Device and method for measuring thermal stratification of fluid on hot side in shell-and-tube heat exchanger
By arranging multiple temperature measurement module groups inside the shell-and-tube heat exchanger, the gas temperature can be monitored in real time, solving the problem in the prior art of measuring the thermal stratification of hot-side fluids without affecting the flow state and cooling capacity. This enables the measurement of the thermal stratification state of various gases and supports the study of flow heat transfer characteristics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-02-05
- Publication Date
- 2026-04-10
AI Technical Summary
Existing temperature measurement devices struggle to achieve multi-point temperature measurement of the thermal stratification of hot-side fluids within shell-and-tube heat exchangers without affecting flow conditions and cooling capacity, especially the thermal stratification of gaseous coolants in the channels.
The device consists of multiple temperature measurement modules, including upper, lower, and side temperature measurement modules. The gas temperature is monitored in real time through direct contact between thermocouple temperature measurement probes and the gas. The measurement is performed through a data acquisition system. The measurement module group is distributed at different positions in the shell-and-tube heat exchanger to realize the measurement of the thermal stratification state of the hot-side fluid.
It can clearly characterize the thermal stratification state of hot-side fluids without affecting the fluid flow state and cooling capacity to the greatest extent, providing technical support for the study of thermal stratification characteristics and flow heat transfer characteristics of gases during the cooling process, and supporting the measurement of thermal stratification state of various gases.
Smart Images
Figure CN121829797A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of engineering fluid thermal engineering and hydraulics, and particularly relates to a device and method for measuring thermal stratification of hot-side fluid in a shell-and-tube heat exchanger. BACKGROUND
[0002] Nuclear energy, with its unique "green energy" gift, is a key force in addressing climate change and achieving the "carbon neutral" goal as a highly efficient energy source that produces almost no greenhouse gases such as carbon dioxide during operation. Small reactors, which are developed from traditional large nuclear power plants, have a wide application prospect in power, electricity and heat supply in specific scenarios, power supply in remote and local areas, etc. due to their flexible layout, wide range of uses and compact structure. As an internationally recognized fourth-generation reactor, the ultra-high temperature gas cooled reactor using inert gas or carbon dioxide as coolant, combined with the direct Brayton cycle power generation method, has the characteristics of system simplification, lightweight and small equipment, easy operation, high power-to-mass ratio and inherent safety, and has broad development prospects.
[0003] Unlike the water coolant used in conventional nuclear power plants, the gas coolant has unique flow and heat transfer characteristics in the channel. Under the influence of flow acceleration, buoyancy and coupling, the gas may have thermal stratification in the channel, resulting in temperature gradients in the channel cross-section, which may affect the flow and heat transfer characteristics of the gas and may cause heat transfer deterioration areas, further affecting the operation safety of the system. The measurement of thermal stratification of gas in the pipe can support the research on the flow and heat transfer characteristics of the gas and provide a basis for the research and development of ultra-high temperature gas cooled reactors.
[0004] The existing temperature measurement device is mainly used for measuring thermal stratification in the heater and does not consider the thermal stratification state of the hot-side fluid in the cooler, especially the commonly used shell-and-tube heat exchanger. It is also difficult to realize multi-point temperature measurement of the gas in the pipe without affecting the flow state and cooling capacity to the greatest extent. SUMMARY
[0005] The purpose of the present application is to provide a device and method for measuring thermal stratification of hot-side fluid in a shell-and-tube heat exchanger to solve the problems raised in the background.
[0006] The purpose of the present application is achieved by the following technical solutions:
[0007] A device for measuring thermal stratification of hot-side fluid in a shell-and-tube heat exchanger, comprising: a shell-and-tube heat exchanger, a temperature measurement module and a data acquisition system.
[0008] The shell-and-tube heat exchanger includes a horizontal circular tube that passes through the centerline of a cylindrical body. The horizontal circular tube contains a flowing medium that needs to be measured for thermal stratification. A cooling water channel annular cavity is formed between the horizontal circular tube and the cylindrical body.
