Liquid lead-bismuth alloy high heat flux heat transfer experimental device and method

Abstract

The application discloses a kind of liquid lead bismuth alloy high heat flow heat transfer experimental device and method, including main circulating pump, filter, flowmeter and test device, main circulating pump, filter, flowmeter and test device are sequentially connected by pipeline and form liquid lead bismuth alloy circulation loop, flowmeter is arranged at the import end of test device, the import end of flowmeter is connected with liquid lead bismuth storage tank by pipeline, the import end of liquid lead bismuth storage tank is connected with argon bottle by pipeline.It also includes the test steps of S1-S7.The application realizes the efficient and low-cost size parameter research, by replacing different sizes of rectangular test flow channel, a variety of narrow slit size series experiments can be quickly completed on one experimental table, and compared with processing multiple whole experimental sections, the manufacturing cost and cycle are significantly reduced.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor engineering experimental technology and safety analysis, and in particular to a high heat transfer experimental apparatus and method for liquid lead-bismuth alloy. Background Technology

[0002] Fast neutron breeder reactors using liquid lead-bismuth as coolant are the preferred reactor type for fourth-generation advanced nuclear energy systems. Their fuel assemblies face extremely high local surface heat flux densities (typically reaching the MW / m² level) during operation. Furthermore, for lead-bismuth fast reactors, the dimensions of their narrow rectangular coolant channels are key geometric parameters affecting their cooling capacity, flow resistance, and safety. Accurately obtaining heat transfer data and wall temperature response between the channel walls and the liquid lead-bismuth alloy under operating conditions of high heat flux density and varying slot size is a crucial prerequisite for core thermal design, safety assessment, and material selection.

[0003] Currently, heat transfer experimental systems for high-temperature liquid metals mainly employ direct electric heating (ohmic heating), where an electric current is directly applied to the test specimen, utilizing its own resistance to generate heat. However, the following problems still exist: 1. Existing direct electric heating methods are difficult to achieve high heat flux density and cannot achieve long-term continuous operation. At the same time, this heating method is physically different from the heat transfer mode in the reactor and cannot accurately simulate the actual heat transfer path and boundary conditions in the reactor. 2. The heating power is strongly coupled with the geometry and resistivity uniformity of the sample, making it difficult to achieve independent, uniform and precise control of the heat flow. At the same time, the introduction of large current also brings additional electrical insulation and safety risks. 3. Existing high-temperature liquid metal heat transfer experimental systems have fixed and unchangeable dimensions. Changing the primary flow channel dimensions requires designing and manufacturing a completely new and costly experimental section, resulting in long development cycles and significant material waste. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a high heat transfer experimental apparatus and method for liquid lead-bismuth alloy. By supplying power to the heating plate, a uniform and constant high heat flux density can be provided to the flow channel plate. By changing the rectangular test flow channels of different sizes, a series of experiments with various narrow slit sizes can be quickly completed on a single experimental platform.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: A high-heat transfer experimental apparatus for liquid lead-bismuth alloy is provided, comprising a main circulation pump, a filter, a flow meter, and an experimental device. The main circulation pump, filter, flow meter, and experimental device are sequentially connected by pipelines to form a liquid lead-bismuth alloy circulation loop. The flow meter is located at the inlet end of the experimental device, and the inlet end of the flow meter is connected to a liquid lead-bismuth storage tank via a pipeline. The inlet end of the liquid lead-bismuth storage tank is connected to an argon cylinder via a pipeline. The experimental device includes two U-shaped flow channel plates, an inlet connector, and an outlet connector. The two U-shaped flow channel plates are fitted together to form an experimental flow channel. An insulating plate is installed on the outside of each U-shaped flow channel plate, and a heating plate is installed on the outside of each insulating plate. An insulation shell is installed on the outside of the experimental flow channel. The inlet connector and the outlet connector are each provided with a flow channel inlet that mates with the experimental flow channel.

[0006] Furthermore, several thermocouples are installed on the outer wall surface of the U-shaped flow channel plate.

[0007] Furthermore, the insulation shell is divided into two parts that cooperate with the U-shaped flow channel plate, and the insulation shell is provided with mounting grooves that cooperate with the U-shaped flow channel plate, the insulation plate, and the heating plate.

