From 68aa65640185537cd566c3739bbe81fd339651cb Mon Sep 17 00:00:00 2001 From: Thomas Beutlich Date: Tue, 16 Jan 2024 23:06:09 +0100 Subject: [PATCH] Fix loss factors in SharpEdgedOrifice (#4258) Co-authored-by: Stefan Wischhusen --- Modelica/Fluid/Fittings.mo | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/Modelica/Fluid/Fittings.mo b/Modelica/Fluid/Fittings.mo index 8243430734..557c1a55a0 100644 --- a/Modelica/Fluid/Fittings.mo +++ b/Modelica/Fluid/Fittings.mo @@ -1050,15 +1050,15 @@ A_a > A_b (Idelchik 1994, diagram 4-9, p. 216 and diagram 4-10, p. 217) output LossFactorData data "Pressure loss factors for both flow directions"; protected - Real D_rel=leastDiameter/diameter; + Real A_rel=(leastDiameter/diameter)^2; Real LD=length/leastDiameter; Real k=0.13 + 0.34*10^(-(3.4*LD + 88.4*LD^2.3)); algorithm data.diameter_a := diameter; data.diameter_b := diameter; - data.zeta1 := ((1 - D_rel) + 0.707*(1 - D_rel)^0.375)^2*(1/D_rel)^2; - data.zeta2 := k*(1 - D_rel)^0.75 + (1 - D_rel)^2 + 2*sqrt(k*(1 - - D_rel)^0.375) + (1 - D_rel); + data.zeta1 := ((1 - A_rel) + 0.707*(1 - A_rel)^0.375)^2*(1/A_rel)^2; + data.zeta2 := k*(1 - A_rel)^0.75 + (1 - A_rel)^2 + 2*sqrt(k*(1 - + A_rel)^0.375) + (1 - A_rel); data.Re_turbulent := 1e4; data.D_Re := leastDiameter; data.zeta1_at_a := true;