ANALYSIS OF CAVITATION IN CENTRIFUGAL PUMP USING CFX

Abstract

In our every day existence we use many things which use concept of vacuum like vacuum cleanser, exhauster and so on. The phenomenon of cavitation use in various industry like hydraulic lifts etc, It’s has various advantages anf also disadvantages like in pumps. In centrifugal pump impeller rotates due to which suction creates (negative pressure), it suck the water from surrounding, due to decrease in these pressure boiling point of water decreases and water is now able to boil at low temperature, if in any instance if surrounding temp is more than boiling point ( due to low temperature ), water start boiling and form a bubble, now it not harmful till it burst, at outlet water have to flow at high pressure hence at this condition boiling point increases hence the present bubbles start bursting on the surface due to which deterioration of surface occurs. This deterioration cause unbalance condition during running result failure of machine. Cavitation also occurs due to air present in water, due to sucking of water at high pressure air coming out from the water and form bubble and leads to cavitation. In this project I am vary discharge at constant rpm to see variation of cavitation and observed that as discharge increases cavitation also increases. I also calculate efficiency at various discharge at constant R.P.M. and calculate change in NPSHA and NPSHR at various discharge and get the result that as discharge increases NPSHA decreases and NPSHR increase due to which cavitation occurs.