Experimental friction factor of a liquid flow in microtubes

The friction factor of a water laminar flow through fused silica microtubes with diameters ranging from 50 to 530 μm is investigated experimentally. The existing works in the literature are analyzed. They show a range of experimental results which agree or not with the conventional theory. Pressure drops and flowing masses are measured to determine the flow characteristics using a transient method. Several experiments are developed for two fluids (distilled and tap water) and tube compositions. The experimental results are discussed. The disparity from the classical theory is found to be due to the fluid’s ionic composition. The experimental results for tap water and classical fused silica surfaces indicate a disparity from the conventional theory. A friction factor increase with small uncertainties (<5%) is observed for decreasing diameters.