ​​represents the mass flow rate of the main working fluid. m g The pressure at the main flow inlet of the experimental section was measured using both a main flow pressure sensor and a secondary flow pressure sensor. P g1 and the secondary flow inlet pressure of the experimental section P c1 The inlet temperature of the main flow in the experimental section was measured using both the main flow thermocouple and the secondary flow thermocouple. T g1 and the secondary flow inlet temperature of the experimental section T c1 An infrared glass and an infrared thermal imager were installed above the experimental specimen to measure the average temperature of the specimen's surface. T w Several thermocouple mounting slots are made on the surface of the test piece to be measured, and calibration thermocouples are embedded therein to obtain wall surface measurement point temperatures with sufficient accuracy. T wi This serves as a reference standard for correcting infrared measurement results. The flow meter, pressure sensor, and thermocouples are connected to a data acquisition unit via signal lines. The data acquisition unit is connected to a computer for data transmission, processing, and storage. The infrared thermal imager is directly connected to the computer to collect temperature field data. The main control scheme includes: controlling the secondary flow fan speed via a fan speed controller to regulate the secondary flow rate; connecting the turbojet engine and oil pump circuits to the engine control console to remotely control the turbojet engine's start / stop and throttle; and adjusting the position of the spiral heat exchanger tubes via a displacement mechanism control console.

[0011] The piping system and measurement and control system maintain a sufficient safe distance in space, and effective safety protection measures are set for the turbojet engine to ensure the safety of the experimental operators.

[0012] Referring to Figures 4(a) to 4(c), the design and connection scheme of the main pipeline after the turbojet engine in this invention will be further explained. As shown in Figure 4(a), the original tail nozzle of the turbojet engine is a converging nozzle, connected after the turbine outlet of the turbojet engine. Its function is to convert the pressure energy of the combustion gas into kinetic energy, so that a high-speed atmospheric pressure airflow is ejected from the nozzle outlet, thereby providing sufficient thrust. When not connected to the main pipeline, that is, when the turbojet engine is working alone, the pressure change along the flow direction in its original tail nozzle is shown by the dotted line in Figure 4(c), gradually decreasing to atmospheric pressure before being discharged into the atmosphere.

[0013] In this invention, the original tail nozzle is removed from the turbojet engine and a new pipeline (such as the mainstream measurement section) is designed as a replacement based on the mainstream pressure and velocity requirements within the experimental section. As shown in Figure 4(b), the turbojet engine is connected to an expansion-type engine outlet transition section. Its inlet cross-section is the same as the original tail nozzle, which is a circular cross-section and is equipped with a flow straightening cone. It is connected to the turbine outlet of the engine. After a smooth transition, the outlet becomes a rectangular cross-section with a larger area than the inlet, forming an expansion-type pipeline. An adjusting orifice plate is installed after the expansion-type engine outlet transition section. Its function is to provide a suitable pressure drop for the pipeline system to match the engine operating characteristics, prevent turbine over-rotation, and also serve as a flow straightening agent. When the required pressure drop of the pipeline is large, multiple layers of tandem adjusting orifice plates can be installed, typically such as straight-hole adjusting orifice plates and expansion-hole adjusting orifice plates. An orifice plate spacing adjusting flange is installed between adjacent orifice plates, and the orifice plate spacing and airflow pressure drop are adjusted by the thickness of the flange. The pressure change along the flow direction in the main pipeline is shown by the solid line in Figure 4(c). When the main working fluid flows through the outlet transition section of the expansion engine, the kinetic energy of the working fluid is converted into pressure energy due to the gradual increase in cross-sectional area, resulting in a decrease in flow velocity and an increase in pressure. Subsequently, after passing through one or more regulating orifice plates, the pressure rapidly decreases to near atmospheric pressure before entering the main pressure stabilization section, maintaining stable flow and providing the required low-speed, normal-pressure main pipeline conditions for the experimental section. This scheme causes the pressure in the main pipeline to first increase and then decrease, with the overall pressure drop value being the same as the original tail nozzle, thus replacing the original tail nozzle and ensuring the safe and stable operation of the turbojet engine under the required experimental conditions.

[0014] Referring to Figures 5(a) and 5(b), the structure of the regulating orifice plate is further explained. As shown in Figure 5(a), the regulating orifice plate is a thin plate with multiple openings in the middle region. These openings are evenly distributed throughout the main flow channel area. The opening shape can be circular, elliptical, or rectangular, etc. Along the flow direction, it can be a straight-hole structure with a constant cross-sectional area, as shown by the straight-hole regulating orifice plate to the left of the center line in Figure 5(a), or an expansion-hole structure with a gradually increasing cross-sectional area, as shown by the expansion-hole regulating orifice plate to the right of the center line in Figure 5(a). To ensure the pressure reduction effect, the openings of adjacent orifice plates are staggered to avoid forming a smooth airflow channel. A typical assembly scheme for a multi-layer orifice plate is shown in Figure 5(b). It is connected to the upstream and downstream pipes via flanges, and an orifice plate spacing adjustment flange is installed between the two orifice plates. Along the flow direction of the working fluid, the hydraulic diameter of the openings in the multi-layer orifice plate gradually decreases, and the thickness of the orifice plate spacing adjustment flange between adjacent orifice plates gradually decreases, which can improve the pressure drop effect. As shown in Figure 4(c), for the expansion orifice regulating plate, since the flow area of ​​its opening gradually increases along the process, the working fluid pressure is restored to a certain extent after being drastically reduced, resulting in a better rectification effect and improving the uniformity of subsequent flow.

