Design Optimization of Valveless Micropump by Parametric Study of Diffuser/Nozzle Angle and Aspect Ratio

Abstract

In this paper, a valveless diffuser/nozzle based micropump is analyzed numerically by using CFD commercial software (Fluent 6.2). Two models are used for numerical calculations. In model-Ⅰ, uniform inlet velocity is applied as a boundary condition at lower wall (diaphragm) of the chamber. The inlet velocity is defined as a function of deflection. In model-Ⅱ, the transient displacement of the diaphragm is modeled by moving mesh. On the basis of numerical results, it is observed that the numerical results of both models agree well with the experimental data. Since model-Ⅰ is more efficient, it is preferred for further study to predict the optimized diffuser/nozzle angle and aspect ratio. Maximum flow rate of 36 ㎕/min is attained at the diffuser/nozzle angle of 16° and aspect ratio of 12.75, under the conditions considered in this study. The flow rate for optimized design is also calculated with model-Ⅱ. The effects of aspect ratio and back pressure on optimized diffuser angle are also examined.