The flow rectification of a vaned microdiffuser: A numerical investigation

Abstract

This paper presents a numerical investigation to characterize the flow rectification of a dynamic vaned microdiffuser pump. To study the impacts of vane configuration in microscale, two vanes stretching from the inlet region to the outlet region are added to divide the microdiffuser into three flowing passages. By imposing a sinusoidal pressure at the inlet, two geometric parameters are considered: half angle of the diverging section θ and half angle between adjacent vanes F. We find that when the angle between adjacent vanes remains the same (fixed F), net flow rate is augmented with increasing θ. In contrast, there exists an optimized vane configuration while the diverging section is unchanged (fixed θ). For F < θ/3, increase in F helps to improve flow rectification. For F > θ/3, further increase of F results in narrower side passages, and net flow rate diminishes consequently. Hence, best flow rectification is achieved when the diverging section is equally divided by the vanes, i.e. F = θ/3. The influences of vane configuration in flow rectification can be categorized into three regimes: central passage dominated, best rectification, and side passage dominated.