Vortex shedding frequency extraction and moisture phase separation flow measurement method combined with disturbance wave frequency characteristics

Abstract

The application discloses a vortex frequency extraction and moisture phase separation flow measurement method combined with disturbance wave frequency characteristics, including a conductance ring sensor and a vortex flowmeter, comprising: a pressure sensor, a conductance ring sensor, a vortex flowmeter, a temperature sensor, an excitation electrode, a measurement electrode, a vortex generator, a piezoelectric probe, temperature, pressure and vortex signals s(t) are collected by a collection card, liquid film fluctuation signals δ(t) are collected by a high-speed AD-DA module and an FPGA, the conductance ring sensor 2 is used for dynamically monitoring the change of the liquid film thickness of the pipe wall, and then the fluctuation frequency, i.e., the disturbance wave frequency, is extracted, the vortex flowmeter is used for dynamically monitoring the vortex frequency, the relationship between the disturbance wave frequency characteristics and the vortex stability is utilized, and the extraction precision of the moisture two-phase vortex characteristic frequency is improved. The application utilizes liquid film fluctuation frequency information to extract the vortex frequency and correct over-reading, does not need to calibrate the liquid film thickness, has low requirements on the medium conductivity, and has a wide range of measurement medium.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas-liquid two-phase flow measurement, in particular to a vortex shedding frequency extraction method combined with disturbance wave frequency characteristics and a wet gas separated phase flow measurement method. BACKGROUND

[0002] Regarding the vortex shedding frequency extraction method, the traditional method is to use fast Fourier transform (FFT) (analog signal) or counting method (digital signal) for extraction. In single-phase flow, the vortex signal is a stationary signal, and the above extraction accuracy is relatively high. However, in wet gas two-phase flow, the loading of a small amount of liquid phase leads to poor stability of the vortex street, which is manifested as a non-stationary signal with amplitude modulation and frequency modulation. At this time, the FFT or counting method suitable for stationary signals will greatly reduce the extraction accuracy. In order to improve the two-phase vortex frequency extraction accuracy, patent CN201810049784.5 proposes a two-phase vortex frequency extraction method based on EMD and frequency spectrum correction, and patent ZL201910469779.4 proposes a two-phase vortex frequency extraction method based on wavelet ridge average. Although the above methods can improve the frequency extraction accuracy, the algorithm complexity is high and the real-time performance is poor, which is difficult to meet the requirements of online measurement.

[0003] In terms of using a vortex flowmeter to measure wet gas separated phase flow (gas phase and liquid phase), the main problem to be solved is to correct the over-reading problem in two-phase vortex measurement. There are currently three methods: one is to directly measure the liquid content information and establish the relationship between over-reading and liquid content to correct the over-reading. Traditional measurement methods include microwave method, ray method, equal-speed sampling method, ultrasonic method, optical method, etc. These measurement methods are limited by cost, measurement environment, complexity, etc., and are difficult to popularize. For example, the microwave method and the ray method have safety hazards, the equal-speed sampling method cannot realize online measurement, the ultrasonic method has a complex signal processing process, and the optical method generally requires a transparent pipeline and low pressure, and the optical element has high cost. In addition, the liquid content in wet gas is small, and the liquid measurement accuracy is difficult to guarantee, which may cause over-correction and cause greater measurement error.

[0004] The second method is to correct the vortex shedding over-reading by using vortex street additional information (such as instantaneous ridge frequency fluctuation and vortex street amplitude), for example, the patent ZL201910469779.4 proposes a vortex street moisture over-reading compensation and flow measurement method combined with wavelet ridge frequency fluctuation, wherein the instantaneous frequency needs to be obtained by means of time-frequency processing method, which has high complexity and high requirement for hardware operation capacity. The patent ZL201910474178.2 proposes a moisture over-reading compensation and flow measurement method combined with vortex street amplitude characteristics, wherein the non-dimensionalization of signal amplitude involves 7 parameters, and the calibration process is complex. In addition, when the liquid phase content is high, the amplitude curve presents asymptotic saturation characteristics, at this time, the sensitivity of signal amplitude to liquid phase change will decrease. In the extreme case, the change of liquid phase content no longer causes the change of amplitude, at this time, the iterative process may not converge to the true value, and the algorithm will fail, so the application range is limited.

