Steam jet -- noise levels
Steam jet -- noise levels
(OP)
When steam under pressure discharges from a vent pipe it creates a noise.
Is anyone aware of a way of calculating the likely noise level given the diameter of the pipe and pressure of dicharge?
Bob B:-)
Is anyone aware of a way of calculating the likely noise level given the diameter of the pipe and pressure of dicharge?
Bob B:-)





RE: Steam jet -- noise levels
I don't really have much more on this but I may have given you a few specific terms which should help you to find the right book.
M
RE: Steam jet -- noise levels
A great lead. Thankyou very much for this.
Bob B
RE: Steam jet -- noise levels
Anywho, there are some results plotted for 0.5 in. diameter and 0.5 in.length orifice showing 1st stage response running from 5 to 9 KHz for Mach 0.3 to 0.7. 2nd stage is from 9-16KHz over same Mach range and 3rd stage is 13.5-20KHz from M=0.3 to 0.5. There's also an L/d =2.0 plot for d=0.5 in. showing 5 stages with disconnected response points over a 0.2-0.6 Mach range. Sounds simple enough doesn't it. If I ever find out what alpha is I'll get back to you.
RE: Steam jet -- noise levels
Perhaps alpha is the meaning of life.
Seriously -- thank you very much for this interesting reference. I enjoyed reading it and thinking.
This is one of the joys of the forum. Now and again it throws up far field stuff which gives you a 'Oh yeah' moment.
Again thanks.
Bob B
RE: Steam jet -- noise levels
read Noise and Vibration Control (1971) by Leo Beranek, there is a chapter dealing with jet noise, I gues the chapter 9 or 10.
luck
RE: Steam jet -- noise levels
The unsilenced noise from a steam vent in dbA refernced to 1E-12W is 17*LOG (Flow tonnes/hour) + 50*Log(Temp degree K)-15
athomas236
RE: Steam jet -- noise levels
There is some amplitude info in the article. For the L/d=1 orifice at Mach 0.48, Fig. 7 shows a frequency amplitude spectrum with peaks at about 6.5, 13.0 and 19.5 KHz with "Relative SPL (dB)" of about 49, 38 and 33. Not much help when it doesn't say relative to what. Otherwise, there is nothing there on how to calculate amplitudes.
Athomas236 has a possible direct answer to your question in A-weighted sound power level providing your geometry conforms exactly to that of a "steam vent" and you haven't got a silencer of any kind. Can you verify that?
RE: Steam jet -- noise levels
Thanks once more for coming back. Though I haven't read the original source -- my reply was misleading - it was your synopsis I enjoyed reading.
My curiousity was prompted by another thread where someone asked for a design of such a silencer. The 'traditional' approach seemed to be very empirically based and I wondered if there were ways in which a silencer could be optimised.
Hence the original query.
Regards
Bob B:-)
RE: Steam jet -- noise levels
Thankyou for sharing this predictive equation for sound power level. Did it mention the distance?
Bob B:-)