[0008] Furthermore, an upper clamp and a lower clamp are provided on the outside of the insulation shell. Both the upper clamp and the lower clamp are provided with clamping grooves that cooperate with the insulation shell. The upper clamp and the lower clamp are connected by several bolts.

[0009] Furthermore, two copper busbars are provided between the upper and lower clamps, and the two copper busbars are respectively attached to the heating plate. The middle of the copper busbar forms a clamping hole that cooperates with the two heating plates. The copper busbar is set into two detachable parts in the middle.

[0010] Furthermore, the inlet of the flow meter is connected to the inlet of the main circulation pump via a pipeline with a first shut-off valve; the inlet of the liquid lead-bismuth storage tank is equipped with a second shut-off valve; and a third shut-off valve is installed between the liquid lead-bismuth storage tank and the argon cylinder.

[0011] Furthermore, an electric regulating valve is installed between the filter and the flow meter.

[0012] Furthermore, an outlet temperature sensor is installed at the outlet end of the test device, and an inlet temperature sensor is installed at the inlet end of the test device.

[0013] Furthermore, a differential pressure transmitter is connected to the inlet and outlet of the test device via a pipeline; a pressure transmitter is installed at the inlet of the test device.

[0014] An experimental method for a high-heat-transfer heat transfer experimental apparatus for liquid lead-bismuth alloy includes the following steps: S1: Set the target inlet temperature and target heat flux density, determine the target slit size, select a U-shaped flow channel plate of the corresponding size, and stack and assemble the test device in the order of U-shaped flow channel plate, insulation plate, heating plate and heat insulation shell to form a closed rectangular test flow channel; S2: Connect the test device to the liquid lead-bismuth alloy circulation loop via the inlet connector and outlet connector; S3: After starting the liquid lead-bismuth alloy circulation loop, heat the lead-bismuth alloy to the target inlet temperature, and fill the circulation loop with liquid lead-bismuth alloy by pressurizing with argon gas; adjust the main circulation pump to make the flow rate in the test channel reach the set value, and monitor the pressure and flow rate in the liquid lead-bismuth alloy circulation loop in real time; S4: Power is supplied to the heating plate using copper busbars. By adjusting the current of the DC power supply, the heat flux density output by the heating plate is made to the target heat flux density. Thermocouples set on the wall of the U-shaped flow channel plate are used to collect thermocouple readings at each heat flux density. Nine thermocouples are evenly distributed on the wall of the U-shaped flow channel plate in the heating section, and the readings of all thermocouples are monitored at each heat flux density. S5: Collect the overall pressure drop of the test section in the liquid lead-bismuth alloy circulation loop using a differential pressure transmitter. Calculate the frictional pressure drop Friction resistance coefficient and Reynolds number The friction drag coefficient was obtained by fitting. With Reynolds number The relationship; specifically: S51: The overall pressure drop of the test section is acquired via a differential pressure transmitter. And calculate the frictional pressure drop. The specific formula is as follows: ; ; ; In the formula, For frictional pressure drop, For gravity pressure drop, To accelerate the pressure drop, The average density of liquid lead-bismuth in the test section. The density of liquid lead-bismuth at the inlet of the test section. The density of liquid lead-bismuth at the outlet of the test section. The height difference between the inlet and outlet of the test section; It is the acceleration due to gravity. For mass flow rate; S52: Calculate the friction resistance coefficient : ; In the formula, The density of liquid lead-bismuth alloy, The flow rate of the liquid lead-bismuth alloy; S53: Calculate the Reynolds number : ; In the formula, For flow rate, The hydraulic diameter of the test section. The dynamic viscosity of liquid lead-bismuth alloy; S54: Based on the coefficient of frictional resistance and Reynolds number The friction drag coefficient was obtained by fitting. With Reynolds number The relationship is expressed as follows: ; In the formula, This is the proportionality coefficient. The decay exponent, For the asymptotic constant term; S6: After completing data acquisition for one operating point, export all thermocouple data to obtain the heat transfer coefficient at that operating point; change the flow rate and heat flux of the liquid lead-bismuth alloy to obtain heat transfer correlations for multiple operating conditions; specifically: S61: Temperature of the outer wall of the test flow channel obtained from thermocouple data. and mainstream temperature Calculate the inner surface temperature of the flow channel The specific formula is as follows: ; In the formula, For heat flux density, The thickness of the U-shaped flow channel plate. The thermal conductivity of the U-shaped flow channel plate; S62: Based on the inner surface temperature of the flow channel Calculate the local heat transfer coefficient The specific formula is as follows: ; S63: Based on the local heat transfer coefficient Calculate the Nusel number Specifically: ; In the formula, The thermal conductivity of lead and bismuth; S64: Calculate Prandtl number Specifically: ; In the formula, For lead-bismuth specific heat capacity, Prandtl number Characterizes the ratio of a fluid's momentum diffusion capacity to its thermal diffusion capacity; S65: By changing the flow rate and heat flux of liquid lead-bismuth alloy, Reynolds numbers can be obtained under multiple operating conditions. With Prandtl number Nusel number The heat transfer correlation of the experimental flow channel was established. The specific heat transfer correlation is as follows: ; In the formula, It is an empirical constant. The Reynolds number exponent, The Prandtl number exponent; S7: After completing the experiment of the current size test flow channel, shut down the system, replace it with a test flow channel of a different size, and repeat steps S2-S5 to conduct experiments on test flow channels of different sizes under the same thermal, electrical, and measurement and control boundary conditions.

