[modeleng] Steam pressure/velocity question
- From: Harry Wade <hww@xxxxxxxx>
- To: modeleng@xxxxxxxxxxxxx
- Date: Fri, 24 Jun 2005 08:56:01 -0500
At 02:14 PM 6/24/05 +0100, you wrote:
>I would like to take a whistle design which is for 150 lbs/sq in+ and make
>it work at 75 lbs/sq in+
Peter,
Normally steam whistles are tuned to different operating pressures by
varying the height of the opening between the lower edge of the bell and
the steam slot. Under normal conditions, where a relatively small range of
pressure must be accomodated, the steam slot for a given whistle diameter
does not change size. Whether this would hold true for a doubling of the
pressure I don't know but my guess is that it would.
I have made several small whistles for between 30 and 125psi and never
"calculated" anything. Not that I avoid or dismiss calculations, I don't,
however most of the things were made using the "that looks about right"
design method and technical information gleaned from various texts on
whistle design, paying particular attention to the width of the steam slot,
the shape of the lower edge of the bell, and the relationship between the
diameters of the two. After tuning they all screamed like banshees.
Regards,
Harry Wade
Nashville Tennessee
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