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CN-122016923-A - Flow heat transfer experimental device and method for narrow slit channel under asymmetric heat conduction blocking condition

CN122016923ACN 122016923 ACN122016923 ACN 122016923ACN-122016923-A

Abstract

The invention belongs to the technical field, and discloses a narrow slit channel flow heat transfer experimental device and a method under the asymmetric heat conduction blocking condition, wherein the device adopts a single heating plate to generate heat which is conducted into coolant in narrow slit channels at two sides of the device through a test element plate, different heat insulation cavities are arranged on the test element plates at two sides and are used for simulating asymmetric heat transfer weakening effects caused by local deformation of the fuel element. The local heat exchange capacity of one side of the heat insulation cavity is reduced, and the heat transfer and boiling process of the narrow slit channel on the other side are influenced due to the thermal coupling effect, including boiling intensity, bubble behavior characteristics and critical boiling characteristics. Therefore, the invention realizes the comparison research on the flow heat transfer characteristics and the heat flow redistribution rule of the narrow slit channels at two sides under the asymmetric heat conduction blocking condition under the same working condition and the same boundary condition by constructing the coupling structure consisting of the single heating plate and the double rectangular narrow slit channels.

Inventors

  • LI WEI
  • Li Qiongtao
  • LU QI
  • SUN HONGPING
  • Wei Zonglan

Assignees

  • 西安交通大学
  • 中国核动力研究设计院

Dates

Publication Date
20260512
Application Date
20260227

Claims (10)

  1. 1. The narrow slit channel flow heat transfer experimental device under the asymmetric heat conduction blocking condition is characterized by comprising a heating plate (11) and two pressure-bearing shells (3) symmetrically arranged on two sides of the heating plate (11), wherein a side insulating plate (12) is arranged on the heating plate (11); Test element plates (9) and channel glass (7) are sequentially arranged in each pressure-bearing shell (3) along the direction away from the heating plate (11), the test element plates (9) are in contact with the heating plate (11) to receive and transfer heat, window glass (5) is arranged on one side, away from the heating plate (11), of each pressure-bearing shell (3), raised features for simulating local heat insulation areas are processed on each test element plate (9), and a heat insulation cavity (10) is formed between each raised feature and the heating plate (11); The pressure-bearing shell (3), the test element plate (9) and the channel glass (7) jointly enclose a rectangular narrow slit channel (8), the inlet end of the rectangular narrow slit channel (8) is connected with the fluid inlet assembly (1), and the outlet end of the rectangular narrow slit channel is connected with the fluid outlet assembly (2).
  2. 2. The narrow slit channel flow heat transfer experimental device under the asymmetric heat conduction blocking condition according to claim 1, wherein sealing rings are arranged between the inner wall of the pressure-bearing shell (3) and the test element plate (9) and between the inner wall of the pressure-bearing shell (3) and the channel glass (7).
  3. 3. The experimental device for flow heat transfer of narrow slit channel under asymmetric heat conduction blocking condition according to claim 2, wherein the sealing ring is made of fluororubber material.
  4. 4. The narrow slit channel flow heat transfer experimental device under the asymmetric heat conduction blocking condition according to claim 1, wherein the heating plate (11) is an inconel 625 alloy electric heating plate and is powered by a direct current power supply.
  5. 5. The narrow slit channel flow heat transfer experimental device under the asymmetric heat conduction blocking condition according to claim 1, wherein the surface of the heating plate (11) is provided with an alumina insulating coating.
  6. 6. The narrow slit channel flow heat transfer experimental apparatus under asymmetric heat conduction blocking conditions as claimed in claim 1, wherein the side insulating plate (12) is made of alumina ceramics for blocking the conductive path between the heating plate (11) and the pressure-bearing housing (3) and the test element plate (9).
  7. 7. The narrow slit channel flow heat transfer experimental device under the asymmetric heat conduction blocking condition according to claim 1, wherein a window cover plate (4) is arranged on the outer side of the window glass (5), and the window glass (5) is pressed and fixed by the window cover plate (4) through a window bolt (13).
  8. 8. The narrow slit channel flow heat transfer experimental device under the asymmetric heat conduction blocking condition according to claim 1, wherein an air gap (6) is formed between the channel glass (7) and the window glass (5), and inert gas is filled in the air gap (6).
  9. 9. The narrow slit channel flow heat transfer experimental device under the asymmetric heat conduction blocking condition according to claim 1, wherein the channel glass (7) is borosilicate glass or quartz glass.
  10. 10. An experimental method of a narrow slit channel flow heat transfer experimental device under the condition of asymmetric heat conduction resistance is characterized by adopting the device of any one of claims 1-9, comprising the following steps: a side insulating plate (12) is arranged on the heating plate (11) to block the conductive paths between the heating plate (11) and the pressure-bearing shell (3) and the test element plate (9); the working medium is introduced into a rectangular narrow slit channel (8) surrounded by the pressure-bearing shell (3), the test element plate (9) and the channel glass (7) through the fluid inlet assembly (1), so that stable flow is formed; Starting a heating plate (11) to increase heating power, so that the overall temperature of the test element plates (9) at two sides is slowly increased, and forming heat flow blocking areas and heat flow redistribution phenomena with different degrees in a rectangular narrow slit channel (8) through a heat insulation cavity (10) formed between the convex features and the heating plate (11); The power is continuously increased, the boiling phenomenon occurs in the rectangular narrow slit channel (8), and when the critical boiling is observed, the power supply of the heating plate (11) is cut off, and the working medium is discharged through the fluid outlet assembly (2).

