Pressure drop measurements in a microchannel (original) (raw)

Recent de®elopments in micro-energy and micro-chemical systems ha®e produced a need for greater understanding of flow in small channels. Se®eral recent studies of friction factors and transition Reynolds numbers in rectangular microchannels ha®e produced results that differ from classical theory. In this work, friction factors and laminar flow friction constants were determined for water flowing in high aspect ratio channels with depths ranging from 128 to 521 m. Reynolds numbers were between 60 and 3,450. Pressure drops were measured within the channel itself to exclude entrance and exit losses. Transitions to turbulence were obser®ed with flow ®isualization. Uncertainties in measured ®ariables were quantified and propagated into the estimated friction constants. Friction factors were also determined in a 1,050-m-deep channel that ser®ed as a control. After considering experimental uncertainties and systematic errors, significant differences remained between the results and classical theory.