NUMERICAL SIMULATION OF DROPLET FLOW IN A THREE DIMENSIONAL MICROFLUIDIC DEVICES
微型管中液滴流动的三维数值模拟

For low Reynolds number flow in a micro-fluidic device,the capillary and viscous stresses are more important than the inertial forces,as is characteristic of the micro-fluidic devices.Based on the free energy function,a phase-field method is applied for the two-phase flow in a micro-fluidic device and the interaction of the fluid components with a wall.The transport equations of dimensionless form for the two-phase flow are obtained.To solve the transport equations for a micro-fluidic square pipe,a numerical method is proposed using the finite difference method.The numerical simulation of the flow and the deformation of a droplet in a cubic pipe is carried out,and the effects of the capillary number and the drop radius on the deformation and the additional pressure drop ahead of and behind the droplet are studied.The simulations show that the additional pressure drop increases with the droplet size,and decreases with the capillary number.