Liquid level height measuring method and system based on microwave and conducting probe self-calibration

Abstract

The invention provides a liquid level height measurement method and system based on microwave and conducting probe self-calibration, and relates to the technical field of fluid parameter measurement. According to the method, phase values of the microwave sensor at accurate moments are synchronously captured as dynamic references through a conducting probe sensor at critical moments generated when two fixed liquid film height points are triggered, and the two references are used for performing sectional normalization processing on the real-time phase of the microwave sensor. According to the method, a double-reference-point segmented calibration strategy is adopted, compared with single-point full-liquid calibration, the engineering problem of obtaining the full-liquid state is avoided, correction can be carried out by adopting the nearest benchmark for different liquid film thickness intervals, possible nonlinear errors of a microwave measurement system are effectively corrected, and the accuracy of the measurement result is improved. Therefore, precision optimization in a full measurement range is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluid parameter measurement, in particular to a liquid level height measurement method and system based on microwave and conductivity probe self-calibration, and especially to a liquid level height measurement method and system based on microwave and conductivity probe self-calibration for realizing online self-calibration based on microwave sensing and conductivity probe sensing. BACKGROUND

[0002] In the gas-liquid two-phase flow conveying process in the industrial fields of petroleum, chemical industry, energy and the like, accurate measurement of the liquid film thickness on the inner wall of the pipeline is crucial for process control, equipment safety and efficiency optimization. Microwave sensors are used for liquid film thickness measurement due to their non-contact, fast response and other advantages, and the basic principle thereof is to measure the phase or amplitude change of a microwave signal after passing through a medium to inversely calculate medium information such as liquid film thickness.

[0003] At present, a common calibration method is to obtain a reference phase value under the full-liquid state of the pipeline, and to normalize the real-time measurement value. However, it is difficult to obtain an accurate full-liquid state reference value in the industrial field of continuous production, and the operation cost is high and will interfere with normal production. The conductivity probe sensor is another means for measuring the liquid level or liquid film thickness, which detects the contact between the electrode and the conductive liquid to determine whether the liquid level reaches a certain fixed height, and has the characteristics of simple structure and sensitive response, but it can only provide discrete point measurement and is difficult to realize continuous thickness measurement.

[0004] Therefore, there is an urgent need in the art for a method and system capable of automatically adapting to changes in liquid properties, realizing online self-calibration, and providing continuous and high-precision liquid film thickness measurement. SUMMARY

[0005] Therefore, the present application provides a liquid level height measurement method and system based on microwave and conductivity probe self-calibration, and the technical problem to be solved is how to realize online, automatic, high-precision and continuous measurement of the liquid film thickness of conductive gas-liquid two-phase flow.

[0006] The present application provides a liquid level height measurement method based on microwave and conductivity probe self-calibration, comprising the following steps: S1: installing a conductivity probe sensor and a microwave sensor in front of and behind a pipeline through which a conductive gas-liquid two-phase fluid flows; S2: monitoring whether the liquid film thickness reaches a first predetermined thickness value or a second predetermined thickness value by using the conductivity probe sensor , and recording a first critical time when the liquid film thickness reaches , and recording a second critical time ; S3: synchronously measuring and recording a real-time phase value of the output microwave signal of the microwave sensor during the measuring process; S4: extracting a first reference phase value corresponding to the first critical time and a second reference phase value corresponding to the second critical time from the phase values recorded by the microwave sensor; S5: calculating a normalized phase value according to the real-time phase value, the first reference phase value and the second reference phase value; S6: determining a real-time liquid film thickness corresponding to the real-time phase value according to a preset function relationship between the normalized phase value and the liquid film thickness.

[0007] Preferably, in step S2, the liquid film thickness is monitored by using the conductivity probe sensor to determine whether the liquid film thickness reaches a predetermined thickness value, specifically: an alternating excitation signal is applied to the excitation electrode of the conductivity probe sensor; the output signal of the reference electrode of the conductivity probe sensor is collected; and whether the liquid film thickness reaches the predetermined thickness value is determined by judging whether the output signal has a chopping phenomenon.

[0008] Preferably, the frequency of the alternating excitation signal is 10 kHz-100 kHz, and the voltage amplitude is 1 V-5 V.

