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, Cv and Kv).
Definitions
| $D$ | : | Internal diameter of the Pipe (mm) |
| $C_{v}$ | : | Flow Coefficient in USgpm, psi |
| $K_{v}$ | : | Flow Coefficient in m3/hr, bar |
| $K$ | : | Resistance Coefficient |
Conversion Relationships
Conversion formulae for converting between K, Cv and Kv.
| Convert To | ||||
|---|---|---|---|---|
| Cv | Kv | K | ||
| Convert From | Cv | - | $$ \displaystyle K_{v} = 0.8646 C_{v} $$ | $$ \displaystyle K = 2.148 \times 10^{-3} \times \frac{D^{4}}{C_{v}^{2}} $$ |
| Kv | $$ \displaystyle C_{v} = 1.157 K_{v} $$ | - | $$ \displaystyle K = 1.604 \times 10^{-3} \times \frac{D^{4}}{K_{v}^{2}} $$ | |
| K | $$ \displaystyle C_{v} = 0.04634 \frac{D^2}{\sqrt{K}} $$ | $$ \displaystyle K_{v} = 0.04007 \frac{D^2}{\sqrt{K}} $$ | - | |
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