A Numerical Simulation Of Microbubble Dynamics Based On Many-Body Dissipative Particle Dynamics Method

Microbubbles have different outstanding characteristics from ordinary bubbles,and their applications in many fields such as environmental pollution control,biomedicine,etc.have received increasing attention in recent years.In-depth study of the dynamic behavior of microbubbles has important engineering application value and scientific significance.In this paper,the scale characteristics of microbubbles are studied in depth using the mesoscopic multi-body dissipative particle dynamics to study the dynamic behavior of microbubbles.Specific research contents include:(1)Combining the connection and difference between the two methods of DPD and MDPD,DPD particles are used to describe the gas phase,and MDPD particles are used to describe the liquid phase,and a microbubble model is constructed.By changing the force between the gas-phase particles and the particles at the gas-liquid interface,a microbubble model with high density difference between gas and liquid is constructed,Simulate and verify the effectiveness of microbubbles.(2)The model is used to study the hydrodynamic behavior of a single microbubble in the gravity field.Studies have shown that the surface tension between the gas-liquid two phases has an important effect on the bubble dynamics.As the surface tension increases,the deformation of the bubble is less obvious,and the bubble tends to be closer to an ellipse when it is stable;as the surface tension decreases,the bubble As the deformation amplitude increases,the influence of the deformation on the surrounding flow field increases.In the micro-channel,when the bubble diameter is constant,as the channel width increases,the rising displacement of the micro-bubble gradually increases,and the rising speed of the micro-bubble increases with the increase of the channel width.The narrower the channel,there is no effect of sliding the fixed wall boundary The more obvious.(3)This model was used to study the oscillation and transportation of microbubbles in an infinitely long microchannel driven by ultrasound.A buffer boundary was used toconstruct an infinitely long microchannel environment.The effects of three factors such as microchannel width,driving sound pressure,and microchannel wall wetting characteristics on microbubble oscillation and transport process were studied.Studies have shown that the width of the microchannel has a limiting effect on the oscillation and translation of the microbubbles.The narrower the channel,the more obvious the limitation.When the width of the microchannel is fixed,the transport distance of the microbubble increases with the increase of the bubble diameter,and there is a critical direct value.When the width of the microchannel and the bubble diameter are fixed,the transport distance of the microbubble will follow the driving sound.The pressure increases.Under the conditions of the microchannel wall surface with different infiltration characteristics,as the hydrophilicity of the wall surface increases,under the action of pressure,it has the effect of promoting the liquid flow inside the microchannel.