A pressure vessel constant boundary condition testing device and method

Abstract

A pressure vessel constant boundary condition test apparatus and method, belonging to the field of thermal hydraulics, is disclosed. The test apparatus includes the pressure vessel to be tested, a heat equalization system, and a control system. The heat equalization system includes an insulation layer, a heating device, and a heat-conducting layer. The insulation layer covers the pressure vessel to be tested, and the heat-conducting layer, made of thermally conductive material, uniformly covers the vessel surface. The control system includes a temperature sensor, a controller, and a heat dissipation power calculation module. The controller controls the heating power of the heating device, the heat dissipation power calculation module calculates the real-time heat dissipation power based on the temperature and heating power, and the controller adjusts the heating power of the heating device to establish feedback control of the surface temperature of the heated vessel to be tested. This test apparatus can effectively eliminate the influence of environmental factors on temperature boundary conditions and improve test accuracy.

Description

Technical Field

[0001] This invention belongs to the field of thermal hydraulics, specifically relating to a pressure vessel constant boundary condition test apparatus and method. Background Technology

[0002] The design and manufacturing of nuclear power equipment involves numerous performance tests on pressure vessels, such as pressure resistance tests, fatigue tests, and thermal cycling tests. The accuracy of these test results directly impacts the economic efficiency and safety of the nuclear power equipment. Currently, some technical solutions employ bare-tank testing devices, where the pressure vessel is directly exposed to the air environment, relying on natural convection and radiation for heat dissipation. Other solutions add insulation structures, such as rock wool or glass wool, to the surface of the pressure vessel to reduce heat loss. However, existing testing methods struggle to guarantee the consistency and stability of boundary conditions. The boundary conditions of bare-tank testing devices are significantly affected by environmental conditions, and simple insulation layers can only increase thermal resistance and reduce the heat dissipation rate, failing to completely prevent the heat dissipation power from being affected by changes in ambient temperature. Therefore, providing a testing device capable of providing constant boundary conditions is crucial for improving the accuracy of pressure vessel testing. Summary of the Invention

[0003] The purpose of this invention is to provide a pressure vessel constant boundary condition testing apparatus to reduce fluctuations in the pressure vessel boundary conditions during testing. This invention also provides a pressure vessel constant boundary condition testing method.

[0004] According to one aspect of the present invention, a pressure vessel constant boundary condition testing apparatus is provided. The apparatus includes a pressure vessel to be tested, a heat equalization system, and a control system. The heat equalization system includes an insulation layer, a heating device, and a heat-conducting layer. The heat-conducting layer is made of a heat-conducting material and uniformly covers the surface of the pressure vessel to be tested. The heating device is used to heat the pressure vessel to be tested. The insulation layer covers both the pressure vessel to be tested and the heat-conducting layer. The control system includes a temperature sensor, a controller, and a heat dissipation power calculation module. The temperature sensor is disposed on the surface of the pressure vessel to be tested and is used to measure the surface temperature of the pressure vessel. The controller is signal-connected to the temperature sensor and the heating device, respectively, and controls the heating power of the heating device. The heat dissipation power calculation module is signal-connected to the temperature sensor and the controller, respectively, and calculates the real-time heat dissipation power based on the heating power command output by the controller and the temperature data measured by the temperature sensor. The control system, based on the temperature data measured by the temperature sensor and the real-time heat dissipation power, adjusts the heating power of the heating device through the controller to establish feedback control of the surface temperature of the pressure vessel to be tested.

[0005] The device calculates the real-time heat dissipation power of the test device based on the heat dissipation power calculation module, and eliminates the influence of ambient temperature on temperature boundary conditions through feedback control, so that the pressure vessel remains in an insulated state during the test. The heat-conducting layer and the insulation layer ensure that the surface temperature distribution of the pressure vessel under test is uniform, improve the spatial consistency of test conditions, and ensure the repeatability of test results.

[0006] Furthermore, in some embodiments, the controller employs a PID control algorithm.

[0007] Furthermore, in some embodiments, the heating device is configured as an electric heating tape, and the heating device is disposed on the surface of the heat-conducting layer.

[0008] Furthermore, in some embodiments, the heat-conducting layer is configured as a metal mesh, manufactured using one or a combination of stainless steel, aluminum or aluminum alloy, copper or copper alloy.

[0009] Furthermore, in some embodiments, the mesh density of the thermally conductive layer is 10-50 mesh.

[0010] Furthermore, in some embodiments, multiple temperature sensors are configured, the heating devices are arranged at intervals, and the multiple temperature sensors are disposed at a certain distance within the intervals between the heating devices, the temperature sensors being disposed within the mesh of the metal wire mesh.

