WO2023245888A1

WO2023245888A1 - Method and apparatus for detecting state of gas-liquid two-phase flow in pipeline

Info

Publication number: WO2023245888A1
Application number: PCT/CN2022/119730
Authority: WO
Inventors: 高国刚; 夏建华
Original assignee: 宝腾智能润滑技术(东莞)有限公司
Priority date: 2022-06-24
Filing date: 2022-09-19
Publication date: 2023-12-28
Also published as: CN115165792A; CN115165792B

Abstract

A method and apparatus for detecting the state of a gas-liquid two-phase flow in a pipeline. In the method, detection is performed on the basis of at least one pair of an optical emitter (10) and an optical receiver (11), which are arranged in the direction of the pipe diameter of a pipeline to be tested and are located outside the pipeline. The method comprises: detecting and processing in real time an optical signal received by an optical receiver (11), so as to generate a power spectrum that reflects an intensity change rate of the optical signal (S1); acquiring a peak value of the power spectrum at the current moment (S2); and comparing the peak value of the power spectrum with a preset first threshold value, and determining the current presence state of a gas-liquid two-phase flow medium in the pipeline according to a comparison result (S3). The state of a medium flow in a pipeline is represented by means of a power spectrum that reflects an intensity change rate of an optical signal, such that a change in the presence state of a gas-liquid two-phase flow medium in the pipeline can be reflected in the power spectrum regardless of the size of the pipe diameter, thereby effectively improving the precision of detecting the state of a gas-liquid two-phase flow medium in a pipe with a small diameter by means of a light sensor.

Description

Method and device for detecting gas-liquid two-phase flow status in pipelines

Technical field

The invention relates to the technical field of gas-liquid two-phase flow detection, and in particular to a method and device for detecting gas-liquid two-phase flow status in a pipeline.

Background technique

Normally, the liquid flow to be transported is directly introduced into the pipeline for transportation. At this time, the medium flow in the pipeline is called single-phase flow. In another case, in order to improve the transportation efficiency of liquid or for special needs, high-pressure gas flow is introduced while introducing liquid into the transportation pipeline, thereby forming a gas-liquid two-phase flow in the transportation pipeline. Therefore, gas-liquid two-phase flow refers to It is a mixed media flow including gas and liquid, generally used in pipeline transportation.

In the application process, infrared detection devices are generally used to monitor the state of the flowing liquid in the transportation pipeline. Its working principle is: the infrared laser transmitter projects infrared light to the pipeline along the diameter direction, and the infrared receiver receives the transmission from the other side of the pipeline. The infrared light is emitted, and then the intensity of the received infrared light is analyzed to calculate the attenuation rate of the infrared light after passing through the pipe. When the attenuation rate of the infrared light is greater than the preset value, it indicates that there is a liquid medium flow in the pipe. For this detection method, when the diameter of the transportation pipeline is particularly small (millimeter level), such as an oil and gas lubrication pipeline (there is a mixed medium of air and oil in the pipeline), because the cross-section of the gas-liquid medium flow in the pipeline is relatively thin, It is difficult to accurately detect the state of the medium flow in the pipeline through the above-mentioned infrared detection processing method. Therefore, in the existing technology, ultrasonic waves are generally used to detect the liquid flow state of small diameter pipes, and the detection results are not ideal.

Compared with single-phase flow, gas-liquid two-phase flow has a unique flow pattern in the pipeline, as shown in Figure 11. Along the flow direction, the liquid medium film is distributed at periodic intervals, and the liquid medium film is attached to the pipe wall. Therefore, based on the flow pattern of the gas-liquid two-phase flow, the data processing measured by the light sensor can be improved, so that the sensor based on light detection can detect the state of the gas-liquid two-phase flow and obtain good results.

Contents of the invention

The object of the present invention is to provide a gas-liquid two-phase flow state detection method and device in a pipeline that can be used in small pipe diameters and uses a light sensor to detect the state of the gas-liquid two-phase flow medium in the pipeline.