[0005] The third method is to use the electric conductivity-vortex street dual-mode detection method, to establish a liquid film parameter model and a vortex shedding over-reading model, to solve the two equations together and combine an iterative algorithm, to establish a moisture phase separation measurement model. For example, the patents CN202110129932.6 and CN202110129883.6 correct the vortex shedding over-reading by using liquid film thickness information and measure the separated flow, the modeling and prediction accuracy thereof depend on the liquid film thickness measurement accuracy, and the calibration of liquid film thickness depends seriously on the medium conductivity. Once the moisture conductivity changes, the moisture prediction accuracy will be greatly reduced. Therefore, the method based on liquid film thickness measurement has limited application occasions and has high requirement for medium conductivity. SUMMARY

[0006] The present application uses the liquid film disturbance wave frequency characteristics to extract the vortex frequency and measure the moisture online. On the one hand, a vortex frequency segmented extraction method based on disturbance wave frequency determination is proposed, which takes into account the frequency extraction accuracy and efficiency, on the other hand, the disturbance wave frequency modeling result is used to correct the vortex shedding over-reading, which improves the moisture measurement accuracy and realizes the online measurement of gas-liquid separated flow.

[0007] To achieve the above-mentioned purposes, the present application provides the following technical solutions: the used sensor is an electric conductivity ring sensor and a vortex flowmeter, comprising: a pressure sensor, an electric conductivity ring sensor, a vortex flowmeter, a temperature sensor, an excitation electrode, a measurement electrode, a vortex generator, a piezoelectric probe, the temperature, pressure and vortex signal s(t) are collected by a collection card, the liquid film fluctuation signal δ(t) is collected by a high-speed AD-DA module and an FPGA, the electric conductivity ring sensor is used to dynamically monitor the change of liquid film thickness on the pipe wall, and then the fluctuation frequency, i.e. the disturbance wave frequency, is extracted, the vortex flowmeter is used to dynamically monitor the vortex frequency, the relationship between the disturbance wave frequency characteristics and the vortex stability is used to improve the vortex frequency extraction accuracy of the moisture two-phase vortex, the disturbance wave frequency modeling result is used to correct the vortex shedding over-reading, the moisture two-phase vortex measurement accuracy is improved, and the moisture phase separation flow measurement is realized.

[0008] The method for extracting vortex shedding frequency and measuring moist gas phase flow by combining the characteristics of perturbation waves includes the following specific steps:

[0009] S1 collects pressure p, temperature T, liquid film fluctuation signal δ(t), and vortex shedding signal s(t);

[0010] S2 calculates the gas density ρ using pressure p and temperature T respectively. g Liquid density ρ l And the surface tension σ of the liquid phase; the frequency f of the disturbance wave is extracted using the FFT algorithm. w and the approximate vortex frequency f vs0 ;

[0011] S3 is based on the vortex shedding frequency f vs0 Preliminary calculations were performed on the readings of the vortex flowmeter without any read corrections to obtain a rough apparent gas velocity U. sg0 ;

[0012] S4 if St LF ≤St cut,off Let the vortex frequency f vs =f vs0 If St LF >St cut,off Then let the vortex frequency Among them, f s f is the sampling frequency. c Let a be the center frequency of the wavelet fundamental. r The scale factor at the wavelet ridge is indicated, and the overline represents the mean of the instantaneous ridge frequency.

[0013] S5 combines the calibrated vortex overreading correlation and the liquid film wave Strouhal number correlation to eliminate the liquid phase Reynolds number Re l ;

[0014] S6 will display the uncorrected vortex flowmeter reading Q. g,tp As the gas phase volumetric flow rate Q g The initial value for iteration, i.e., Q g,0 =Q g,tp The subscript n = 0 represents the initial value;

[0015] S7 determines the optimal iteration step size for the damped Newton iteration based on the Armijo line search principle.

[0016] S8 is substituted into the Armijo-based damped Newton iteration scheme for solution;

[0017] S9 sets the convergence threshold, compares the gas phase volumetric flow rates obtained from two iterations, and determines whether the convergence condition is met, i.e., |Q g,n+1 -Qg,n | / Q g,n whether less than the convergence threshold value; if the convergence condition is met, the iteration ends and the next step is performed; if the convergence condition is not met, n=n+1 is set, whether the maximum iteration number is reached is determined, if not, the iteration is continued to step S7 until the calculation converges or the maximum iteration number is reached;

[0018] S10 obtains the gas phase volume flow rate Q g from the latest iteration calculation result;

[0019] S11 calculates the liquid phase Reynolds number, calculates the liquid phase superficial velocity, and finally obtains the liquid phase volume flow rate Q l =πD 2 U sl / 4;

[0020] S12 outputs the gas phase and liquid phase volume flow rates Q g and Q l , realizing the separated phase flow measurement.