[0015] Furthermore, the relative orifice diameter of the regulating orifice plate is defined. φ :

[0016] For straight-hole adjusting plate φ = d o / d m

[0017] For expansion hole adjustment plate φ = d o1 / d m

[0018] In the formula, d o The single-hole hydraulic diameter of the straight-hole regulating orifice plate. d o1 To adjust the hydraulic diameter of the small end of a single orifice of the expansion orifice plate, d m The hydraulic diameter of the main channel section with equal cross-section.

[0019] Define the orifice ratio of the regulating orifice plate k = A o / A m

[0020] In the formula, A o This represents the total open area of ​​the orifice plate. For expansion orifice plates, the area is calculated based on the smaller end of the orifice. A m It is the cross-sectional area of ​​the main channel section.

[0021] Define the taper of the expansion orifice adjustment plate. c =( d o2 - d o1 ) / t

[0022] In the formula, d o2 To adjust the hydraulic diameter of the large end of a single orifice of the expansion orifice plate, t To adjust the thickness of the perforated plate.

[0023] While ensuring sufficient strength, adjust the relative aperture of the orifice plate. φ The porosity can be 0.03~0.15. k The taper can be 0.2~0.7. c It can be 0 to 0.4.

[0024] The double-sided blowing test section scheme will now be further explained with reference to Figures 6(a) and 6(b). The assembly process is shown in Figure 6(a). The main flow channel of the double-sided blowing test section is connected to the main flow measurement section. An infrared window is opened on the upper wall of the test section, and after the infrared glass is installed, it is fixed using a flange cover. A mounting hole for the double-sided blowing test piece is set in the middle of the side of the main flow channel. The mounting hole has the same cross-sectional shape as the test piece and ensures sufficient assembly clearance. Several thermocouple mounting slots are set on the measured surface of the double-sided blowing test piece, and calibration thermocouples are embedded to correct the infrared measurement results. Before installing the test piece, the leads of the calibration thermocouples are first passed through the mounting hole of the double-sided blowing test piece on the side and led out from the flow channel outlet. Then, the double-sided blowing test piece is pushed into the main flow channel of the double-sided blowing test section through the mounting hole and fixed to the pipe by the flange structure, so that both the upper and lower sides of the test piece are in contact with the main flow. Finally, the secondary flow channel of the test piece is connected to the secondary flow measurement section through the flange structure. After the pipeline assembly is completed, an infrared thermal imager is fixed above the area to be measured to measure the surface temperature field of the experimental piece. The assembled experimental section is shown in Figure 6(b).

[0025] The structure and working principle of the secondary flow temperature control system will now be further explained with reference to Figures 7(a) to 7(d). As shown in Figure 7(a), the spiral heat exchange tube has a spiral coil in the middle, which is the main part that exchanges heat with the main flow. Straight pipes extend from both ends and connect to the front and rear metal hoses. The length of the spiral section of the heat exchange tube is... l s outer diameter of heat exchange tube spiral d s Slightly smaller than the width of the main road w m and mainstream height h m This ensures that the central spiral section of the pipe is completely covered by the main exhaust flow. Furthermore, l s / w m and d s / h m The preferred value is within the range of 0.80 to 0.95.

[0026] The temperature adjustment process is shown in Figures 7(b) and 7(c). The spiral heat exchange tube is placed downstream of the outlet of the main channel in the double-sided blowing test section, and the distance between the heat exchange tube and the outlet of the main channel is adjusted. s Maintaining a suitable value prevents both excessive proximity, which could obstruct flow within the main channel, and excessive distance, which could reduce heat exchange efficiency. Furthermore, s / d mIt exhibits relatively ideal performance within the range of 0.3 to 2.0. Both ends of the spiral heat exchanger tube are fixed to the displacement mechanism via pipe clamping devices, and their position is adjusted as the sliding table of the displacement mechanism moves up and down, thereby changing the depth of the heat exchanger tube's intrusion into the mainstream exhaust. This alters the heating area of ​​the spiral heat exchanger tube, thus changing the heating power and secondary flow temperature. The secondary flow inlet temperature in the experimental section... T c1 Insertion depth of heat exchanger tubes as needed h The variation curve is shown in Figure 7(d). When the spiral heat exchange tube is completely outside the mainstream exhaust range, that is, when the heat exchange tube is inserted into the mainstream depth... h When the value is 0, the secondary flow is not heated by the mainstream. T c1 This is the minimum value, approximately the atmospheric temperature. As the spiral heat exchanger tube gradually penetrates deeper into the mainstream, the heat exchange with it increases, causing the secondary flow temperature to gradually rise. When h Equal to the outer diameter of the heat exchange tube spiral d s At that time, the entire spiral section of the heat exchange tube is within the mainstream exhaust range. T c1 Reaching its maximum value, it continues to increase. h At that point, the temperature stopped increasing until... h Equal to the height of the main channel h m After that, it continued to increase. h The spiral heat exchanger tubes gradually moved out of the mainstream exhaust range. T c1 It changes in the opposite trend to the curve in the figure.