In order to achieve the above object, the present invention discloses a method for detecting the state of gas-liquid two-phase flow in a pipeline. The detection is based on at least a pair of light emitters and light receivers located outside the pipeline arranged along the diameter direction of the pipeline to be tested. , the detection method includes:

Detect and process the optical signal received by the optical receiver in real time to generate a power spectrum that reflects the change rate of optical signal intensity;

Obtain the peak value at the current moment in the power spectrum;

The peak value of the power spectrum is compared with a preset first threshold, and the current existence state of the gas-liquid two-phase flow medium in the pipeline is determined based on the comparison result.

Preferably, determining the current existence state of the gas-liquid two-phase flow medium in the pipeline includes:

Determine whether the peak value of the power spectrum is less than a first threshold, and if so,

Then, there is no gas-liquid two-phase flow medium in the pipeline, or the gas-liquid two-phase flow medium in the pipeline does not flow;

If not, there is a flowing gas-liquid two-phase flow medium in the pipeline.

Preferably, when the peak value of the power spectrum is not less than the first threshold, calculate the frequency difference between the peak values of the power spectrum at the previous and next moments, compare the frequency difference with a preset second threshold, and determine based on the comparison result. The current flow state of the gas-liquid two-phase flow medium in the pipeline.

Preferably, determining the current flow state of the gas-liquid two-phase flow medium in the pipeline includes:

Determine whether the frequency difference between the peaks of the power spectrum at the preceding and following moments is greater than the second threshold, and if so,

Then, the gas-liquid two-phase flow medium in the pipeline flows unevenly;

If not, the gas-liquid two-phase flow medium in the pipeline flows uniformly.

Preferably, the method for processing the optical signal includes:

Convert the optical signal into an electrical signal suitable for its light intensity;

Perform noise removal and decomposition processing on the electrical signal to obtain the target signal;

The peak frequencies of a series of obtained target signals are estimated by a power spectrum estimation method to obtain the power spectrum.

Preferably, the first threshold is a, e-5<a<e-3.

Preferably, the second threshold is b, b≤1Hz.

Preferably, the outer diameter of the pipeline is c, the inner diameter is d, 3mm≤c≤5mm, and 1.5mm≤d≤3mm.

Preferably, the light emitter includes an LED lamp.

Preferably, the gas-liquid two-phase flow medium includes a mixed medium of air and oil.

Preferably, the absorption rate of the light emitted by the light emitter by the pipeline is smaller than the absorption rate by the oil.

Preferably, the light emitted by the light emitter is infrared light with a wavelength of 923 nm.

The invention also discloses a device for detecting the state of gas-liquid two-phase flow in a pipeline, which includes:

at least a pair of light emitters and light receivers located outside the pipeline, arranged along the diameter direction of the pipeline to be tested;

A signal processing module that detects and processes the optical signal received by the optical receiver in real time to generate a power spectrum that reflects the change rate of optical signal intensity;

A first comparison module, configured to compare the peak value of the power spectrum with a preset first threshold;

The first determination module is used to determine the current existence state of the gas-liquid two-phase flow medium in the pipeline according to the comparison result of the first comparison module.

Preferably, it also includes a calculation module, a second comparison module and a second determination module;

The calculation module is used to calculate the frequency difference between the peak values of the power spectrum at the preceding and following moments when the peak value of the power spectrum is not less than the first threshold;

The second comparison module is used to compare the frequency difference with a preset second threshold;

The second determination module is used to determine the current flow state of the gas-liquid two-phase flow medium in the pipeline according to the comparison result of the second comparison module.

Preferably, the signal processing module is provided with a photoelectric conversion module, a noise processing module and a power spectrum generation module;

The photoelectric conversion module is used to convert the optical signal received by the optical receiver into an electrical signal that matches its light intensity;

The noise processing module is used to perform noise removal and decomposition processing on the electrical signal to obtain the target signal;

The power spectrum generation module is configured to estimate the peak frequencies of a series of obtained target signals through a power spectrum estimation method to obtain the power spectrum.