[0021] Preferably, the conductance ring sensor is ring-shaped, including an excitation electrode and a measurement electrode, both electrodes are located in the same radial section of the pipeline and are parallel to each other, the vortex flowmeter uses a piezoelectric probe as a sensor, in step S1, the disturbance wave frequency f w and the rough vortex frequency f vs0 are extracted by using the FFT algorithm.

[0022] Preferably, the critical Strouhal number St cut,off of the disturbance wave is 0.004, in step S3, the vortex flowmeter indication value is Q g,tp0 =3600f VS0 / K v , and the liquid film fluctuation Strouhal number is calculated as St LF =f w D / U sg0 .

[0023] Preferably, in step S5, the vortex over-reading correlation formula is the liquid film fluctuation Strouhal number correlation formula is the equation with the gas phase volume flow rate Q g as the parameter is constructed wherein C1=16ρ g (Δρ / ρ g ) 0.25 / σπ 2 D 3 , the gas-liquid phase density difference Δρ=ρ l -ρ g, D is the nominal diameter of the pipe, the vortex shedding over-read factor OR = Q g,tp / Q g , k1 is a constant coefficient, n3 and n4 are power indexes, the gas phase Weber number The liquid phase Reynolds number Re l = ρ l U sl D / μ l , μ l is the dynamic viscosity of the liquid phase, the liquid film fluctuation Strouhal number St LF = f w D / U sg , a is a constant coefficient, n1 and n2 are power indexes, the gas phase superficial velocity U sg = 4Q g / πD 2 , in the step S6, Q g,tp = 3600f VS / K v , wherein K v is the meter coefficient, unit: m -3 .

[0024] Preferably, in the step S7, m k is the minimum non-negative integer that makes hold, σ, γ are constants between 0 and 1, the subscript k represents the iteration number, d k is the descent direction of the Newton iteration algorithm, represents the gradient of the function f(Q g ), and represents the transpose of the gradient , and the convergence threshold is 0.1%.

[0025] Preferably, in the step S8, the damped Newton iteration format is wherein: the gradient Q g,n represents the last iteration result, and Q g,n+1 represents the current iteration result.

[0026] Preferably, in the step S10, the vortex shedding over-read factor OR = Q g,tp / Q g is calculated, the gas phase superficial velocity U sg = 4Q g / πD 2 is calculated, and the gas phase Weber number The coefficients k1, power indexes n3 and n4 are calibrated by the least square method, and the coefficients a, power indexes n1 and n2 are calibrated by the least square method.

[0027] Preferably, the liquid Reynolds number calculated in the S11 step is The liquid apparent flow velocity is calculated as U sl = Re l μ l / ρ l D, and the maximum number of iterations is set to 20.

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] 1. The present application is aimed at the non-stationary characteristics of vortex signals in wet gas two-phase flow, and proposes a vortex frequency segmentation extraction method based on disturbance wave frequency determination, which can effectively improve the vortex frequency extraction accuracy and reliability, while taking into account the extraction efficiency;

[0030] 2. The present application is based on the liquid film fluctuation signal output by the electric conductance ring and the vortex signal detected by the piezoelectric probe, and proposes a vortex street over-reading correction method combined with the disturbance wave frequency, which can effectively improve the measurement accuracy of the gas phase flow in wet gas;

[0031] 3. The measurement method proposed by the present application can simultaneously measure the gas phase and liquid phase volume flow in wet gas, realizing online measurement of wet gas component flow;

[0032] 4. The present application has high prediction accuracy. The prediction error of the gas phase volume flow is within ±1.5%, and the prediction error of the liquid phase volume flow is within ±5% in the full range;

[0033] 5. The present application also uses liquid film fluctuation frequency information for vortex frequency extraction and over-reading correction, without the need for liquid film thickness calibration, and has low requirements for medium conductivity and wide measurement medium range. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The electric conductance ring-vortex street dual-mode detection system for the vortex street frequency extraction and wet gas component flow measurement method combined with the disturbance wave frequency characteristics of the present application;

[0035] Figure 2 The signal acquisition flowchart for the vortex street frequency extraction and wet gas component flow measurement method combined with the disturbance wave frequency characteristics of the present application;

