Experimental investigation on basic characteristics of multi-component two-phase flow in an inclined mini pipe

Research on basic characteristics of gas-liquid two-phase flow (flow patterns, void fraction, and pressure gradient) has been carried out experimentally. Dry air and mixture of 65% distilled water, 30% glycerin, and 5% butanol represented the gas and liquid phases, respectively. The addition of butanol was aimed to decrease the liquid surface tension, while the addition of glycerin was to increase the viscosity of the liquid. The density, kinematic viscosity, and surface tension of the liquid were 1080.7 kg/m3, 2.558 mm2/s, and 61.2 milli N/m, respectively. The test section was a 1.6 mm inside diameter glass pipe which occupied with optical correction box. The gas superficial velocities (JG) were in the range of 0.025 - 66.3 m/s, while the range of liquid superficial velocities (JL) were 0.033 - 4.935 m/s. The experiment was carried-out at adiabatic condition. The bubbly, plug, slug annular, churn, and annular flow patterns were emerged, while separated flow were absent. For plug flow, the increase of JG proportionally affected to the increase of the void fraction. However, for the other ones, there was no specific relation between JG and their void fraction. It was because of the slip between the velocity of the gas and liquid. In term of pressure gradient, the increase in JG and/or JL affected the increase in the pressure gradient.