Pipe Flow Calculations Forum

Hi, I'm new to the forum and new to flow calculations (apart from a module at University 5 years ago). I'm currently looking into manually calculating flow through an SAO (Smooth Approach Orifice). I've hit a roadblock recently, and I'm not sure where I've gone wrong.

I've attached a document which hopefully explains what I am trying to do and the formulae involved. The SAO flow is derived from equation 4 in the document and equations 5, 6 and 7 are used to calculate variables for this formula.

I know I've gone wrong somewhere and I've been over it a hundred times but can't figure it out.

In terms of Raw Data, I have 10Hz data for SAO inlet P (kPa), SAO dP ("H2O), SAO T(degC) and Barometric Pressure (kPa). The SAO inlet diameter is 100inches (which I believe is just entered as a large number) and the throat diameter is 3.348in.

Can anyone please have a look through this and try to spot the error for me?

let me know if you need more info or example data.

If you can give me values for pressures and temperature, with calculator on:
http://www.pipeflowcalculations.com/orifice/index.htm you can calculate flow through orifice with ease.

Also, theory that is used for that calculator you can find at:
http://www.pipeflowcalculations.com/pip ... ifices.htm

Now, if you can use these two to compare with your document, maybe you can find if there are any differences.