[0036] Figure 3 The wet gas component measurement flowchart based on disturbance wave frequency and vortex street frequency for the vortex street frequency extraction and wet gas component flow measurement method combined with the disturbance wave frequency characteristics of the present application;

[0037] Figure 4 The disturbance wave Strouhal number-vortex signal quality factor diagram for the vortex street frequency extraction and wet gas component flow measurement method combined with the disturbance wave frequency characteristics of the present application;

[0038] Figure 5Figure of vortex frequency segment extraction method based on disturbance wave frequency determination for vortex frequency extraction and wet gas phase separation flow measurement method combined with disturbance wave frequency characteristics of the application;

[0039] Figure 6 Figure of vortex street over-reading modeling results for vortex frequency extraction and wet gas phase separation flow measurement method combined with disturbance wave frequency characteristics of the application;

[0040] Figure 7 Figure of disturbance wave Strouhal number modeling results for vortex frequency extraction and wet gas phase separation flow measurement method combined with disturbance wave frequency characteristics of the application;

[0041] Figure 8 Figure of gas phase volume flow error distribution in wet gas for vortex frequency extraction and wet gas phase separation flow measurement method combined with disturbance wave frequency characteristics of the application;

[0042] Figure 9 Figure of liquid phase volume flow error distribution in wet gas for vortex frequency extraction and wet gas phase separation flow measurement method combined with disturbance wave frequency characteristics of the application.

[0043] In the figure: 1, pressure sensor; 2, conductivity ring sensor; 3, vortex flowmeter; 4, temperature sensor; 5, excitation electrode; 6, measurement electrode; 7, vortex generator; 8, piezoelectric probe. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0045] The present application will be further described in combination with the drawings and embodiments.

[0046] The present example is a specific implementation of vortex frequency extraction and wet gas phase separation flow measurement method combined with disturbance wave characteristics. The wet gas working condition pressure p=(150-350) kPa, gas phase volume flow Q g =(18-24) m 3 / h, liquid phase volume content LVF=0-0.8‰, and the medium is compressed air and water. The pipe diameter is nominal diameter D=0.015 m.

[0047] The measurement device is shown in the attached Figure 1 figure, mainly composed of pressure sensor 1, conductivity ring sensor 2, vortex flowmeter 3, temperature sensor 4, excitation electrode 5, measurement electrode 6, vortex generator 7, and piezoelectric probe 8. The signal acquisition flow chart is shown in the attached Figure 2The shown: acquisition conditions pressure p, working temperature T, vortex street signal s(t), and liquid film fluctuation signal δ(t). Among them, s(t) is measured by piezoelectric sensor: the probe converts the flow signal into an electrical signal, the original signal is amplified by charge and voltage by hardware circuit, and band-pass filtered (f=200~2500Hz), and the data is collected by NI-USB acquisition card, and displayed and stored by Labview software, the sampling frequency is 20kHz. δ(t) is measured by conductance ring sensor: PFGA sends a sinusoidal excitation signal to the excitation electrode through high-speed DA, and the measured electrode signal is amplified, high-speed AD converted, and collected by FPGA, the sampling frequency is 100kHz.

[0048] In the wet gas two-phase vortex field, due to the loading of a small amount of liquid phase, the two-phase vortex signal is a non-stationary signal with amplitude modulation and frequency modulation. The specific performance is that the instantaneous frequency and instantaneous amplitude of the signal fluctuate within a certain range. If the traditional FFT algorithm is used for main frequency extraction, it will cause a large measurement error, and the higher the liquid content, the greater the frequency extraction error. Through real flow experiment, it is found that when the liquid content increases, the disturbance wave frequency increases, and at the same time the vortex street stability decreases. In order to analyze the relationship between the disturbance wave frequency and the vortex street stability, the disturbance wave Strouhal number St LF and the vortex street signal quality factor S q are made, as shown in the accompanying Figure 4 , wherein St LF =f w D / U sg , S q =10log 10 P s / P r , P s is the energy between 0.98f max and 1.02f max , P r is the remaining energy, and f max is the frequency corresponding to the power spectrum peak (vortex street frequency). It can be seen that the two are negatively correlated, that is: the larger the vortex signal quality factor S q (corresponding to the better vortex signal quality), the smaller the liquid film Strouhal number St LF . Therefore, when St LF is small, the vortex signal quality is high, and at this time the FFT is used to extract the vortex street frequency; when St LF is large, the vortex signal quality is poor, and at this time the CWT ridge average method is used to extract the vortex street frequency, which can improve the vortex street frequency extraction accuracy and also consider the signal processing speed.

