Numerical Simulation Of Rough Surface Effects On Microchannel Fluid Flow

Micro-irrigation is an effective technology of economizing water.in agricultural irrigation. One of the most important parts in micro-irrigation is emitter which performance is depended on the configuration of channel. So studying fluid flow in emitter-channel is very important usefulness to optimize emitte's design and advance its performance.This paper is to take the squarely straight emitter-channel as the research subject and simulating these channels' fluid flow on different section sizes and flux. Based on the porous media model, we simulated and analyzed these channels' fluid flow with commercial CFD software. And numerically studied is compared with Micro—PIV experimentation. The main studies are variational rules of flow field in rough surface and rough elements effect on the pressure drop in microchannel fluid flow.Through the numerical simulation analysis of different case and comparing PIV experimental dates, we get some conclusion: by using porous media to simulate and study the rough elements is a simple and feasible means in numerical compute. Rough elements have big effects on the pressure drop in microchannel fluid flow. The roughness of relativity k/d, flux G and section sizes d are main factors of effect pressure drop and take on definite variational rule. The pressure drop becoming logarithmic larger when the roughness of relativity k/d becoming bigger , the pressure drop becoming power larger when flux G becoming bigger, the pressure drop becoming exponential smaller when the section sizes d becoming larger, but the density distribution e effect pressure drop insignificant. In different density distribution condition, the pressure drop is almost invariable. Rough elements also have some effects on flow filed in complicated microchannels: subtractive pressure filed becoming punily larger when the roughness of relativity , flux, section sizes becoming bigger, subtractive pressure filed being almost invariable when density distribution being variational. Circumfluence filed has corresponding variational trend. It is obvious that rough elements have insignificant effects on flow filed relatively to the configuration of channels when the roughness of relativity is less than 5%.