A literature review has been conducted on pressure drop in mini/microchannels to evaluate major discrepancies in experimental work dealing with pressure drop in these small passages. The aim of the present work is to investigate the effects of surface roughness elements on pressure drop in minichannels in an effort to determine if conventional friction factor equations are valid in predicting the friction factor in minichannels. In the present work, an experimental study is carried out to investigate the effects of surface roughness on air and water flow through rectangular channels with hydraulic diameters ranging from 325µm to 1819µm. Smooth surface conditions are tested over a range of Reynolds numbers from 199 to 7206. Friction factors are calculated and compared to theoretical laminar and turbulent friction factor values to validate the test section. The effect of roughness orientation is studied by using a repeated roughness feature in (i) aligned sawtooth roughness profile and (ii) offset sawtooth roughness profile on the two sides of a 10mm wide rectangular minichannel. The roughness profile test setup consists of a rectangular minichannel, with its two sides featuring a repeating roughness profile. The aligned sawtooth roughness profile will have the roughness elements lined up peak to peak, while the offset sawtooth roughness profile will have the roughness elements lined up peak to trough. Results show that aligned peak to peak roughness yields friction factors higher than the offset peak to trough configuration.

Library of Congress Subject Headings

Fluid-structure interaction; Surface roughness; Pressure--Measurement; Microstructure; Microreactors; Friction

Publication Date


Document Type


Student Type


Degree Name

Mechanical Engineering (MS)

Department, Program, or Center

Mechanical Engineering (KGCOE)


Satish Kandlikar

Advisor/Committee Member

James Taylor

Advisor/Committee Member

Andres Carrano


Physical copy available from RIT's Wallace Library at TA357.5.F58 S36 2004


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