| With China fully opening up the oil and gas exploration and exploitation market,the proportion of petrochemical industry in economic production is increasing day by day.The flow phenomenon of petroleum gas in pipeline belongs to the typical multiphase flow,and the detection of multiphase flow has become the object of many experts and scholars.As the basis of multiphase flow detection,the study of flow characteristics of two-phase flow has become an urgent problem for researchers.Nowadays,the detection method of two-phase flow generally selects a single measurement parameter,Due to the disadvantage of single parameter selection.,So the detection of two-phase flow can only stay on the surface,and the study of the characteristic parameters of the fluid in the pipeline is few.This paper mainly completes the following research work:(1)Test 45 operating points of different flow patterns under horizontal tubes by means of measuring devices combining acoustic emission and porous orifice plates,The differential pressure signal and acoustic emission signal were recorded simultaneously.(2)Analysis of test data: Based on the analysis of time domain characteristics of acoustic emission noise signal of horizontal tube,the variation diagram of each characteristic parameter and volume gas content under different flow patterns is drawn,the fourier transform(FFT)algorithm in matlab software is used to process the acoustic emission noise signal to obtain the frequency characteristics of different operating points.By analyzing the spectrum of acoustic emission noise signal,the frequency segment to be analyzed is determined according to the distribution of frequency variation and amplitude in the graph.The wavelet packet decomposition algorithm is used to extract the energy eigenvalues in the specific frequency segment of the flow noise signal.The relationship between the energy eigenvalues of different segments in the frequency segment and the volume gas content is analyzed,and the energy eigenvalues with obvious changes to the volume gas content are extracted.(3)By combining the extracted time-domain characteristic parameters with the frequency-domain energy characteristic values,a gas-bearing rate measurement model of horizontal tube gas-liquid two-phase fluid volume isestablished,and a volume gas-bearing rate measurement model is obtained.The two-phase flow measurement model of horizontal tube gas-liquid under different flow patterns is obtained by combining the volume gas-bearing rate model with the test differential pressure signal.The main innovation points are:(1)A two-phase flow test was conducted for a two-parameter measurement system combining acoustic emission-differential pressure and porous orifice plates.The 45 operating points under different flow patterns were tested respectively,various data of gas-liquid two-phase flow through porous plates are obtained to prepare for subsequent research.(2)The time domain and frequency domain characteristic parameters of acoustic emission signal on porous orifice plate are extracted.In time domain analysis,it is obtained that the variation of the skewness and skewness with the gas holdup of two-phase fluid is linear,the energy characteristics of ca1 and cd1 in frequency domain analysis show a linear growth trend with the gas holdup of two-phase fluid volume.(3)The volumetric gas holdup measurement model and the flow rate measurement model of the two-phase flow of horizontal pipe gas and liquid are obtained.The four different characteristic parameters extracted above are fitted and analyzed with the volume gas content,and the volume gas content measurement model is obtained,the maximum relative error is 2.6.Combining the volumetric gas content model with the differential pressure signal,revision of empirical formulas,a two-phase flow measurement model under different flow patterns is obtained,its errors are within 3%. |
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