[0015] The beneficial effects of this invention are as follows: The liquid lead-bismuth alloy high heat transfer experimental system of the present invention realizes efficient and low-cost dimensional parameter research. By changing the rectangular test channel of different sizes, a series of experiments with various narrow slit sizes can be quickly completed on a single test bench. At the same time, compared with processing multiple integral test sections, the manufacturing cost and cycle are significantly reduced.

[0016] The liquid lead-bismuth alloy high heat transfer experimental system of the present invention ensures the consistency of the experiment. Key factors such as channel width, heating method, temperature measurement method, and sealing form remain unchanged when the size changes, which minimizes the system error and makes the experimental data under different sizes highly comparable.

[0017] The liquid lead-bismuth alloy high heat transfer experimental system of the present invention realizes efficient decoupling of heat source and flow channel and precise implementation of high heat flux density. By powering the heating plate, a uniform and constant high heat flux density can be provided to the flow channel plate. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the liquid lead-bismuth alloy high heat transfer heat transfer test system of the present invention.

[0019] Figure 2 This is a schematic diagram of the overall structure of the experimental setup; Figure 3 A partial structural diagram of the experimental setup. Figure 1 ; Figure 4 A partial structural diagram of the experimental setup. Figure 2 ; Figure 5 This is an overall sectional view of the test apparatus along its length. Figure 6 This is a schematic diagram of the flow channel section; Figure 7 This is a schematic diagram of the copper busbar structure; The symbols for the main components in the diagram are explained below: 1. Test apparatus; 101. U-shaped flow channel plate; 102. Insulating plate; 103. Heating plate; 104. Insulation shell; 105. Inlet connector; 106. Outlet connector; 107. Upper clamp; 108. Lower clamp; 109. Bolts; 1010. Copper busbar; 2. Main circulation pump; 3. Filter; 4. Flow meter; 5. Liquid lead-bismuth storage tank; 6. Argon cylinder; 7. Pressure transmitter; 8. Differential pressure transmitter; 9. Outlet temperature sensor; 10. Inlet temperature sensor; 11. First shut-off valve; 12. Second shut-off valve; 13. Third shut-off valve; 14. Electric regulating valve. Detailed Implementation

