An open-parallel-channel flow instability experimental device and experimental method thereof

Abstract

The application discloses an open parallel channel flow instability experimental device and an experimental method thereof, and the experimental loop and the experimental section are connected in one-way circulation through a stainless steel pipeline; the experimental loop comprises a pump, a water tank, a steam-water separator, a pressure stabilizer, upper and lower chambers and a large bypass, etc.; the pump is used for pumping out or pumping in single-phase experimental medium, namely deionized water; the water tank is used for providing and storing single-phase experimental working medium to stabilize the pressure of the experimental loop system; the upper and lower chambers and the large bypass are used for stabilizing the pressure at the two ends of the experimental section and the inlet time-average flow, and isolating the influence of the disturbance of other devices in the loop on the experimental section; and the heating power supply and the experimental section are used for preheating and heating the single-phase experimental medium and forming a two-phase mixture; the upper and lower chambers and the large bypass are arranged at the two ends of the experimental section, and a plurality of transverse communication pipes are arranged at the axial position of the parallel channel, so as to construct a reasonable, accurate and convenient-to-analyze two-phase flow instability test system for the open parallel channel.

Description

Technical Field

[0001] This invention belongs to the field of multiphase flow heat transfer technology in parallel channels, specifically relating to an experimental apparatus and method for experimental instability of flow in open parallel channels. Background Technology

[0002] Energy is the driving force and foundation for the survival and development of modern society. The contradiction between increasing energy demand and the current energy shortage poses a significant challenge to energy utilization efficiency. Two-phase flow boiling heat transfer typically has a heat transfer efficiency several times higher than single-phase heat transfer, resulting in significant energy-saving benefits and close relevance to the power, aviation, and refrigeration sectors. However, heat transfer systems involving flow boiling are often accompanied by two-phase flow boiling instability. Two-phase flow instability refers to self-sustaining pulsations with constant amplitude, divergent pulsations with varying amplitude, and zero-frequency flow drift in two-phase flow systems. Under certain conditions, changes in system mass flow rate, density, pressure drop, and bubble disturbance can cause flow oscillations in the two-phase flow system, which can damage two-phase equipment. For power plant boilers, steam generators, heat exchangers, oil and gas pipelines, water-cooled reactor cores, and any other two-phase flow heat exchange equipment, the occurrence of flow instability not only reduces their performance, but the forced mechanical vibration of system components caused by flow oscillations can lead to fatigue damage, affect the local heat transfer characteristics within the flow channels, and cause premature boiling, seriously impacting the safe operation of the equipment. To ensure efficient and safe operation, any two-phase industrial equipment should avoid flow instability as much as possible. Therefore, a deep understanding and accurate prediction of potential two-phase flow instability phenomena in various types of two-phase equipment has significant engineering application value.

[0003] Currently, many two-phase industrial equipment systems do not employ simple single-channel or parallel-channel flow boiling systems. Instead, numerous interconnecting components exist between channels, particularly in water-cooled reactor cores. In these systems, the flow boiling channels within individual fuel assemblies are often fully open sub-channels, with interconnected spaces between assemblies. Compared to conventional single-channel and parallel-channel systems, these partially or fully open flow boiling channels have unique structures. Due to their openness, these open-channel systems are partially or everywhere interconnected, facilitating the exchange of mass, energy, and momentum between channels. Under two-phase conditions, this can also lead to bubble drift between channels and mutual influence of flow patterns between adjacent channels, resulting in flow pattern transitions. These factors alter the flow heat transfer characteristics within the channels, affecting system stability and complicating flow instability. Furthermore, the open locations of these channels create localized throttling effects, influencing the distribution of flow resistance and impacting system stability. All of these factors affect the flow heat transfer characteristics of fuel rods and coolant channels, influencing flow boiling within the channels and consequently affecting their flow stability. Furthermore, due to the asymmetry of axial and radial power distribution and the change of power distribution with operating time, the three-dimensional distribution of axial and circumferential power in each channel of the open channel system will result in a complex and diverse distribution of flow and heat transfer characteristics, with its three-dimensional effect being particularly significant. Figure 2 The typical characteristics of a typical parallel open channel compared to a conventional channel and the resulting differences in flow and heat transfer characteristics are summarized. The typical characteristics of a typical parallel open channel are as follows: 1. Channel openness (e.g., three-dimensional flow, cross-flow mixing between channels), 2. Axial non-uniform and radial asymmetric heating of the channel, 3. Special geometric features of the channel (e.g., throttling distribution).