[0049] The specific calculation process of the vortex frequency segmented extraction method based on disturbance wave frequency judgment (referred to as improved method) is shown in the accompanying Figure 5As shown. Since only piecewise calculations are involved, and not an exact solution for the gas phase flow rate, St can be estimated using the uncorrected gas phase flow rate indication. LF Specifically:

[0050] (1) Input the vortex shedding signal s(t) and the liquid film ripple signal δ(t);

[0051] (2) Perform FFT transformation on both to roughly extract the vortex shedding frequency f. vs0 And extract the disturbance wave frequency f w ;

[0052] (3) Roughly calculate the uncorrected vortex flowmeter reading Q g,tp0 =3600f VS0 / K v The rough apparent air velocity U is obtained. sg0 ;

[0053] (4) Calculate the Strouhal number of liquid film fluctuation. LF =f w D / U sg0 ;

[0054] (5) If St LF ≤St cut,off Let the vortex frequency f vs =f vs0 If St LF >St cut,off Then let the vortex frequency Among them, f s f is the sampling frequency. c Let a be the center frequency of the wavelet fundamental. r The scale factor at the wavelet ridge is indicated, and the overline represents the mean of the instantaneous ridge frequency.

[0055] Table 1 shows a comparison of the extraction accuracy between the improved method and the FFT method under different liquid content conditions. The relative change of the traditional FFT method after three repeated measurements reached a maximum of 4.5%, while the improved method was within 1.0%, which greatly improved the extraction accuracy of vortex shedding frequency, while also taking into account the signal processing speed.

[0056] Table 1 Comparison of the improved method and FFT extraction accuracy

[0057]

[0058]

[0059] Before establishing a moisture measurement model, it is necessary to analyze the vortex overreading OR and the liquid film Postlauhal number St. LF Calibration was performed to obtain the coefficients and power exponent. The vortex street overread calibration results are attached. Figure 6The determination coefficient R 2 =0.97, the relative root mean square error rRMSE=0.45%, and the relative error is within ±1.0. St LF The calibration results are shown in the following table: Figure 7 The determination coefficient R 2 =0.98, the relative root mean square error rRMSE=7.03%, and the relative error is within ±10%, and the regression effect is good. Thus, the calibration coefficient is obtained: , wherein k1=8.74, n3=-1, and n4=0.48; , wherein a=0.000467, n1=0.79, and n2=0.36.

[0060] According to the process in the technical scheme, the wet gas phase separation measurement is performed, and the specific process is as follows:

[0061] S1: collect the pressure p, the temperature T, the liquid film fluctuation signal δ(t), and the vortex street signal s(t);

[0062] S2: calculate the gas density ρ g , the liquid density ρ l , and the liquid phase surface tension σ by using the pressure p and the temperature T respectively; and extract the disturbance wave frequency f w and the rough vortex frequency f vs0 by using the FFT algorithm;

[0063] S3: according to the vortex shedding frequency f vs0 , preliminarily calculate the uncorrected vortex flowmeter indication value Q g,tp0 =3600f VS0 / K v , obtain the rough apparent gas velocity U sg0 , and calculate the liquid film fluctuation Strouhal number St LF =f w D / U sg0 ;

[0064] S4: if St LF ≤0.004, then the vortex frequency f vs =f vs0 , and if St LF >0.004, then the vortex frequency f

[0065] S5: construct an equation with the gas phase volume flow Q g as a parameter

[0066] S6: take the uncorrected vortex flowmeter indication value Q g,tp =3600f VS / K v as the gas phase volume flow Qg the iteration initial value, i.e. Q g,0 g,tp , subscript n=0 represents the initial value;

[0067] S7 Determine the optimal iteration step of the damped Newton iteration according to the Armijo line search principle wherein m k is the minimum non-negative integer satisfying

[0068] S8 Substitute into the damped Newton iteration format based on Armijo to solve:

[0069] S9 Set the convergence threshold, compare the gas phase volume flow rates obtained by the previous and the next iteration, and judge whether the convergence condition is met, i.e. whether |Q g,n+1 -Q g,n | / Q g,n is less than 0.1%; if the convergence condition is met, the iteration ends and the next step is performed; if the convergence condition is not met, let n=n+1, judge whether the maximum iteration number 20 is reached, if not, jump to step 7) and continue the iteration solution until the calculation converges or the maximum iteration number 20 is reached;