Preferably, the first threshold is a, e-5<a<e-3.

Preferably, the second threshold is b, b≤1Hz.

Preferably, the light emitter includes an LED lamp.

The invention also discloses a gas-liquid two-phase flow state detection system in a pipeline, which includes:

one or more processors;

memory;

and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the program including for performing the gas-in-pipeline process as described above. Instructions for liquid two-phase flow state detection methods.

The present invention also discloses a computer-readable storage medium, which includes a computer program that can be executed by a processor to complete the above-mentioned method for detecting gas-liquid two-phase flow status in a pipeline.

Compared with the existing technology, this application detects the state of the gas-liquid two-phase flow medium in the pipeline through a light sensor, that is, a pair of light emitters and light receivers located outside the pipeline arranged along the diameter direction of the pipeline to be measured, and The detected data is processed according to the unique flow pattern of the gas-liquid two-phase flow in the pipeline to obtain a power spectrum that reflects the change rate of the optical signal intensity, and the peak value of the power spectrum is compared with the preset first threshold, according to The comparison results can determine the current existence state of the gas-liquid two-phase flow medium in the pipeline; it can be seen that this application uses the power spectrum that reflects the change rate of the light signal intensity to characterize the medium flow state in the pipeline, regardless of the size of the pipe diameter. That is to say, even for pipelines with extremely small diameters, changes in the existence state of the gas-liquid two-phase flow medium in the pipeline will be reflected in the power spectrum, thereby effectively improving the detection of gas-liquid two-phase flow media in small pipe diameters through the light sensor. Accuracy of status detection.

Description of the drawings

Figure 1 is a schematic diagram of the layout structure for optical inspection of pipelines in an embodiment of the present invention.

Figure 2 is a flow chart of a detection method in one embodiment of the present invention.

Figure 3 is a flow chart of a detection method in another embodiment of the present invention.

Figure 4 is one of the power spectrum diagrams in the embodiment of the present invention, in which the medium in the tube does not flow.

Figure 5 is another power spectrum diagram in an embodiment of the present invention, in which there is no medium in the tube.

Figure 6 is another power spectrum diagram in an embodiment of the present invention, in which the medium in the tube flows normally.

Figure 7 is a power spectrum collected when detecting oil and gas lubrication pipelines in the embodiment of the present invention, in which the oil flows evenly.

Figure 8 is a power spectrum collected when detecting oil and gas lubrication pipelines in the embodiment of the present invention, in which the oil flow is uneven.

Figure 9 is a power spectrum collected when detecting oil and gas lubrication pipelines in the embodiment of the present invention, in which the oil does not flow.

Figure 7 is a power spectrum collected when detecting oil and gas lubrication pipelines in the embodiment of the present invention, where there is no oil in the pipeline.

Figure 11 is a flow pattern diagram of the oil-gas mixture in the embodiment of the present invention.

Figure 12 is a schematic structural diagram of a detection device in one embodiment of the present invention.

Figure 13 is a schematic structural diagram of a detection device in another embodiment of the present invention.

Detailed ways

In order to describe in detail the technical content, structural features, achieved objectives and effects of the present invention, the following will be described in detail in combination with the embodiments and the accompanying drawings.

This embodiment discloses a gas-liquid two-phase flow state detection method to detect the state of a gas-liquid two-phase flow medium transported through a pipeline. The gas-liquid two-phase flow medium is a mixture of gas and liquid introduced into the pipeline. Mixed media, such as a mixture of oil and air in an oil-gas lubrication pipe, this detection method can effectively detect the state of the oil-gas mixture in the oil-gas lubrication pipe. The detection method in this embodiment is based on optical sensors. Specifically, as shown in Figure 1, at least a pair of light emitters 10 and light receivers 11 located outside the pipeline are arranged along the diameter direction of the pipeline to be tested. The light emitter 10 is In order to emit detection light into the pipeline, the detection light passes through the pipeline along the radial direction of the pipeline, and the light receiver 11 is used to receive the optical signal emitted from the radial direction of the pipeline.