[0027] The beneficial effects of this invention are:

[0028] By making full use of the turbojet engine's effect, multiple heating and pressurizing devices were replaced, simplifying the experimental system and reducing experimental costs;

[0029] Existing heat transfer experimental methods typically address the temperature and pressure requirements of the working fluid separately. First, a fan is used to increase the working fluid pressure and generate flow, then an electric heater is used to raise the working fluid temperature. Both of these devices are often costly and bulky, especially for high-power electric heaters, which usually require large power supplies and power control equipment. This invention uses a turbojet engine to supply air to the main flow path. Due to its high power density, it occupies less space and can simultaneously pressurize and heat the working fluid to meet its temperature and pressure requirements, replacing the functions of both the main flow fan and the main flow electric heater with a single device. Furthermore, this invention utilizes the waste heat from the main flow exhaust to heat and regulate the secondary flow temperature, eliminating the need for a secondary flow heating device and its energy input. Therefore, compared to the previous experimental scheme, the experimental system of this invention reduces the length of the experimental platform piping and the floor space by more than 40% while achieving the same operating conditions, simplifying the experimental system and reducing experimental costs.

[0030] Using the combustion gas produced by turbojet engines as the main working fluid, its composition is closer to the working environment of real engine parts, and the experimental results are more reliable.

[0031] The experimental system of this invention uses high-temperature combustion gas generated by turbojet engine combustion as the main working fluid. Compared with the air working fluid heated by an electric heater in the background scheme, it is closer to the working environment of real engine parts, reduces experimental errors caused by differences in working fluid properties, and increases the reliability of experimental results.

[0032] By directly using high-temperature gas as the main working fluid, the energy conversion efficiency is high, and the secondary flow is heated by the waste heat of the main exhaust, which reduces energy consumption.

[0033] The electric heater in the background scheme first needs to extract electrical energy from the power grid, then convert the electrical energy into heat energy, and then transfer the heat energy to the flowing gaseous working fluid. This process involves some energy loss. If the electrical energy comes from thermal power generation burning fuel, the final thermal efficiency transferred to the experimental working fluid is usually below 60%, failing to fully utilize the fuel. The experimental system of this invention uses the high-temperature gas directly combusted from a turbojet engine as the mainstream working fluid. All the heat generated by the fuel can be absorbed by the working fluid to produce a heating effect, with a conversion efficiency close to 100%. Compared to the electric heater method, energy conversion is more direct and utilization is higher. Furthermore, this invention utilizes a secondary flow temperature control system to heat the secondary flow using the residual heat of the mainstream flow after the experimental section is discharged, achieving secondary energy utilization and eliminating the need for energy input for heating the secondary flow, thus improving the overall energy utilization rate. Compared to the background heat transfer experimental scheme, the experimental system of this invention reduces energy consumption by approximately 30% under the same operating conditions.

[0034] The secondary flow temperature control system has a simple structure, a large adjustment range, and high safety.

[0035] The secondary flow temperature regulation system of this invention controls the depth of the spiral heat exchanger tube's insertion into the mainstream exhaust, thereby altering the heating power of the mainstream exhaust on the secondary flow and translating the temperature change of the secondary flow into a change in the insertion depth of the heat exchanger tube into the mainstream. Based on this, a simple displacement control device flexibly and effectively achieves remote temperature regulation of the secondary flow. Furthermore, this invention employs a spiral heat exchanger tube, which boasts high heat exchange efficiency. The length of its spiral section, the outer diameter of the spiral, and the distance from the mainstream outlet have all been carefully considered and designed, resulting in excellent heat exchange between the secondary flow and the mainstream. Therefore, this scheme has a wide temperature regulation range. From a safety perspective, the spiral heat exchanger tube in this invention is located outside the mainstream outlet, and a reasonable range is set for the distance between the heat exchanger tube and the mainstream outlet, ensuring that the heat exchanger tube does not interfere with the mainstream flow within the pipeline and affect the safe operation of the turbojet engine. Moreover, through the secondary flow temperature regulation system of this invention, the working fluids in the two flow paths only exchange heat, eliminating the need to transfer heat from the mainstream to the secondary flow via mass transfer. This avoids complex pipeline design and prevents potential hazards when extracting high-temperature gas. Meanwhile, this invention provides a high level of safety for experimental operators by remotely controlling and adjusting the secondary flow temperature.

[0036] The combination of transfer piping and adjusting orifice plate design flexibly and effectively achieves the matching of engine performance with various experimental conditions;

[0037] The experimental scheme of this invention uses a turbojet engine as the air and heat source for the main flow path. The primary challenge is matching the experimental conditions with the engine performance. Based on fluid mechanics principles, and fully considering the relationship between engine operating characteristics and various experimental conditions, a combined structure of a transfer pipe and an adjusting orifice plate is proposed to solve this problem. When a low-speed, atmospheric-pressure main flow condition is required, an expansion-type transfer pipe and adjusting orifice plate are used after the engine outlet. While ensuring the overall pressure drop is the same as the original tailpipe, the flow velocity and pressure in the main flow path of the experimental section are adjusted to the required low-speed, atmospheric-pressure level. When the required main flow condition changes to low-speed, high-pressure, the installation position of the adjusting orifice plate can be moved to the outlet of the main flow path of the experimental section, adjusting the main flow condition to a low-speed, high-pressure level while maintaining the overall pressure drop of the main flow path. When a high-speed, atmospheric-pressure main flow condition is required, a contraction-type transfer pipe is used after the engine outlet to reduce the pressure and increase the speed of the main flow medium, providing the required high-speed, atmospheric-pressure main flow condition for the experimental section while maintaining the overall pressure drop of the main flow path. By changing the structure of the transition section and adjusting the installation position and combination of the orifice plate, the pressure and flow rate of the mainstream working fluid can be flexibly adjusted simply and effectively. At the same time, it can ensure that the turbojet engine can operate safely and stably under different experimental conditions, thereby expanding the applicable range of experimental conditions.

