Authors: A. Olsson, G. Stemme and E. Stemme
Affilation: Royal Institute of Technology, Sweden
Pages: 585 - 588
Keywords: numerical simulations, flat-walled diffuser elements, valveless micropumps
The flow directing capability of micromachined flat-walled diffuser elements for valve-less micropumps have been investigated. The diffuser element is a small angle flow channel with a rounded inlet and a preferably sharp outlet. The diverging-wall direction is the positive flow direction. The commercial Computational Fluid Dynamics program ANSYS/Flotran (version 5.3) was used to simulate the flow pressure characteristic of several diffuser elements. The simulations are compared with experimental results. It is found that the simulated flow-pressure characteristic agrees well with the measured in the converging-wall direction and for Reynolds number below 300-400 in the diverging-wall direction. For higher Reynolds numbers the pressure loss in the diverging-wall direction is underestimated. The simulations are not sufficient for design optimization, but is very useful to increase the qualitative understanding of the flow in the diffuser element.