[0070] S10 From the calculation result of the latest iteration, obtain the gas phase volume flow rate Q g , calculate the vortex street over-reading factor OR=Q g,tp / Q g , calculate the gas phase superficial velocity U sg =4Q g / πD 2 , and calculate the gas phase Weber number

[0071] S11 Calculate the liquid phase Reynolds number Calculate the liquid phase superficial velocity U sl =Re l μ l / ρ l D, and finally obtain the liquid phase volume flow rate Q l =πD 2 U sl / 4;

[0072] S12 Output the gas phase and liquid phase volume flow rates Q g and Q l in the wet gas, and realize the separated phase flow measurement.

[0073] In this example, the gas phase volume flow rate prediction error distribution under different carrier gas pressure and flow conditions is shown in the attached Figure 8 ​​Figure 6 shows the prediction error of the gas phase flow rate, where LVF is the liquid volume fraction, and the error PE (%) = (predicted value - true value) / true value x 100. In the wet gas measurement, the maximum error of the gas phase measurement before correction is 9%, and the prediction error of the gas phase flow rate after correction is all within ±1.0%, and the measurement accuracy is greatly improved. The prediction error distribution of the liquid phase full-range flow rate is shown in Figure 7, where FSPE (%) = (maximum value of predicted value - true value) / true value x 100. The prediction error of the liquid phase full-range is within ±10%, and the measurement accuracy is high. Figure 9

[0074] It should be noted that the relational terms herein, such as first and second, are used solely to distinguish one from another entity or action without necessarily requiring or implying any actual relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0075] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, alternatives, and variations can be made in the embodiments without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents.​

Claims

1. A method for extracting vortex frequency and measuring moist gas phase flow by combining the characteristics of disturbance wave frequency, including the use of a conductivity ring sensor and a vortex flowmeter, characterized in that: include: Pressure sensor (1), conductivity ring sensor (2), vortex flow meter (3), temperature sensor (4), excitation electrode (5), measuring electrode (6), vortex generator (7), piezoelectric probe (8). Temperature, pressure and vortex signal s(t) are acquired by the acquisition card, and liquid film fluctuation signal δ(t) is acquired by the high-speed AD-DA module and FPGA. The conductivity ring sensor (2) is used to dynamically monitor the change in the thickness of the liquid film on the pipe wall, and then extract the fluctuation frequency, i.e. the disturbance wave frequency. The vortex flow meter (3) is used to dynamically monitor the vortex frequency. By utilizing the relationship between the disturbance wave frequency characteristics and the vortex stability, the extraction accuracy of the characteristic frequency of the wet gas two-phase vortex is improved. At the same time, the vortex overreading is corrected by using the disturbance wave frequency modeling results, thereby improving the measurement accuracy of the wet gas two-phase vortex and realizing the measurement of wet gas phase-separated flow. The method for extracting vortex shedding frequency and measuring moist gas phase flow by combining the characteristics of perturbation waves includes the following specific steps: S1 collects pressure p, temperature T, liquid film fluctuation signal δ(t), and vortex shedding signal s(t); S2 calculates the gas density ρ using pressure p and temperature T respectively. g Liquid density ρ l and the surface tension σ of the liquid phase; S3 is based on the vortex shedding frequency f vs0 Preliminary calculations were performed on the readings of the vortex flowmeter without any read corrections to obtain a rough apparent gas velocity U. sg0 ; S4 If the liquid film fluctuation Strouhal number St LF ≤ Critical Strouhal number for liquid film fluctuations St cut,off Let the vortex frequency f vs =f vs0 If St LF >St cut,off Then let the vortex frequency Among them, f s f is the sampling frequency. c Let a be the center frequency of the wavelet fundamental. r The scale factor at the wavelet ridge is indicated, and the overline represents the mean of the instantaneous ridge frequency. S5 combines the calibrated vortex overreading correlation and the liquid film wave Strouhal number correlation to eliminate the liquid phase Reynolds number Re. l The vortex street overread correlation is The correlation for the Strauhal number of liquid film fluctuations is as follows: Construct an equation with gas phase volumetric flow rate Qg as a parameter. Where: C1=16ρ g (Δρ / ρ g ) 0.25 / σπ 2 D 3 , The density difference between the gas and liquid phases Δρ = ρ l -ρ g D is the nominal diameter of the pipe, and the vortex overreading factor OR = Q. g,tp / Q g k1 is a constant coefficient, n3 and n4 are power exponents, and the gas phase Weber number is... Liquid phase Reynolds number Re l =ρ l U sl D / μ l μ l U is the dynamic viscosity of the liquid phase. sl For the apparent flow rate of the liquid phase, the Strouhal number of the liquid film fluctuation is St. LF =f w D / U sg 'a' is a constant coefficient, 'n1' and 'n2' are power exponents, and 'U' is the apparent gas velocity. sg =4Q g / πD 2 ; S6 will display the uncorrected vortex flowmeter reading Q. g,tp As the gas phase volumetric flow rate Q g The initial value for iteration, i.e., Q g,0 =Q g,tp The subscript n = 0 represents the initial value; S7 determines the optimal iteration step size for the damped Newton iteration based on the Armijo line search principle. Where m k In order to make The smallest non-negative integer that holds true, where σ and γ are constants between 0 and 1, the subscript k represents the iteration number, and d k This represents the descent direction of Newton's iterative algorithm. Representative function f(Q) g The gradient of ) Represents gradient The transpose of has a convergence threshold of 0.1%. S8 is substituted into the Armijo-based damped Newton iteration scheme for solution; S9 sets the convergence threshold, compares the gas phase volumetric flow rates obtained from two iterations, and determines whether the convergence condition is met, i.e., |Q g,n+1 -Q g,n | / Q g,n Is it less than the convergence threshold? If the convergence condition is met, the iteration ends and the next operation is performed. If the convergence condition is not met, let n = n + 1 and determine whether the maximum number of iterations has been reached. If not, jump to step S7 to continue iterative solution until convergence is achieved or the maximum number of iterations is reached. S10 yields the gas phase volumetric flow rate Q based on the results of the most recent iteration. g ; S11 calculates the Reynolds number of the liquid phase, calculates the apparent velocity of the liquid phase, and finally obtains the volumetric flow rate Q of the liquid phase. l =πD 2 U sl / 4; S12 outputs the volumetric flow rates Q of the gas and liquid phases in the moist gas. g and Q l This enables phase-separated flow measurement.