[0038] The experimental system has wide applicability;

[0039] The experimental system described in this invention is suitable for heat transfer characteristic experiments in dual-flow paths with both hot and cold fluids, including but not limited to heat transfer characteristic experiments of double-sided blowing test specimens, applicable to turbine blades or support plate-like parts; heat transfer characteristic experiments of single-sided blowing test specimens, applicable to combustion chambers and nozzle cylinder walls; and heat exchanger experiments, applicable to air system regulating parts, etc. Furthermore, the experimental system of this invention can flexibly adjust parameters such as temperature, flow rate, and pressure of the main and secondary flows to achieve a wide operating range. The device has a simple structure, flexible and ingenious design, low experimental cost, low energy consumption, and good universality for various heat transfer characteristic experiments. Attached Figure Description

[0040] Figure 1 Schematic diagram of the experimental setup for the dual-flow-path heat transfer characteristics.

[0041] Figure 2 Schematic diagram of an experimental setup for low-energy-consumption dual-flow-path wide-condition heat transfer characteristics.

[0042] Figure 3 Schematic diagram of the measurement and control system circuit connection.

[0043] Figure 4(a) Schematic diagram of turbojet engine and tail nozzle assembly.

[0044] Figure 4(b) Schematic diagram of turbojet engine and subsequent pipeline assembly under low-speed, normal-pressure mainstream operating conditions.

[0045] Figure 4(c) shows the pressure variation curve in the mainstream pipeline under low-speed, normal-pressure mainstream operating conditions.

[0046] Figure 5(a) Schematic diagram of the structure of the straight hole adjustment plate and the expansion hole adjustment plate.

[0047] Figure 5(b) Assembly diagram of double-layer adjustment orifice plate.

[0048] Figure 6(a) Schematic diagram of the assembly of the experimental section for the heat transfer characteristics experiment of the double-sided blowing test specimen.

[0049] Figure 6(b) Experimental section of the heat transfer characteristics test of the double-sided blowing test specimen.

[0050] Figure 7(a) Schematic diagram of spiral heat exchanger tube structure.

[0051] Figure 7(b) Assembly diagram of the secondary flow temperature control system.

[0052] Figure 7(c) Schematic diagram of secondary flow temperature regulation process.

[0053] Figure 7(d) Secondary flow inlet temperature of the experimental section T c1 With insertion mainstream depth h The change curve.

[0054] Figure 8 Characteristic curve of exhaust temperature versus speed of a certain type of turbojet engine.

[0055] Figure 9 Experimental component wall cooling efficiency η With flow ratio ζ Compared to temperature κ The trend chart.

[0056] Figure 10 Schematic diagram of heat transfer characteristics of a single-sided blowing test specimen.

[0057] Figure 11 Schematic diagram of heat exchanger heat transfer characteristics experiment.

[0058] Figure 12(a) Schematic diagram of turbojet engine and subsequent pipeline assembly under low-speed and high-pressure mainstream operating conditions.

[0059] Figure 12(b) shows the pressure variation curve in the mainstream pipeline under low-speed, high-pressure mainstream operating conditions.

[0060] Figure 13(a) Schematic diagram of turbojet engine and subsequent pipeline assembly under high-speed atmospheric pressure mainstream operating conditions.

[0061] Figure 13(b) shows the pressure variation curve in the mainstream pipeline under high-speed, normal-pressure mainstream operating conditions.

[0062] In the diagram: 1. Mainstream fan, 2. Mainstream inlet section, 3. Mainstream flow meter, 4. Engine inlet transition section, 5. Turbojet engine, 6. Mainstream electric heater, 7. Oil pump, 8. Fuel flow meter, 9. Expansion type engine outlet transition section, 10. Adjusting orifice plate, 10-1. Straight orifice adjusting orifice plate, 10-2. Orifice plate spacing adjusting flange, 10-3. Expansion orifice adjusting orifice plate, 11. Mainstream pressure stabilizing section, 12. Mainstream measuring section, 13. Mainstream pressure sensor, 14. Mainstream thermocouple, 15. 16. Main channel of the double-sided blowing test section; 17. Secondary flow fan; 18. Secondary flow flow meter; 19. Secondary flow electric heater; 20. Metal hose; 21. Spiral heat exchange tube; 22. Pipe clamping device; 23. Displacement mechanism; 24. Secondary flow pressure stabilizing section; 25. Secondary flow measuring section; 26. Secondary flow pressure sensor; 27. Secondary flow thermocouple; 28. Double-sided blowing test piece; 29. ​​Thermal insulation layer; 30. Calibration thermocouple; 31. Original tail nozzle; 32. Main channel area; 33. Single-hole hydraulic diameter of straight-hole regulating orifice plate. d o 33. Hydraulic diameter of the small end of a single orifice in an expansion orifice regulating plate. d o1 34. Expansion hole regulating orifice plate single hole large end hydraulic diameter d o2 35. Adjusting the thickness of the orifice plate t 36. Infrared glass; 37. Flange cover; 38. Mounting holes for double-sided air-blowing test specimen; 39. Infrared thermal imager; 40. Length of the spiral section of the heat exchange tube. l s 41. Outer diameter of the heat exchanger tube spiral d s 42. Main road width w m 43. Mainstream lane height h m 44. Distance between heat exchanger tubes and mains outlet s 45. Heat exchanger tube insertion depth h 46. ​​Main channel of single-sided blowing test section; 47. Single-sided blowing test piece; 48. Main channel of heat exchanger test section; 49. Heat exchanger; 50. Outlet transition section of shrink-type engine. Detailed Implementation