[0011] Furthermore, in some embodiments, the insulation layer includes a reflective layer and a heat insulation layer from the inside out. The reflective layer is used to reflect heat radiation, and the heat insulation layer is made of heat insulation material.

[0012] Furthermore, in some embodiments, a protective layer is provided outside the heat insulation layer, and the protective layer is configured as a rigid structure.

[0013] Furthermore, in some embodiments, the reflective layer is made of metal foil, and the heat insulation layer is made of rock wool, glass wool, or composite fibers.

[0014] According to another embodiment of the present invention, a constant boundary condition test method for a pressure vessel is provided. The method uses the constant boundary condition test apparatus for a pressure vessel provided in any of the foregoing embodiments to establish constant temperature boundary conditions for the pressure vessel to be tested and to carry out the test. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the cross-sectional structure of a pressure vessel constant boundary condition test device in one embodiment; Figure 2 This is a schematic diagram showing the arrangement of the temperature sensor in one embodiment.

[0016] Meaning of the reference numerals in the attached figures: 1-Pressure vessel to be tested; 2-Metal wire mesh; 3-Electric heating tape; 4-Insulation layer; 5-Temperature sensor; 6-Controller; 7-Heat dissipation power calculation module.

[0017] The purpose of the above-described drawings is to provide a detailed description of the present invention so that those skilled in the art can understand the technical concept of the invention, and is not intended to limit the invention. For the sake of brevity, the above-described drawings only schematically depict the structures related to the technical features of the present invention, and do not depict the complete structure and all details strictly according to actual scale. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0019] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment herein. The phrase appearing in various places in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive, independent, or alternative embodiments. Those skilled in the art will understand that the embodiments herein can be combined with other embodiments without causing structural conflicts.

[0020] In this description, unless otherwise explicitly specified and limited, the technical terms "installation," "connection," "joining," etc., should be interpreted broadly, for example, referring to movable connections, fixed connections, or integration. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0021] In this description, terms such as "upper," "lower," "left," "right," "lateral," "longitudinal," "height," "length," and "width," which indicate orientation or positional relationships, are intended to accurately describe the embodiments and simplify the description, and are not intended to limit the parts or structures involved to have a specific orientation, or to be installed or operated in a specific orientation, and should not be construed as limiting the embodiments described herein. In this description, "a plurality of" means at least two.

[0022] Nuclear power facilities extensively utilize various pressure vessels, such as fuel rod cladding and control rod cladding in pressurized water reactors, and heavy water tanks in heavy water reactors. The performance and reliability of these pressure vessels have a significant impact on the economy and safety of nuclear power facilities. Therefore, during the design and manufacturing process, numerous high-temperature and high-pressure tests under constant boundary conditions are required for these pressure vessels to verify their safety and reliability. However, current testing equipment often struggles to completely eliminate the influence of environmental changes on test conditions during long-term testing. Even with insulation materials provided to the pressure vessels to reduce heat loss, fluctuations in ambient temperature still affect the heat dissipation capacity of the test system, hindering further improvements in test accuracy.

[0023] To overcome the aforementioned problems of the prior art, one embodiment of the present invention provides a pressure vessel constant boundary condition testing apparatus. The apparatus structure is as follows: Figure 1 and Figure 2 As shown, the device can provide constant temperature boundary conditions for the pressure vessel 1 under test, effectively improving the accuracy of high-temperature and high-pressure test results, especially long-cycle tests. The test apparatus includes a heat homogenization system and a control system. The heat homogenization system provides the physical boundary for the pressure vessel 1 under test, while the control system controls the formation of constant temperature conditions within the physical boundary.

