Development of the microbubble pump having ‘S-shape’ impeller using experimental and numerical analysis

Abstract

Microbubble pumps for water treatment can be used in a variety of fields, including wastewater treatment of semiconductor factories, sewage treatment, and aquaculture. In this study, a microbubble pump, with the ‘S-shape’ impeller, for sewage treatment has been developed in two steps. In the first step, a numerical design optimization was performed to develop a small-scaled microbubble pump. In the second step, a microbubble pump with a capacity that can be used in an actual water treatment facility has been developed through the scale-up process of a small-scaled optimum design of microbubble pump. The experimental test rig of the microbubble pump has been developed to investigate the performances of the microbubble pump, such as air and water flow rate, pressure differences and torque. To analyse three-dimensional flow field in the micro-bubble pump, general analysis code, CFX, has been employed. SST turbulence model has been employed to estimate the eddy viscosity and compared the pump performance to k-ε model. Unstructured grids have been used to represent a hybrid grid system including blade, casing and inlet casing. The results in the first step, a small-scaled optimum design shows the efficiency about 30.4%, which corresponds to a 0.4 percentage points increase compared to the conventional one. The results in the second step, the final design of microbubble pump shows an efficiency of 32.5% at the flow rate of 200 lpm.