In order to facilitate understanding of the detection method in this embodiment, the influence of the unique flow pattern of the gas-liquid two-phase flow in the pipeline on the incident light is first explained. As shown in Figure 11, for the gas-liquid two-phase flow medium in the pipeline, taking the oil-liquid-air mixed medium as an example, the oil film breaks periodically. Therefore, when the detection light is projected at a certain side wall of the pipeline through the direction of the pipe diameter , the emitted light should also change periodically. Moreover, within a cycle, as the oil flows forward, the disturbance peak of the oil film at the bottom of the pipeline will first pass through the detection area. At this time, the thickness of the oil film increases sharply. Since the intensity of the emergent light is negatively correlated with the thickness of the oil, it leads to The intensity of the emergent light decreases sharply. Then, as the liquid film thickness in the detection area gradually decreases, it will also encounter the disturbance wave peak of the top oil film, so the corresponding emitted light intensity will decrease sharply again. After that, the oil film thickness gradually decreases to 0. At this point, A cycle ends.

Based on the above-mentioned principle of the influence of the unique flow pattern of gas-liquid two-phase flow in pipelines on incident light, as shown in Figure 1 and Figure 2, the detection method in this embodiment includes the following steps:

S1: Detect and process the optical signal received by the optical receiver 11 in real time to generate a power spectrum reflecting the change rate of the intensity of the optical signal. Power spectrum, also called power spectral density function, defines the signal power within the unit frequency band. In this embodiment, for the power spectrum at any time, as shown in Figure 4, the abscissa represents the signal change frequency, which is positively related to the flow speed of the medium flow in the pipeline, and the ordinate represents the amplitude of the optical signal intensity change rate. value reflects the change in optical signal intensity, and its size is also positively related to the flow speed of the medium flow in the pipeline. That is, the faster the flow speed of the medium flow in the pipeline, the change in the intensity of the optical signal received by the optical receiver 11 The faster, correspondingly, the greater the amplitude of the optical signal intensity change rate. On the contrary, the slower the flow speed of the medium flow in the pipeline, the slower the optical signal intensity received by the optical receiver 11 changes. Correspondingly, the optical signal The amplitude of the intensity change rate is smaller.

S2: Get the peak value at the current moment in the power spectrum.

S3: Compare the peak value of the power spectrum with the preset first threshold, and determine the existing state of the current gas-liquid two-phase flow medium in the pipeline based on the comparison result.

Specifically, there are three states of existence of the gas-liquid two-phase flow medium in the pipeline. One state is that there is no gas-liquid two-phase flow medium in the pipeline, and the other state is that there is stagnant gas-liquid two-phase flow in the pipeline. Medium, in another state, there is a flowing gas-liquid two-phase flow medium in the pipeline. In this regard, the method to determine the current existence status of the gas-liquid two-phase flow medium in the pipeline is:

S30: Determine whether the peak value of the power spectrum is less than the first threshold. If yes, proceed to S31. If not, proceed to S32.

S31: There is no gas-liquid two-phase flow medium in the pipeline, or the gas-liquid two-phase flow medium in the pipeline does not flow.

S32: There is a flowing gas-liquid two-phase flow medium in the pipeline.

