Experimental Data Analysis Of Flow Around Bluff Body In Horizontal Gas-liquid Two-phase Flow

Gas-liquid two-phase flow exists widely in nature and industry field, fullyunderstanding the law of gas-liquid two-phase flow around a blunt body and flowfield distribution characteristics is useful, which can provide a theoretical guaranteefor the measurement of flow parameters. However considering the complexity ofgas-liquid two-phase flow field, measuring and analyzing the flow field is verydifficult. In this paper, through analyzing the experimental data of gas-liquidtwo-phase flow in horizontal pipe, the mechanism of vortex shedding around bluffbody is received. Contents are completed below:First, through analyzing the repeatability and measurement error, we found whenthe gas volume fraction is below15%, the repeatability is good, and the measurementerror is within10%, the flow field is stable. Different methods are used in differentflow patterns, then the conclusion is received that the transition of flow pattern is themain reason of this phenomenon, and the existence of gas-phase will influence thevortex shedding.Then EMD decomposition is used to analysis the vortex street signal, throughresearching the data, the ratio of vortex street energy is present as a standard toidentify the flow pattern, and in two-phase flow, when the ratio of vortex street energyis more than60%, there is stable vortex shedding in the flow field.At last, GP algorithm is used to analysis the characteristics of two-phase flowsignal which is denoised by HHT. Kolmogorov entropy is present as a standard toidentify whether there is stable vortex shedding in the flow field or not. Then theconclusion is received: when the gas volume fraction is more than15%in gas-liquidtwo-phase, there is no stable vortex shedding.