[0024] Specifically, the heat equalization system includes an insulation layer 4, a heating device, and a heat-conducting layer. The heat-conducting layer is made of a heat-conducting material. In a preferred embodiment, the heat-conducting layer is configured as a metal mesh 2. The metal mesh 2 is made of a material with good thermal conductivity. In different embodiments, the metal mesh 2 can be made of one or more of the following materials: stainless steel, aluminum or aluminum alloy, copper or copper alloy. The metal mesh 2 uniformly covers the surface of the pressure vessel 1 under test, and its good thermal conductivity ensures a uniform temperature field on the surface of the pressure vessel 1 under test, eliminating uneven temperature distribution in space. In a preferred embodiment, the mesh density of the metal mesh 2 is 10-50 mesh. The heating device is used to heat the pressure vessel 1 under test. In different embodiments, the heating device can take various forms and can be located inside or outside the pressure vessel 1 under test. In a preferred embodiment, such as... Figure 2As shown, the heating device is equipped with an electric heating tape 3, which is evenly distributed at certain intervals on the surface of the pressure vessel 1 to be tested. According to the test design requirements, the electric heating tape can be wrapped circumferentially around the surface of the pressure vessel 1, or it can be arranged axially on the surface of the pressure vessel 1. An insulation layer 4 covers the pressure vessel 1 to be tested and the metal wire mesh 2, which serves as a heat-conducting layer. The electric heating tape 3 is laid between the insulation layer 4 and the metal wire mesh 2. The insulation layer 4 is used to reduce heat loss and decrease heat exchange between the pressure vessel 1 to be tested and the environment. In a preferred embodiment, the insulation layer 4 has a multi-layer structure, with a reflective layer and a heat insulation layer arranged sequentially from the inside out. The reflective layer reflects thermal radiation, while the heat insulation layer blocks heat conduction. In a preferred embodiment, the reflective layer is made of metal foil with good radiation reflection capabilities, while the heat insulation layer can be made of porous rock wool, glass wool, or flocculent composite fibers. In a further preferred embodiment, the outermost part of the insulation layer 4 is provided with a protective layer with a rigid structure, which serves as the external physical boundary of the test device and protects the internal structure. The protective layer can be made of metal plate, ceramic plate or composite material plate.

[0025] The control system includes a temperature sensor 5, a controller 6, and a heat dissipation power calculation module 7. The temperature sensor is installed on the surface of the pressure vessel 1 under test to measure its surface temperature. In a preferred embodiment, as shown... Figure 2As shown, temperature sensors are arranged at certain intervals within the gaps between the electric heating cables 3 and the mesh of the wire mesh 2. The specific spacing is determined according to the temperature spatial distribution measurement accuracy required by the experimental design. The controller 6 is signal-connected to the temperature sensors 5 and the electric heating cables 3. The controller 6 can issue power control commands to the electric heating cables 3 to adjust their heating power. The heat dissipation power calculation module 7 is signal-connected to the temperature sensors 5 and the controller 6 respectively, and can calculate the real-time heat dissipation power based on the real-time temperature data measured by the temperature sensors 5 and the power control commands issued by the controller 6. Therefore, the control system can adjust the heating power of the electric heating cables 3 through the controller 6 based on the temperature data measured by the temperature sensors 5 and the real-time heat dissipation power data calculated by the heat dissipation power calculation module 7, establishing feedback control of the surface temperature of the pressure vessel 1 under test. This ensures that the surface temperature of the pressure vessel 1 under test can be strictly kept constant without being affected by environmental factors and achieve uniform spatial distribution. In a preferred embodiment, the controller 6 uses a PID control algorithm to achieve temperature control of the experimental device. Among them, the temperature sensor 5 can be a thermocouple or other types of sensors; the controller 6 can be a general-purpose computer or a special-purpose computing device such as a microcontroller; the heat dissipation power calculation module 7 can be configured as an independent computing device, such as a separate general-purpose computer or a special-purpose computing device, or it can be integrated with the controller 6 in the same general-purpose computer, and the computing resources required for the computer to execute the functions of the controller 6 and the heat dissipation power calculation module 7 can be allocated by software instructions.

[0026] In a preferred embodiment, the specific process of conducting the test using the pressure vessel constant boundary condition test apparatus provided in the above embodiments is as follows: At the start of the test, the ambient temperature was 25℃, and the surface temperature of the pressure vessel 1 under test, measured by temperature sensor 5, was also 25℃. A pressure medium at 120℃ was injected into the vessel, and the test temperature boundary condition was set to 120℃ through the control system. Controller 6 compared the temperature data measured by temperature sensor 5 with the preset test condition of 120℃, obtaining a temperature difference of 95℃. The PID algorithm calculated the required heating power based on this deviation and output a control signal to instruct the electric heating tape 3 to start heating. The heat generated by the electric heating tape 3 was evenly transferred to the surface of the pressure vessel 1 under test through the metal mesh 2, causing the surface temperature to rise uniformly. During the heating process, the heat dissipation power calculation module 7 calculated the current heat dissipation power in real time based on the heating power commanded by controller 6 and the temperature data measured by temperature sensor 5, and fed it back to controller 6. Since the temperature had not yet reached the preset temperature, the heating power remained unchanged. As the surface temperature of the pressure vessel 1 under test approached 120℃, the temperature deviation decreased, and the PID algorithm automatically reduced the heating power to avoid overshoot. When the external surface temperature stabilizes within a preset threshold range, such as 120±1℃, the inner and outer walls of the pressure vessel 1 under test are considered to have no temperature difference, the heat conduction driving force is 0, and the pressure vessel 1 under test presents an adiabatic state. During the subsequent test, the heat dissipation power calculation module 7 records in real time the heating power of the electric heating tape 3 as instructed by the controller 6 and the temperature data measured by the temperature sensor 5, and calculates the current heat dissipation power of 2.5kW. The controller 6 adjusts the heating power of the electric heating tape 3 according to the real-time heat dissipation power data and temperature data, establishes feedback control of the surface temperature of the pressure vessel 1 under test, and maintains a constant temperature boundary condition during the test.

