Rectangular channel for simulating dynamic environment thermal parameter feedback effect and experimental method

Abstract

The embodiment of the invention discloses a rectangular channel for simulating a dynamic environment thermal parameter feedback effect and an experimental method. The rectangular channel comprises a plurality of electric heating element connecting pieces arranged at different positions, different electric heating element connecting pieces can be respectively connected with a power supply to provide a heat flow density condition corresponding to introduction of a thermal parameter feedback effect for a working medium, so that a dynamic environment in which the thermal parameter feedback effect is introduced is simulated, thermal experiment data closer to real complex conditions are obtained, and the thermal safety limit is determined.

Description

Technical Field

[0001] This application relates to the technical field of energy engineering, and in particular to a rectangular channel and experimental method for simulating the feedback effect of dynamic environmental thermal parameters. Background Technology

[0002] In the field of energy engineering, rectangular channels are a typical channel structure, widely used in various heating or heat exchange devices. Current experimental studies on rectangular channels mainly employ simulations using stable thermal parameter boundary conditions (such as fixed heating power).

[0003] However, the inventors discovered that, in reality, due to the influence of upstream and downstream equipment and the physicochemical characteristics of the working fluid, thermal parameters are generally variable. For example, when the power increases to the point where a boiling crisis occurs, the thermal parameters (such as temperature, flow rate, and two-phase fraction) in the rectangular channel will change drastically. These parameters theoretically have a dynamic impact on the heat flux density at the channel boundary, making it difficult to predict and capture the thermal parameters when a boiling crisis occurs in real-world environments. Existing experiments generally ignore the dynamic changes in heat flux density and only consider a fixed power input to simplify the process. Therefore, the conclusions obtained from the experiments may not be accurate and cannot meet the needs of high-precision thermal safety limit research. Summary of the Invention

[0004] This application provides a rectangular channel and experimental method for simulating the feedback effect of thermal parameters in a dynamic environment. The rectangular channel includes multiple electric heating element connectors set at different positions. The different electric heating element connectors can be connected to a power source to provide the working fluid with heat flux density conditions corresponding to the thermal parameter feedback effect, thereby simulating the dynamic environment with the thermal parameter feedback effect, obtaining thermal experimental data that are closer to real complex conditions, and determining the thermal safety limit.

[0005] This application provides a rectangular channel for simulating the feedback effect of dynamic environmental thermal parameters, including a working fluid channel, two insulating components, and multiple electric heating element assemblies; The working fluid channel is disposed between the two insulating components; Multiple electric heating element assemblies are arranged from top to bottom on the outside of the insulating component; The electric heating element assembly includes two electric heating elements symmetrically arranged about the working fluid channel, one of the electric heating elements being disposed outside one of the insulating components, and the other electric heating element being disposed outside the other of the insulating components; The electric heating element includes an electric heating element body and a plurality of electric heating element connectors arranged from top to bottom on the electric heating element body; the electric heating element body is disposed outside the insulating component; the electric heating connectors on two symmetrically arranged electric heating elements are symmetrically arranged.

[0006] In some embodiments, the number of the electric heating element assemblies is three.

[0007] In some embodiments, the working fluid channel is made of metal.

[0008] This application also provides an experimental method for simulating the feedback effect of dynamic environmental thermal parameters in a rectangular channel, applied to the rectangular channel, the method comprising: The working conditions for regulating the working fluid are preset working conditions, which include ambient pressure, inlet temperature and inlet velocity; Set a first given power, and calculate the first output power of each electric heating element connector based on the first given power using a power dynamic correction formula; control the electric heating element connector to be energized and output according to the first output power; Gradually increase the first given power until the second given power obtained by the power dynamic correction formula based on the increase of the first given power reaches the preset thermal power; After the second output power, inlet temperature and inlet velocity remain stable, the second given power is increased at a constant rate until a boiling crisis occurs in the working fluid channel; the second output power calculated based on the current second given power, the corresponding ambient pressure, inlet temperature and inlet velocity are recorded. Reduce the second given power.