Description

Flow heat transfer experimental device and method for narrow slit channel under asymmetric heat conduction blocking condition Technical Field The invention belongs to the field, and particularly relates to a narrow slit channel flow heat transfer experimental device and method under asymmetric heat conduction blocking conditions. Background The particle reinforced fuel element takes ceramic particles made of fission materials as reinforcement, is compounded with a metal matrix to form a core body, is wrapped by a metal cladding to form the nuclear fuel element, and has the advantages of large specific surface area, short heat transfer path, stable neutron irradiation structure and the like. Rectangular slot channels formed by particle-enhanced fuel elements are widely used in high-throughput research stacks. However, under high burnup, high temperature conditions, fissile gas atoms tend to accumulate inside the fuel element to form localized high pressures, resulting in crack initiation. As the fissile gas pressure increases, the crack gradually expands and opens, eventually forming a localized bulge on the fuel element surface, below which is a cavity filled with a low thermal conductivity fissile gas. Such cavity protrusions can significantly impair the ability of heat to transfer from the core to the coolant. The partial heat transfer process inside the fuel element is affected by this, and the asymmetric nature of the partial heat transfer process occurs in that the heat taken up by the slotted channels on one side of the cavity bulge is reduced, while the cladding on the other side assumes a higher heat flow, resulting in a passive heat flow offset between the otherwise approximately symmetrical double-sided channels. The bias of heat flow caused by local heat insulation can change the flow boiling behavior of narrow slit channels at two sides, so that one side can enter critical boiling in advance when the overall average heat flow is still in an acceptable range, and the safety margin of the system is reduced. In the prior art, most of researches on boiling criticality and heat flow density distribution of narrow slit channels are based on single channels, and the influence on heat flow redistribution conditions and flow boiling phenomena of two adjacent narrow slit channels under the condition of non-symmetrical heat conduction blocking cannot be overcome. In summary, it is needed to construct an experimental platform capable of blocking asymmetric heat conduction caused by a local cavity and comparing the two-channel heat flow redistribution behaviors at the same time, so as to systematically reveal the influence mechanism of the local heat insulation area on the narrow-slit channel boiling characteristics, especially the critical boiling behavior. Disclosure of Invention The invention aims to solve the problem that the prior single-channel research in the prior art cannot reflect the influence of the double-channel heat flow redistribution and boiling characteristics under the asymmetric heat conduction blocking condition, and provides a narrow-slit channel flow heat transfer experimental device and a narrow-slit channel flow heat transfer experimental method under the asymmetric heat conduction blocking condition. In order to achieve the purpose, the invention is realized by adopting the following technical scheme: The invention provides a narrow slit channel flow heat transfer experimental device under an asymmetric heat conduction blocking condition, which comprises a heating plate and two pressure-bearing shells symmetrically arranged on two sides of the heating plate, wherein a side insulating plate is arranged on the heating plate; The test element plates are contacted with the heating plates to receive and transfer heat, and window glass is arranged on one side of the two pressure-bearing shells, which is far away from the heating plates; The pressure-bearing shell, the test element plate and the channel glass jointly enclose a rectangular narrow slit channel, the inlet end of the rectangular narrow slit channel is connected with the fluid inlet assembly, and the outlet end of the rectangular narrow slit channel is connected with the fluid outlet assembly. Preferably, sealing rings are arranged between the inner wall of the pressure-bearing shell and the test element plate and between the inner wall of the pressure-bearing shell and the channel glass. Preferably, the sealing ring is made of fluororubber material. Preferably, the heating plate is an inconel 625 alloy electric heating plate and is powered by a direct current power supply. Preferably, the surface of the heating plate is provided with an alumina insulation coating. Preferably, the side insulating plates are made of alumina ceramic for blocking the conductive paths between the heating plate and the pressure-bearing housing and test element plate. Preferably, a window cover plate is arranged on the outer side of the window glass,