Numerical Study of Periodical Flows of Piezoelectric Valveless Micropump for Biochips
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摘要: 采用浅水波模型把浅薄形微泵的三维流动近似为二维厚度平均流动, 并采用有限元/压强修正法求解水平流场和计算微泵流量A·D2数值结果表明：1) 在微泵扩散管的过流截面上流速有时间相位差和回流现象．2) 微泵在吸流末期泵腔出现对称旋涡．3) 微流体泵的定向净流量来自于Navier-Stokes方程的非线性．还给出微泵流量与扩散管长宽比、厚宽比、液体粘度和进出口反压差的定量关系．通过参数优化可以使微泵得到尽可能大的流量．Abstract: Shallow water model was employed to approximate the three-dimensional flows of a thin micropump to a two-dimensional thickness-averaged flows. The finite element method and pressure correction algorithm were used to solve the two-dimensional flows of the pump and calculate the pump flow rate. The numerical results indicate that 1) Phase differences in time of flow velocities and backflows occur across section of diffuser connecting to pump chamber; 2) A pair of symmetric vortexes appears inside the pump chamber by the end of suction flow phase; 3) The directional flow rate of the pump is dominated by nonlinearity of Navier-Stokes equations. Quantitative relations of the pump flow rate versus the ratio of diffuser length to width, the ratio of diffuser thickness to width, fluid viscosity and backpressure were also given. Possibly maximal flow rate can be achieved by optimizing the pump parameters.
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Key words:
- micro-pump /
- diffuser /
- finite element method
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