Calculation of Flow rate - Intergraph Smart Instrumentation - Reference - Hexagon

Calculate internal pipe diameter at flow temperature:

Calculate correction factor for steam quality (for liquid, water, and gas FS=1);

Calculate orifice diameter at flow temperature.

1. For Lo-Loss tube, nozzles,and Venturi tubes:

   

2. For other orifices:

   

Calculate b ratio.

1. For all Flow meters except Segmental orifices:

   

2. Segmental orifices.

   1. Calculate segmental radius:

      

   2. Calculate b ratio.

      

      HS is calculated with the help of HS0 in accordance with step 3b.

Calculate gas expansion factor (for liquid and water, EPS=1).

1. For square edge orifice with 2½D and 8D pipe taps:

   

2. For Lo-Loss tube, nozzles,and Venturi tubes:

   

3. For eccentric orifices:

   

4. For square-edge orifices specified in ISO 5167-2003 (flange tappings, corner tappings, and radius tappings):

   

5. For other Flow meters:

   

Calculate first estimate for flow rate:

*W0 [kg/s]

Calculate Pipe Reynolds number:

*W0 [kg/s]

Calculate discharge coefficient.For more information see the Appendix.

Calculate new flow rate:

*W[kg/s]

For quarter of circle (Quadrant Edge) orifice, Lo-loss tube, Venturi tubes, and Segmental orifices go to step 13.

Calculate the relative change in Flow rate:

Repeat steps 7 to 11 until the relative change in the flow rate is less than 0.0001.

For quarter of circle (Quadrant Edge) orifice, calculate radius of upstream profile: