I am trying to set up a Mathcad document in which we can carry out our Thermal Relief Valve sizing based on the API 520 method.
All was working fine until I tried to run equation number 29 - A=((11.788*Q)/(Kd*Kw*Kc*Kv))*sqrt(G1/(P1-P2))
Mathcad gives a result with the units m^(7/2) / kg^(1/2). The only reason I can think that this is (I've checked all the units and carried out a unit balance and got the same unit result as mathcad) is that the constant 11.788 is not actually dimensionless and to give me an area unit result, this constant must have a unit of kg^(1/2) / m^(1 1/2).
Can anyone confirm this? And if this is the case, what is the best way for me to get around Mathcad's automatic unit balancing to get the answer in cm^2 as the API suggests that the outcome of the equation should be?
Thanks in advance for any help.
Stuart