[0009] Multiple temperature measurement module groups are installed on the horizontal circular tube and the cylindrical body. The temperature measurement module groups include an upper temperature measurement module, a lower temperature measurement module and a side temperature measurement module.
[0010] The upper temperature measurement module, the lower temperature measurement module, and the side temperature measurement module each include a temperature measurement module. The thermocouple temperature measurement probe of the temperature measurement module is in direct contact with the gas inside the horizontal circular tube. The temperature measurement module is connected to a data acquisition system for simultaneous measurement, real-time monitoring of the gas temperature at the position of the thermocouple temperature measurement probe, and obtaining the thermal stratification state of the fluid inside the tube during horizontal cooling.
[0011] Furthermore, the temperature measurement module includes a thermocouple holder, through which a thermocouple data transmission line passes, and a thermocouple sealing sleeve is provided between the thermocouple holder and the thermocouple data transmission line. The thermocouple data transmission line passes through the thermocouple sheath, and the thermocouple sheath is mounted on the horizontal circular tube.
[0012] Furthermore, one end of the thermocouple data transmission line is connected to the data acquisition system, and the other end is connected to the thermocouple temperature measurement probe.
[0013] Furthermore, the upper temperature measurement module is arranged directly above the device cross-section to measure the near-wall fluid temperature on the upper wall of the tube; the lower temperature measurement module is arranged directly below the device cross-section to measure the near-wall fluid temperature on the lower wall of the tube; and the side temperature measurement module is arranged on the side of the device cross-section to measure the fluid temperature at the center of the tube cross-section.
[0014] Furthermore, the temperature measurement module group measures the fluid temperature at N cross-sections to describe the thermal stratification state of the fluid inside the pipe, wherein the temperature measurement module group consists of N groups, where N≥5.
[0015] Furthermore, the cylindrical body has an opening at the upper part of the fluid inlet side inside the pipe, and a cooling water outlet pipe with a vertical upward direction is installed inside the opening; the cylindrical body also has an opening at the lower part of the fluid outlet side inside the pipe, and a cooling water inlet pipe with a vertical downward direction is installed inside the opening.
[0016] Furthermore, the gas inside the horizontal circular tube is one of helium, argon, carbon dioxide, or one of an inert mixture of helium and argon, or an inert mixture of helium and xenon.
[0017] Further, the gas pressure in the horizontal circular pipe is 0.1-5 MPa, and the temperature is 0-500 DEG C.
[0018] Further, the distance A1 between the first group of temperature measurement module groups and the fluid flow inlet is 30-50 mm, the distance A2 between the last group of temperature measurement module groups and the fluid flow outlet is 30-50 mm, and the distance A3 between the temperature measurement module groups is 20-100 mm.
[0019] The application can also include:
[0020] A measurement method of the heat-side fluid thermal stratification measurement device of the shell-and-tube heat exchanger is provided, and the method comprises the following steps:
[0021] The horizontal circular pipe passes through the cylindrical barrel along a center line to form a shell-and-tube heat exchanger, the horizontal circular pipe is used for flowing gas which needs to be measured for thermal stratification, and the horizontal circular pipe is provided with an annular cavity outside the pipe, which is used as a cooling water channel; the high-temperature gas in the pipe transmits heat to the cooling water through the pipe wall to realize cooling, and the cooling water continuously takes away the heat of the high-temperature gas in the pipe; in the process, the cooled gas appears thermal stratification phenomenon that the temperature difference between the upper and lower parts of the pipe cross section is large during the flowing process.
[0022] The temperature measurement module is arranged to measure the gas temperature at the position of the temperature probe in real time, the thermocouple data transmission line is connected to the data acquisition system to display the real-time temperature; a group of temperature measurement modules on one cross section are analyzed to represent the thermal stratification characteristics of the gas on the cross section; and a plurality of groups of temperature measurement modules in the axial direction are cooperatively measured to represent the thermal stratification characteristics of the gas in the flowing direction.