[0009] In some embodiments, the power dynamic correction formula is: ; in, This refers to the output power. The temperature of the working fluid closest to the middle position of the end of the connector to the electric heating element; The feedback coefficient for the working fluid temperature; The surface temperature of the working fluid channel closest to the middle position of the end of the connector to the electric heating element; This is the feedback coefficient for the surface temperature of the working fluid channel; Mass flow density; The feedback coefficient for mass flow density; The two phases of the working fluid; The feedback coefficient represents the two-phase proportion of the working fluid; The given power is a first given power; when the given power is a first given power, the corresponding output power is a first output power; when the given power is a second given power, the corresponding output power is a second output power.

[0010] In some embodiments, the method further includes: Detect the surface temperature of the working fluid channel closest to the middle position of the end of the connector of the electric heating element; Detect the temperature of the working fluid closest to the middle position of the end of the connector of the electric heating element; The mass flow rate is detected using a flow meter, and the mass flow density is obtained by dividing the mass flow rate by the cross-sectional area of ​​the working fluid channel.

[0011] In some embodiments, the two-phase fraction is the thermal equilibrium vapor content; the thermal equilibrium vapor content is calculated according to the following formula: ; in, For thermal equilibrium vapor content; Enthalpy at a local location; The enthalpy of the saturated working fluid; The latent heat of vaporization; the local position refers to the middle position of the two symmetrically arranged electric heating element connectors.

[0012] In some embodiments, the method further includes: Based on the environmental pressure, determine the enthalpy and latent heat of vaporization of the saturated working fluid.

[0013] In some embodiments, the enthalpy at the local location is calculated according to the following formula: ; in, Enthalpy at a local location; The enthalpy of the inlet working fluid; The power absorbed by the working fluid from the inlet to the local location; The mass flow rate of the working fluid within the working fluid channel.

[0014] In some embodiments, the method further includes: Determine the enthalpy of the inlet working fluid based on environmental pressure; The sum of the output power of all the electric heating element connections through which the working fluid passes from the inlet to the local position determines the power absorbed by the working fluid from the inlet to the local position.

[0015] The above embodiments provide a rectangular channel and experimental method for simulating the feedback effect of thermal parameters in a dynamic environment. The rectangular channel includes multiple electric heating element connectors set at different positions. Different electric heating element connectors can be connected to a power source to provide the working fluid with heat flux density conditions corresponding to the feedback effect of thermal parameters, thereby simulating the dynamic environment with the feedback effect of thermal parameters, obtaining thermal experimental data that are closer to real complex conditions, and determining the thermal safety limit. Attached Figure Description

[0016] Figure 1An exemplary perspective view of a rectangular channel simulating the feedback effect of dynamic environmental thermal parameters is shown according to some embodiments; Figure 2 An exemplary side view of a rectangular channel simulating the feedback effect of dynamic environmental thermal parameters is shown according to some embodiments; Figure 3 Exemplary cross-sectional views are shown of a working fluid channel, portions of two insulating components, and an electric heating element assembly according to some embodiments. Detailed Implementation

[0017] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0018] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0019] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms are interchangeable where appropriate.

[0020] The terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0021] To address the aforementioned technical problems, this application provides a rectangular channel and experimental method for simulating the feedback effect of thermal parameters in a dynamic environment. The rectangular channel includes multiple electric heating element connectors located at different positions. Each electric heating element connector can be connected to a power source to provide the working fluid with heat flux density conditions corresponding to the feedback effect of thermal parameters, thereby simulating the dynamic environment with the feedback effect of thermal parameters, obtaining thermal experimental data that more closely approximates real complex conditions, and determining the thermal safety limits.

[0022] like Figures 1-3 As shown, the rectangular channel includes a working fluid channel 1, two insulating components 2, and multiple electric heating element assemblies 3; the working fluid channel 1 is disposed between the two insulating components 2; Multiple electric heating element assemblies 3 are arranged from top to bottom on the outside of the insulating component 2; The electric heating element assembly 3 includes two electric heating elements 31 symmetrically arranged with respect to the working fluid channel; one of the electric heating elements 31 is disposed outside one of the insulating components 2, and the other electric heating element 31 is disposed outside the other of the insulating component 2.

[0023] In this embodiment, the working fluid flows within a working fluid channel, and can flow from one end of the channel to the other. Taking a channel placed perpendicular to the ground as an example, the working fluid can flow from top to bottom within the channel. The working fluid is a fluid medium flowing through a rectangular channel. Common working fluids in the field of energy engineering include water, steam, helium, and liquid metal.