[0009] Preferably, in step S4, the first reference phase value and the second reference phase value are extracted, specifically: within a preset time window, a plurality of first critical times and a plurality of first phase values corresponding thereto are collected, and the average value of the plurality of first phase values is calculated as the first reference phase value; within the preset time window, a plurality of second critical times and a plurality of second phase values corresponding thereto are collected, and the average value of the plurality of second phase values is calculated as the second reference phase value.

[0010] Preferably, in step S5, the normalized phase value is calculated, specifically: if the real-time liquid film thickness is less than or equal to a threshold value, the real-time phase value is normalized using the first reference phase value; if the real-time liquid film thickness is greater than the threshold value, the real-time phase value is normalized using the second reference phase value; wherein the threshold value is between the first predetermined thickness value and the second predetermined thickness value .

[0011] The embodiment also provides a system for implementing the above-mentioned liquid level height measurement method based on microwave and conductivity probe self-calibration, comprising: a conductivity probe sensor installed on a pipeline for monitoring whether the liquid film thickness reaches a first predetermined thickness value or a second predetermined thickness value and outputting an indication of the first critical time and the second critical time a signal; a microwave sensor installed on the pipeline; the microwave sensor is spaced apart from the conductivity probe sensor by a preset distance, and is configured to measure and output a real-time phase value of a microwave signal thereof; a signal processing and control unit in communication connection with the conductivity probe sensor and the microwave sensor; wherein the signal processing and control unit is configured to: receive a signal from the conductivity probe sensor and record a first critical time point and a second critical time point of the microwave sensor; and determine a real-time liquid film thickness corresponding to the real-time phase value according to a preset functional relationship between the normalized phase value and the liquid film thickness.

[0012] The embodiment also provides a readable storage medium, which stores a computer program; the computer program is executed by a processor to implement the liquid level height measurement method based on self-calibration of a microwave and a conductivity probe as described above.

[0013] The embodiment also provides a computer program product, which includes computer programs / instructions, and the computer programs / instructions are executed by a processor to implement the steps of the liquid level height measurement method based on self-calibration of a microwave and a conductivity probe as described above.

[0014] The embodiment also provides a sensor device for measuring a liquid film thickness of a gas-liquid two-phase flow, which includes: a tubular shell installed on a measurement pipeline; a conductivity probe module installed on the tubular shell, including a through-type excitation electrode and a non-through-type reference electrode, and an end of the reference electrode is spaced apart from a bottom of the pipeline by a predetermined thickness value; and a microwave sensor module installed on the tubular shell and located in front of or behind the conductivity probe module in a fluid flow direction, and the microwave sensor module includes two through-type microwave transmission lines; wherein the conductivity probe module and the microwave sensor module are arranged such that their measurement regions are spatially associated.

[0015] A fluid delivery control system, which includes the liquid film thickness measurement system and a flow or pressure regulating device; the liquid film thickness measurement system generates a control signal according to the measured real-time liquid film thickness and sends the control signal to the flow or pressure regulating device to regulate a fluid flow or pressure in the pipeline.

[0016] Implementing the present application includes the following beneficial effects: the present application provides a liquid film thickness online measurement method with high reliability, high precision, high adaptability and easy implementation. The first predetermined thickness value and the second predetermined thickness value of the two fixed liquid film height points trigger the first critical time point and the second critical time point The phase values of the microwave sensor at these precise time points are captured as dynamic reference benchmarks (first reference phase value, second reference phase value), and the real-time phase of the microwave sensor is segmented and normalized using the two reference benchmarks. Compared with single-point full-liquid calibration, the double-reference-point segmentation calibration strategy avoids the engineering difficulties of obtaining full-liquid state, can correct the nearest benchmark for different liquid film thickness intervals, effectively corrects the possible nonlinear errors of the microwave measurement system, and thus realizes the precision optimization in the whole measurement range.

[0017] Further, by extracting a plurality of critical time points and their corresponding phases in a time window and taking the average, transient interference caused by bubbles, fluctuations, etc. can be effectively filtered out, further improving the robustness and stability of the measurement.

[0018] Further, by providing an integrated sensor device, the conductivity probe module and the microwave sensor module are integrated in the same tubular housing and the spatial correlation is ensured, which simplifies the system installation and ensures the consistency of the measurement data of the two sensors in time and space.