[0023] The application has the following beneficial effects:
[0024] In the application, the temperature of the heat-side fluid of the shell-and-tube heat exchanger is measured by the penetrating method, which can not affect the flowing state of the heat-side fluid and the cooling capacity of the cold side to the greatest extent; the temperature of the heat-side fluid near the wall and the center fluid at different positions in the axial direction of the shell-and-tube heat exchanger is measured by the distributed arrangement, and the thermal stratification state of the heat-side fluid is clearly represented, which provides technical support for the research on the thermal stratification characteristics and the flowing and heat exchange characteristics of the gas in the cooling process.
[0025] The application can measure the thermal stratification state of various single-component gases and multi-component gases in the cooling process, and effectively ensures the diversity of the measurement medium. BRIEF DESCRIPTION OF DRAWINGS
[0026] The application is a structural schematic diagram; Figure 1
[0027] Figure 1 is a structural schematic diagram of the temperature measuring module of the present application; Figure 2 Figure 2 is a structural schematic diagram of the temperature measuring module of the present application;
[0028] Figure 3 is an installation position schematic diagram of the temperature measuring module group of the present application. Figure 3
[0029] In the drawings:
[0030] 1. horizontal circular pipe; 2. cylindrical shell; 3. temperature measuring module; 4. outlet side temperature measuring module group; 5. inlet side temperature measuring module group; 6. cooling water inlet pipeline; 7. cooling water outlet pipeline;
[0031] 3-1. thermocouple data transmission line; 3-2. thermocouple sealing sleeve; 3-3. thermocouple seat; 3-4. thermocouple sleeve;
[0032] 4-1. upper temperature measuring module; 4-2. lower temperature measuring module; 4-3. side temperature measuring module. DETAILED DESCRIPTION
[0033] The present application is further described below in conjunction with the drawings.
[0034] The present application provides a device for measuring thermal stratification of hot side fluid in a shell-and-tube heat exchanger, as shown in Figure 1, comprising a horizontal circular pipe 1, a cylindrical shell 2, a temperature measuring module 3, and a data acquisition system. Figures 1-3
[0035] The horizontal circular pipe 1 passes through the cylindrical shell 2 along the center line to form a shell-and-tube heat exchanger, the flow medium in the horizontal circular pipe 1 is subjected to thermal stratification measurement, and the pipe outside forms an annular cavity with the cylindrical shell 2, which is a cooling water passage.
[0036] The temperature measuring module is installed on the horizontal circular pipe 1 and the cylindrical shell 2, and the thermocouple temperature measuring probe of the temperature measuring module 3 is inserted through the hole on the pipe and directly contacts the gas.
[0037] The multiple sets of temperature measuring modules 3 are connected to the data acquisition system for simultaneous measurement, real-time monitoring of the gas temperature at the position of the thermocouple temperature measuring probe, and obtaining the thermal stratification state of the fluid in the pipe during horizontal cooling.
[0038] Figure 2 is a structural schematic diagram of the temperature measuring module of the present application; Figure 1 As shown, the cooling water outlet pipe 7 is arranged on the upper opening of the cylindrical barrel 2 on the inlet side of the in-pipe fluid, vertically upward; the cooling water inlet pipe 6 is arranged on the lower opening of the cylindrical barrel 2 on the outlet side of the in-pipe fluid, vertically downward, the outer diameter B1 of the pipe is 12mm~20mm; the wall thickness B2 is 0.5mm~2mm; the distance C1 between the center of the cooling water outlet pipe 7 and the inlet section of the in-pipe fluid is 6mm~10mm, and the distance C2 between the center of the cooling water inlet pipe 6 and the outlet section of the in-pipe fluid is 6mm~10mm. In this way, the cooling water enters the cylindrical barrel vertically upward and flows out from the outlet pipe after completely flooding the annular cavity, avoiding excessive flow impact on the thermocouple and ensuring the stability of the thermocouple; at the same time, the residence time of the cooling water in the annular cavity is long, which can realize efficient cooling of the in-pipe gas.