[0020] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0021] like Figure 1 As shown, the high-heat transfer experimental apparatus for liquid lead-bismuth alloy includes a main circulation pump 2, a filter 3, a flow meter 4, and an experimental device 1. The main circulation pump 2, filter 3, flow meter 4, and experimental device 1 are sequentially connected by pipes to form a liquid lead-bismuth alloy circulation loop. The flow meter 4 is located at the inlet end of the experimental device 1. The inlet end of the flow meter 4 is connected to a liquid lead-bismuth storage tank 5 via a pipe. The inlet end of the liquid lead-bismuth storage tank 5 is connected to an argon cylinder 6 via a pipe. A first shut-off valve 11 connects the inlet end of the flow meter 4 to the inlet end of the main circulation pump 2 via a pipe. A second shut-off valve 12 is installed at the inlet end of the liquid lead-bismuth storage tank 5. A third shut-off valve 13 is installed between the liquid lead-bismuth storage tank 5 and the argon cylinder 6. An electric regulating valve 14 is installed between the filter 3 and the flow meter 4. An outlet temperature sensor 9 is installed at the outlet end of the experimental device 1, and an inlet temperature sensor 10 is installed at the inlet end of the experimental device 1. A differential pressure transmitter 8 is connected to the inlet and outlet ends of the experimental device 1 via a pipe. A pressure transmitter 7 is installed at the inlet end of the test device 1.

[0022] like Figure 2 , 3As shown in Figures 4, 5, and 6, the test apparatus 1 includes two U-shaped flow channel plates 101, an inlet connector 105, and an outlet connector 106. The two U-shaped flow channel plates 101 are fitted together to form a test flow channel. Each U-shaped flow channel plate 101 is externally provided with an insulating plate 102, and each insulating plate 102 is externally provided with a heating plate 103. An insulation shell 104 is provided externally to the test flow channel. Both the inlet connector 105 and the outlet connector 106 are provided with flow channel insertion ports that mate with the test flow channel. The U-shaped flow channel plate 101 is preferably made of 316L stainless steel, which has good corrosion resistance. The insulating plate 102 is preferably made of Al2O3, which provides electrical insulation and has a high thermal conductivity (approximately 30–35 W / m). The heating plate 103 (K) effectively transfers heat from the heating plate; it is powered by a DC power supply and provides a uniform and constant high heat flux density for an extended period. The narrow slit size is changed by adjusting the distance between the U-shaped flow channel plates 101, while the rest of the experimental setup remains the same. Specifically, liquid lead-bismuth alloy enters the heating section through the inlet connector 105 and exits through the outlet connector 106. A high current is supplied to the heating copper busbar via a DC power supply, enabling the heating plate to provide a uniform and constant high heat flux density to the heating section. Simultaneously, a wall temperature testing system is installed on the wall of the heating section to measure the wall temperature under different heat fluxes and dimensions. The heating plate 103 heats the U-shaped flow channel plates 101 through the insulating plate 102, and the heat is transferred to the lead-bismuth alloy through the flow channel plates via thermal convection.

[0023] Several thermocouples are disposed on the outer wall surface of the U-shaped flow channel plate 101. In this embodiment, nine thermocouples are evenly distributed on the wall surface of the U-shaped flow channel plate in the heating section. The thermocouples are all distributed at the center of the rectangular flow channel. The readings of all thermocouples are monitored at each heat flux density. The nine thermocouples are arranged such that the first thermocouple is placed 50mm away from the inlet, and adjacent thermocouples are spaced 50mm apart, all at the center of the flow channel plate wall surface.

[0024] The insulation shell 104 is divided into two parts that mate with the U-shaped flow channel plate 101. The insulation shell 104 has mounting grooves that mate with the U-shaped flow channel plate 101, the insulation plate 102, and the heating plate 103. An upper clamp 107 and a lower clamp 108 are provided on the outside of the insulation shell 104. Both the upper clamp 107 and the lower clamp 108 have clamping grooves that mate with the insulation shell 104. The upper clamp 107 and the lower clamp 108 are connected by several bolts 109. The insulation shell 104 is preferably made of fused cast mica, which has good electrical insulation properties (volume resistivity of approximately 6.8 × 10⁹ Ω). (cm) and thermal insulation properties (thermal conductivity approximately 0.892 W / m) K), to ensure the safety and reliability of the experimental setup.

[0025] like Figure 7As shown, two copper busbars 1010 are provided between the upper clamp 107 and the lower clamp 108. The two copper busbars 1010 are respectively attached to the heating plate 103. The middle part of the copper busbar 1010 forms a clamping hole that cooperates with the two heating plates 103. The copper busbar 1010 is configured into two detachable parts in the middle.