In the above embodiment, by processing the optical signal received by the optical receiver 11, a power spectrum reflecting the change rate of the intensity of the optical signal is generated, and based on the comparison between the peak value of the effective signal in the power spectrum and the preset first threshold. Determine the status of the gas-liquid two-phase flow in the current pipeline. When the peak value in the power spectrum is small (less than the first threshold), it means that the influence of the medium in the pipeline on the change of detected light intensity is almost negligible. Therefore, it can be determined that there is no gas-liquid two-phase flow medium in the pipeline (as shown in Figure 5 ), or the gas-liquid two-phase flow medium in the pipeline does not flow (as shown in Figure 4). When the peak value in the power spectrum is large (not less than the first threshold), it means that the medium in the pipeline has a greater impact on the change of detected light intensity. Therefore, it can be determined that there is a gas-liquid two-phase flow medium flowing in the pipeline (as shown in the figure) 6).

In another embodiment, as shown in Figure 3, when the peak value of the power spectrum is not less than the first threshold, the above detection method further includes the following steps:

S4: Calculate the frequency difference between the peaks of the power spectrum at the preceding and following moments.

S5: Compare the frequency difference with the preset second threshold, and determine the current flow state of the gas-liquid two-phase flow medium in the pipeline based on the comparison result.

In the power spectrum, since the frequency of the peak value of the power spectrum is related to the flow speed of the gas-liquid two-phase flow medium, when the flow rate of the gas-liquid two-phase flow medium in the pipeline is constant, theoretically the peak value of the power spectrum at two moments before and after is The frequency difference is zero. On the contrary, the greater the change in the flow rate of the gas-liquid two-phase flow medium in the pipeline, the greater the frequency difference between the peaks of the power spectrum at the two moments. Therefore, specifically, the method for determining the current flow state of the gas-liquid two-phase flow medium in the pipeline in this embodiment includes:

S50: Determine whether the frequency difference between the peaks of the power spectrum at the preceding and following moments is greater than the second threshold. If yes, proceed to S51. If not, proceed to S52.

S51: The gas-liquid two-phase flow medium in the pipeline flows unevenly;

S52: The gas-liquid two-phase flow medium in the pipeline flows evenly.

When the detection method disclosed in the above embodiment is used to detect the oil and air mixed medium in the oil and gas lubrication pipeline, the optical signal emitted by the optical transmitter 10 in the radial direction of the pipeline is received in real time by the optical receiver 11, and the optical signal is It is converted into a corresponding electrical signal, and then the electrical signal is used to generate a power spectrum that reflects the change rate of the intensity of the optical signal. Next, the peak value of the effective signal is obtained from the power spectrum, and then the peak value is compared with the first preset value. If the peak value is less than the first preset value, the following detection result is given: there is no oil in the pipeline ( (See Figure 5, Figure 10), or the oil in the pipeline does not flow (Figure 4, Figure 9). If the peak value is not less than the first preset value, the following detection result is given: there is flowing oil in the pipeline (as shown in Figure 6). In addition, when it is determined that there is flowing oil in the pipeline, the frequency difference of a set of peaks at the previous and next moments is taken from the power spectrum, and it is determined whether the frequency difference is greater than the second preset value. If so, the following detection results are given : The oil flow in the pipeline is uneven (as shown in Figure 8). If not, the following test results are given: The oil flow in the pipeline is uniform (as shown in Figure 7). From this, the staff can determine the current working status of the oil and gas lubrication pipeline based on the inspection results. When a fault occurs, such as there is no oil in the pipeline, countermeasures can be taken in a timely manner.

In another embodiment, a method for processing optical signals includes:

First, the optical signal is converted into an electrical signal that matches its light intensity. Secondly, perform noise removal and decomposition processing on the electrical signal to obtain the target signal. Then, the peak frequencies of the obtained series of target signals are estimated through the power spectrum estimation method to obtain the power spectrum.

Specifically, after obtaining the electrical signal, the baseline drift is first removed. The purpose of baseline drift removal is mainly to remove the interference of the DC component in the signal. Then perform wavelet packet signal decomposition. Wavelet decomposition decomposes the signal into multiple frequency bands. By calculating the correlation coefficient between each frequency band signal and the original signal, we can find out the frequency band where the actual signal and noise are distributed, and then combine it with the wavelet threshold for noise reduction. Perform grouping processing, and then perform wavelet reconstruction on each processed frequency band. Finally, the peak frequency of the signal is estimated through power spectrum estimation to obtain the power spectrum.

