Single-rod tube outside pool boiling experiment system and method

Abstract

The present disclosure provides a single-rod tube outside pool boiling test system and method, belonging to the technical field of thermal fluid test, comprising a boiling water tank, a test piece and a support, the test piece is fixed on the inner wall of the boiling water tank through the support; the test piece comprises a single rod and a guide rod, the single rod is a hollow circular tube, one end of which is closed, and the other end is open, the guide rod is a solid insulating tube, the outer diameter of the guide rod is smaller than the inner diameter of the single rod, and the guide rod is arranged inside the single rod. Different types of single-rod tube outside pool boiling tests can be performed, the test cost is reduced, and the uncertainty in the test process is reduced.

Description

Technical Field

[0001] This disclosure belongs to the field of thermal fluid testing technology, specifically relating to a single-rod tube external pool boiling test system and method. Background Technology

[0002] Boiling heat transfer is a process in which bubbles are generated inside a liquid and the liquid state is transformed into a gaseous state. It is widely present in energy, chemical, petroleum and nuclear energy fields. Studying the form and mechanism of boiling heat transfer is not only of practical significance for the design and manufacture of heat transfer equipment such as steam generators, but can also promote the development of the power industry.

[0003] Boiling heat transfer mechanisms are complex, involving bubble formation, growth, detachment, and movement. Numerous factors influence pool-type boiling heat transfer, including liquid properties, the physical properties and roughness of the heated surface, and gravity. For nuclear power plants, maximizing heat transfer efficiency within limited space is crucial. Current methods primarily employ experimental and numerical approaches; however, numerical methods have limitations in fully simulating the entire heat transfer process. Furthermore, experimental research is costly and carries significant uncertainty. Therefore, a simple and effective pool-type boiling experimental setup is needed to clearly investigate the heat transfer process and reduce experimental costs. Summary of the Invention

[0004] To address the deficiencies or shortcomings in existing technologies, this disclosure provides a single-rod tube external pool boiling test system and method, which can clearly investigate the heat transfer process. In addition, the test system is simple, has a wide range of applications, and greatly reduces test costs.

[0005] To achieve the above objectives, the present disclosure adopts the following technical solution:

[0006] In a first aspect, embodiments of this disclosure provide a single-rod tube external pool type boiling test system, including a boiling water tank, a test piece, and a support member, wherein the test piece is fixed to the inner wall of the boiling water tank by the support member;

[0007] The test piece includes a single rod and a guide rod. The single rod is a hollow circular tube with one end closed and the other end open. The guide rod is a solid insulating tube with an outer diameter smaller than the inner diameter of the single rod. The guide rod is disposed inside the single rod.

[0008] Furthermore, a rubber stopper is provided at the open end of the single rod.

[0009] Furthermore, the test piece is provided with a first temperature measuring device and a second temperature measuring device. Multiple first temperature measuring devices are provided and are evenly distributed on the outer surface of the guide rod. The first temperature measuring device measures the inner wall temperature of the single rod. Multiple second temperature measuring devices are provided and are evenly distributed on the outer wall of the single rod. The second measuring device measures the outer wall temperature of the single rod.

[0010] Furthermore, the support member is made of stainless steel, with one side connected to the inner wall of the boiling water tank and the other side equipped with an insulating clamp.

[0011] Furthermore, an insulating plate is provided between the test piece and the support.

[0012] Furthermore, a third temperature measuring device is also provided on the support member, which measures the fluid temperature near the single rod.

[0013] Furthermore, the first, second, and third temperature measuring devices all employ type N armored thermocouples.

[0014] Furthermore, an electric heating rod is provided at the bottom of the boiling water tank, and the electric heating rod is fixed to the inner wall of the boiling water tank by a flange.

[0015] Furthermore, a pressure regulator and a data acquisition device are also provided on the outside of the boiling water tank. The positive and negative terminals of the pressure regulator are connected to copper clamps set at both ends of the single rod through copper braids. The data acquisition device is electrically connected to the first temperature measuring device, the second temperature measuring device and the third temperature measuring device inside the boiling water tank.