[0063] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0064] A low-energy-consumption dual-flow-path wide-condition heat transfer characteristic experimental system consists of two parts: a piping system and a measurement and control system. The piping system includes two flow paths: a main flow path and a secondary flow path. Figure 2 As shown. Unlike the previous scheme that used a fan and an electric heater, the main flow path of this invention uses a turbojet engine 5 to provide a high-temperature, high-pressure gaseous working fluid. After the turbojet engine 5 is ignited, air is drawn into the pipeline through the main flow inlet section 2, and its mass flow rate is measured after passing through the main flow meter 3. m a Then, through engine inlet transfer section 4, fuel enters turbojet engine 5. Simultaneously, turbojet engine 5 draws fuel from the fuel tank via fuel pump 7, and its mass flow rate is measured by fuel flow meter 8. m f Subsequently, the turbojet engine 5 ejects high-temperature, high-pressure combustion gas, which enters the expansion engine outlet transition section 9 as the mainstream working fluid. The pressure increases and the flow velocity decreases as the pipe cross-sectional area gradually expands. The gas then flows through the regulating orifice plate 10, where the pressure is reduced to approximately atmospheric pressure while maintaining the flow velocity, and the flow is rectified. Through the combined regulating effect of the transition pipe and orifice plate structure, the mainstream reaches the experimental operating conditions. The working fluid then enters the mainstream pressure stabilization section 11, and after flow stabilization, it enters the mainstream measurement section 12. Here, the mainstream pressure sensor 13 and the mainstream thermocouple 14 measure the mainstream inlet pressure of the experimental section, respectively. P g1 and the mainstream inlet temperature of the experimental section T g1 Then it enters the main channel 15 of the double-sided blowing test section, flows through both sides of the double-sided blowing test piece 27, and finally exits from the outlet of the test section pipe.

[0065] The secondary flow path draws in air working fluid through the secondary flow fan 16 and increases its pressure, then flows through the secondary flow meter 17 to measure its mass flow rate. m c The fluid then flows through the metal hose 19 into the spiral heat exchange tube 20. The spiral heat exchange tube 20 is positioned downstream of the outlet of the main flow channel 15 in the double-sided blowing test section via the pipe clamping device 21 and the displacement mechanism 22. It utilizes the residual heat of the main flow exhaust for heating, and the displacement mechanism 22 controls the depth of the spiral heat exchange tube 20's penetration into the main flow exhaust gas to regulate the secondary flow temperature. After passing through the spiral heat exchange tube 20, the secondary flow working fluid flows through the metal hose 19 into the secondary flow stabilization section 23. After stabilization, it enters the secondary flow measurement section 24, where the secondary flow pressure sensor 25 and the secondary flow thermocouple 26 measure the secondary flow inlet pressure of the test section, respectively. P c1 and the secondary flow inlet temperature of the experimental section T c1It then enters the internal channel of the double-sided blowing test piece 27, exchanges heat with it, flows out from the outlet of the test piece, and finally merges into the mainstream and is discharged from the test section pipeline.

[0066] The pipelines after heating the main and secondary flows are covered with a heat insulation layer 28 to reduce heat loss of the experimental system and prevent experimental personnel from being burned by the high-temperature pipelines.

[0067] The circuit connection scheme of the measurement and control system of the present invention is as follows: Figure 3 As shown. The main measurement scheme includes: using a main flow meter 3, a fuel flow meter 8, and a secondary flow meter 17 to measure the main flow intake air mass flow rate. m a Engine fuel mass flow rate m f and the mass flow rate of the secondary working fluid m c Among them, the mainstream intake air mass flow rate m a With engine fuel mass flow rate m f The sum of these values ​​represents the mass flow rate of the main working fluid. m g The pressure at the main flow inlet of the experimental section was measured using the main flow pressure sensor 13 and the secondary flow pressure sensor 25, respectively. P g1 and the secondary flow inlet pressure of the experimental section P c1 The mainstream inlet temperature of the experimental section was measured using mainstream thermocouple 14 and secondary flow thermocouple 26, respectively. T g1 and the secondary flow inlet temperature of the experimental section T c1 Infrared glass 36 and an infrared thermal imager 39 were installed above the experimental specimen to measure the average temperature of the specimen's wall surface. T w Several thermocouple mounting slots are made on the test surface of the experimental piece, and calibration thermocouples 29 are embedded therein to obtain the wall surface measuring point temperature with sufficient accuracy. T wi This serves as a reference standard for correcting infrared measurement results. The flow meter, pressure sensor, and thermocouple are connected to a data acquisition unit via signal lines. The data acquisition unit is connected to a computer for data transmission, processing, and storage. The infrared thermal imager is directly connected to the computer to collect temperature field data. The main control scheme includes: controlling the speed of the secondary flow fan 16 via a fan speed controller to adjust the secondary flow rate; connecting the turbojet engine 5 and oil pump 7 to the engine control console to remotely control the turbojet engine's start / stop and throttle; and adjusting the position of the spiral heat exchanger tube 20 via a displacement mechanism control console.

[0068] The pipeline system and data acquisition and control system maintain a sufficient safe distance in space, and effective safety protection measures are set for the turbojet engine 5 to ensure the safety of the experimental operators.