[0004] Domestic and international research on flow instability primarily focuses on conventional channels (single-channel and parallel-channel), with limited research on partially or fully open channels. Therefore, it is essential to construct a reasonable, accurate, and easily analyzable two-phase flow instability testing system for parallel open channels. This system should be capable of analyzing the effects of factors such as channel openness and asymmetric heating on flow instability. This will provide a reference for the optimized design and safe operation of reactor cores and other similar two-phase equipment. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing an experimental apparatus and method for open parallel channel flow instability. This invention addresses the technical problem of the difficulty in effectively assessing the combined effects of parallel channel characteristics such as asymmetric and non-uniform heating, channel openness, channel irregularity, and throttling distribution on the flow instability of a system. This invention can be used to predict the critical instability of two-phase flow in complex open channel systems, provide a research approach for the evolution of flow instability characteristics from conventional parallel channels to open bar bundle channels, and improve the research map of flow instability in parallel channels.

[0006] The present invention adopts the following technical solution:

[0007] An experimental apparatus for flow instability in an open parallel channel includes an experimental section, which is unidirectionally connected to the experimental loop via a stainless steel pipeline. The experimental section is used to preheat and heat the single-phase experimental medium to form a two-phase state. Multiple transverse connecting pipes are arranged along the axial direction of the experimental section. The transverse connecting pipes are used to connect the parallel channel system. The degree of openness and position of the parallel channel system are controlled by adjusting the opening of the transverse connecting pipes.

[0008] Specifically, an inlet visible section and an outlet visible section are respectively set between the transverse connecting pipe and the experimental circuit.

[0009] Furthermore, a flow regulating valve and a flow meter are sequentially installed between the visible section of the inlet of the transverse connecting pipe and the experimental circuit.

[0010] Specifically, each channel of the parallel channel system is connected to an independent heating power supply.

[0011] Specifically, the experimental circuit includes a water storage tank. The input end of the water storage tank is divided into two paths via a circulating pump, a lower chamber, and an upper chamber. One path is connected to a pressure stabilizing tank, and the other path is connected to the output end and input end of the water storage tank via a steam-water separator. A large bypass and a test section are connected in parallel between the lower chamber and the upper chamber.

[0012] Furthermore, a first process channel and a second flow channel are connected in parallel between the circulating pump and the lower chamber, and a flow meter, a thermometer and a flow regulating valve are respectively installed on the first process channel and the second flow channel.

[0013] Furthermore, a flow regulating valve is installed between the lower chamber and the large bypass.

[0014] Specifically, an exhaust valve, a pressure gauge, and a temperature gauge are installed on the connecting pipe between the upper chamber and the steam-water separator.

[0015] Specifically, the pressure stabilizing tank is connected to a high-pressure gas cylinder.

[0016] Another technical solution of the present invention is an experimental method for flow instability in open parallel channels, comprising the following steps:

[0017] S1. The single-phase experimental medium enters the lower chamber of the experimental circuit through the circulating pump of the experimental circuit, and the pressure status is monitored by the pressure sensor.

[0018] S2. Fill the upper chamber of the experimental circuit with stabilizing gas to stabilize the working pressure of the experimental medium;

[0019] S3. Preheat the single-phase experimental medium through the experimental section, and monitor and record the pressure and temperature values ​​of the single-phase experimental medium at the inlet of the experimental section; after the temperature and pressure reach the set values ​​and stabilize, heat the single-phase experimental medium to a two-phase state through the experimental section, and monitor and record the pressure and temperature values ​​of the experimental medium in the experimental section.

