Water Flow Rate Through a Valve

Water Flow Rate Through a Valve formula

\(\large{ p_1 - p_2 < F_l^2  \left( p_1 - F_f  \; p_{av} \right) \rightarrow }\)
(Eq. 1)  \(\large{ Q_w = C_v \; \sqrt { \frac{ p_1 \;-\; p_2 }{ SG }  }   }\)
\(\large{ p_1 - p_2 \ge F_l^2  \left( p_1 - F_f \; p_{av} \right) \rightarrow }\)
(Eq. 2)  \(\large{ Q_w =  C_v \; F_l \;  \sqrt { \frac{ p_1 \;-\; F_f \; p_{av} }{ SG }  }   }\)

Where:

\(\large{ Q_w }\) = water flow rate

\(\large{ p_{av} }\) = absolute vapor pressure of the water at inlet temperature

\(\large{ F_f }\) = liquid critical pressure ratio factor

\(\large{ p_1 }\) = primary pressure

\(\large{ p_2 }\) = secondary pressure

\(\large{ F_l }\) =id pressure recovery factor (= 0.9)

\(\large{ C_v }\) = valve flow coefficient

\(\large{ SG }\) = specific gravity of water