Flow periodicity analysis in an additively manufactured metal microchannel heat transfer device using micro-PIV

Abstract

The flow periodicity in an additively manufactured microchannel heat transfer device is analysed using the micro-particle image velocimetry technique. A metal offset strip fin (OSF) microchannel is additively manufactured using laser powder bed fusion to overcome the limitations of conventional production techniques in manufacturing small complex features. This study demonstrates the capability of measuring the velocity field in an OSF microchannel up to 1 mm deep with a resolution of 10μm and a velocity uncertainty smaller than 0.5% for laminar flows with a Reynolds number below 10. Higher measurement uncertainties are encountered in regions close to the channel walls due to particle deposition. A methodology aiming to evaluate and minimise the uncertainties is presented. The experimentally obtained velocity fields are compared to a numerical simulation of the flow in the offset strip fin microchannel. The results verify that flow periodicity can be observed and the extent of the flow development region can be studied. Nevertheless, in regions with a large velocity gradient, a considerable uncertainty on the velocity measurements exists due to manufacturing imperfections.