Effects of the half angle on the flow rectification of a microdiffuser
Journal
Journal of Micromechanics and Microengineering
Journal Volume
17
Journal Issue
10
Pages
2031-2038
Date Issued
2007
Author(s)
Abstract
This paper presents an experimental investigation of the influences of the half angle on the flow rectification of the microdiffuser pump and reports on flow visualization results to exhibit the flow separation characteristics in microdiffusers. The tested half angles vary from 5° to 55° with 5° increments, and constant pressures (290–550 Pa) are supplied to measure the volume flow rates in both expansion and contraction directions. The results show that the flow rate in the expansion direction is always larger than that in the contraction direction regardless of the half angle, indicating that the flow rectification tends to cause a net flow in the diffuser direction. For Re1 30°, a pair of symmetric recirculations is observed by the flow visualization technique. The effective area of the circulation grows with increasing half angle and driving pressure, suppressing the core flow and deteriorating the flow rectification consequently.
Type
journal article