Flow patterns and pressure drop measurements in a circular 1.22 mm ID glass channel were investigated for two immiscible liquids; namely: simulated fuel and a deep eutectic solvent (DES). The effect of the inlet junction and initial channel saturation phase were studied by using two different configurations (T and cross) and two initial saturation phases (DES and fuel). Annular, drop, dispersed and plug were the major flow patterns observed, but the area covered on the map by each type varied to some extent from each other. For the T junction; plug flow was observed when the DES was the saturation phase but it did not exist when the fuel was the saturation phase. In contrast, the area covered by the drop flow increased when the fuel was introduced first. For the cross junction; the flow pattern map was dominated by annular flow while minor presence of dispersed and plug flow patterns was noticed in comparison to those reported using the T-junction. For constant fuel velocity, the pressure drop was found to increase as the DES velocity increased. On the other hand and for constant DES velocity, the pressure drop was found to fluctuate as the fuel velocity increased. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.