[0069] Now combined Figure 4a ~ Figure 4c The design and connection scheme of the main pipeline after the turbojet engine in this invention will be further explained. For example... Figure 4a As shown, the primary exhaust nozzle 30 of the turbojet engine 5 is a converging nozzle, connected to the turbine outlet of the turbojet engine 5. Its function is to convert the pressure energy of the combustion gas into kinetic energy, causing a high-speed, atmospheric-pressure airflow to be ejected from the nozzle outlet, thereby providing sufficient thrust. When not connected to the main pipeline, i.e., when the turbojet engine is operating alone, the pressure change along the flow direction within its primary exhaust nozzle 30 is as follows: Figure 4c As shown by the dashed line, the pressure gradually decreases to atmospheric pressure along the way before being released into the atmosphere.

[0070] In this invention, the original tail nozzle 30 is removed from the turbojet engine 5, and a new pipeline expansion type engine outlet transition section 9 to mainstream measurement section 12 is designed as a replacement based on the mainstream pressure and speed requirements in the experimental section. For example... Figure 4b As shown, the turbojet engine 5 is connected to the expansion engine outlet transition section 9. Its inlet cross-section is the same as the original tail nozzle, a circular cross-section, and it is equipped with a flow straightener cone, connecting to the turbine outlet of the engine. After a smooth transition, the outlet becomes a rectangular cross-section with a larger area than the inlet, forming an overall expansion pipe. An adjusting orifice plate 10 is installed after the expansion engine outlet transition section 9. Its function is to provide a suitable pressure drop for the piping system, matching its operating characteristics and preventing turbine over-spinning, while also serving a flow straightener function. When the required pressure drop in the pipeline is large, multiple layers of tandem adjusting orifice plates can be installed, typically such as a straight orifice adjusting orifice plate 10-1 and an expansion orifice adjusting orifice plate 10-3. An orifice plate spacing adjusting flange 10-2 is installed between adjacent orifice plates, and the orifice plate spacing and airflow pressure drop are adjusted by the thickness of this flange. The pressure variation along the flow direction in the main pipeline is referenced. Figure 4c The solid line in the diagram illustrates how, as the main working fluid flows through the expansion engine outlet transition section 9, the gradual increase in cross-sectional area converts the kinetic energy of the working fluid into pressure energy, resulting in a decrease in velocity and an increase in pressure. Subsequently, after passing through one or more regulating orifice plates, the pressure rapidly decreases to near atmospheric pressure before entering the main flow stabilization section, maintaining stable flow and providing the required low-speed, atmospheric-pressure main flow conditions for the experimental section pipeline. This scheme ensures that the pressure in the main flow pipeline first increases and then decreases, with the overall pressure drop being the same as the original tail nozzle, thus replacing the original tail nozzle and guaranteeing the safe and stable operation of the turbojet engine under the required experimental conditions.

[0071] Combination Figure 5a ~ Figure 5b The structure of the adjusting orifice plate 10 will be further explained. For example... Figure 5a As shown, the regulating orifice plate 10 is a thin plate with multiple openings in the middle region. These openings are evenly distributed within the main flow channel region 31. The opening shape can be circular, elliptical, or rectangular, etc., and along the flow direction, it can be a straight hole structure with a constant cross-section. A typical structure is shown below. Figure 5a The straight-hole adjusting plate 10-1 shown on the left side of the centerline, or the expansion hole structure with gradually increasing cross-sectional area, is a typical structure as follows: Figure 5a The expansion orifice plate 10-3 is shown on the right side of the centerline. To ensure the pressure reduction effect, the openings of adjacent orifice plates are staggered to avoid forming a smooth airflow channel. A typical assembly scheme for multi-layer orifice plates is as follows. Figure 5b As shown, it is connected to the upstream and downstream pipelines via flanges, and an orifice plate spacing adjustment flange 10-2 is installed between the two orifice plates. Along the flow direction of the working fluid, the hydraulic diameter of the orifice openings in the multi-layer orifice plates gradually decreases, and the thickness of the orifice plate spacing adjustment flange 10-2 between adjacent orifice plates gradually decreases, which can improve the pressure drop effect. Figure 4c As shown, for the expansion orifice regulating plate, since the flow area of ​​its opening gradually increases along the process, the working fluid pressure is restored to a certain extent after a sharp drop, resulting in a better rectification effect and improving the uniformity of subsequent flow.

[0072] Define the relative orifice diameter of the regulating orifice plate. φ :

[0073] For straight-hole adjusting plate φ = d o / d m 1

[0074] For expansion hole adjustment plate φ = d o1 / d m 2

[0075] In the formula, d o The hydraulic diameter of a single orifice in a straight-hole regulating orifice plate is 32. d o1 The hydraulic diameter of the small end of the expansion orifice regulating plate is 33. d m The hydraulic diameter of the main channel section with equal cross-section.

[0076] Define the orifice ratio of the regulating orifice plate k = A o / A m 3

[0077] In the formula, Ao This represents the total open area of ​​the orifice plate. For expansion orifice plates, the area is calculated based on the smaller end of the orifice. A m It is the cross-sectional area of ​​the main channel section.

[0078] Define the taper of the expansion orifice adjustment plate. c =( d o2 - d o1 ) / t 4

[0079] In the formula, d o2 The hydraulic diameter of the large end of the expansion orifice regulating plate is 34 mm. t To adjust the thickness of the orifice plate to 35.

[0080] While ensuring sufficient strength, adjust the relative aperture of the orifice plate. φ The porosity can be 0.03~0.15. k The taper can be 0.2~0.7. c It can be 0 to 0.4.

