Mechanism Research Of Flow Around Bluff Body In Horizontal Gas-liquid Two-phase Flow

Gas-liquid two-phase flow exists widely in industry field. At present, theresearch about gas-liquid two-phase flow around a bluff body is mostly carried outunder vertical conduit flow due to its symmetry and relatively simple analysisconditions. But asymmetric pipe flow is more common in actual working conditions,and horizontal tube gas-liquid two-phase flow is the typical representative. So fullyunderstanding the law of gas-liquid two-phase flow around a blunt body is of greatsignificance. The main completed work of this paper are as followed:Firstly, The experiment of gas-liquid two-phase flow around blunt body isresearched, and the results were classified into bubble flow and slug flow accordingto horizontal tube gas-liquid two-phase flow pattern map, high-speed video. Thestability of vortex street was studied through analyzing the repeatability ofmeasurements, Strouhal number changing along with the gas volume fraction and thecorrelation of Strouhal number. The conclusion is received that it exists stable vortexstreet when the gas volume fraction is less than15%and the stability is damagedwhen gas volume fraction is more than15%, however there is still a vortex shedding.Secondly，combined with experimental conditions, the3d simulation model isestablished and meshed by appropriate grid. The feasibility of the model is analyzed.VOF multiphase and RNG κ εturbulence model are selected to simulate one kindof experiment condition through Fluent software. The correctness of simulationresults were verified through comparing the frequency, Strouhal number betweenexperiment and simulation, the theoretic h/l with emulational h/l, and high-speedvideo with cloud picture of simulation.Finally, by analyzing the post-processing of simulation results to research themechanism of gas-liquid two-phase flow around bluff body in horizontal tube, theinfluence of electrical signal acquisition limitation in the experiment can be solved.Research shows that the vortex shedding location is backward with the increase of gasvolume fraction. The influence of gas phase on vortex shedding, the mutualrelationship among the flow field parameters and the mechanism informationcontained in these parameters are further studied.