[0016] Secondly, embodiments of this disclosure provide a single-rod external tank boiling test method, utilizing a single-rod external tank boiling test system as described above, including the following steps:

[0017] Multiple first temperature measuring devices are fixed on the guide rod, the guide rod together with the first temperature measuring devices is inserted into the single rod, and the front measuring point of the first temperature measuring device is pressed against the inner wall of the single rod. Multiple second temperature measuring devices are fixed on the outer wall of the single rod.

[0018] The prepared test specimen is fixed to the support on the inner wall of the boiling water tank with an insulating clamp, and an insulating plate is placed between the test specimen and the support.

[0019] Copper braids are connected to both ends of the single rod, and the distance between the two copper braids is the effective length of the test section. Then, deionized water is added to the boiling water tank to a certain height through the water inlet, and it is confirmed that the insulation of the test piece to ground meets the test requirements.

[0020] Start the data acquisition device to verify that the measurement point signals in the test system are accurate;

[0021] Turn on the electric heating rod to heat the deionized water in the boiling water tank to saturation and maintain it for 30 minutes to remove non-condensable gases from the deionized water;

[0022] Turn on the voltage regulator and gradually increase the output power to heat the test piece. The initial input power of the voltage regulator is 0, and it is increased by 2KW each time until the output signal of the first temperature measuring device reaches the upper limit value, at which point the test stops.

[0023] Compared with the prior art, the beneficial effects of this disclosure are as follows:

[0024] 1. This disclosure allows for arbitrary adjustment of the placement of the test specimen by setting up support components, thereby meeting the requirements of different tests and conducting different types of single-rod tube external pool boiling tests.

[0025] 2. This disclosure uses a water tank with a viewing glass as a pool boiling container, which allows for a more intuitive observation of the pool boiling reaction phenomenon. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the test system in Embodiment 1 of this disclosure;

[0027] Figure 2 This is a schematic diagram of the test specimen structure in Example 1 of this common invention;

[0028] Figure 3 This is a schematic diagram of the support structure in Embodiment 1 of this disclosure;

[0029] The components include: 1. Boiling water tank; 2. Test piece; 201. Single rod; 202. Guide rod; 203. First temperature measuring device; 204. Rubber stopper; 205. Second temperature measuring device; 3. Support component; 301. Rubber clamp; 302. Insulating board; 4. Electric heating rod; 5. Voltage regulator; 6. Data acquisition device; 7. Copper braid; 8. Copper clamp; 9. Water inlet; 10. Drain outlet. Detailed Implementation

[0030] The present disclosure will be further described below with reference to the accompanying drawings and embodiments.

[0031] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this disclosure. Unless otherwise specified, all technical and scientific terms in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0032] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this disclosure. As used herein, the singular form is intended to include the plural form as well, unless expressly indicated by this disclosure. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0033] For ease of description, the words "up," "down," "left," and "right" appearing in this disclosure only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this disclosure and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this disclosure.

[0034] Terminology Explanation: The terms “installation,” “connection,” “linking,” and “fixing” in this disclosure should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to an internal connection between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0035] Example 1

[0036] One typical implementation of this disclosure is as follows: Figures 1-3 As shown, a single-rod external pool boiling test system includes a boiling water tank 1, a test piece 2, and a support 3. The test piece 2 is fixed to the inner wall of the boiling water tank 1 by the support 3.

[0037] The test piece includes a single rod 201, a guide rod 202, a first temperature measuring device 203, and a second temperature measuring device 205. The single rod 201 is a hollow round tube with one end closed and the other end open. A rubber stopper 204 is also provided at the open end of the single rod 201. The guide rod 202 is a solid insulating tube. The outer diameter of the guide rod 202 is smaller than the inner diameter of the single rod 201, allowing the guide rod 202 to be inserted into the interior of the single rod 201 from its open end. A rubber stopper 204 seals the guide rod 202 inside the single rod 201. Multiple first temperature measuring devices 203 are evenly distributed on the outer surface of the guide rod 202. When the guide rod 202 is inserted into the single rod 201, the front measuring point of each first temperature measuring device 203 is in close contact with the inner wall of the single rod 201, thereby measuring the temperature of the inner wall of the single rod 201. Simultaneously, the multiple first temperature measuring devices 203 support the outer surface of the guide rod 202, preventing it from shaking inside the single rod 201. Multiple second temperature measuring devices 205 are evenly distributed on the outer wall of the single rod 201, thereby measuring the temperature of the outer wall of the single rod 201.