[0024] The working fluid channel has a hollow structure in the middle, through which the working fluid flows. The working fluid channel is made of metal, specifically stainless steel or high-strength alloys, or other high-resistivity metals. The working fluid channel needs to have a certain thickness to withstand the internal pressure.

[0025] In this embodiment, two insulating components are disposed on both sides of the working fluid channel. The main function of the insulating components is to isolate the electrical influence of the electric heating element on the working fluid channel, while simultaneously transferring heat from the electric heating element to the working fluid channel, allowing heat to be transferred to the working fluid through the working fluid channel. The insulating components are made of insulating ceramic, typically Al2O3.

[0026] In this embodiment, the electric heating element simulates a heat source and generates heat by connecting to a power source. The input current value can generate heat according to Joule's law.

[0027] In some embodiments, the electric heating element includes an electric heating element body 311 and a plurality of electric heating element connectors 312 disposed from top to bottom on the electric heating element body; the electric heating element body is disposed outside the insulating component; the electric heating connectors on two symmetrically disposed electric heating elements are symmetrically disposed.

[0028] The main function of an electric heating element is to generate heat. The heating element connector is connected to the power supply. Because the connector is connected to the main body of the heating element, the current output from the power supply can be transferred to the heating element through the connector, causing both the connector and the main body to generate heat. Encased in external insulation material, the heat is conducted only into the channel and absorbed by the flowing working fluid. The main body of the heating element and the connector can be integrally molded or connected using an assembly method.

[0029] In some embodiments, the number of electric heating element assemblies is three, for a total of six electric heating elements. In each of the three electric heating element assemblies, one electric heating element is disposed on an insulating component, and the other electric heating element is disposed on a different insulating component.

[0030] In this embodiment, the six electric heating elements can be configured to have a certain proportion of non-uniform or uniform heating conditions according to the thermal boundary conditions of the application environment. For example, one or more electric heating element connectors on the electric heating elements can be de-energized.

[0031] This application embodiment also provides an experimental method for simulating the feedback effect of dynamic environmental thermal parameters in a rectangular channel, applied to the rectangular channel, the method comprising: S100, the working conditions of the conditioning working fluid are preset working conditions, which include ambient pressure, inlet temperature and inlet velocity.

[0032] In this embodiment of the application, the ambient pressure, inlet temperature, and inlet velocity are controlled by the loop system during the experiment. These parameters are not related to the heat power affected by feedback. Therefore, the ambient pressure, inlet temperature, and inlet velocity must first reach the desired predetermined values ​​(i.e., preset operating conditions) before the experiment can begin.

[0033] In some embodiments, the preset operating conditions include a preset ambient pressure, a preset inlet temperature, and a preset inlet velocity. The preset ambient pressure is typically between 2 and 15 MPa. The preset inlet temperature and preset inlet velocity can both be set according to actual conditions.

[0034] S200. Set a first given power, and calculate the first output power of each electric heating element connector based on the first given power using the power dynamic correction formula; control the electric heating element connector to be energized and output according to the first output power.

[0035] In this embodiment, the first given power is the initial given power, which is a relatively small power. After the electric heating element connector is powered on, it is adjusted according to the first output power. Specifically, based on Joule's law and the first output power, the first input current value is calculated, and the current output of the power supply connected to the electric heating element connector is adjusted to the first input current value. This ensures that the electric heating element connector can output power to the working fluid according to the first output power.

[0036] In this embodiment, the feedback effect of simulated dynamic environmental thermal parameters is mainly achieved by correcting the given power of the electric heating element connector to obtain the output power. A dynamic power correction formula for thermal power (i.e., given power) is given based on the principle of simulated feedback effect, thus simulating the feedback effect of the working fluid within the working fluid channel. The thermal parameters include working fluid temperature, working fluid flow rate, and the two-phase fraction of the working fluid.

[0037] In this embodiment of the application, if multiple electric heating element connectors are energized and need to output according to the first output power, it is necessary to calculate the first output power corresponding to each of the multiple electric heating element connectors.