[0020] S4. The two-phase experimental medium flowing out of the experimental section flows into the water storage tank after passing through the steam-water separator in the experimental circuit. The pressure and temperature of the experimental medium in the water tank are controlled by controlling the flow rate of cold water in the water storage tank, and a stable single-phase experimental medium is output.

[0021] S5. The single-phase experimental medium output from the water storage tank of the experimental circuit is filtered by the filter and then fed back into the circulation pump. S1 to S5 are repeated for the next cycle.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] An open parallel channel flow instability experimental apparatus has the following advantages:

[0024] 1. The connection method of this invention is simple and can realize two-phase circulating flow in open parallel channels. By isolating the experimental section and the equipment on the pump side, the pressure and flow disturbances of the experimental section will not be transmitted to the pump and other equipment, reducing the impact of pressure and flow on the pump and other equipment, and increasing the stability and reliability of the operation of these devices.

[0025] 2. The flow and pressure disturbances generated by equipment outside the experimental section, such as pumps, will not be transmitted to the experimental section. This allows researchers to focus on testing and analyzing the response mechanism of pipelines and related components in the experimental section in the two-phase flow instability phenomenon, without having to consider the influence of factors outside the experimental section on flow instability.

[0026] 3. The pressure regulator dissipates energy from pressure disturbances in the regulator by using a large volume and pressure-stabilizing gas output from a high-pressure gas cylinder, thereby reducing the amplitude of pressure disturbances and playing a stabilizing role. The stabilized liquid experimental working fluid will flow back into the loop to form a cycle and complete the relevant instability tests.

[0027] 4. The cold fluid in the upper chamber, lower chamber and large bypass condenses the gaseous experimental working fluid in the heating experimental section. Its flow rate can control the rate at which the working fluid at the outlet of the experimental section changes from the gas phase to the liquid phase, thereby achieving the regulation of the inlet and outlet pressures.

[0028] 5. Transverse connecting pipes are arranged at different axial positions in each pipeline of the experimental section to connect the parallel pipeline experimental sections. The degree and position of opening of the parallel experimental sections are controlled by controlling the opening of the transverse connecting pipes, which is used to study the influence of openness on the flow instability of the parallel channels.

[0029] 6. Transverse connecting pipes are arranged at different axial positions in each pipeline of the experimental section. By adjusting the position of the throttling device inserted from the transverse connecting pipe into the pipeline of the experimental section, the pipeline channel of the experimental section is set with different shapes and different throttling distributions. This is used to study the influence of different shapes and different throttling distributions of the pipeline channel of the experimental section on the flow instability of parallel channels.

[0030] 7. Each pipeline in the experimental section is controlled independently and connected by different insulating components, enabling independent radial asymmetric heating of the channels. This is used to study the effect of asymmetric heating on the flow instability of parallel channels.

[0031] 8. By replacing the experimental section of the pipeline with uneven wall thickness distribution along the axial direction, the influence of axial non-uniform heating on the flow instability of the parallel channel was realized.

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0033] Figure 1 This is a diagram showing the overall structural layout of the present invention;

[0034] Figure 2 This is a schematic diagram illustrating the typical characteristics of parallel open channels.

[0035] The components include: 1. Water storage tank; 2. Circulation pump; 3. First flow channel; 4. Second flow channel; 5. Lower chamber; 6. Upper chamber; 7. Large bypass; 8. Horizontal connecting pipe; 9. Exhaust valve; 10. Pressure stabilizing tank; 11. High-pressure gas cylinder; 12. Gas-water separator. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0038] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0040] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0041] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0042] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0043] Please see Figure 1 This invention provides an open parallel channel flow instability experimental device, comprising an experimental loop and an experimental section. The experimental loop and the experimental section are connected in one direction via a stainless steel pipeline. Temperature sensors, pressure sensors, and flow sensors are respectively installed in each device (steam-water separator, water tank, etc.) in the experimental loop and at various points in the loop (pump inlet and outlet, upper and lower chamber inlet and outlet, etc.). Pressure sensors and temperature sensors are respectively installed at different axial heights in the experimental section. The experimental section is used to preheat and heat the single-phase experimental medium to form a two-phase state.