[0038] The support member 3 is made of stainless steel. One side is connected to the inner wall of the boiling water tank 1 and is fixed to the inner wall of the boiling water tank 1 by welding or bolting. The other side is provided with an insulating clamp 301, which fixes the outer wall of the single rod 201, thereby fixing the test piece 2 to the inner wall of the boiling water tank 1. An insulating plate 302 with a thickness of 8mm is also provided between the test piece 2 and the support member 3 to ensure the insulation effect between the test piece 2 and the support member 3.

[0039] The inner wall of the boiling water tank 1 is provided with multiple support members 3. By fixing the test piece 2 to different support members 3, the test piece 2 can be placed vertically or horizontally inside the boiling water tank 1, thereby meeting the requirements of different tests.

[0040] The support member 3 is also equipped with a third temperature measuring device, which measures the fluid temperature near the single rod 201. The first temperature measuring device 203, the second temperature measuring device 205, and the third temperature measuring device all use N-type armored thermocouples.

[0041] An electric heating rod 4 is installed at the bottom of the boiling water tank 1. The electric heating rod 4 is fixed to the inner wall of the boiling water tank 1 by a flange. The electric heating rod 4 heats the liquid in the boiling water tank 1. The liquid in the boiling water tank 1 is deionized water.

[0042] The boiling water tank 1 is also equipped with a pressure regulator 5 and a data acquisition device 6. The positive and negative terminals of the pressure regulator 5 are connected to copper clamps 8 located at both ends of the single rod 201 via copper braids 7. The data acquisition device 6 is electrically connected to the first temperature measuring device 203, the second temperature measuring device 205, and the third temperature measuring device inside the boiling water tank 1, and is used to read and acquire the temperature data measured by the temperature measuring devices.

[0043] Specifically, the first, second, and third temperature measuring devices each have a measuring contact at one end and are connected to a data acquisition device via a data acquisition board at the other end. The data acquisition device transmits the collected data to a computer in real time via a network cable to facilitate the reading, storage, and analysis of the experimental data.

[0044] A viewing glass is provided on the outer wall of the boiling water tank 1, through which the specific phenomena on the surface of the test specimen inside the boiling water tank 1 can be observed. A water inlet 9 is provided at the top of the boiling water tank 1 for adding deionized water required for the test, and a drain outlet 10 is provided at the bottom of the boiling water tank 1 for draining the deionized water in the boiling water tank 1 after the test.

[0045] Example 2

[0046] This embodiment provides a single-rod external tank boiling test method, utilizing a single-rod external tank boiling test system as described in Embodiment 1, including the following steps:

[0047] First, multiple first temperature measuring devices are fixed on a guide rod, which is an epoxy resin rod. The guide rod, together with the first temperature measuring devices, is inserted into a single rod, and the front measuring point of the first temperature measuring device is made to be in close contact with the inner wall of the single rod, so as to measure the temperature of the inner wall of the single rod. Then, multiple second temperature measuring devices are fixed on the outer wall of the single rod, so as to measure the temperature of the outer wall of the single rod.

[0048] The prepared test specimen is then fixed to the support on the inner wall of the boiling water tank using insulating clamps, and an insulating plate is placed between the test specimen and the support. The insulating plate is made of epoxy resin. The test specimen can be placed horizontally or vertically through the support to meet the requirements of different tests.

[0049] Copper braids are connected to both ends of the single rod, and the distance between the two braids is the effective length of the test section. Then, deionized water is added to the boiling water tank to a certain height through the water inlet, specifically the deionized water level is 1.4m, and it is confirmed that the insulation of the test piece to ground meets the test requirements.

[0050] Start the data acquisition device to verify that the measurement point signals in the test system are accurate.

[0051] Turn on the electric heating rod to heat the deionized water in the boiling water tank to saturation and maintain it for 30 minutes to remove non-condensable gases from the deionized water.

[0052] Turn on the voltage regulator and gradually increase the output power to heat the test piece.

[0053] Specifically, the voltage regulator is connected to an external AC heater, controlling the output voltage to adjust the output power of the AC heater. The positive and negative terminals of the voltage regulator are connected to both ends of the test piece, respectively, and the test piece is heated through a copper braid.

