DIERS Benchmarks page 283
Case 6
Churn-turbulent Download
DIERS case 6 is two-phase flow using the churn -turbulent flow regime model. The program will utilize the coupling equation to determine the flowing mass fraction entering the relief nozzle. The coupling equation is one of the most interesting DIERS two-phase models. To converge the coupling equation the flowing mass fraction must equal to the vapor volume fraction based on the flow regime model which in this case is churn-turbulent, where Ψ = α / (1-Coα). For convergence the LHS (left-hand side) of the coupling equation must equal the RHS(right-hand side). The Mach II shows the convergence as the intersection of the LHS and RHS below. The mass fraction converges at 0.054 quality. The flowrate is reduced to 64,204 lbs/hr which is less than the homogeneous flow rate calculated in DIERS safety valve benchmark case 7.
Mach II Output Graph and Report
Flowrate (lbs/hr) Choke(psia) Quality inlet dP / %Pset Outlet dP /%Pset Pipe
Churn-turbulent 64,624 52.7 0.078 ----------- ---------- nozzle
61,552 50.9 0.081 1.8 / 3.4 0.91 / 1.7 4 X 6
DIERS REsults
RRERSP 64,204 51.7 0.084 -------- -------- nozzle
RRERSP 62,273 50.4 0.059 1.5 / 2.8 3.1 / 6.0 4 X 6
