Is there any off the shelf converging diverging supersonic nozzle / ejector that uses momentum transfer to increase flow rate at the expense of pressure?
Maybe you have a shop compressor that puts out 4CFM @ 90 psi and you want 8 CFM @ 18 psi.
Bret Cahill
Dear Bret Cahill:
Yes. Exair makes an "air amplifier". It uses the "coanda effect" to produce a thin wall of high velocity air around the inside of a cylinder, and ambient air is induced to flow thereby. But no way you'll get pressure out of it.
An air compressor powered by an air motor might work.
David A. Smith
The idea wasn't to compress the air but to partially expand already compressed air. Trade a lot of psi for a significant volume at STP increase.
Bret Cahill
Maybe I'm missing something here. If you start with 4CFM@90 psi and you adiabatically expand the air to 18 psi, don't you end up with 90/18 *4 =
200CFM?So no need for an ejector with any secondary flow.
---------- Ed Ruf Lifetime AMA# 344007 ( snipped-for-privacy@EdwardG.Ruf.com)
Dear Ed Ruf:
This is where the air compressor manufacturers (and others) employ: acfm = actual cfm (effective displacement of the compressor in delivering ambient air into outlet pressure) scfm = "standard cfm" (an attempt to define mass flow, given a few choices of "standard temperature and pressure")
Because you are right, based on the units presented, there is no issue.
David A. Smith
Bret;
I would use an Air Line Regulator set at 18 PSI if the end result was to power an air cylinder that worked fine at 18 PSI. That way the 80 PSI air puts out a lot more than 4 CFM of work since it expands and gives more volume.
Ross Controls has an air valve that cuts off flow at whatever pressure it takes to move a cylinder to its end position. This allows high pressure to start and move the cylinder but pressure does not continue to build at the end of stroke and waste compressor HP after the work is done.
BudT
"N:dlzc D:aol T:com (dlzc)" wrote in message news:KyeWe.22980$sx2.3464@fed1read02...
I'm aware of the others. As you mentioned the OP didn't use either, hence my reply as it was.
---------- Ed Ruf Lifetime AMA# 344007 ( snipped-for-privacy@EdwardG.Ruf.com)
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