Optimization of the India Mark II Hand Pump to create maximum cavitation for disinfection of water

Abstract

The India Mark II hand pump has been modified based on CFD analysis for creating cavitating conditions and is being used to disinfect water that passes and pumped through the pump. Cavitation is created through a restriction in the flow area opening as a function of lift of the check valve. When cavities collapse, they let out a high velocity microjet and a spherical shockwave that, if the former is incident on a cell wall of a microbe, will cause the cell wall to rupture and the microbe will be rendered unviable. Intensity of cavitation has been optimised in the hand pump to give a maximum disinfection. The flow area opening as a function of lift was restricted by placing a ring of particular width over the check valve. Computational fluid dynamics simulations were used to optimize the dimensions of the ring. ANSYS 16.0 FLUENT was used to simulate the geometry of the India Mark II hand-pump. Simulations showed that the optimum level of cavitation occurred when lift is 60%, with instantaneous cavity collapse pressure of 401 atm. Experiments were carried out to validate the results at a pilot plant installed at ICT. Maximum disinfection of 92% was observed at ring width which gave 60% of flow area similar to that 60% predicted by simulations. Thus, experimental results corroborated the simulation predictions.