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Redredkickmeinthehead
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Water Bubble Noise

10/25/2010 10:32 PM

I have a water jacketed vessel which has several through pipes. The jacket has flowing cold water. When reaching higher temperature within the vessel small popping noises can be heard around the areas of the full penetration pipes. These pipes are also exposed to the most heat as they pass directly into the insulated heats area. My theory is that the area of the pipe, which passes through the water jacketed vessel is hot enough to start localized boiling on the small section of pipe. This boiling is making the popping or clicking sounds. Sine the overall temperature of the water is not increasing and the area is less than a full percent of the volume of the water jacket no indication of boiling is evident at the outlet. I am looking for comments, concerns, other theories, realities?? I am happy to provide additional info

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vermin
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#1

Re: Water Bubble Noise

10/26/2010 2:19 AM

Do you have something going into cavitation? Perhaps you need to tune the flow of one or the other flows.

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ChaoticIntellect
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#2

Re: Water Bubble Noise

10/26/2010 9:56 AM

In my experience the heat exchangers that experience this are often cooling hot, high pressure water and cooling it and dropping it to low pressure, such as a boiler water sample line. It sounds like it is dropping the pressure too fast for the rate it is being cooled and therefore you do have localized boiling and subsequent collapse (pops or pings) as is cools further.

The solution that has worked for me is to install a throttle valve at the sample outlet to maintain a higher back-pressure while it is cooling. I don't know if your system configuration allows for this, but hopefully this points you in a helpful direction.

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Kilowatt0
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#3

Re: Water Bubble Noise

10/26/2010 11:55 AM

Post 1&2 are correct. I would only add that if you do have cavitation occurring, make whatever changes are necessary to rid the problem. Cavitation essentially rips chunks of the tube wall off, leaving you in danger of a leak between the cooling water and the heat source. NOT something you want.

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ChaoticIntellect
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#4
In reply to #3

Re: Water Bubble Noise

10/26/2010 12:34 PM

Thanks KW... I failed to mention the ramifications of not correcting it. Good catch.

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farmatt
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#5

Re: Water Bubble Noise

10/26/2010 12:51 PM

In a diesel engine that problem is solved with a thermostat to restrict flow and an antifreeze coolant that has chemicals and minerals in it to prevent cavitation. The thermostat also brings the water temperature up to a point where the temperature differential is not so huge between the coolant and the cylinder wall.

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Redredkickmeinthehead
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#6

Re: Water Bubble Noise

10/27/2010 5:30 AM

Thank you for the input. This issue occurred since the installation of a chiller, and thus reduction of back pressure from about 20 pig to almost nothing. I am going to put a ball valve and pressure gauge on the outlet and throttle back some. Should be able to report results Monday.

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LAA_Lucke
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#7
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Re: Water Bubble Noise

10/27/2010 7:18 AM

MAKE sure that you do not backpressure too much: The jacket has a maximum rated pressure. if you exceed that you have a risk of buckling the inside of the vessel.

Check the nameplate of the Jacketted vaessel.
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Icarus
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#8

Re: Water Bubble Noise

10/27/2010 8:35 AM

My past experience with what you call popping noises, has been with boilers and hot water tanks. This was caused by mineral scale build up, which acted like insullation on the vessel walls. This allowed for flash heating inside and underneeth the scale. The result is small bubles of steam, that colapse when they exit the scale layer creating a popping noise.
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ChaoticIntellect (2); farmatt (1); Icarus (1); Kilowatt0 (1); LAA_Lucke (1); Redredkickmeinthehead (1); vermin (1)

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