[0038] In this embodiment of the application, in a complex dynamic environment, the thermal parameters that can generate feedback effects include temperature, flow rate, and the two-phase fraction of the working fluid, specifically the working fluid channel surface temperature, working fluid temperature, mass flow density, and the two-phase fraction of the working fluid. In some embodiments, the power dynamic correction formula is: ; in, This refers to the output power. The temperature of the working fluid closest to the middle position of the end of the connector to the electric heating element; Feedback coefficient for working fluid temperature (unit: ...) ), generally less than 0; The surface temperature of the working fluid channel closest to the middle position of the end of the connector to the electric heating element; Feedback coefficient for the surface temperature of the working fluid channel (unit: ...) ), generally less than 0; Mass flow density; Feedback coefficient for mass flow density (unit) ); The two-phase ratio of the working fluid (i.e., vapor content); Feedback coefficient for the two-phase proportion of the working fluid (unit: ), generally less than 0; The given power is a first given power; when the given power is a first given power, the corresponding output power is a first output power; when the given power is a second given power, the corresponding output power is a second output power. , , and Budgets need to be prepared based on the target application environment and specified before the experiment. , , , Physical quantities need to be measured in real time during experiments.

[0039] In this embodiment, the surface temperature of the working fluid channel is the temperature of the surface of the working fluid channel in contact with the working fluid. The working fluid temperature refers to the temperature of the working fluid within the working fluid channel.

[0040] The working fluid temperature or the working fluid channel surface temperature can cause negative feedback in thermal power, meaning that the higher the temperature, the less heat enters the working fluid channel. Therefore, the feedback coefficients of both the working fluid temperature and the working fluid channel surface temperature are less than 0.

[0041] In this embodiment of the application, when the working fluid boils in the working fluid channel and the heat power changes, the mass flow density (G) of the working fluid in the channel may change dynamically. The mass flow density (G) may have positive or negative feedback to the heat power.

[0042] In this embodiment, the two-phase ratio of the working fluid will generate negative feedback on the thermal power, so the feedback coefficient of the two-phase ratio of the working fluid is less than 0.

[0043] In some embodiments, the method further includes: Detect the surface temperature of the working fluid channel closest to the middle position of the end of the connector of the electric heating element; Detect the temperature of the working fluid closest to the middle position of the end of the connector of the electric heating element; In this embodiment, the surface temperature of the working fluid channel and the working fluid temperature can be detected by correspondingly arranged thermocouples.

[0044] The mass flow rate is detected using a flow meter, and the mass flow density is obtained by dividing the mass flow rate by the cross-sectional area of ​​the working fluid channel.

[0045] The cross-sectional area of ​​the working medium channel here refers to the cross-sectional area of ​​the space in the working medium channel used for the flow of the working medium.

[0046] mass flow density The flow rate is measured by a loop system flow meter assembled in a rectangular channel. According to the principle of mass conservation, the mass flow rate in the inlet section of the pipe is equal to the mass flow rate in the channel. The mass flow density can then be calculated based on the cross-sectional area.

[0047] The end of the electric heating element connector refers to the end that connects to the electric heating element body.

[0048] In one example, if eight electric heating element connectors are energized and require output according to a first output power, the first output power corresponding to each of the eight electric heating element connectors needs to be calculated. Correspondingly, the surface temperatures of the eight working fluid channels and the temperatures of the eight working fluids will be detected. Since the mass flow rate and cross-sectional area of ​​the working fluid channels are the same, the mass flow density is also the same, meaning there is only one mass flow density. In some embodiments, the two-phase fraction is the thermal equilibrium vapor content; the thermal equilibrium vapor content is calculated according to the following formula: ; in, For thermal equilibrium vapor content; Enthalpy at a local location (unit: kJ / kg); Enthalpy of the saturated working fluid (unit: kJ / kg); The latent heat of vaporization (unit: kJ / kg); the local position refers to the middle position of the two symmetrically arranged electric heating element connectors.

[0049] Since obtaining the vapor content is relatively complex, the embodiments of this application use the thermal equilibrium vapor content (…). ) instead of vapor content ( ).

[0050] In this embodiment, the electric heating element connectors on the symmetrically arranged electric heating elements are also symmetrically arranged. The local position refers to the middle position of the two symmetrically arranged electric heating element connectors, specifically located in the space for working fluid flow in the working fluid channel.

[0051] In some embodiments, the method further includes: Based on the environmental pressure, determine the enthalpy and latent heat of vaporization of the saturated working fluid.

[0052] In the embodiments of this application, the enthalpy and latent heat of vaporization of the saturated working fluid are physical property parameters, which can be obtained by looking up a table based on the ambient pressure.