2. The method for extracting vortex shedding frequency and measuring moist gas phase flow by combining disturbance wave frequency characteristics according to claim 1, characterized in that: The conductivity ring sensor is ring-shaped and includes an excitation electrode and a measuring electrode. The two electrodes are located on the same radial cross section of the pipe and are parallel to each other. The vortex flowmeter uses a piezoelectric probe as the sensor. In step S1, the disturbance wave frequency f is extracted using the FFT algorithm. w and the approximate vortex frequency f vs0 .

3. The method for extracting vortex shedding frequency and measuring moist gas phase flow by combining disturbance wave frequency characteristics according to claim 2, characterized in that: The critical Strouhal number St of the disturbance wave cut,off =0.004, in step S3, the vortex flowmeter reading is Q g,tp0 =3600f VS0 / K v And calculate the Strouhal number of liquid film fluctuations as St LF =f w D / U sg0 K v Instrument coefficient, unit: m -3 .

4. The method for extracting vortex street frequency and measuring moist gas phase flow by combining disturbance wave frequency characteristics according to claim 1, characterized in that: In step S8, the damped Newton iteration format is as follows: in: gradient Q g,n Q represents the result of the previous iteration. g,n+1 This represents the result of this iteration.

5. The method for extracting vortex street frequency and measuring moist gas phase flow by combining disturbance wave frequency characteristics according to claim 1, characterized in that: In step S10, the vortex overread factor OR = Q is calculated. g,tp / Q g Calculate the apparent gas velocity U sg =4Q g / πD 2 And calculate the gas phase Weber number. The coefficients k1, power exponents n3 and n4 are calibrated using the least squares method, and the coefficients a, power exponents n1 and n2 are calibrated using the least squares method.

6. The method for extracting vortex shedding frequency and measuring moist gas phase flow by combining disturbance wave frequency characteristics according to claim 1, characterized in that: In step S11, the liquid phase Reynolds number is calculated as follows: Calculate the apparent flow rate of the liquid phase as U sl =Re l μ l / ρ l D, the maximum number of iterations is set to 20.

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