Measurement of two-phase refrigerant liquid-vapor mass flow rate - Part II: turbine and void fraction meters

The use of a turbine meter for the measurement of refrigerant liquid-vapor mass flow rate in a horizontal pipe is presented. Various models that utilize the output of the turbine flowmeter and the measured void fraction and/or quality to calculate the two-phase mass flow rate were examined. It was found that, although no model performed particularly well, Rouhani's model gave the best overall predictions of the actual mass flow rates and had the lowest sensitivity to quality and flow pattern. However this model tended to overpredict the mass flow rate. The overprediction was up to 40% in the intermediate quality range. On the other hand, the ability of the volumetric homogeneous model to predict the actual mass flow rate was found to be quality dependent. Its predictions improved with increasing quality. This volumetric model performed better than the Rouhani's model at intermediate and high qualities.