[0044] The experimental circuit includes a water storage tank 1, a circulating pump 2, a steam-water separator 12, a pressure stabilizing tank 10, an upper chamber 6, a lower chamber 5, and a large bypass 7. The output of the water storage tank 1 is split into two paths after passing through the circulating pump 2, and enters the lower chamber 5 through the first process channel 3 and the second flow channel 4, respectively. The lower chamber 5 is connected to the upper chamber 6 through a transverse connecting pipe and a parallel channel test section 8. The large bypass 7 is also connected between the lower chamber 5 and the upper chamber 6. The upper chamber 6 is split into two paths through a pipeline. One path is connected to the pressure stabilizing tank 10, which is connected to a high-pressure gas cylinder 11. The other path is connected to the input and output ends of the water storage tank 1 after passing through the exhaust valve 9 and the steam-water separator 12, respectively.

[0045] The upper chamber 6 is filled with a pressure-stabilized gas, and the lower chamber 5 is filled with a single-phase experimental medium.

[0046] The circulating pump 2 is used to pump out or pump in a single-phase experimental medium. The upper chamber 6, the lower chamber 5, and the large bypass 7 are respectively located at both ends of the experimental section to stabilize the pressure at both ends of the experimental section and the inlet hourly flow rate, and to isolate the influence of disturbances from other equipment in the circuit on the experimental section.

[0047] Circulation pump 2 is a vertical multistage centrifugal pump.

[0048] The experimental medium is deionized water. The single-phase experimental medium is deionized water liquid, and the two-phase state is deionized water gas and liquid two-phase.

[0049] The first flow channel 3 and the second flow channel 4 are connected in parallel between the circulating pump 2 and the lower chamber 5. A flow meter, a thermometer and a flow regulating valve are respectively installed on the first flow channel 3 and the second flow channel 4.

[0050] A flow regulating valve is installed between the lower chamber 5 and the large bypass 7, and the flow meter is a turbine flow meter.

[0051] The large bypass 7 is connected in parallel with both ends of the experimental section between the upper chamber 6 and the lower chamber 5. It is used to adjust the time-averaged flow rate at the inlet of the experimental section and stabilize the pressure of the experimental medium at the inlet and outlet of the experimental section.

[0052] Multiple transverse connecting pipes 8 are arranged along the axial direction in the experimental section to connect parallel channels. The opening degree and position of the parallel channel system are controlled by adjusting the opening degree of the transverse connecting pipes 8 to realize the study of the influence of openness on the parallel channel system. Each channel of the parallel channel system is connected to an independent heating power supply to heat the single-phase experimental medium to a preset single-phase temperature, and then heat the single-phase experimental medium to a two-phase state.

[0053] The transverse connecting pipe 8 has an inlet visible section near the lower chamber 5, and a flow regulating valve and a flow meter are installed sequentially between the transverse connecting pipe 8 and the lower chamber 5; the transverse connecting pipe 8 has an outlet visible section near the upper chamber 6.

[0054] A pressure gauge and a temperature gauge are installed on the connecting pipe between the upper chamber 6 and the exhaust valve 9.

[0055] The pressure stabilizing tank 10 is used to stabilize the system pressure of the experimental circuit. The pressure stabilizing tank 10 has a cavity structure.

[0056] The pressure stabilizing tank 10 is sealed to the high-pressure gas cylinder 11 and the outlet of the experimental section of the experimental circuit. The pressure at the outlet of the experimental section is kept stable by filling the high-pressure gas cylinder 11 with pressure stabilizing gas.

[0057] Valves are installed at the inlet and outlet ends of the steam-water separator 12 and the water storage tank 1, respectively.

[0058] The upper chamber 6 and lower chamber 5 at both ends of the experimental section have ample space. The two ends of the experimental section are connected to the inlet and outlet of the open channel experimental body to stabilize the pressure of the experimental medium at the inlet and outlet of the experimental section.

