Experimental Study On Dynamic Characteristic Of Gas Liquid Two Phase Flow Measured With V-cone Flow Meter

The dynamic characteristics of gas-liquid two phase flow is complex，while flow pattern as one of the most important dynamic characteristics is the hotand difficult research point in current two phase flow filed. In this thesis, in order toresearch the flow pattern of horizon pipe two phase flows, adapting V-cone flowmeter as the throttle device, the differential pressure signal of the two phase flow asthe research basis, at last realized the flow pattern recognition. The specific researchand achievements are as follows:(1) Building the horizon pipe two phase flow experimental system andcollecting the differential pressure data as the research object. V-cone flow meter wasadopted to produce differential pressure fluctuation as a throttle device. Three typicalflow patterns were collected, that is bubble flow, slug flow and plug flow.(2) Mathematical morphology filter method was applied on the preprocessing ofdifferential pressure signal. Through comparing spectrum before and after filteringshow that there are obvious glitch decreases between60-100Hz of bubble flow andslug flow, the signal between10-20Hz was recognized as noise of slug flow, plugflow has an obvious glitch decrease between20-40Hz. The SNR values of thetwo-phase flow pressure signal mathematical morphological filter indicates thefiltering effect is weakened with the increase of gas flow.(3) Generalized S-transform with variable factor method was used on two phaseflow signal time-frequency analysis. Improving the time domain and frequencydomain resolution at the same time by adding a variable factor for S-transformwindow which makes the time-frequency results obvious. Through the results oftime-frequency analysis indicates the energy of bubble flow mainly distributes inhigh-frequency band20-30Hz, slug flow mainly distributes in high-frequency band20-30Hz and low-frequency band0-10Hz, plug flow mainly distributes inlow-frequency0-5Hz.(4) Extracting characteristic variables from differential pressure signal andgeneralized S-transform with variable factor time-frequency spectrogram as the basis for two phase flow pattern recognition, according to the scatter results of twocharacteristic variables, picking five characteristic variables as the fuzzy input offuzzy recognition system. Building the two phase flow pattern recognition systemusing the LabVIEW toolkit, five characteristic variables as input and the resultsshows that the two phase flow pattern recognition rate can research99.17%.