[0019] Further, by combining the above measurement system with a flow or pressure regulating device to form a closed-loop control system, the fluid delivery process can be accurately regulated according to the real-time measured liquid film thickness, improving the system automation level and operation efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a flow chart of the liquid level height measurement method based on microwave and conductivity probe self-calibration in the embodiments of the present application.

[0021] Figure 2 is a schematic diagram of the installation of the microwave sensor and the conductivity probe sensor on the pipeline in the embodiments of the present application.

[0022] Figure 3 is a schematic diagram of the installation of the double-antenna microwave sensor in the embodiments of the present application.

[0023] Figure 4 is a schematic diagram of the installation of the microwave sensor in the embodiments of the present application.

[0024] Figure 5 is a normalized liquid film thickness and normalized phase relationship curve obtained in the embodiments of the present application.

[0025] In the figure: 1, excitation electrode; 2, high reference electrode; 3, low reference electrode; 4, pipeline; 5, conductive liquid; 6, first microwave transmission line; 7, second microwave transmission line. DETAILED DESCRIPTION

[0026] The application will be described in further detail below with reference to the drawings and specific embodiments. For the step numbers in the following embodiments, they are only set for the convenience of description and explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0027] The terms used in the embodiments of the present application are merely for the purpose of describing specific embodiments and are not intended to limit the embodiments of the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein means and includes any or all possible combinations of one or more associated listed items.

[0028] Embodiment one In the present embodiment, the present embodiment provides a liquid level height measurement method based on self-calibration of microwave and conductivity probe, comprising the following steps: S1: The conductivity probe sensor and the microwave sensor are installed in front of and behind the pipeline through which the conductive gas-liquid two-phase fluid flows; S2: The liquid film thickness is monitored by the conductivity probe sensor to determine whether it reaches a first predetermined thickness value Or a second predetermined thickness value , and the first critical moment is recorded when the liquid film thickness reaches , the second critical moment is recorded when the liquid film thickness reaches ; ; S3: During the measurement process, the real-time phase value of the output microwave signal is measured and recorded by the microwave sensor synchronously; S4: From the phase value recorded by the microwave sensor, the first reference phase value corresponding to the first critical moment , and the second reference phase value corresponding to the second critical moment are extracted ; ; S5: The normalized phase value is calculated according to the real-time phase value, the first reference phase value and the second reference phase value; S6: The real-time liquid film thickness corresponding to the real-time phase value is determined according to the preset function relationship between the normalized phase value and the liquid film thickness.

[0029] In the present embodiment, in step S2, the liquid film thickness is monitored by the conductivity probe sensor to determine whether it reaches a predetermined thickness value, specifically: an alternating excitation signal is applied to the excitation electrode of the conductivity probe sensor; The output signal of the reference electrode of the conductivity probe sensor is collected; ​The liquid film thickness is determined by judging whether the output signal has a chopping phenomenon.

[0030] In the embodiment, the first reference phase value and the second reference phase value are extracted in step S4, specifically: In a preset time window, a plurality of first critical time points and a plurality of first phase values corresponding thereto are collected, and an average value of the plurality of first phase values is calculated as the first reference phase value; In a preset time window, a plurality of second critical time points and a plurality of second phase values corresponding thereto are collected, and an average value of the plurality of second phase values is calculated as the second reference phase value.

[0031] In the embodiment, as shown in Figures 2-4 , the conductance probe sensor includes an excitation electrode 1 and a reference electrode, the reference electrode of the conductance probe sensor includes a high reference electrode 2 and a low reference electrode 3, and the high reference electrode 2 and the low reference electrode 3 are electrically connected with the excitation electrode 1. The excitation electrode 1 is installed through the pipeline 4, and the excitation electrode 1 penetrates from the top of the pipeline 4 to the bottom, and the high reference electrode 2 and the low reference electrode 3 only penetrate into the pipeline from the top to a certain length, without touching the bottom of the pipeline.

[0032] In the embodiment, the conductive gas-liquid two-phase fluid in the pipeline 4 includes a conductive liquid 5 at the bottom and a gas phase fluid above the conductive liquid 5.