[0053] In some embodiments, the enthalpy at the local location is calculated according to the following formula: ; in, Enthalpy at a local location; The enthalpy of the inlet working fluid (unit: kJ / kg); Power absorbed by the working fluid from the inlet to a local location (in W). The mass flow rate of the working fluid within the working fluid channel (unit: kg / s).

[0054] In some embodiments, the method further includes: Determine the enthalpy of the inlet working fluid based on environmental pressure; The sum of the output power of all the electric heating element connections through which the working fluid passes from the inlet to the local position determines the power absorbed by the working fluid from the inlet to the local position.

[0055] In this embodiment, each group of symmetrically arranged electric heating element connectors has a corresponding local position. Consequently, the enthalpy at the corresponding local position of the symmetrically arranged electric heating element connectors is the same.

[0056] See again Figure 2The number of all electric heating element connections from the inlet to local position A is 10. Therefore, the power absorbed by the working fluid from the inlet to the local position is the sum of the output power of the 10 electric heating element connections.

[0057] S300. Gradually increase the first given power until the second given power obtained by increasing the first given power reaches the preset thermal power, which is then calculated using the power dynamic correction formula.

[0058] In this embodiment of the application, since the boiling crisis experiment is conducted under relatively dangerous conditions and there is a possibility of a rapid temperature rise, the thermal power that may occur under the corresponding conditions needs to be estimated before the experiment. For example, the preset thermal power is 95% of the thermal power that may occur under the corresponding conditions.

[0059] In this embodiment of the application, increasing the first given power can be achieved by increasing the current value input to the electric heating component.

[0060] S400: After the second output power, inlet temperature and inlet velocity remain stable, the second given power is increased at a constant speed until a boiling crisis occurs in the working fluid channel; the second output power calculated based on the current second given power, the corresponding ambient pressure, inlet temperature and inlet velocity are recorded; the second given power is then reduced.

[0061] In this embodiment, after the second output power, inlet temperature, and inlet velocity stabilize, the second given power is increased uniformly until a boiling crisis occurs in the working fluid channel. The second output power, inlet temperature, and inlet velocity stabilizing means that their fluctuations within 5 minutes must be less than 1%. The uniform increase in the second given power can be achieved at a rate of 2 amperes per second. Simultaneously with the increase in the second given power, the second output power calculated using the power dynamic correction formula is also increased. The second output power calculated from the second given power when the boiling crisis occurs, along with the corresponding ambient pressure, inlet temperature, and inlet velocity, are recorded.

[0062] In this embodiment of the application, after a boiling crisis occurs, the second given power is reduced, which can prevent the boiling crisis from continuing.

[0063] In one example, reducing the second given power can be done by reducing it to 0. This will also result in a second output power calculated based on the second given power being 0, ensuring that the boiling crisis does not occur again. Reducing the second given power to 0 can be achieved by controlling the current input to the electric heating element to be 0.

[0064] In some embodiments, if it is necessary to continue to carry out the next experiment, steps S100-S400 can be repeated. It should be noted that if the electric heating element was not previously de-energized when performing step S200, it is not necessary to energize the electric heating element again, and the first output power can be adjusted directly.

[0065] In this embodiment, a special rectangular channel design and a real-time thermal power adjustment method are used to simulate the thermal parameter feedback effect under complex dynamic environment, and the special thermal-hydraulic phenomena of the rectangular channel caused by parameter feedback are obtained based on this rectangular channel and method.

[0066] In the field of energy engineering, such as thermal power generation, nuclear power generation, and chemical engineering, rectangular channel structures are a typical heat exchange or heating channel structure. This application aims to provide research and design solutions in this field, requiring the acquisition of thermal parameters of the rectangular channel structure to analyze heat exchange or heating efficiency under specific power conditions, supporting the optimal design of the heat exchanger or heating structure, and also obtaining the thermal safety limits of a specific structure under specific power conditions.

[0067] The above embodiments provide a rectangular channel and experimental method for simulating the feedback effect of thermal parameters in a dynamic environment. The rectangular channel includes multiple electric heating element connectors set at different positions. Different electric heating element connectors can be connected to a power source to provide the working fluid with heat flux density conditions corresponding to the feedback effect of thermal parameters, thereby simulating the dynamic environment with the feedback effect of thermal parameters, obtaining thermal experimental data that are closer to real complex conditions, and determining the thermal safety limit.