[0054] The initial input power of the voltage regulator is 0, and it increases by 2KW each time until the rate of change of the temperature signal measured and output to the computer by the first temperature measuring device exceeds a certain upper limit value, for example, the rate of change of temperature exceeds 5℃ / s. At this time, it can be determined that the heat transfer state has reached the critical point and the heat transfer has deteriorated. At this time, the test is stopped.

[0055] The test piece was heated by an electric heater, and the output signals of the first, second and third temperature measuring devices under different power conditions were obtained. Based on the relationship between power, temperature and heat transfer coefficient, a general empirical formula for pool boiling heat transfer was fitted. At the same time, the heat transfer mechanism was studied in depth by combining the visualized experimental phenomena.

[0056] The above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A single-rod tube outside pool boiling test system, characterized by, It comprises a boiling water tank, a test piece and a support, the test piece is fixed on the inner wall of the boiling water tank by the support; The test piece comprises a single rod and a guide rod, the single rod is a hollow circular tube with one end closed and the other end open, the guide rod is a solid insulating tube, the outer diameter of the guide rod is smaller than the inner diameter of the single rod, and the guide rod is arranged inside the single rod; The support is also provided with a third temperature measuring device, which measures the temperature of the fluid near the single rod.

2. A single rod tube outside pool boiling test system as claimed in claim 1, wherein, The open end of the single rod is provided with a rubber plug.

3. A single rod tube outside pool boiling test system as claimed in claim 1, wherein, The test piece is provided with a first temperature measuring device and a second temperature measuring device, the first temperature measuring device is provided with multiple devices and is uniformly arranged on the outer surface of the guide rod, and the first temperature measuring device measures the temperature of the inner wall of the single rod; the second temperature measuring device is provided with multiple devices and is uniformly arranged on the outer wall of the single rod, and the second temperature measuring device measures the temperature of the outer wall of the single rod.

4. A single rod tube outside pool boiling test system as claimed in claim 1, wherein, The support is made of stainless steel, one side of which is connected with the inner wall of the boiling water tank, and the other side is provided with an insulating clamp.

5. A single rod tube outside pool boiling test system as claimed in claim 1, wherein, An insulating plate is arranged between the test piece and the support.

6. A single rod tube outside pool boiling experiment system according to claim 3, wherein The first temperature measuring device, the second temperature measuring device and the third temperature measuring device all adopt N type armored thermocouples.

7. A single rod tube outside pool boiling experiment system according to claim 1, wherein, The bottom of the boiling water tank is provided with an electric heating rod, which is fixed on the inner wall of the boiling water tank by a flange.

8. A single rod tube outside pool boiling test system as claimed in claim 1, wherein, The boiling water tank is also provided with a pressure regulator and a data acquisition device, the positive and negative electrodes of the pressure regulator are connected with copper clamps arranged at both ends of the single rod through copper braids, and the data acquisition device is electrically connected with the first temperature measuring device, the second temperature measuring device and the third temperature measuring device in the boiling water tank.

9. A single rod out-of-pipe boiling test method using a single rod out-of-pipe boiling test system according to any one of claims 1 to 8, characterized in that, It comprises the following steps: Fix multiple first temperature measuring devices on the guide rod, insert the guide rod with the first temperature measuring devices into the single rod, and make the front end of the first temperature measuring device close to the inner wall of the single rod, and fix multiple second temperature measuring devices on the outer wall of the single rod; Fix the prepared test piece on the support on the inner wall of the boiling water tank through the insulating clamp, and arrange an insulating plate between the test piece and the support; Connect copper braids at both ends of the single rod, the distance between the two copper braids is the effective length of the test section; then supplement a certain height of deionized water into the boiling water tank through the water inlet, and confirm that the test piece meets the test requirements for ground insulation; Start the data acquisition device to verify that the signal of the test point in the test system is accurate; Start the electric heating rod to heat the deionized water in the boiling water tank to the saturated state, maintain for 30 minutes, and remove the non-condensable gas in the deionized water; Turn on the pressure regulator and gradually increase the output power to heat the test piece; the initial input power of the pressure regulator is 0, and each time it is increased by 2KW until the output signal of the first temperature measuring device reaches the upper limit value, and the test is stopped.

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