Numerical Simulation And Experiment Research Of Pressure-driven Liquid Flow In Microtubes

The investigation of micro- and nano-scale liquid flow is the key for the further developments of MEMS and nano science and technology. It also fufill the requirements of research for micro-pumps and Lab-on-a-Chip Technology. It is very important to analyze and discuss the flow rules due to the decreased characteristic length. Because liquid flow in micro-pipe is different from the macro-scale flow. This paper built the flow model of deionization water in micro-pipe at the basis of miro-flow theory to simulate the flow under different pressure-driven by famous fluid analysis software Fluent. It also analyzed the effect of surface roughness and gravity in micro-pipe. It also compared the results in experiment research with the simulation and discussed the physical theory.The simulation results showed that the behavior of flow was still in agreement with the macro-scale predictions when the diamter of mico-pipe is 20μm.The pressure-flow rate by different pressure-driven showed good agreement with Hagen-Poiseuille equation. The results also showed that gravity had hardly effect on flow charactertics in micro-scale and nearly can be neglected. Because of the decreased characteristic length and the growth of relative roughness, friction of surface increase and flow-rate decrease.Experiment research proved the water flow rules with diamter 20μm. When the characterics length still decreased, some micro-scale effect may be realized and boundary layer would slip. But the water flow rules are decided by many reasons not only by the diamter of micro-pipe.