Calculation of a generic pressure loss in dependence of a pressure loss coefficient.
The mass flow rate m_flow is determined by:
m_flow = rho*A_cross*(dp/(zeta_TOT *(rho/2))^0.5
with
| A_cross | as cross sectional area [m2], | 
| dp | as pressure loss [Pa], | 
| rho | as density of fluid [kg/m3], | 
| m_flow | as mass flow rate [kg/s], | 
| zeta_TOT | as pressure loss coefficient [-]. | 
Compressible case [Mass flow rate = f(dp)]:
The mass flow rate M_FLOW in dependence of the pressure loss dp for a constant pressure loss coefficient zeta_TOT is shown in the figure below.
 
Note that the verification for dp_pressureLossCoefficient is also valid for this inverse calculation due to using the same functions.