I wish to add density compensation in high pressure superheated steam flow measurement. The pressure and temp variations are very high. I have temp sensor and press transmitter located near the orifice plate. Can anyone suggest the perfect formula for the same please??

 

One easy answer would be to use a multi-variable xmtr and let the Xmtr do the work. This allows the xmtr to dynamically compensate for your P&T swings. It is an easy retro-fit. Rosemount 3095MA for instance...

Hope this helps.

Cheers!!
Roley

 

Dear VGN,

Steam Tables -> Table Lookup -> Interpolation in the DCS/SCADA/PLC or some custom flow computer to calculate the same.

Tomy Zacharia

 

Agree with Roley. We use that method for steam turbines.

JC

 

The program FlowCalc can calculate a good flow formula to use with your orifice plate. It will also show diagrams of the accuracy of the formula compared to a ISO 5167 flow calculation.

There is a description of density and temperaure compensation if the program manual.

The program and manual can be downloaded from http://www.controlengineering.se

Hope this helps.
Kristian Rapp
Control Engineering Sweden AB

 

Density = ( Molecylar weigth * Pressure) / (8.3143 * Temp).

Example N2:
Molycular weight N2 = 0.028kg/mol
Pressure 101.35 Pa (1atm)
Temp = 25 deg C

=> Denisty = 1.25kg/m3

For steam: put in molecylar weigth and recalculate

 

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What about this formula: http://2v6.hit.bg/images/f1.gif

It's for specific volume v [m3/kg]
density [kg/m3]=1/v

 

Could somebody tell me what will be the velocity of steam in 3" pipe under 32 bar pressure.