[0033] In the embodiment, the bottom end of the high reference electrode 2 is higher than the bottom end of the low reference electrode 3. The distance between the high reference electrode 2 and the lowest point of the inner cavity of the pipeline 4 constitutes a first predetermined thickness , and the distance between the low reference electrode 3 and the lowest point of the inner cavity of the pipeline 4 constitutes a second predetermined thickness . And only when the liquid film thickness of the conductive liquid 5 is greater than , the low reference electrode 3 will have a signal output; similarly, only when the liquid film thickness of the conductive liquid 5 is greater than , the high reference electrode 2 will have a signal output, otherwise no signal output. Taking as an example, in the dynamic measurement process, the liquid film thickness changes continuously, so when the liquid film thickness reaches , the chopping phenomenon of the signal output of the low reference electrode 3 from no signal to signal (rising edge) or from signal to no signal (falling edge) will appear, and the critical occurrence time of the chopping phenomenon is recorded as , so that the liquid film thickness at this time is determined.

[0034] It should be noted that the triggering mechanism of the electrical conductivity probe sensor is based on the contact of the liquid with the bottom end of the reference electrode. Under the condition of severe fluctuation of flow pattern (such as plug flow, annular flow with a large number of entrained droplets), the splashing droplets may cause instantaneous short circuit of the reference electrode, resulting in unexpected false trigger signals. In order to reduce the interference of false trigger signals, the present application not only detects the amplitude jump (chopping) of the signal, but also analyzes the duration and shape of the jump. An effective liquid film covering signal should have a long duration (for example, > 10 ms), while the droplet impact signal is usually a sharp pulse. At the same time, the trigger signals of the high reference electrode 2 and the low reference electrode 3 should have a reasonable timing relationship (for example, when the liquid level rises, the low electrode should trigger before the high electrode). The single electrode trigger that violates this logic can be judged as invalid. At the same time, when calculating the real-time phase value, only after collecting multiple (for example, more than 3 times) logical and valid triggers within a preset time window, the average value of the corresponding phase value is taken as the reference benchmark, so as to ensure the reliability of the reference phase value.

[0035] In the present embodiment, the electrical conductivity probe sensor and the microwave sensor are installed in the pipeline 4 along the length direction of the pipeline 4, and the spacing L between the electrical conductivity probe sensor and the microwave sensor in the length direction of the pipeline 4 is set to a certain value (i.e. a preset distance) as required. The spacing L should be much smaller than the dominant wavelength λ of the liquid wave in the gas-liquid two-phase flow. λ can be estimated according to the flow velocity and fluctuation frequency under typical working conditions (for example, L < λ / 10). In order to ensure that the liquid film thickness changes smoothly within the sensor spacing, the two sensors can sense highly correlated liquid film information. In the present embodiment, in order to facilitate calculation, the spacing between the electrical conductivity probe sensor and the microwave sensor in the length direction of the pipeline 4 is set to 50 mm, and the spacing is sufficient to ensure that the measurement regions of the electrical conductivity probe sensor and the microwave sensor have high correlation under wavy flow, while avoiding mutual electromagnetic interference. In order to avoid the thickness of the liquid film in the pipeline axial direction under special circumstances, which causes the liquid film thickness of the microwave sensor and the electrical conductivity probe sensor at the same time to be different, the average value of the reference phase obtained within 60s is taken as the final calibration value, so as to accurately measure the liquid film thickness in the gas-liquid two-phase flow.

[0036] In the present embodiment, during measurement, a sinusoidal alternating signal needs to be applied to the excitation electrode, and the output signals of the two reference electrode ends are collected, so the measurement circuit needs to have a double-channel design. In order to ensure measurement accuracy, the sampling frequency should be high enough, usually 10-100 kHz; in order to prevent high voltage that may cause electrochemical effects such as electrolysis, pollute the electrode and the liquid, the amplitude of the excitation signal is set to 1V-5V. A typical excitation signal of 4V, 2kHz is used to ensure the signal-to-noise ratio and sensitivity of the measurement.

[0037] In the present embodiment, the two reference electrodes of the electrical conductivity probe sensor are respectively covered by liquid films with fixed thicknesses and Real-time dynamic monitoring is performed, and when the liquid film thickness reaches a predetermined value , the reference electrode outputs a signal indicating the corresponding time , and similarly when occurs, it indicates the corresponding time .

