A pump is used to transport water to a higher reservoir. If the water temperature is 30°C, determine the lowest pressure that can exist in the pump without cavitation.
Solution to 22P
We need to find the lowest pressure that can exist in the pump without cavitation. Cavitation is the existence of empty space.
Thus to avoid the cavitation, we need to maintain a minimum pressure throughout the pump. This pressure must not be less than the vapour pressure at that temperature.
We know that the flow is from higher pressure to lowest pressure, thus the pump at lower pressure compared to the vapour pressure will not be able to pump the water to higher reservoir.
Vapour pressure at 300C=4.23kPa
Thus minimum pressure in the pump=4.23x103Pa