The Characteristics Of Fluid Flowing And Mixing In The Micro Channel Drived By Electromagnetic Forces

Micro mechanical devices are becoming more and more prevalent whether in commercial applications or in scientific research. As one of the main branches of MEMS, micro flow systems have achieved a great development and wide application. The micro flow systems consist of micro-sensors, micro-pump, micro-valve, micro-pipe, micro-meter, and other component. It make sampled, mixing, reaction, separation, detection and other functions integrate into the smallest possible operating platform. The precise controlling of the order of magnitude of micro liter liquid is the core and key of micro flow system, and micro mixing is an important tache. The procedure is usually made two or more fluid mixing. In fact the Re is small when the flow in the micro channel is driving only by pressure, and the flow is laminar flow. The main way of mixing between adjacent liquid is diffusion. The liquid molecular diffusion coefficient is about 10-10m2/s. The mixing efficiency is very low only rely on the diffusion. So how to improve the mixing efficiency becomes the major goal of the research.An active mixing scheme in the micro channel has been present. The principle of the mixing is that through the action of the electromagnetic force induced a second flow in the micro channel. Then the eddy engendered. This made the fluid in the channel moved reciprocating and the interface bent to extend. The contact area between different fluids is greatly enhanced. This facilitates the spread, thereby improving the efficiency.The flowing and mixing process are studied by experimental and numerical. First the effect of electromagnet force on the flow has been studied. A small device that drives fluid mixing by electromagnetic force is designed. The experiment research and numerical simulation have been made. The results are agreed with each other. Based on the theory a T shaped micro mixer has been designed. The influence of the different electromagnetic force on the process of flowing and mixing has been studied detailed.The case of both qualitative and quantitative has been adept in the process of experimental study. The effects of electromagnetic force on flow in the micro channels have been research qualitatively by adding a trace method. The advanced microscopic particle image velocity (Micro-PIV) has been used in the detailed quantitative research of flowing and mixing in the micro channel. The numerical simulation has been done base on the theory of the continuous medium model. In the numerical simulation the finite volume method has been used for solving the N-S equation, electromagnetic force and component equation and Maxwell equation. The flow field distribution of the fluids has been got. The performance evaluation index of the fluids mixing intensity in the micro mixer has been given. The efficiency of mixing has been evaluated through the analysis of the section in the mixer of different fluids volume fraction. The mixing have been analyzed and compared under the action of the different electromagnetic force. On this basis the micro mixer has been design optimized.This paper showed that:the electromagnetic force can disturb the flow of fluid in the mixing devices and enhance the mixing between different fluids effectively. Then through the study of the disturblance about different electromagnetic force and different way of disorder on the flow state showed that, the more complex of the disturbance the higher mixing efficiency between different fluids.