[0038] In this embodiment, as shown in Figures 2-4 , the first microwave transmission 6 and the second microwave transmission line 7 both pass through the pipe 4 from the top to the bottom, and the first microwave transmission 6 and the second microwave transmission line 7 are symmetrically distributed on both sides of the pipe 4. The first microwave transmission 6 and the second microwave transmission line 7 both use coaxial cables, the center conductor of which penetrates the pipe, and the metal shielding layer is well connected with the outer wall of the pipe. When measuring, high-frequency microwave signals need to be applied to the emission end of the first microwave transmission 6 and the second microwave transmission line 7, and the phase value of the output signal of the receiving end of the first microwave transmission 6 and the second microwave transmission line 7 is collected. In order to avoid mutual interference between the microwave emission circuit and the conductance probe measurement circuit, different working frequency bands need to be used, and the microwave frequency is generally between 1-100GHz.

[0039] In this embodiment, during the measurement process, the microwave signal will be affected by the medium when passing through the medium. The liquid with high dielectric constant will reduce the propagation speed of the microwave signal, while the gas has a low dielectric constant and the microwave signal propagates faster. Because the propagation speed of the microwave signal is different in different media, when the signal passes through the boundary between the liquid and the gas, its phase will change. Different liquid film thicknesses will cause changes in phase delay, so by measuring the change in phase, the liquid film thickness of the gas-liquid two-phase flow can be analyzed and obtained.

[0040] In this embodiment, every time the chopping phenomenon occurs in the reference electrode output signal, a or time can be extracted or corresponding to the phase value output by the microwave sensor or at that time. In order to reduce the error caused by factors such as gas bubble entrainment and fluid noise in the liquid phase, the average value of all or in a predetermined time window (typical value, 60 seconds) can be collected as the final phase value result, thereby improving the robustness of the measurement.

[0041] In this embodiment, in step S5, the normalized phase value is calculated, specifically: If the real-time liquid film thickness is less than or equal to a threshold value, the real-time phase value is normalized using a first reference phase value; if the real-time liquid film thickness is greater than the threshold value, the real-time phase value is normalized using a second reference phase value; wherein the threshold value is between a first predetermined thickness value and a second predetermined thickness value .

[0042] Specifically, when the liquid film thickness is less than or equal to , the real-time phase value is normalized using ; when the liquid film thickness is greater than , the real-time phase value is normalized using , to obtain a normalized phase value .

[0043] Specifically, the calculation formula of the normalized phase is: Formula (1); The relationship between the normalized phase and the normalized liquid film thickness is: Formula (2); is a function relationship between the normalized phase and the normalized liquid film thickness, and the specific relationship is determined by actual experimental conditions.

[0044] In this embodiment, the conductivity probe sensor is combined with the microwave sensor of the double antenna, and self-calibration is completed by introducing a reference electrode. On the one hand, the difficulty of engineering operation can be reduced. In actual production, the full liquid value needs to be obtained by filling the pipeline with water, which is time-consuming and laborious, and residual bubbles in the pipeline cannot be completely discharged, causing inaccurate full liquid phase measurement. The introduction of the self-calibration probe does not require measurement of the full liquid value, reducing the complexity of the project. On the other hand, compared with single-point calibration which requires measurement of the full liquid value, the present application can establish a reference by using the calibration liquid level of the corresponding interval, correct the nonlinear error of each interval, realize precision optimization in the whole interval, and realize accurate measurement of the target interval in the case of small change of the liquid film height. For scenarios with a wide range of liquid film height fluctuations, accurate measurement in the whole range can also be ensured.

[0045] In one possible embodiment, tap water is used for static experiments, and the relationship between the normalized liquid film thickness and the normalized phase is as shown in Figure 5 .

[0046] In one possible embodiment, the specific relationship is as follows: Formula (3); wherein the piecewise expression is based on Figure 5 a cubic polynomial fitting of the data points in the interval. The power terms in the expression (e.g. , , ) are only mathematical forms in the fitting formula and have no specific physical meaning; the coefficients involved are fitting results and are intended to ensure accurate description of the data trend in different height intervals.

[0047] Thus, the liquid film thickness corresponding to each of the 60 seconds can be obtained, and the above steps can be repeatedly executed to realize online self-calibration measurement of the liquid film thickness.

[0048] Embodiment Two The embodiment provides a system for the above-mentioned liquid level height measurement based on microwave and conductivity probe self-calibration.

