Many thanks for this great presentation, I was wondering if submerging the return pipe to below the level of liquid in the tank could assist in getting rid of creating bubbles?
hi, you presented the concept very well. We pressurized the reservoir to get more NPSH and this could be another way to increase suction head. This method will create pressure in the lines returning to tank but is another way. What do you think?
In my reliability/plant engineering experience, he is wrong about cavitation "almost always" coming from an issue before the pump, and that there's "no way to solve cavitation after the pump". You've never heard of recirculation cavitation and high temperature vaporization cavitation? Those are very common in the field and are almost always fixable after the pump. High head+low flow = High temps and high recirculation chances. Haha sorry for the rant, just felt that strong language was used and needed a reply.
What you are seeing in the setup is a closed loop, but certainly having more water in the tank will mean more NPSHa which will mean a lower chance of cavitation.
In some cases where the discharge pressure is very high and forcing internal recirculation you will see cavitation. This is less common, but certainly a very real thing.
Our setup is a closed system so there is a fine line to be able to showcase cavitation in the way we were going for. Adding more water to the tank would absolutely lower the turbulence, increase NPSHa, and decrease the onset of cavitation.
That is a Beautiful piping layout and pump. So shiny!
Thanks!
Many thanks for this great presentation, I was wondering if submerging the return pipe to below the level of liquid in the tank could assist in getting rid of creating bubbles?
Thank you
You're welcome!
hi, you presented the concept very well. We pressurized the reservoir to get more NPSH and this could be another way to increase suction head. This method will create pressure in the lines returning to tank but is another way. What do you think?
Increasing the NPSHa will always be a good way to combat the onset of cavitation.
Can you tell us more about fluid temperature and viscosity of the fluid?
In all cases we were using city water at ambient temperature. Let’s call it 70° F and because it is water, the viscosity is at or around 1 cPs.
Wow, thanks. Going for a paper in 5hours, thanks
Glad we could help! :)
In my reliability/plant engineering experience, he is wrong about cavitation "almost always" coming from an issue before the pump, and that there's "no way to solve cavitation after the pump". You've never heard of recirculation cavitation and high temperature vaporization cavitation? Those are very common in the field and are almost always fixable after the pump. High head+low flow = High temps and high recirculation chances. Haha sorry for the rant, just felt that strong language was used and needed a reply.
Thank you for your input.
No priming or closing the discharge line to let water build up?
What you are seeing in the setup is a closed loop, but certainly having more water in the tank will mean more NPSHa which will mean a lower chance of cavitation.
What about discharge cavitation
In some cases where the discharge pressure is very high and forcing internal recirculation you will see cavitation. This is less common, but certainly a very real thing.
Put more water in your tank. You have a lot of turbulence not good
Our setup is a closed system so there is a fine line to be able to showcase cavitation in the way we were going for. Adding more water to the tank would absolutely lower the turbulence, increase NPSHa, and decrease the onset of cavitation.
IF YOU'VE GOT ANY AIR IN THE SYSTEM IT WILL CAVITATE AND LOSE PRESSURE AND MAYBE BURN YOUR PUMP OUT!
It is true that air in the system can be problematic. Whenever NPSHa < NSPHr cavitation will occur.