[0081] Now combined Figure 6a ~ Figure 6b The design of the dual-sided air-blowing test section will be further explained. The assembly process is as follows: Figure 6a As shown, the main flow channel 15 of the double-sided blowing test section is connected to the main flow measurement section 12. An infrared window is opened on its upper wall, and after the infrared glass 36 is installed, it is fixed by the flange cover 37. A double-sided blowing test piece mounting hole 38 is set in the middle of the side of the main flow channel. The mounting hole has the same cross-sectional shape as the test piece and ensures sufficient assembly clearance. Several thermocouple mounting grooves are set on the measured surface of the double-sided blowing test piece 27, and calibration thermocouples 29 are embedded to correct the infrared measurement results. Before installing the test piece, the leads of the calibration thermocouples 29 are first passed through the double-sided blowing test piece mounting hole 38 on the side and led out from the flow channel outlet. Then, the double-sided blowing test piece 27 is pushed into the main flow channel of the double-sided blowing test section through the double-sided blowing test piece mounting hole 38 and fixed to the pipe by the flange structure, so that both the upper and lower sides of the test piece are in contact with the main flow. Then, the secondary flow channel of the test piece is connected to the secondary flow measurement section 24 by the flange structure. After the pipeline assembly is completed, the infrared thermal imager 39 is fixed above the area to be measured to measure the surface temperature field of the experimental piece. The assembled experimental section is shown below. Figure 6b As shown.

[0082] Now combined Figure 7a ~ Figure 7d The structure and working principle of the secondary flow temperature control system will be further explained. For example... Figure 7aAs shown, the spiral heat exchanger tube 20 has a spiral coil in the middle, which is the main part that exchanges heat with the mainstream. Straight pipes extend from both ends and connect to the front and rear metal hoses 19. The length of the spiral section of the heat exchanger tube is... l s 40 and the outer diameter of the heat exchange tube spiral d s 41 is slightly smaller than the width of the main road. w m 42 and the height of the main road h m 43, to ensure that the intermediate spiral section of the pipe is completely covered by the mainstream exhaust range. Furthermore, l s / w m and d s / h m The preferred value is within the range of 0.80 to 0.95.

[0083] Temperature regulation process as follows Figure 7b As shown in Figure 7c, the spiral heat exchange tube 20 is placed downstream of the outlet of the main channel 15 in the double-sided blowing test section, and the distance between the heat exchange tube and the outlet of the main channel is... s 44 is maintained at an appropriate value, preventing both excessive proximity that would obstruct flow within the main channel and excessive distance that would reduce heat exchange efficiency. Furthermore, s / d m It exhibits relatively ideal performance within the range of 0.3 to 2.0. Both ends of the spiral heat exchanger tube 20 are fixed to the displacement mechanism 22 via pipe clamping devices 21, and their positions are adjusted as the sliding table of the displacement mechanism moves up and down, thereby changing the depth of the heat exchanger tube's intrusion into the mainstream exhaust. This alters the heating area of ​​the spiral heat exchanger tube 20, thus changing the heating power and secondary flow temperature. The secondary flow inlet temperature in the experimental section... T c1 Insertion depth of heat exchanger tubes as needed h The curve of change of 45 is as follows Figure 7d As shown, when the spiral heat exchange tube 20 is completely outside the mainstream exhaust range, that is, the heat exchange tube is inserted to the mainstream depth... h When 45 is 0, the secondary flow is not heated by the mainstream. T c1 This is the minimum value, approximately the atmospheric temperature. As the spiral heat exchanger tube 20 gradually penetrates deeper into the mainstream, the heat exchange with it increases, causing the secondary flow temperature to gradually rise. When h Equal to the outer diameter of the heat exchange tube spiral d s At 41 o'clock, the entire spiral section of the heat exchanger tube was within the mainstream exhaust range. T c1Reaching its maximum value, it continues to increase. h At that point, the temperature no longer increased, until h Equal to the height of the main channel h m 43. After that, it continued to increase. h The spiral heat exchanger tube 20 gradually moved out of the mainstream exhaust range. T c1 It changes in the opposite trend to the curve in the figure.

Claims

1. A low-energy-consumption two-stream wide-operation-heat-transfer-characteristics experimental system, characterized in that, The system includes a piping system and a measurement and control system. The piping system includes a main flow path and a secondary flow path. The main flow path is supplied with a high-temperature and high-pressure gaseous working fluid by a turbojet engine (5). After the turbojet engine (5) is ignited, air is drawn into the pipeline through the main flow inlet section (2) and its mass flow rate is measured after passing through the main flow meter (3). m a Then, through the engine inlet transition section (4), the fuel enters the turbojet engine (5); at the same time, the turbojet engine (5) draws fuel from the fuel tank through the oil pump (7) and measures its mass flow rate through the fuel flow meter (8). m f Subsequently, the turbojet engine (5) ejects high-temperature and high-pressure gas, which enters the expansion engine outlet transition section (9) as the mainstream working fluid. It then flows through the regulating orifice plate (10). Through the combined regulation of the transition pipe and the orifice plate structure, the mainstream reaches the working condition required for the experiment. The working fluid then enters the mainstream pressure stabilization section (11), and after stabilization, it enters the mainstream measurement section (12). Here, the mainstream pressure sensor (13) and the mainstream thermocouple (14) measure the mainstream inlet pressure of the experimental section, respectively. P g1 and the mainstream inlet temperature of the experimental section T g1 Then it enters the main channel (15) of the double-sided blowing test section, flows through both sides of the double-sided blowing test piece (27), and finally exits from the outlet of the test section pipe. The secondary flow path sucks in air working substance by a secondary flow fan (16) and increases its pressure, flows through a secondary flow flowmeter (17) and measures its mass flow m c and then enters a spiral heat exchange pipe (20) through a metal hose (19); the spiral heat exchange pipe (20) is placed downstream of an outlet of a main flow passage (15) of a double-side blowing experiment section by a pipe clamping device (21) and a displacement mechanism (22), heats by using waste heat of main flow exhaust gas, and adjusts the secondary flow temperature by controlling the depth of the spiral heat exchange pipe (20) invading the main flow exhaust gas by the displacement mechanism (22); after passing through the spiral heat exchange pipe (20), the secondary flow working substance flows into a secondary flow pressure stabilizing section (23) by the metal hose (19), enters a secondary flow measuring section (24) after being stabilized, and is measured by a secondary flow pressure sensor (25) and a secondary flow thermocouple (26) respectively at the secondary flow measuring section (24) P c1 for measuring the inlet pressure of the experiment section secondary flow and the inlet temperature of the experiment section secondary flow T c1 , and then enters an internal passage of a double-side blowing experiment section (27), exchanges heat with the internal passage, flows out from an outlet of the experiment section, and finally converges into the main flow and is discharged from the experiment section pipe.

2. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 1, characterized in that, The measurement and control system comprises a main flow meter (3), a fuel flow meter (8) and a secondary flow meter (17); the main flow meter (3), the fuel flow meter (8) and the secondary flow meter (17) are used to measure the main flow air mass flow m a , the engine fuel mass flow m f and the secondary flow working medium mass flow m c respectively; the main flow pressure sensor (13) and the secondary flow pressure sensor (25) are used to measure the experimental section main flow inlet pressure P g1 and the experimental section secondary flow inlet pressure P c1 respectively; the main flow thermocouple (14) and the secondary flow thermocouple (26) are used to measure the experimental section main flow inlet temperature T g1 and the experimental section secondary flow inlet temperature T c1 respectively; the infrared glass (36) and the infrared thermal imager (39) are installed above the experimental piece to measure the experimental piece wall surface average temperature T w ; a plurality of thermocouple installation grooves are formed on the measured surface of the experimental piece, and the calibrated thermocouple (29) is embedded to obtain the wall surface measured point temperature T wi , which is used as a reference benchmark for correction of the infrared measurement result.

3. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 1, characterized in that, The turbojet engine (5) is connected with an expanding engine outlet adapter (9) at the back, the inlet section of which is circular and provided with a fairing cone, and is connected with the turbine outlet of the engine; after a smooth transition, the outlet becomes a rectangular section with a larger area than the inlet, and the whole forms an expanding pipe; an adjusting orifice plate (10) is installed behind the expanding engine outlet adapter (9), and the adjusting orifice plate (10) comprises a straight orifice adjusting orifice plate (10-1) and an expanding orifice adjusting orifice plate (10-3).

4. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 3, characterized in that, The adjusting orifice plate (10) is a thin plate with a plurality of openings in the middle area, the openings are uniformly distributed in the main flow channel area (31), the hole type is circular, oval or rectangular, and along the flow direction, the opening section is a straight hole structure with an unchanged opening section, namely a straight orifice adjusting orifice plate (10-1); or an expanding hole structure with a gradually increasing section area, namely an expanding orifice adjusting orifice plate (10-3).

5. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 4, characterized in that, The relative aperture of the aperture plate (10) is adjusted φ : For the straight-hole adjustment orifice plate (10-1), φ = d o / d m (1) For the expansion hole adjustment hole plate (10-3), φ = d o1 / d m (2) wherein d o Dh is the single-hole hydraulic diameter of the orifice plate (32) for a straight orifice, d o1 Dh is the single-hole hydraulic diameter of the orifice plate (33) for an expanded orifice, d m Dh is the hydraulic diameter of the constant cross-section section of the main flow channel. Said adjusting the open area ratio of the orifice plate (10) k = A o / A m (3) wherein A o total open area of the orifice plate, for an orifice plate regulating an orifice, calculated as the small end of the orifice; A m cross-sectional area of the main flow channel The opening taper of the expansion hole adjusting hole plate (10-3) is adjusted c =( d o2 - d o1 ) / t (4) wherein d o2 to adjust the hydraulic diameter (34) of the large end of the single hole of the orifice plate, t to adjust the thickness (35) of the orifice plate.

6. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 5, characterized in that, The relative aperture of the adjustment aperture plate (10) φ is 0.03-0.15, the opening rate k is 0.2-0.7, the opening taper c is 0-0.

4.

7. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 1, characterized in that, The spiral heat exchange pipe (20) is a spiral coil in the middle, and the two ends extend out straight pipes to connect with the front and rear metal hoses (19); the length of the spiral section of the heat exchange pipe l s (40) and the outer diameter of the spiral of the heat exchange pipe (41) are less than the width of the main flow channel (42) and the height of the main flow channel (43) respectively. d s w m h m ​​​ 8. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 7, characterized in that, The l s / w m and d s / h m range from 0.80 to 0.

95.

9. The low-energy-consumption two-stream wide-operating-range heat transfer characteristic experiment system according to claim 4, characterized in that, The openings of the adjusting orifice plates (10) of the adjacent two layers are arranged in a staggered manner, and an orifice plate spacing adjusting flange (10-2) is installed between the adjacent two orifice plates, and the orifice plate spacing and the air flow pressure drop are adjusted by the thickness of the flange.

10. The low-energy double-channel wide-operation-heat-transfer-characteristics experimental system according to claim 1, wherein, The main flow path and the secondary flow path are provided with a heat-insulating layer (28) after heating.

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