Effect of Surface Roughness on the Pressure Drop of Liquid Flow in Micro-Channels

Experimental results in the literature of the surface roughness effect on pressure drop of liquid flow in mini and micro channels were examined. Also, three prominent theories, which are the constricted flow model, the constricted model considering roughness distribution, and the roughness viscosity model are reviewed based upon this broad data base. It is found that all the normalized data of fRe can be predicted, within an error of about ±15%, by the classical pressure drop theory with the channel dimension using the constricted flow model. On the other hand, it appears that the viscosity model is difficult to use generally and the roughness distribution information is frequently hard to obtain for natural rough-surfaces. However, the data, which supports these two theories, can also be predicted well by the constricted flow method at a similar accuracy. It is possible that the viscosity model and the constricted model with roughness distribution can be further developed to become easier to use, for the time being the simple constricted flow model could be a general and reliable method for mini and micro channel pressure drop predictions.