Experimental Studies on Void Fraction Measurement on Air-Lift Loop with Multiple Risers

Abstract

Online, continuous two phase flow measurements is often necessary for analysis of the two phase flow particularly in oil and gas, nuclear energy and chemical processing industries. Reliable measurements of void fraction and flow pattern identification are important for accurate modeling of two phase systems. Void fraction is one of the most important parameters used to characterize two-phase flows. It is the key physical value for determining numerous other important parameters, such as the two-phase density and the two-phase viscosity, for obtaining the relative average velocity of the two phases and is of fundamental importance in models for predicting the flow pattern transitions, heat transfer and pressure drop. Experiments are performed in atmospheric vertical air-water flows for void fraction measurement between the pipe size of 12.5mm diameter to 4.5mm diameter to emphasize on developing the measuring techniques of two-phase flow void fraction by using ‘Conducting probe circuit’ which uses a ‘needle probe’ for measurement of void fraction in an air lift loop. The process involves the immersion of probe tip in two phase mixture in order to detect the two phases instantaneously present at the tip and the corresponding readings for the measurement of void fraction are obtained from the processing circuit.