Analysis of fluid flow through microchannels with manufactured roughness level

Abstract

The fluid flow through microchannels is very complex in nature. The flow characteristics newlineof microchannels show contradicting behavior compared with the conventional newlinetheories of transport phenomena. These special characteristics are the results of the micro newlinesize of the channel, surface roughness, the electro-kinetic effects near the interface newlineof the channel, rarefaction effects, etc. The experimental studies on fluid flow through newlinemicrochannels revealed that the surface roughness plays a major role in the flow friction newlinecharacteristics. The average manufacturing surface roughness of the microchannel fabricated newlinefrom different materials with commonly used fabrication techniques falls in the newlinerange of 0-6 and#956;m. For microchannels, a correlation for friction factor which relates explicitly to surface roughness is scarce. To use the available correlations presented in the literature one has to conduct experiments to find out the unknown empirical constants. newlineIn the present study, the effect of surface roughness on fluid flow through microchannels newlineis studied at manufacturing roughness level. newlineA 2D analysis of water flow through microchannels is studied by modeling the surface newlineroughness as a sinusoidal function. The geometry of the channel is created by a newlineMATLAB code and the simulation is performed with the commercial software ANSYS newlineFluent. The analysis is carried out for a range of geometric parameters of the channel newlineviz, channel height 100-250 and#956;m, roughness height 1-30 and#956;m and phase angle 0-and#960;/2. The newlineReynolds number is chosen within the range of 100-500. The study revealed that the newlinesurface roughness has an apparent effect on the frictional characteristics of the flow. The newlinenumerical study also revealed that the phase angle doesn t have any significant effect newlineon friction factor for the range of roughness height selected for the analysis. Based on newlinethe numerical data a correlation for friction factor is proposed as a function of Reynolds newlinenumber and a non-dimensional roughness parameter and#946;.