[0039] As shown in the accompanying drawings, Figure 1 The outer diameter B3 of the horizontal circular pipe 1 is 16mm~50mm; the wall thickness B4 of the horizontal circular pipe 1 is 1.5mm~4mm; the outer diameter B5 of the cylindrical barrel 2 is 70mm~200mm; and the wall thickness B6 of the cylindrical barrel 2 is 1mm~2mm. The thermal stratification state of the hot side fluid is directly related to the pipe diameter, and in this way, the thermal stratification measurement of the hot side fluid under a wider range of working conditions can be realized; at the same time, the pipe wall thickness changes with the pipe diameter, which can ensure the measurement of in-pipe high-pressure gas under large pipe diameter; at the same time, the size of the cylindrical barrel changes with the pipe diameter, which can still have appropriate cooling capacity under large pipe diameter.
[0040] In this embodiment, the distance A1 between the first group of temperature measurement module groups 4 and the in-pipe fluid flow inlet is 30mm~50mm; the distance A2 between the last group of temperature measurement module groups 5 and the in-pipe fluid flow outlet is 30mm~50mm; and the distance A3 between the temperature measurement module groups is 20mm~100mm. The hot side fluid thermal stratification measurement device needs to measure the fluid temperature of N sections to describe the thermal stratification state of the in-pipe fluid, that is, the temperature measurement module group 4 needs N groups, wherein, In this way, the temperature variation of the hot side fluid in the axial direction of the shell-and-tube heat exchanger can be clearly characterized, and the thermal stratification characteristics of the hot side fluid can be accurately characterized.
[0041] As shown in the accompanying drawings, Figure 2 The temperature measurement module 3 includes a thermocouple seat 3-3, a thermocouple sealing sleeve 3-2, a thermocouple sleeve 3-4, and a thermocouple data transmission line 3-1 with a temperature measurement probe, one end of the thermocouple data transmission line 3-1 is connected with the thermocouple temperature measurement probe, and the other end is connected with the data acquisition system.
[0042] In this embodiment, the thermocouple measuring probe penetrates the cylinder and pipe wall to measure the fluid temperature near the inner wall or the central fluid temperature. The thermocouple sheath 3-4 is laser-welded to the thermocouple, and the thermocouple sheath 3-4 is argon-arc-welded to the outer wall of the horizontal circular pipe 1. The thermocouple holder 3-3 is argon-arc-welded to the cylindrical cylinder 2. During installation, the thermocouple holder 3-3 is first welded to the cylindrical cylinder 2. After cooling, the thermocouple is passed through the thermocouple holder 3-3, and the thermocouple is laser-welded to the thermocouple sheath 3-4. Finally, the thermocouple sheath 3-4 is welded to a pre-drilled hole in the horizontal circular pipe 1. This design ensures the sealing of the gas flow channel and the cooling water channel within the annular cavity while simultaneously measuring the gas temperature inside the pipe.
[0043] In this embodiment, the diameter of the thermocouple temperature measurement probe is 1mm~2mm. This design effectively ensures the real-time performance of the thermocouple temperature measurement, and at the same time, it prevents the thermocouple from bending due to the scouring of cooling water when there is a large flow rate in the annular cavity, effectively ensuring the reliability of the system.
[0044] As attached Figure 3 As shown, temperature measurement module 3 requires three sets to form a group for coordinated measurement. The three sets of temperature measurement modules are arranged on the same cross section to form a temperature measurement module group 4, including an upper temperature measurement module 4-1, a lower temperature measurement module 4-2, and a side temperature measurement module 4-3. The upper temperature measurement module 4-1 is arranged directly above the cross section and measures the fluid temperature near the upper wall of the tube; the lower temperature measurement module 4-2 is arranged directly below the cross section and measures the fluid temperature near the lower wall of the tube; the side temperature measurement module 4-3 is arranged on the side of the cross section, with a thermocouple extending into the tube to measure the fluid temperature at the center of the tube cross section.