[0049] In the embodiment, the liquid film thickness measurement system of gas-liquid two-phase flow includes: a conductivity probe sensor installed on the pipeline for monitoring whether the liquid film thickness reaches a first predetermined thickness value or a second predetermined thickness value and outputting a signal indicating the critical moment , ; a microwave sensor installed on the pipeline; the microwave sensor is spaced apart from the conductivity probe sensor by a preset distance, and is used for measuring and outputting a real-time phase value of the microwave signal thereof; a signal processing and control unit in communication connection with the conductivity probe sensor and the microwave sensor; wherein the signal processing and control unit is used for: receiving the signal from the conductivity probe sensor and recording the critical moment , ; receiving the real-time phase value from the microwave sensor; and determining a real-time liquid film thickness corresponding to the real-time phase value according to a preset functional relationship between the normalized phase value and the liquid film thickness.

[0050] Embodiment Three The embodiment provides a readable storage medium based on any of the above-mentioned embodiments.

[0051] In the embodiment, the readable storage medium stores a computer program; the computer program is executed by a processor to implement the above-mentioned liquid level height measurement method based on microwave and conductivity probe self-calibration.

[0052] Embodiment Four The embodiment provides a readable storage medium based on any of the above embodiments.

[0053] The computer program product in the embodiment comprises computer programs / instructions which, when executed by a processor, implement the steps of the liquid level height measurement method based on self-calibration of a microwave and conductivity probe.

[0054] Embodiment five The embodiment provides a sensor device for measuring the liquid film thickness of gas-liquid two-phase flow based on any of the above embodiments.

[0055] The sensor device in the embodiment comprises a tubular shell installed on a measuring pipeline; The conductivity probe module installed on the tubular shell comprises a through excitation electrode and a non-through reference electrode, and the end of the reference electrode is away from the bottom of the pipeline by a predetermined thickness value; and the microwave sensor module installed on the tubular shell is located in front of or behind the conductivity probe module along the fluid flow direction, and the microwave sensor module comprises two through microwave transmission lines; wherein the conductivity probe module and the microwave sensor module are arranged such that their measurement regions are spatially associated.

[0056] In the embodiment, the tubular shell of the conductivity probe module adopts a rigid mechanical structure and is firmly installed on the pipeline through a flange or a thread to resist fluid impact and vibration. The reference electrode is fixed to the shell through a precision thread or a locking mechanism, and the insertion depth can be finely adjusted and locked during installation to ensure the installation accuracy of the distance of the end of the reference electrode from the bottom of the pipeline. Reliable insulation and sealing designs are adopted between the excitation electrode and the reference electrode and between the reference electrode and the shell to prevent short circuit and leakage.

[0057] Embodiment six The embodiment provides a fluid delivery control system based on any of the above embodiments.

[0058] In the embodiment, the fluid delivery control system comprises the liquid film thickness measurement system and a flow or pressure regulating device, and the liquid film thickness measurement system generates a control signal according to the measured real-time liquid film thickness and sends the control signal to the flow or pressure regulating device to regulate the fluid flow or pressure in the pipeline.

[0059] The above is a specific description of the preferred embodiment of the application, but the application is not limited to the above-mentioned embodiments. Those skilled in the art can make various equivalent modifications or replacements without departing from the spirit of the application. These equivalent modifications or replacements are all included in the scope defined by the claims of the present application.

Claims

1. A method for measuring liquid level height based on microwave and conductivity probe self-calibration, characterized in that, Includes the following steps: S1: A pipe through which a conductive gas-liquid two-phase fluid flows is provided, wherein a conductivity probe sensor and a microwave sensor are installed on the pipe; S2: Use the conductivity probe sensor to monitor whether the liquid film thickness has reached a predetermined thickness value, the predetermined thickness value including a first predetermined thickness value. Second predetermined thickness value And when the liquid film thickness reaches Record the first critical moment. When the liquid film thickness reaches Record the second critical moment. ; S3: During the measurement process, the real-time phase value of the output microwave signal is simultaneously measured and recorded using the microwave sensor. S4: Extract the phase values ​​from the real-time phase values ​​recorded by the microwave sensor, relative to the first critical moment. The corresponding first reference phase value and the second critical time The corresponding second reference phase value; S5: Calculate the normalized phase value based on the real-time phase value, the first reference phase value, and the second reference phase value; S6: Determine the real-time liquid film thickness corresponding to the real-time phase value based on the preset functional relationship between the normalized phase value and the liquid film thickness.

