Orifice plate ( superheated steam)
Orifice plate ( superheated steam)
(OP)
My Orifice plate calculator gives me my permanant pressure loss, but on superheated steam do I get a temperature change.
For example 750 psi 750 F steam, I require a DP across my orifice of about 500" water to get turndown and Beta ratio. ( yes I know its high but pipe dia fixed.)
My permanant pressure loss is 7" water, about the same as a vortex meter, but do I get a temperature effect.
I cant find data for this, I can argue its a pressure to velocity to pressure effect and thus the steam does not expand, therefore no cooling. But I can say the jet out of the orifice expands to the larger pipe diameter and thus must cool.
Anyone with hard data or a table
For example 750 psi 750 F steam, I require a DP across my orifice of about 500" water to get turndown and Beta ratio. ( yes I know its high but pipe dia fixed.)
My permanant pressure loss is 7" water, about the same as a vortex meter, but do I get a temperature effect.
I cant find data for this, I can argue its a pressure to velocity to pressure effect and thus the steam does not expand, therefore no cooling. But I can say the jet out of the orifice expands to the larger pipe diameter and thus must cool.
Anyone with hard data or a table





RE: Orifice plate ( superheated steam)
David
RE: Orifice plate ( superheated steam)
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Orifice plate ( superheated steam)
You can check how much cooling you will see using the steam tables for the inlet pressure and temperature to determine the inlet enthalphy. Determine the outlet temperature for the outlet pressure (based on your permanent dP) keeping dH = 0 but it won't be very much.
Google SteamTab, good program for steam properties.
RE: Orifice plate ( superheated steam)
Yes, you lower the flowing temperature while the stagnation temperature stays more or less unchanged.
RE: Orifice plate ( superheated steam)
In general, for flowing steam in insulated piping, the enthalpy plus kinetic energy are constant, H1 + KE1 = H2 + KE2. This will define temperatures at every point along the flow path.
Enthalpy is from ASME steam tables, Kinetic Energy is = 1/2 M*V*V
Be sure to use proper dimensional units, the equations given above are dimensionally consistant, and will prove correct in any rational system of units.
RE: Orifice plate ( superheated steam)
And I have done the enthalphy calc, and i didnt see any real temperature lose till far higher pressure losses.
Thanks all for confirming...