Experimental Investigation on Flow Characteristics of Gas in Micro-channels

AbstractAn experimental apparatus is developed for further study of flow characteristics in microchannels, compressible gas—air, is used as a workfluid.The experimental study were performed in copper micro tubes and plexiglass tubes with the diameters 0.2mm, 0.3mm, 0.4mm,0.5mm and 1.0mm, and the roughness less than 3%. The results show that the material of micro-tubes does not affect the experimental results; transition from laminar to turbulent flow occurred at critical Reynolds number about 1100 in the tubes with diameter 0.2mm, the critical Reynolds numbers are respectively about 1300,1600,1800 in the tubes with diameters 0.3mm, 0.4mm and 0.5mm, so the conclusion show the descending direction of the critical Reynolds number with the decreasing tube diameters, and the phenomena of transition in advance from laminar to turbulent flow is apparently observed. At the same time, the larger the diameter, the Reynolds number increases, the pressure drop increases even faster. And the results do not change with the change of tube number