Summary

There are several common ways to express the losses caused by pipe fittings and equipment. Depending on the calculation programs or methods available and engineer may require to convert between one form or another. This article details the equations required to convert between the resistance coefficient and flow coefficient methods (K, CvC_{v} and KvK_{v} ).

Definitions

DD:Internal diameter of the Pipe (mm)
CvC_{v}:Flow Coefficient in USgpm, psi
KvK_{v}:Flow Coefficient in m3/hr, bar
KK:Resistance Coefficient

Conversion Relationships

Conversion formulae for converting between K, CvC_{v} and KvK_{v} .

Convert FromConvert ToFormula
CvC_{v}KvK_{v}Kv=0.8646CvK_{v} = 0.8646 C_{v}
CvC_{v}KKK=2.148×10−3×D4Cv2K = 2.148 \times 10^{-3} \times \frac{D^{4}}{C_{v}^{2}}
KvK_{v}CvC_{v}Cv=1.157KvC_{v} = 1.157 K_{v}
KvK_{v}KKK=1.604×10−3×D4Kv2K = 1.604 \times 10^{-3} \times \frac{D^{4}}{K_{v}^{2}}
KKCvC_{v}Cv=0.04634D2KC_{v} = 0.04634 \frac{D^2}{\sqrt{K}}
KKKvK_{v}Kv=0.04007D2KK_{v} = 0.04007 \frac{D^2}{\sqrt{K}}