[0045] In this embodiment, in temperature measurement module group 4, the thermocouple insertion depth of the upper temperature measurement module 4-1, i.e., the distance D1 from the inner wall surface, is 0mm~10mm; the thermocouple insertion depth of the lower temperature measurement module, i.e., the distance D2 from the inner wall surface, is 0mm~10mm. This design enables temperature measurement of the hot-side fluid at different radial positions according to actual needs, providing more experimental data support for the analysis of thermal stratification characteristics.
[0046] In this embodiment, the measurable gas pressure inside the horizontal circular tube 1 is 0.1 MPa to 5 MPa, and the temperature is 0℃ to 500℃. This allows for the measurement of gas thermal stratification characteristics under high temperature and high pressure conditions, effectively enabling the measurement of thermal stratification characteristics under various operating parameters.
[0047] The measurable in-pipe flowing gas in the application includes but is not limited to helium, argon, carbon dioxide and other single non-corrosive gas and multi-component inert mixed gas such as helium and argon, helium and xenon.
[0048] The working principle of the application is as follows:
[0049] The horizontal circular pipe 1 passes through the cylindrical barrel 2 along the center line to form a tube-shell heat exchanger, the horizontal circular pipe 1 is filled with flowing gas which needs to be measured for thermal stratification, and the pipe outside and the cylindrical barrel 2 form an annular cavity which is a cooling water channel; the high-temperature gas in the pipe transfers heat to the cooling water through the pipe wall to realize cooling, and the cooling water flow continuously takes away the heat of the high-temperature gas in the pipe. In this process, there is a large temperature difference from the inlet to the outlet of the heat exchanger, and the density of the gas changes greatly with temperature, and the density of the gas is low at high temperature, so in the process of horizontal flow cooling, the density of the gas increases, and due to the influence of buoyancy, the cooled gas will appear in the upper part of the pipe cross section during the flow process. The phenomenon of thermal stratification with a large difference between the temperature of the gas in the upper part and the temperature of the gas in the lower part.
[0050] The temperature measuring module arranged can measure the temperature of the gas at the position of the temperature probe in real time, the thermocouple data transmission line 3-1 transmits the real-time temperature to the acquisition system and displays the real-time temperature; a group of temperature measuring modules on one cross section are analyzed to represent the thermal stratification characteristics of the gas on one cross section; a plurality of groups of temperature measuring modules in the axial direction are cooperatively measured to represent the thermal stratification characteristics of the gas in the flow direction.
[0051] In the application, the thermal stratification measuring device designed can measure the temperature of the gas at multiple points in the pipe of the tube-shell heat exchanger, and through the matching use of the measuring device, the temperature of the gas in any cross section of the pipe can be measured to represent the thermal stratification characteristics of the gas in the axial and radial directions of the tube-shell heat exchanger.
[0052] The above only describes the preferred embodiments of the application and is not used to limit the application, and the application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.
Claims
1. A device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger, characterized in that, include: Shell-and-tube heat exchanger, temperature measurement module (3) and data acquisition system; The shell-and-tube heat exchanger includes a horizontal circular tube (1) that passes through the center line of a cylindrical body (2). The horizontal circular tube (1) contains a flowing medium that needs to be measured for thermal stratification. A cooling water channel annular cavity is formed between the horizontal circular tube (1) and the cylindrical body (2). Multiple temperature measurement module groups (4) are installed on the horizontal circular tube (1) and the cylindrical body (2). The temperature measurement module group (4) includes an upper temperature measurement module (4-1), a lower temperature measurement module (4-2), and a side temperature measurement module (4-3). The upper temperature measurement module (4-1), the lower temperature measurement module (4-2), and the side temperature measurement module (4-3) each include a temperature measurement module (3). The thermocouple temperature measurement probe of the temperature measurement module (3) is in direct contact with the gas inside the horizontal circular tube (1). The temperature measurement module (3) is connected to a data acquisition system for simultaneous measurement, and the gas temperature at the position of the thermocouple temperature measurement probe is monitored in real time to obtain the thermal stratification state of the fluid inside the tube during horizontal cooling.
2. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 1, characterized in that, The temperature measurement module (3) includes a thermocouple holder (3-3), a thermocouple data transmission line (3-1) passing through the thermocouple holder (3-3), a thermocouple sealing sleeve (3-2) between the thermocouple holder (3-3) and the thermocouple data transmission line (3-1), the thermocouple data transmission line (3-1) passing through the thermocouple sheath (3-4), and the thermocouple sheath (3-4) being mounted on the horizontal circular tube (1).
3. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 2, characterized in that, One end of the thermocouple data transmission line (3-1) is connected to the data acquisition system, and the other end is connected to the thermocouple temperature measurement probe.
4. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 1, characterized in that, The upper temperature measurement module (4-1) is arranged directly above the device cross-section and measures the near-wall fluid temperature on the upper wall of the tube; the lower temperature measurement module (4-2) is arranged directly below the device cross-section and measures the near-wall fluid temperature on the lower wall of the tube; the side temperature measurement module (4-3) is arranged on the side of the device cross-section and measures the fluid temperature at the center of the tube cross-section.
5. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 1 or 4, characterized in that, The temperature measurement module group (4) measures the fluid temperature at N cross sections to describe the thermal stratification state of the fluid inside the pipe. The temperature measurement module group (4) consists of N groups, where N ≥ 5.
6. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 1, characterized in that, The cylindrical body (2) has an opening at the upper part of the fluid inlet side of the pipe, and a cooling water outlet pipe (7) with a vertical upward direction is installed in the opening; the cylindrical body (2) has an opening at the lower part of the fluid outlet side of the pipe, and a cooling water inlet pipe (6) with a vertical downward direction is installed in the opening.
7. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 1, characterized in that, The gas inside the horizontal circular tube (1) is one of helium, argon, carbon dioxide, or an inert mixture of helium and argon, or an inert mixture of helium and xenon.
8. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 7, characterized in that, The horizontal circular tube (1) has a measurable gas pressure of 0.1MPa to 5MPa and a temperature of 0℃ to 500℃.
9. The device for measuring thermal stratification of the hot-side fluid in a shell-and-tube heat exchanger according to claim 1, characterized in that, The distance A1 between the temperature measurement module group (4) in the first group and the fluid inlet in the pipe is 30mm~50mm; the distance A2 between the temperature measurement module group (5) in the last group and the fluid outlet in the pipe is 30mm~50mm; the distance A3 between the temperature measurement module groups is 20mm~100mm.
10. A measurement method for a shell-and-tube heat exchanger thermal stratification measuring device according to any one of claims 1-9, characterized in that, The method includes the following steps: A horizontal circular tube (1) passes through a cylindrical body (2) along the center line to form a shell-and-tube heat exchanger. The horizontal circular tube (1) contains the flowing gas that needs to be measured for thermal stratification. The horizontal circular tube (1) and the cylindrical body (2) form an annular cavity, which is a cooling water channel. The high-temperature gas inside the tube transfers heat to the cooling water through the tube wall to achieve cooling. The cooling water continuously carries away the heat of the high-temperature gas inside the tube. During this process, the cooled gas will exhibit thermal stratification with a large temperature difference between the upper and lower parts of the pipe cross section. The gas temperature at the location of the temperature probe is measured in real time by the temperature measurement module (3) arranged in the array, and transmitted to the data acquisition system via the thermocouple data transmission line (3-1) and the real-time temperature is displayed; by analyzing a group of temperature measurement modules on a cross section, the gas thermal stratification characteristics on a cross section are characterized. By coordinating measurements with multiple temperature measurement modules along the axial direction, the gas thermal stratification characteristics in the flow direction are characterized.