[0026] The experimental method for a high-heat-transfer heat transfer apparatus for liquid lead-bismuth alloy includes the following steps: S1: Set the target inlet temperature and target heat flux density, determine the target slit size, select a U-shaped flow channel plate of the corresponding size, and stack and assemble the test device in the order of U-shaped flow channel plate, insulation plate, heating plate and heat insulation shell to form a closed rectangular test flow channel; S2: Connect the test device to the liquid lead-bismuth alloy circulation loop via the inlet connector and outlet connector; S3: After starting the liquid lead-bismuth alloy circulation loop, heat the lead-bismuth alloy to the target inlet temperature. The inlet temperature is set to seven temperatures: 170℃, 200℃, 230℃, 260℃, 290℃, 320℃, and 350℃. The liquid lead-bismuth alloy is filled into the circulation loop by pressurizing with argon gas. Adjust the main circulation pump to make the flow rate in the test channel reach the set value, and monitor the pressure and flow rate in the liquid lead-bismuth alloy circulation loop in real time. S4: Power is supplied to the heating plate using a copper busbar. By adjusting the current of the DC power supply, the heat flux density output by the heating plate is made to the target heat flux density, which is set to 0.2. 0.4 0.6 0.8 Four values ​​are used in conjunction with thermocouples installed on the wall of the U-shaped flow channel plate to collect thermocouple readings at each heat flux density. Nine thermocouples are evenly distributed on the wall of the U-shaped flow channel plate in the heating section, and the readings of all thermocouples are monitored at each heat flux density. S5: Collect the overall pressure drop in the liquid lead-bismuth alloy circulation loop using a differential pressure transmitter. Calculate the frictional pressure drop Friction resistance coefficient and Reynolds number The friction drag coefficient was obtained by fitting. With Reynolds number The relationship; specifically: S51: The overall pressure drop of the test section is acquired via a differential pressure transmitter. And calculate the frictional pressure drop. The specific formula is as follows: ; ; ; In the formula, For frictional pressure drop, For gravity pressure drop, To accelerate the pressure drop, The average density of liquid lead-bismuth in the test section. The density of liquid lead-bismuth at the inlet of the test section. The density of liquid lead-bismuth at the outlet of the test section. The height difference between the inlet and outlet of the test section; For gravitational acceleration, in units ; For mass flow rate, per unit ; S52: Calculate the friction resistance coefficient : ; In the formula, The density of liquid lead-bismuth alloy, ; The flow rate of the liquid lead-bismuth alloy. ; S53: Calculate the Reynolds number : ; In the formula, For flow rate, The hydraulic diameter, The dynamic viscosity of liquid lead-bismuth alloy; S54: Based on the coefficient of frictional resistance and Reynolds number The friction drag coefficient was obtained by fitting. With Reynolds number The relationship is expressed as follows: ; In the formula, This is a proportionality coefficient, which mainly characterizes the comprehensive influence of pipeline geometry (such as relative roughness and cross-sectional shape) on frictional resistance. The decay exponent determines the rate at which the friction coefficient decreases as the Reynolds number increases; This is an asymptotic constant term, corresponding to the ultimate frictional resistance at extremely high Reynolds numbers; S6: After completing data acquisition for one operating point, export all thermocouple data to obtain the heat transfer coefficient at that operating point; change the flow rate and heat flux of the liquid lead-bismuth alloy to obtain heat transfer correlations for multiple operating conditions; specifically: S61: Temperature of the outer wall of the test flow channel obtained from thermocouple data. and mainstream temperature Calculate the inner surface temperature of the flow channel The specific formula is as follows: ; In the formula, For heat flux density, The thickness of the U-shaped flow channel plate. The thermal conductivity of the U-shaped flow channel plate; S62: Based on the inner surface temperature of the flow channel Calculate the local heat transfer coefficient The specific formula is as follows: ; S63: Based on the local heat transfer coefficient Calculate the Nusel number Specifically: ; In the formula, The thermal conductivity of lead and bismuth; S64: Calculate Prandtl number Specifically: ; In the formula, For lead-bismuth specific heat capacity, Prandtl number Characterizes the ratio of a fluid's momentum diffusion capacity to its thermal diffusion capacity; S65: By changing the flow rate and heat flux of liquid lead-bismuth alloy, Reynolds numbers can be obtained under multiple operating conditions. With Prandtl number Nusel number The heat transfer correlation of the experimental flow channel was established. The specific heat transfer correlation is as follows: ; In the formula, It is an empirical constant that comprehensively considers the overall influence of factors such as flow geometry, boundary conditions, inlet effect, and fluid properties on heat transfer intensity. The Reynolds number index reflects the degree of influence of the flow state on heat transfer; Prandtl number is the exponent that reflects the degree of influence of fluid properties on heat transfer (mainly momentum diffusivity and thermal diffusivity; the Prandtl number is the ratio of momentum diffusivity to thermal diffusivity). S7: After completing the experiment of the current size test flow channel, shut down the system, replace it with a test flow channel of a different size, and repeat steps S2-S5 to conduct experiments on test flow channels of different sizes under the same thermal, electrical, and measurement and control boundary conditions.

