Calculation of Beta Ratio - 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 scale reading factor:

Calculate differential pressure at normal flow rate:

Calculate Pipe Reynolds number at normal flow rate:

Calculate first estimate for b ratio:

1. For Venturi tubes:

   

2. For other Flow meters:

   

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

1. For square-edge orifice with 21/2D and 8D pipe taps:

   

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

   

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 discharge coefficient.For more information see the Appendix.

Calculate new b - ratio

Calculate the relative change in b - ratio.

Repeat steps 7 to 10 until the relative change in the b -ratio is less than 0.0001.

Calculate orifice diameter at flow temperature:

1. For all Flow meters except Segmental orifices:

   

2. Segmental orifices:

   1. Calculate Segmental radius:

      

   2. Calculate Segmental height at flow temperature using the equation:

      

For further calculation of Segmental orifices, HS and HS0 are analogous to d and d0 respectivly.

Calculate orifice diameter at ambient temperature:

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

   

2. For other orifices:

   

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