Experimental Research Of Wafer Cone Flowmeter On Its Expansibility Factor And Wet Gas Flow Measurement

As a new type of differential pressure flowmeter, Wafer-cone flowmeter has many advantages when compared with traditional differential pressure flowmeter. Wafer-cone has lower permanent pressure loss, shorter straight pipe requirement of upstream and downstream and can be used in dirty fields and so on. The research on the Wafer-cone is becoming more and more popular both at home and abroad. Wet gas flow, as one special type of the two-phase flow, occurs widely in oil-gas exploration, steam power generation and so on. The research of the wet gas measuring with Wafer-cone flowmeter is at the very outset, and primarily focuses on high pressure conditions. This research aims to carry out in low pressure condition.From the study of experimental derivation of the expansibility factor, half-empirical equation of Wafer-cone is acquired. The half-empirical equation is used by the following study of wet gas measuring in low pressure and low L-M parameters. The concrete work include the designs of wafer-cone, both the hardware and software systems used in the expansibility factor research, experiments to acquire half-empirical formula of expansibility factor, the research on physical experiments of wet gas measurement and analysis the results. Here, the De Leeuw model is deeply analyzed.Based on sonic nozzle calibration device, the hardware and the software experimental platform are designed so as to find expansibility factor half-empirical formula. It is composed of data sampling, device controlling, parameters monitoring, data processing, saving and printing and so on. The platform makes the experiments more efficient.Based a great number of latest experiments,an expansibility factor formula with high precision is fitted. Moreover, comparisons between this expansibility factor formula and its classical siblings is carried out.Physical wet gas experiments on the wafer cone flowmeter is done under the condition of low pressure and low L-M parameter range. The relationship between"Over-reading"and the main factors, viz. liquid volume fraction, gas superficial velocity, equivalent diameter ratio and pressure are analyzed in wet gas Wafer-cone metering.The adaptabilities of several wet gas"Over-reading"models are compared by the experiments data. It is found that①the models with physics background are more applicative on a wide pressure range;②De Leeuw Model is relatively more applicable to the wet gas measurement under this working condition.The parameter of n in De Leeuw Model is deeply analyzed according to test data. Affected by several main parameters, the intrinsic mechanism is discussed. Then, a set of fomulaes of"n"are obtained. Furthermore, the prediction deviations of"Over-reading"models with different equivalent diameter ratio were calculated. The results indicated that both prediction deviation and dispersancy are lowest when the equivalent diameter ratio equals 0.55. It seems that the dispersancy increase higher when the equivalent diameter ratios are different.When the equivalent diameter ratio equals 0.45, the deviations are less than1.5%, except a few outlying points. When the equivalent diameter ratio equals 0.55 or 0.65, most of the deviations are less than 1.5%.Finally, analysising the correlations the error and the uncertainty over reading equation, we can know there is lower dispersibility whenβ=0.55.Combine with the influence of Gas Froude number the reason is analysed.