[0059] The circulation process of the experimental working fluid in the open parallel channel flow instability experimental apparatus of this invention is as follows:

[0060] First, the pure liquid experimental working fluid is stably discharged from the circulating pump 2. After its flow rate is measured by the flow meter, it flows into the first process channel 3 and the second flow channel 4 for diversion. Its pressure and temperature are monitored by the pressure sensor and the thermocouple.

[0061] The fluid then flows into the lower chamber 5, and the experimental working fluid enters the experimental section and the main bypass 7. Flow regulating valves and flow meters are arranged on each experimental pipe section, and multiple thermocouples and pressure differential measuring points are arranged along the axial position. The channels are connected by a transverse connecting pipe 8. The degree of openness and position of the parallel channels are controlled by controlling the opening of the transverse connecting pipe 8, which is used to study the influence of openness.

[0062] The large bypass 7 is also equipped with a flow regulating valve to control the flow rate of the working medium in the bypass experiment; then the working medium is collected in the upper chamber 6, and the inlet and outlet pressures and the inlet hourly flow rate of the experimental section are controlled through the large bypass 7, the upper chamber 6 and the lower chamber 5.

[0063] The experimental working medium is first heated to the preset temperature in the experimental section, and then the heating power is gradually increased. The experimental working medium under the preset working conditions is continued to be heated to two phases until the temperature and pressure oscillation of different nodes in the experimental section are measured at each measuring point in the experimental section.

[0064] When the two-phase experimental working fluid flows out of the experimental section, it has oscillating pressure and flow rate. After entering the large-volume upper chamber 6, the pressure oscillation amplitude decreases. It mixes with the low-temperature liquid experimental working fluid flowing in through the large bypass 7, condenses into a liquid phase, and enters the pressure stabilizing tank 10 to isolate pressure fluctuations. Then it flows into the gas-water separator 12 to discharge the residual gas phase experimental working fluid and flows back to the water storage tank 10.

[0065] The water storage tank 10 is connected to the atmosphere. By controlling the cooling water flow rate and hot water drainage of the water storage tank 10, the water temperature and water level are controlled, thereby controlling the water temperature and water pressure on the circulating pump side of the experimental loop. Finally, the water flows into the circulating pump 2 for the next cycle.

[0066] This invention discloses an experimental method for flow instability in open parallel channels, comprising the following steps:

[0067] S1. The single-phase experimental medium is pumped out of the water tank 1 by the circulating pump 2, and then flows to the lower chamber 5 through the first process channel 3 and the second flow channel 4, and the pressure status is monitored by the pressure sensor.

[0068] S2. Pressure stabilizing gas is injected into the upper space of the pressure stabilizing box 10 through the connection of the high-pressure gas cylinder 11 to stabilize the working pressure of the experimental medium.

[0069] S3. The single-phase experimental medium is preheated through the heating section of the experimental section, and the pressure and temperature values ​​of the single-phase experimental medium at the inlet of the experimental section are monitored and recorded. After the temperature and pressure reach the set values ​​and the operation is stable, the single-phase experimental medium is heated to a two-phase state through the experimental heating section, and the pressure and temperature values ​​of the experimental medium in the experimental section are monitored and recorded.

[0070] S4. The two-phase experimental medium flowing out of the experimental section has oscillating pressure and flow rate. After passing through the steam-water separator, it flows into the large water tank. By controlling the flow rate of cold water in the large water tank, the pressure and temperature of the experimental medium in the water tank are controlled, and a stable single-phase experimental medium is output.

[0071] S5. The single-phase experimental medium output from the water storage tank is filtered through a filter and then fed back into the circulation pump, repeating S1 to S5 for the next cycle.

