what is the relationship between cavitation of pumps and pressure of liquid and temperature of liquid? Answered

"vapor pressure" is a good search term to help understand cavitation.

You guys really like answering homework questions it seems ;)

Intuitively, I would expect cavitation, like near a propeller blade in water, to become more active, as the temperature of the water is increased, or as the pressure of the water is decreased.

I mean, if I look at the phase diagram for water,

https://en.wikipedia.org/wiki/File:Phase_diagram_o...

and assuming I start in a point, in P-T space, somewhere the area that represents liquid water, from there a increase in temperature or a decrease in pressure will move the point closer to the line that separates liquid from vapor.

I guess what I am saying is, the distance from that line is sort of like a measure of how much energy is needed to go from liquid to vapor.

Based on that logic, I would guess that in water at 0 C, and 1000 atm, cold and at really high pressure, it would be difficult to make cavitation happen. In contrast, for water at 90 C and 1 atm, water that is almost boiling anyway, I would expect it would be easy to make cavitation happen.

Also I asked Google(r) to search for, "cavitation submarine screws temperature pressure", and one of the links I found, a Google Books look into a book titled, Military Technologies of the World [2 volumes], by T.W. Lee, has some words that seem to confirm this guess. Here's the quote, from the bottom of page 343:

"However, one way to suppress the cavitation noise is to operate at deeper depths, and therefore higher pressure, in which case the cavitation (boiling) temperature would be higher than the seawater temperature."

Cavitation is lost mechanical energy in impeller style pumps...

Tell your teacher that pressurizing a liquid will raise the liquid temperature and the lost cavitation energy does also heat the liquid..