Numerical Simulation And Mechanism Study On Vortex Flow Of Low Liquid Void Fraction Around A Bluff Body In Horizontal Wet Stream Flow

Wet steam is the extensive medium in the industry production and the accurate measurement of wet steam is very important for the industry control.Vortex flowmeter is an effective way to measure velocity of flow because of its reliability,simplicity and economy.Using the principle of the vortex to measure wet steam has gradually become an optional method.Research on the vortex shedding characteristics and mechanism of wet steam flow around a bluff body not only has a great guide significance on measurement of wet steam,but also promotes the development of gas-liquid two-phase vortex street theory of fluid dynamics.In this paper,the wet steam around a blunt body research was completed as following:1.It is discussed by numerical simulation and experiment that gas-liquid two phase flow around a bluff body.It is researched by using the Euler model that the effect of droplet on the stability of two phase vortex street.The influence of different liquid volume fraction,droplet diameter and liquid phase density on the stability of two-phase vortex street is compared.In the end,the effect of different liquid volume fraction on vortex street is studied experimentally,and the results are compared with simulation.2.It is researched by numerical simulation that wet steam around a bluff body.The effect of droplet on vortex street is studied further by using DPM model,and in consideration of the droplet evaporation and condensation.It is analyzed in detail by using the ability of DPM model capture that the influence of the droplet number and diameter on the vortex street.Finally,the effect of film on vortex street is discussed simply by wall film model.3.The influence of droplet on the stability of the vortex street is verified through the research on vortex theory.The motion and force of droplet is analyzed and the mechanism of the vortex instability is studied by comparing the characteristic parameter of droplet.A useful exploration is provides that the vortex theory of Wet steam and gas liquid two phase flow.