[0068] It will be readily understood by those skilled in the art that the above-described advantageous methods can be freely combined and superimposed without conflict. The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application. The above are merely preferred embodiments of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of this application, and these improvements and modifications should also be considered within the protection scope of this application.

Claims

1. A rectangular channel for simulating the feedback effect of dynamic environmental thermal parameters, characterized in that, It includes a working fluid channel, two insulating components, and multiple electric heating element assemblies; The working fluid channel is disposed between the two insulating components; Multiple electric heating element assemblies are arranged from top to bottom on the outside of the insulating component; The electric heating element assembly includes two electric heating elements symmetrically arranged about the working fluid channel, one of the electric heating elements being disposed outside one of the insulating components, and the other electric heating element being disposed outside the other of the insulating components; The electric heating element includes an electric heating element body and a plurality of electric heating element connectors arranged from top to bottom on the electric heating element body; The main body of the electric heating element is disposed outside the insulating component; the electric heating connectors on the two symmetrically disposed electric heating elements are symmetrically disposed.

2. The rectangular channel according to claim 1, characterized in that, The number of electric heating element assemblies is three.

3. The rectangular channel according to claim 1, characterized in that, The working medium channel is made of metal.

4. An experimental method for simulating the feedback effect of dynamic environmental thermal parameters using a rectangular channel, characterized in that, Applied to the rectangular channel according to any one of claims 1-3, the method comprises: The working conditions for regulating the working fluid are preset working conditions, which include ambient pressure, inlet temperature and inlet velocity; Set a first given power, and calculate the first output power of each electric heating element connector based on the first given power using a power dynamic correction formula; control the electric heating element connector to be energized and output according to the first output power; Gradually increase the first given power until the second given power obtained by the power dynamic correction formula based on the increase of the first given power reaches the preset thermal power; After the second output power, inlet temperature and inlet velocity remain stable, the second given power is increased at a constant rate until a boiling crisis occurs in the working fluid channel; the second output power calculated based on the current second given power, the corresponding ambient pressure, inlet temperature and inlet velocity are recorded. Reduce the second given power.

5. The method according to claim 4, characterized in that, The power dynamic correction formula is as follows: ； in, This refers to the output power. The temperature of the working fluid closest to the middle position of the end of the connector to the electric heating element; The feedback coefficient for the working fluid temperature; The surface temperature of the working fluid channel closest to the middle position of the end of the connector to the electric heating element; This is the feedback coefficient for the surface temperature of the working fluid channel; Mass flow density; The feedback coefficient for mass flow density; The two phases of the working fluid; The feedback coefficient represents the two-phase proportion of the working fluid; The given power is a first given power; when the given power is a first given power, the corresponding output power is a first output power; when the given power is a second given power, the corresponding output power is a second output power.

6. The method according to claim 5, characterized in that, Also includes: Detect the surface temperature of the working fluid channel closest to the middle position of the end of the connector of the electric heating element; Detect the temperature of the working fluid closest to the middle position of the end of the connector of the electric heating element; The mass flow rate is detected using a flow meter, and the mass flow density is obtained by dividing the mass flow rate by the cross-sectional area of ​​the working fluid channel.

7. The method according to claim 5, characterized in that, The two-phase fraction is the thermal equilibrium vapor content; the thermal equilibrium vapor content is calculated according to the following formula: ； in, For thermal equilibrium vapor content; Enthalpy at a local location; The enthalpy of the saturated working fluid; The latent heat of vaporization; the local position refers to the middle position of the two symmetrically arranged electric heating element connectors.

8. The method according to claim 7, characterized in that, Also includes: Based on the environmental pressure, determine the enthalpy and latent heat of vaporization of the saturated working fluid.

9. The method according to claim 7, characterized in that, The enthalpy at the local location is calculated according to the following formula: ； in, Enthalpy at a local location; The enthalpy of the inlet working fluid; The power absorbed by the working fluid from the inlet to the local location; The mass flow rate of the working fluid within the working fluid channel.

10. The method according to claim 9, characterized in that, Also includes: Determine the enthalpy of the inlet working fluid based on environmental pressure; The sum of the output power of all the electric heating element connections through which the working fluid passes from the inlet to the local position determines the power absorbed by the working fluid from the inlet to the local position.

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