2. The liquid level height measurement method based on microwave and conductivity probe self-calibration according to claim 1, characterized in that, In step S2, the conductivity probe sensor is used to monitor whether the liquid film thickness has reached the predetermined thickness value, specifically as follows: An alternating excitation signal is applied to the excitation electrode of the conductivity probe sensor; The output signal of the reference electrode of the conductivity probe sensor is acquired; By determining whether the output signal exhibits chopping, it is possible to determine whether the liquid film thickness has reached the predetermined thickness value.

3. The liquid level height measurement method based on microwave and conductivity probe self-calibration according to claim 2, characterized in that, The frequency of the alternating excitation signal is 10kHz~100kHz, and the voltage amplitude is 1V~5V.

4. The liquid level height measurement method based on microwave and conductivity probe self-calibration according to claim 1, characterized in that, In step S4, the first reference phase value and the second reference phase value are extracted, specifically as follows: Within a preset time window, multiple first critical moments are collected. And its corresponding multiple first phase values, and calculate the average value of the multiple first phase values ​​as the first reference phase value; Within a preset time window, multiple second critical moments are collected. And its corresponding multiple second phase values, and calculate the average value of the multiple second phase values ​​as the second reference phase value.

5. The liquid level height measurement method based on microwave and conductivity probe self-calibration according to claim 1, characterized in that, In step S5, the normalized phase value is calculated, specifically as follows: If the real-time liquid film thickness is less than or equal to a threshold, then the real-time phase value is normalized using the first reference phase value; If the real-time liquid film thickness is greater than the threshold, the real-time phase value is normalized using the second reference phase value; Wherein, the threshold is between the first predetermined thickness value. and the second predetermined thickness value between.

6. A system for implementing the liquid level height measurement method based on microwave and conductivity probe self-calibration as described in any one of claims 1 to 5, characterized in that, include: A conductivity probe sensor, installed on the pipeline, is used to monitor whether the liquid film thickness has reached a first predetermined thickness value. Or a second predetermined thickness value and output an indication of the first critical moment. Second critical moment The signal; A microwave sensor is installed on the pipeline; the microwave sensor and the conductivity probe sensor are spaced at a preset distance apart, and the microwave sensor is used to measure and output the real-time phase value of its microwave signal. The signal processing and control unit is communicatively connected to the conductivity probe sensor and the microwave sensor. The signal processing and control unit is used for: Receive signals from the conductivity probe sensor and record the first critical moment. The corresponding first reference phase value and the second critical time The corresponding second reference phase value; Receive the real-time phase value from the microwave sensor; Calculate the normalized phase value based on the real-time phase value, the first reference phase value, and the second reference phase value; And based on the preset functional relationship between the normalized phase value and the liquid film thickness, the real-time liquid film thickness corresponding to the real-time phase value is determined.

7. A readable storage medium, characterized in that, The readable storage medium stores a computer program; when the computer program is executed by a processor, it implements the liquid level height measurement method based on microwave and conductivity probe self-calibration as described in any one of claims 1 to 5.

8. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the liquid level height measurement method based on microwave and conductivity probe self-calibration as described in any one of claims 1 to 5.

9. A sensor device for measuring the thickness of a liquid film in a gas-liquid two-phase flow, characterized in that, include: A tubular housing, installed on the measuring pipe; A conductivity probe module, mounted on the tubular housing, includes a through-type excitation electrode and a non-through-type reference electrode, wherein the distance from the end of the reference electrode to the bottom of the pipe is a predetermined thickness value; And a microwave sensor module, which is mounted on the tubular housing and located in front of or behind the conductivity probe module along the fluid flow direction, the microwave sensor module including two through microwave transmission lines; The conductivity probe module and the microwave sensor module are configured such that their measurement areas are spatially correlated.

10. A fluid transport control system, characterized in that, include: The system for implementing a liquid level height measurement method based on microwave and conductivity probe self-calibration as described in claim 6; The system also includes a flow or pressure regulating device; the liquid film thickness measurement system generates a control signal based on the measured real-time liquid film thickness and sends it to the flow or pressure regulating device to regulate the fluid flow or pressure in the pipeline.

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