Numerical Investigation of the Effects of Geometrical Parameters of a Viscous Micro-pump on the Flow Rate and Entropy Generation.

Viscous micro-pumps have attracted researchers' attention due to their simple design and fabrication and many applications in various industrial and medical fields. Therefore, a wide range of numerical and experimental studies has focused on this topic. In the present paper, a numerical study has been performed to investigate the effect of geometrical parameters of a viscous micro-pump on the flow rate and entropy generation. The governing equations have been solved using the finite volume method. The present research has been carried out for three geometrical parameters of micro-pump including eccentricity (ε), sizes (S) of rotors and also their distance from each other (L) in the range of 0.1 to 0.9, 1.5 to 3.5 and 0.85 to 4.5, respectively. The results show that by increasing ε, the micro-pump flow rate also increases. On size variation effects, it is observed that decreasing the downstream rotor diameter while keeping constant the upstream rotor diameter, decreases the flow rate exponentially. By increasing L, a steep increase in flow rate is initially observed, which becomes almost constant when rotors are sufficiently far apart. With regard to entropy analysis, with increasing z, the ratio of Rs also increases. However, more complex variations of RS are observed for other examined geometrical parameters due to the relatively complex micro-pump flow patterns. Also in this paper, for obtaining the maximum flow rate at the minimum frictional dissipation, optimal geometrical parameters are extracted. In this regard, the values of L = 2, ε = 0.5, S₁ = 1.5 and S₂ = 2.5 are selected as the optimum geometrical parameters of viscous micro-pump. Finally, it should be noted that the effect of simultaneous variations of the rotors diameters on the flow rate and entropy generation and, moreover, obtaining the optimal geometrical parameters based on the entropy analysis, are among the novelties of the present paper. [ABSTRACT FROM AUTHOR]