In another embodiment, the first threshold is a, e-5<a<e-3. Specifically, a is preferably e-4.

In another embodiment, regarding the selection of the second threshold, when the pipeline forms a stable gas-liquid two-phase flow, the signal waveforms at 5 moments under each pressure working condition can be intercepted, and the data processing process can be repeated to extract the peak value. The frequencies are shown in Table 1-1 below. It can be seen from this that during the stable operation of the pipeline, the peak frequency of the signal changes very little. Statistics on the range of the peak frequency under each pressure indicate that the maximum does not exceed 1 Hz. Therefore, the second threshold is b, b≤1Hz.

Table 1-1

According to the principle of the detection method disclosed in the above embodiment, it can be known that it can be applied to pipelines with extremely small diameters. In this embodiment, the outer diameter of the pipeline is c, the inner diameter is d, 3mm≤c≤5mm, 1.5mm≤d≤ 3mm. Specifically, c is 4mm and d is 2.5mm. In addition, for the small-diameter pipeline disclosed in this embodiment, since the path of the detection light is short, even if the detection light diverges slightly during the process of passing through the pipeline, it can be effectively received by the light receiver 11 . Therefore, using LED lamps serve as light emitters 10 and can effectively reduce equipment costs compared to laser sources.

In yet another embodiment, in order to achieve better detection results, the absorption rate of the light emitted by the light emitter 10 by the pipeline is smaller than the absorption rate by the oil, so that the state of the oil-liquid mixed medium in the pipeline can be effectively distinguished. Specifically, the light emitted by the light emitter 10 is preferably infrared light with a wavelength of 923 nm.

As shown in Figure 12, the present invention also discloses a gas-liquid two-phase flow state detection device in a pipeline, which includes:

At least a pair of light emitters 10 and light receivers 11 located outside the pipeline, a signal processing module 12, a first comparison module 13 and a first determination module 14 are arranged along the diameter direction of the pipeline to be measured.

The optical transmitter 10 is used to emit detection light into the pipeline, and the optical receiver 11 is used to receive the optical signal emitted from the radial direction of the pipeline.

The signal processing module 12 is used to detect and process the optical signal received by the optical receiver 11 in real time to generate a power spectrum that reflects the change rate of the intensity of the optical signal.

The first comparison module 13 is used to compare the peak value of the power spectrum with the size of the preset first threshold.

The first determination module 14 is used to determine the current existence state of the gas-liquid two-phase flow medium in the pipeline according to the comparison result of the first comparison module 13 .

Further, as shown in Figure 13, the detection device also includes a calculation module 15, a second comparison module 16 and a second determination module 17.

The calculation module 15 is configured to calculate the frequency difference between the peak values of the power spectrum at the preceding and following moments when the peak value of the power spectrum is not less than the first threshold.

The second comparison module 16 is used to compare the frequency difference with a preset second threshold.

The second determination module 17 is used to determine the current flow state of the gas-liquid two-phase flow medium in the pipeline according to the comparison result of the second comparison module 16 .

Furthermore, the signal processing module 12 is provided with a photoelectric conversion module 120, a noise processing module 121 and a power spectrum generation module 122.

The photoelectric conversion module 120 is used to convert the optical signal received by the optical receiver 11 into an electrical signal suitable for its light intensity.

The noise processing module 121 is used to perform noise removal and decomposition processing on the electrical signal to obtain the target signal.

The power spectrum generation module 122 is configured to estimate the peak frequencies of a series of obtained target signals through a power spectrum estimation method to obtain a power spectrum.

In addition, it should be noted that the working principle and usage of the detection device in the above embodiment can be found in the above detection method embodiment, and will not be described again here.

