# A pump is used to transport water to a higher

A pump is used to transport water to a higher reservoir. If the water temperature is ${20}^{\circ }C$, determine the lowest pressure that can exist in the pump without cavitation.
You can still ask an expert for help

• Questions are typically answered in as fast as 30 minutes

Solve your problem for the price of one coffee

• Math expert for every subject
• Pay only if we can solve it

In this problem, a pump is operating to transport water at temperature is (20°C), we can expect the lowest pressure that can exist in the pump without cavitation as followingю
Cavitation is the phenomenon, which is a common cause for drop in performance and even the erosion of impeller blades, when the pressure during liquid flow system drop below the vapor pressure at some locations, and it resulted in unpredictable vaporization for the liquid, Cavitation bubbles collapse because the are move from the low-pressure regions, producing a high destructive pressure waves which damage the propeller.
So, to prevent cavitation from occurrence, the pressure of the flow should be above the vapor pressure at the condition temperature.
At the given condition ( 20°C ) From TABLE (A-4):
${P}_{v}={P}_{sat}=2.3392kPa$
So, the minimum pressure that can exist in the pump to avoid cavitation occurrence at any position on the pump surface should not be allowed to drop below ${P}_{v}={P}_{sat}=2.3392kPa$

Neil Dismukes
Step 1
Cavitation is the phenomenon which causes drop in performance or erosion of impeller blades, when the pressure during liquid flow system drop below the vapor pressure at some locations.
Step 2
To prevent cavitation, the pressure of the flow should be above the vapor pressure at given temperature.
Hence, at 20°C, the saturation pressure is,
${P}_{sat}=2.3392kPa$
The minimum pressure that can exist in the pump to avoid cavitation to occur, should not be dropped below 2.3392 kPa, in the given case.