R4j4n
Chemical
- Oct 22, 2018
- 4
I have two orifices ( Capillary type ) in series in H2 service at 30 kg/cm2_g and 40 Deg C. Line size is 0.75 inch. As per their datasheet
1st Orifice: Do = 0.51 mm & L = 50 mm ; Pressure drop at Max flow : 6.89 kg/cm2_g
2nd orifice: Do = 0.51 mm & L = 50.83 mm ; ; Pressure drop at Max flow : 3.44 kg/cm2_g
Data sheet mentions that both are [highlight #A40000]restriction (choke)[/highlight] type venturi.
However, when I calculated critical pressure under the given condition to check the whether the flow is choked or not, Critical pressure comes out to be 15.2 kg/cm2_g, which is less that the combined pressure drop the two orifices can provide.
In plant, pressure drop measurement is only available across the last orifice.I need to calculate flow rate under operating conditions.
Need expert guidance.
1st Orifice: Do = 0.51 mm & L = 50 mm ; Pressure drop at Max flow : 6.89 kg/cm2_g
2nd orifice: Do = 0.51 mm & L = 50.83 mm ; ; Pressure drop at Max flow : 3.44 kg/cm2_g
Data sheet mentions that both are [highlight #A40000]restriction (choke)[/highlight] type venturi.
However, when I calculated critical pressure under the given condition to check the whether the flow is choked or not, Critical pressure comes out to be 15.2 kg/cm2_g, which is less that the combined pressure drop the two orifices can provide.
In plant, pressure drop measurement is only available across the last orifice.I need to calculate flow rate under operating conditions.
Need expert guidance.