[0027] The pressure vessel constant boundary condition test apparatus provided in the above embodiments effectively eliminates the interference of environmental factors on temperature boundary conditions by establishing real-time feedback control based on heat dissipation power and surface temperature, thus effectively improving the accuracy of test conditions and enhancing the comparability and repeatability of test results. Simultaneously, the precise calculation of heat dissipation power during the test can accumulate data on the heat exchange process of nuclear power facility pressure vessels under different conditions, supporting further research and verification testing. The heat equalization system ensures the uniformity of temperature boundary conditions in space, guaranteeing that the boundary heat conduction driving force is zero. Furthermore, the apparatus achieves efficient, stable, and precise temperature control, ensuring temperature control accuracy during both heating and cooling processes and avoiding overshoot.

[0028] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, optimization or substitution of the technical features involved, as well as combination of technical solutions in different embodiments without causing structural or principle conflicts, all fall within the protection scope of the present invention.

Claims

1. A pressure vessel constant boundary condition test apparatus, comprising a pressure vessel to be tested, characterized in that, It also includes a heat equalization system and a control system; among which, The heat dissipation system includes an insulation layer, a heating device, and a heat-conducting layer; the heat-conducting layer is made of a heat-conducting material and is uniformly covered on the surface of the pressure vessel to be tested; the heating device is used to heat the pressure vessel to be tested; the insulation layer covers the pressure vessel to be tested and the heat-conducting layer. The control system includes a temperature sensor, a controller, and a heat dissipation power calculation module. The temperature sensor is installed on the surface of the pressure vessel under test to measure its surface temperature. The controller is signal-connected to the temperature sensor and the heating device, respectively, and controls the heating power of the heating device. The heat dissipation power calculation module is signal-connected to the temperature sensor and the controller, respectively, and calculates the real-time heat dissipation power based on the heating power command output by the controller and the temperature data measured by the temperature sensor. Based on the temperature data measured by the temperature sensor and the real-time heat dissipation power, the control system adjusts the heating power of the heating device through the controller to establish feedback control of the surface temperature of the pressure vessel under test.

2. The pressure vessel constant boundary condition test apparatus according to claim 1, characterized in that, The controller uses a PID control algorithm.

3. The pressure vessel constant boundary condition test apparatus according to claim 1 or 2, characterized in that, The heating device is configured as an electric heating tape, and the heating device is disposed on the surface of the heat-conducting layer.

4. The pressure vessel constant boundary condition test apparatus according to claim 3, characterized in that, The heat-conducting layer is configured as a metal mesh, and is made of one or a combination of stainless steel, aluminum or aluminum alloy, copper or copper alloy.

5. The pressure vessel constant boundary condition test apparatus according to claim 4, characterized in that, The mesh density of the heat-conducting layer is 10-50 mesh.

6. The pressure vessel constant boundary condition test apparatus according to claim 4, characterized in that, The temperature sensor is configured in multiple ways, the heating devices are arranged at intervals, and the multiple temperature sensors are arranged at a certain interval in the interval between the heating devices. The temperature sensor is arranged in the mesh of the metal wire mesh.

7. The pressure vessel constant boundary condition test apparatus according to claim 1 or 2, characterized in that, The insulation layer comprises a reflective layer and a heat insulation layer from the inside out. The reflective layer is used to reflect heat radiation, and the heat insulation layer is made of heat insulation material.

8. The pressure vessel constant boundary condition test apparatus according to claim 7, characterized in that, A protective layer is provided outside the insulation layer, and the protective layer is configured as a rigid structure.

9. The pressure vessel constant boundary condition test apparatus according to claim 7, characterized in that, The reflective layer is made of metal foil, and the heat insulation layer is made of rock wool, glass wool, or composite fiber.

10. A method for testing pressure vessels under constant boundary conditions, characterized in that, The pressure vessel under test is subjected to constant temperature boundary conditions using the pressure vessel constant boundary condition test apparatus as described in any one of claims 1 to 9, and the test is carried out.

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