The invention also discloses another gas-liquid two-phase flow state detection system, which includes one or more processors, memories and one or more programs, wherein one or more programs are stored in the memory and configured To be executed by the one or more processors, the program includes instructions for executing the gas-liquid two-phase flow state detection method as described above. The processing module can use a general central processing module (Central Processing Unit, CPU), a microprocessing module, an application specific integrated circuit (Application Specific Integrated Circuit, ASIC), or one or more integrated circuits to execute related programs to achieve The modules in the gas-liquid two-phase flow state detection system of the embodiment of the present application need to perform functions, or perform the gas-liquid two-phase flow state detection method of the method embodiment of the present application.

The present invention also discloses a computer-readable storage medium, which includes a computer program that can be executed by a processor to complete the gas-liquid two-phase flow state detection method as described above. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center integrated with one or more available media. The available media may be read-only memory (ROM), random access memory (RAM), or magnetic media, such as floppy disks, hard disks, tapes, disks, or optical media, such as, Digital versatile disc (digital versatile disc, DVD), or semiconductor media, such as solid state drive (solid state disk, SSD), etc.

The embodiment of the present application also discloses a computer program product or computer program. The computer program product or computer program includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the electronic device performs the above gas-liquid two-phase flow state detection method.

What is disclosed above is only the preferred embodiment of the present invention. Of course, it cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the patent scope of the present invention still fall within the scope of the present invention.

Claims

A method for detecting the state of gas-liquid two-phase flow in a pipeline, which is characterized in that detection is based on at least a pair of light emitters and light receivers located outside the pipeline arranged along the diameter direction of the pipeline to be tested. The detection method include:

Detect and process the optical signal received by the optical receiver in real time to generate a power spectrum that reflects the change rate of optical signal intensity;

Obtain the peak value at the current moment in the power spectrum;

The peak value of the power spectrum is compared with a preset first threshold, and the current existence state of the gas-liquid two-phase flow medium in the pipeline is determined based on the comparison result.
The method for detecting gas-liquid two-phase flow status in a pipeline according to claim 1, wherein determining the current existence status of the gas-liquid two-phase flow medium in the pipeline includes:

Determine whether the peak value of the power spectrum is less than a first threshold, and if so,

Then, there is no gas-liquid two-phase flow medium in the pipeline, or the gas-liquid two-phase flow medium in the pipeline does not flow;

If not, there is a flowing gas-liquid two-phase flow medium in the pipeline.
The gas-liquid two-phase flow state detection method in pipelines according to claim 1, characterized in that when the peak value of the power spectrum is not less than the first threshold, the frequency difference of the peak value of the power spectrum at the previous and next moments is calculated, The frequency difference is compared with a preset second threshold, and the current flow state of the gas-liquid two-phase flow medium in the pipeline is determined based on the comparison result.
The method for detecting gas-liquid two-phase flow status in pipelines according to claim 3, wherein determining the flow status of the current gas-liquid two-phase flow medium in the pipeline includes:

Determine whether the frequency difference between the peaks of the power spectrum at the preceding and following moments is greater than the second threshold, and if so,

Then, the gas-liquid two-phase flow medium in the pipeline flows unevenly;

If not, the gas-liquid two-phase flow medium in the pipeline flows uniformly.
The method for detecting gas-liquid two-phase flow status in pipelines according to claim 1, wherein the method for processing the optical signal includes:

Convert the optical signal into an electrical signal suitable for its light intensity;

Perform noise removal and decomposition processing on the electrical signal to obtain the target signal;

