Hydrodynamic Characteristics of Gas-Liquid Ejectors

In the present work, experimental investigations have been carried out on ejectors employing gas (air) as a motive fluid and liquid (water) as the entrained fluid. A semi-empirical model has been developed to predict the liquid entrainment rate taking into account, (1) the compressible nature of air, (2) pressure drop for two phase flow and (3) losses due to changes in cross sectional area. The effects of gas velocity, liquid level in the suction chamber, nozzle diameter, throat height and throat diameter on the liquid entrainment, entrainment ratio and pressure drop have been investigated. It has been observed that the liquid entrainment rate increases with an increase in the liquid level in the suction chamber. It was also found to increase with an increase in the gas velocity. The ratio of throat cross-sectional area to the nozzle cross-sectional area (area ratio) was found to be a critical parameter. The results have been explained on the basis of pressure profiles. The values of liquid entrainment rate predicted from the semi-empirical model were found to be in good agreement with the experimental measurements.