Numerical Simulation And Experimental Study On The Flow Influence Of The Configuration In Microchannels

One of the most important parts in micro-irngation is emitter which performance is depended on the configuration of channel. To enhance the friction of emitters, small and complicated configuration v/hich causes emitters jammed easily is used. In this paper, the CFD software was used to simulate the liquid flow in microchannels whose conditions were varying. The Micro-PIV was utilized to get the flow distribution in the straight channels.The liquid flow in complicated channels with different conditions was simulated. When Re=100, laminar modeling was used;when Re=200, 300, the standard k-εemodeling was used. The results of numerical simulation indicated that with the increasing of the Re and channel size the area of the dead zones became larger;the pressure drop became larger as the Re increased, and the pressure drop became smaller as size increased. The standard of the optimum Micro-irrigation was that the flow rate of all emitters was uniform, so emitters must have a large pressure drop. The first channel's pressure drop was larger and its dead zone: was smaller than others, so it was best.The liquid flow in straight channels with different conditions was measured through Micro-PIV. The suitable trace particle and magnification were chosen. The results of the measurement indicated that the streamlines near the wall curled obviously, the reason was that the relative roughness of the straight microchannels became larger comparing with the traditional channels. It was also found that the effect of the relative roughness was reduced when the size and Re increased.