Estimate the peak frequencies of the obtained series of target signals through a power spectrum estimation method to obtain the power spectrum.
The method for detecting gas-liquid two-phase flow status in pipelines according to claim 1, wherein the first threshold is a, e-5<a<e-3.
The method for detecting gas-liquid two-phase flow status in pipelines according to claim 3, wherein the second threshold is b, b≤1Hz.
The gas-liquid two-phase flow state detection method in a pipeline according to claim 1, characterized in that the outer diameter of the pipeline is c, the inner diameter is d, 3mm≤c≤5mm, and 1.5mm≤d≤3mm.
The method for detecting gas-liquid two-phase flow status in pipelines according to claim 8, wherein the light emitter includes an LED lamp.
The gas-liquid two-phase flow state detection method in a pipeline according to claim 1, characterized in that the gas-liquid two-phase flow medium includes a mixed medium of air and oil.
The gas-liquid two-phase flow state detection method in a pipeline according to claim 10, characterized in that the absorption rate of the light emitted by the light emitter by the pipeline is smaller than the absorption rate by the oil.
The method for detecting the gas-liquid two-phase flow state in a pipeline according to claim 11, wherein the light emitted by the light emitter is infrared light with a wavelength of 923 nm.
A device for detecting the state of gas-liquid two-phase flow in a pipeline, which is characterized by including:

at least a pair of light emitters and light receivers located outside the pipeline, arranged along the diameter direction of the pipeline to be tested;

A signal processing module that detects and processes the optical signal received by the optical receiver in real time to generate a power spectrum that reflects the change rate of optical signal intensity;

A first comparison module, configured to compare the peak value of the power spectrum with a preset first threshold;

The first determination module is used to determine the current existence state of the gas-liquid two-phase flow medium in the pipeline according to the comparison result of the first comparison module.
The gas-liquid two-phase flow state detection device in a pipeline according to claim 13, further comprising a calculation module, a second comparison module and a second determination module;

The calculation module is used to calculate the frequency difference between the peak values of the power spectrum at the preceding and following moments when the peak value of the power spectrum is not less than the first threshold;

The second comparison module is used to compare the frequency difference with a preset second threshold;

The second determination module is used to determine the current flow state of the gas-liquid two-phase flow medium in the pipeline according to the comparison result of the second comparison module.
The gas-liquid two-phase flow state detection device in a pipeline according to claim 13, wherein the signal processing module is provided with a photoelectric conversion module, a noise processing module and a power spectrum generation module;

The photoelectric conversion module is used to convert the optical signal received by the optical receiver into an electrical signal that matches its light intensity;

The noise processing module is used to perform noise removal and decomposition processing on the electrical signal to obtain the target signal;

The power spectrum generation module is configured to estimate the peak frequencies of a series of obtained target signals through a power spectrum estimation method to obtain the power spectrum.
The device for detecting gas-liquid two-phase flow status in pipelines according to claim 13, characterized in that the first threshold is a, e-5<a<e-3.
The device for detecting gas-liquid two-phase flow status in pipelines according to claim 14, wherein the second threshold is b, b≤1Hz.
The gas-liquid two-phase flow state detection device in a pipeline according to claim 13, characterized in that the outer diameter of the pipeline is c, the inner diameter is d, 3mm≤c≤5mm, and 1.5mm≤d≤3mm.
The device for detecting gas-liquid two-phase flow conditions in pipelines according to claim 18, wherein the light emitter includes an LED light.
The device for detecting gas-liquid two-phase flow status in pipelines according to claim 13, wherein the gas-liquid two-phase flow medium includes a mixed medium of air and oil.
The device for detecting gas-liquid two-phase flow status in pipelines according to claim 13, wherein the light emitted by the light emitter is infrared light with a wavelength of 923 nm.
A gas-liquid two-phase flow state detection system in a pipeline, which is characterized by including:

one or more processors;

memory;

and one or more programs, wherein one or more programs are stored in said memory and configured to be executed by said one or more processors, said program comprising means for performing any of claims 1 to 12 An instruction for the method for detecting the state of gas-liquid two-phase flow in a pipeline.
A computer-readable storage medium, characterized by including a computer program, which can be executed by a processor to complete the gas-liquid two-phase flow state detection method in a pipeline according to any one of claims 1 to 12.