Noise from Discharge Side of Centrifugal Pump 2

[SrinivasAluri]

I am trying to create a demo centrifugal pump to show increased vibration from cavitation. I have a pump running at 2900 RPM and a 2 inch suction side pipe and 2 inch discharge pipe with a increaser. The pump is a Kirloskar DB 32/13 End Suction Pump.

I can get cavitation by closing the suction side valve and my pressure sensor on the inlet side is confirming that -pressure is close to vacuum and I can see bubbles. The problem is the pump is too noisy without closing the suction valve i.e., without cavitation. As you can see in the picture I use transparent piping and when I run the pump, I see a vortex of air bubbles on the discharge pipe. The increaser (1 inch to 2 inch) is not smooth.

Ideally, I want the vibration to increase when cavitation is simulated but in my case the pump is too noisy without closing the suction valve and the noise is going down once I start closing my suction valve, which unfortunately is opposite of what I want to show. The broadband noise around 5000Hz is going down when I close the inlet valve.

Initially I had water from discharge pipe fall openly not submerged, but I fixed that. The noise on the discharge side sounds like gravel moving.

Appreciate any help.

 

[LittleInch]

Increase the length so that the friction losses increase for the same flow to better match the output of your pump. It won't increase the discharge head per se, but will reduce the flow for the same discharge head, which is where your issue lie and allow your valve to work in a better place.

A couple of elbows will increase the head loss, but not very much. A few metres of coiled plastic pipe would be much better as Artisi says.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[SrinivasAluri]

Artisi - Thanks for reminding me of my improper pump selection . I needed a pump which was separate from the motor and that was the lowest capacity pump available in the market and the demo had to be small. I ran the pump at half the speed, but closing the suction valve is not quite getting me the cavitation. I will check again.

So for now, it is round and round in circles and luckily for me there is a steel tank where I can put the coil of pipe, which will help me hide my skeletons!

Thanks a lot guys.