Department of Mechanical Engineering, University of Birjand, Birjand, Iran
In viscous micropumps one of the main reasons for a flow rate reduction is vortices which are located at the top of the rotating rotor. In this paper, we have tried to add proper additional walls in the micropump channel, to eliminate or decrease the size of these vortices. Among the all investigated new models, only one, the I-Shaped micropump with an extra step above the rotor, could reduce the size of the vortices and also increase the outlet flow rate. In this paper, the numerical simulations were conducted by using the Lattice Boltzmann Method and by exploiting the Immersed Boundary method and the Blocking technique in order to overcome the LBM drawbacks. The results show that at the channel height H^*=3.7, this new model can produce a flow rate of 150% more than the normal I-Shaped micropumps. Also, one can tune the maximum produced pressure by adjusting the height of this step and micropump with higher channel height can be much more efficient and usable. In addition, by using this new structure for micropump, the designers can also use bigger channel heights which were not efficient in the original design.