Claims

1. A high-heat-transfer experimental apparatus for liquid lead-bismuth alloy, characterized in that, The device includes a main circulation pump (2), a filter (3), a flow meter (4), and a test device (1). The main circulation pump (2), the filter (3), the flow meter (4), and the test device (1) are connected in sequence through pipes to form a liquid lead-bismuth alloy circulation loop. The flow meter (4) is installed at the inlet end of the test device (1). The inlet end of the flow meter (4) is connected to a liquid lead-bismuth storage tank (5) through a pipe. The inlet end of the liquid lead-bismuth storage tank (5) is connected to an argon cylinder (6) through a pipe. The test device (1) includes two U-shaped flow channel plates (101), an inlet connector (105), and an outlet connector (106). The two U-shaped flow channel plates (101) are fitted together to form a test flow channel. An insulating plate (102) is provided on the outside of each U-shaped flow channel plate (101). A heating plate (103) is provided on the outside of each insulating plate (102). An insulation shell (104) is provided on the outside of the test flow channel. Flow channel inlets that cooperate with the test flow channel are provided on the inlet connector (105) and the outlet connector (106).

2. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 1, characterized in that, Several thermocouples are provided on the outer wall surface of the U-shaped flow channel plate (101).

3. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 2, characterized in that, The heat insulation shell (104) is divided into two parts that cooperate with the U-shaped flow channel plate (101). The heat insulation shell (104) is provided with mounting grooves that cooperate with the U-shaped flow channel plate (101), the insulation plate (102), and the heating plate (103).

4. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 3, characterized in that, The insulation shell (104) is provided with an upper clamp (107) and a lower clamp (108) on its exterior. Both the upper clamp (107) and the lower clamp (108) are provided with clamping grooves that cooperate with the insulation shell (104). The upper clamp (107) and the lower clamp (108) are connected by a number of bolts (109).

5. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 4, characterized in that, Two copper busbars (1010) are provided between the upper clamp (107) and the lower clamp (108). The two copper busbars (1010) are respectively attached to the heating plate (103). The middle part of the copper busbar (1010) forms a clamping hole that cooperates with the two heating plates (103). The copper busbar (1010) is provided in two detachable parts in the middle.

6. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 5, characterized in that, The inlet of the flow meter (4) is connected to the inlet of the main circulation pump (2) by a first shut-off valve (11) through a pipeline; the inlet of the liquid lead-bismuth storage tank (5) is provided with a second shut-off valve (12); and a third shut-off valve (13) is provided between the liquid lead-bismuth storage tank (5) and the argon cylinder (6).

7. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 6, characterized in that, An electric regulating valve (14) is provided between the filter (3) and the flow meter (4).

8. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 7, characterized in that, The outlet end of the test device (1) is provided with an outlet temperature sensor (9), and the inlet end of the test device (1) is provided with an inlet temperature sensor (10).

9. The high heat transfer experimental apparatus for liquid lead-bismuth alloy according to claim 8, characterized in that, The inlet and outlet of the test device (1) are connected by a differential pressure transmitter (8) through a pipeline; a pressure transmitter (7) is installed at the inlet of the test device (1).