[0072] In summary, this invention provides an experimental apparatus and method for studying the flow instability of open parallel channels. Compared to studies of flow instability characteristics in conventional parallel channels and open rod bundle channels, this invention offers a research approach to understanding the evolution of flow instability characteristics from conventional parallel channels to open rod bundle channels, thus enriching the research landscape of flow instability in parallel channels. The open parallel channel flow instability studies conducted using this invention can provide in-depth research on the impact of open channel characteristics such as asymmetric and non-uniform heating, channel openness, and channel irregularities on system flow instability. This enables the prediction of the critical instability threshold for two-phase flow in complex open channel systems, thereby providing a reference for the optimized design and safe operation of reactor cores and other similar two-phase equipment.

[0073] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An experimental apparatus for flow instability in open parallel channels, characterized in that, The experimental section is connected to the experimental circuit in one direction via a stainless steel pipeline. The experimental section is used to preheat and heat the single-phase experimental medium and form a two-phase state. Multiple transverse connecting pipes (8) are arranged along the axial direction in the experimental section. The transverse connecting pipes (8) are used to connect the parallel channel system. The opening degree and position of the parallel channel system are controlled by adjusting the opening degree of the transverse connecting pipes (8).

2. The experimental apparatus for open parallel channel flow instability according to claim 1, characterized in that, An inlet visible section and an outlet visible section are respectively provided between the transverse connecting pipe (8) and the experimental circuit.

3. The experimental apparatus for open parallel channel flow instability according to claim 2, characterized in that, A flow regulating valve and a flow meter are sequentially installed between the visible section of the inlet of the transverse connecting pipe (8) and the experimental circuit.

4. The experimental apparatus for open parallel channel flow instability according to claim 1, characterized in that, Each channel in the parallel channel system is connected to an independent heating power supply.

5. The experimental apparatus for open parallel channel flow instability according to claim 1, characterized in that, The experimental circuit includes a water storage tank (1). The input end of the water storage tank (1) is divided into two paths via a circulating pump (2), a lower chamber (5), and an upper chamber (6). One path is connected to a pressure stabilizing tank (10), and the other path is connected to the output end and the input end of the water storage tank (1) via a steam-water separator (12). A large bypass (7) and a test section are connected in parallel between the lower chamber (5) and the upper chamber (6).

6. The experimental apparatus for open parallel channel flow instability according to claim 5, characterized in that, A first flow channel (3) and a second flow channel (4) are connected in parallel before the circulating pump (2) and the lower chamber (5). A flow meter, a thermometer and a flow regulating valve are respectively installed on the first flow channel (3) and the second flow channel (4).

7. The experimental apparatus for open parallel channel flow instability according to claim 5, characterized in that, A flow regulating valve is installed between the lower chamber (5) and the large bypass (7).

8. The experimental apparatus for open parallel channel flow instability according to claim 1, characterized in that, An exhaust valve (9), a pressure gauge, and a temperature gauge are installed on the connecting pipe between the upper chamber (6) and the steam-water separator (12).

9. The experimental apparatus for open parallel channel flow instability according to claim 1, characterized in that, The pressure stabilizing tank (10) is connected to a high-pressure gas cylinder (11).

10. The experimental method of the open parallel channel flow instability experimental apparatus according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. The single-phase experimental medium enters the lower chamber of the experimental circuit through the circulating pump of the experimental circuit, and the pressure status is monitored by the pressure sensor. S2. Fill the upper chamber of the experimental circuit with stabilizing gas to stabilize the working pressure of the experimental medium; S3. Preheat the single-phase experimental medium through the experimental section, and monitor and record the pressure and temperature values ​​of the single-phase experimental medium at the inlet of the experimental section; after the temperature and pressure reach the set values ​​and stabilize, heat the single-phase experimental medium to a two-phase state through the experimental section, and monitor and record the pressure and temperature values ​​of the experimental medium in the experimental section. S4. The two-phase experimental medium flowing out of the experimental section flows into the water storage tank after passing through the steam-water separator in the experimental circuit. The pressure and temperature of the experimental medium in the water tank are controlled by controlling the flow rate of cold water in the water storage tank, and a stable single-phase experimental medium is output. S5. The single-phase experimental medium output from the water storage tank of the experimental circuit is filtered by the filter and then fed back into the circulation pump. S1 to S5 are repeated for the next cycle.

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