10. An experimental method for the high heat transfer experimental apparatus for liquid lead-bismuth alloy as described in any one of claims 1-9, characterized in that, Includes the following steps: S1: Set the target inlet temperature and target heat flux density, determine the target slit size, select a U-shaped flow channel plate of the corresponding size, and stack and assemble the test device in the order of U-shaped flow channel plate, insulation plate, heating plate and heat insulation shell to form a closed rectangular test flow channel; S2: Connect the test device to the liquid lead-bismuth alloy circulation loop via the inlet connector and outlet connector; S3: After starting the liquid lead-bismuth alloy circulation loop, heat the lead-bismuth alloy to the target inlet temperature, and fill the circulation loop with liquid lead-bismuth alloy by pressurizing with argon gas; adjust the main circulation pump to make the flow rate in the test channel reach the set value, and monitor the pressure and flow rate in the liquid lead-bismuth alloy circulation loop in real time; S4: Power is supplied to the heating plate using copper busbars. By adjusting the current of the DC power supply, the heat flux density output by the heating plate is made to the target heat flux density. Thermocouples set on the wall of the U-shaped flow channel plate are used to collect thermocouple readings at each heat flux density. Nine thermocouples are evenly distributed on the wall of the U-shaped flow channel plate in the heating section, and the readings of all thermocouples are monitored at each heat flux density. S5: Collect the overall pressure drop of the test section in the liquid lead-bismuth alloy circulation loop using the differential pressure transmitter (8). Calculate the frictional pressure drop Friction resistance coefficient and Reynolds number The friction drag coefficient was obtained by fitting. With Reynolds number The relationship; specifically: S51: The overall pressure drop of the test section is obtained by the differential pressure transmitter (8). And calculate the frictional pressure drop. The specific formula is as follows: ； ； ； In the formula, For frictional pressure drop, For gravity pressure drop, To accelerate the pressure drop, The average density of liquid lead-bismuth in the test section. The density of liquid lead-bismuth at the inlet of the test section. The density of liquid lead-bismuth at the outlet of the test section. The height difference between the inlet and outlet of the test section; It is the acceleration due to gravity. For mass flow rate; S52: Calculate the friction resistance coefficient : ； In the formula, The density of liquid lead-bismuth alloy, The flow rate of the liquid lead-bismuth alloy; S53: Calculate the Reynolds number : ； In the formula, For flow rate, The hydraulic diameter of the test section. The dynamic viscosity of liquid lead-bismuth alloy; S54: Based on the coefficient of frictional resistance and Reynolds number The friction drag coefficient was obtained by fitting. With Reynolds number The relationship is expressed as follows: ； In the formula, This is the proportionality coefficient. The decay exponent, For the asymptotic constant term; S6: After completing data acquisition for one operating point, export all thermocouple data to obtain the heat transfer coefficient at that operating point; change the flow rate and heat flux of the liquid lead-bismuth alloy to obtain heat transfer correlations for multiple operating conditions; specifically: S61: Temperature of the outer wall of the test flow channel obtained from thermocouple data. and mainstream temperature Calculate the inner surface temperature of the flow channel The specific formula is as follows: ； In the formula, For heat flux density, The thickness of the U-shaped flow channel plate. The thermal conductivity of the U-shaped flow channel plate; S62: Based on the inner surface temperature of the flow channel Calculate the local heat transfer coefficient The specific formula is as follows: ； S63: Based on the local heat transfer coefficient Calculate the Nusel number Specifically: ； In the formula, The thermal conductivity of lead and bismuth; S64: Calculate Prandtl number Specifically: ； In the formula, For lead-bismuth specific heat capacity, Prandtl number Characterizes the ratio of a fluid's momentum diffusion capacity to its thermal diffusion capacity; S65: By changing the flow rate and heat flux of liquid lead-bismuth alloy, Reynolds numbers can be obtained under multiple operating conditions. With Prandtl number Nusel number The heat transfer correlation of the experimental flow channel was established. The specific heat transfer correlation is as follows: ； In the formula, It is an empirical constant. The Reynolds number exponent, The Prandtl number exponent; S7: After completing the experiment of the current size test flow channel, shut down the system, replace it with a test flow channel of a different size, and repeat steps S2-S5 to conduct experiments on test flow channels of different sizes under the same thermal, electrical, and measurement and control boundary conditions.

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