Question

the fan has total head of 190 m and A static pressure of 20 cm wg. If the air density is 1.15 kg/m3, what is the velocity of air flowing.

Answer 1

$\rho_{air}*h_a=\rho_{water}*h_w$

$h_a=\frac{200*10^{3}*10^{-3}}{1.15}$

=173.913

$∆h=190-173.913$

$=16.087$

$\frac{P_1-P_2}{\rho g}=\frac{V_2^{2}-V_1^{2}}{2g}$

$\frac{P_1-P_2}{\rho}=\frac{V_2^{2}-V_1^{2}}{2}$

V₁=0

$\therefore V_2=\sqrt{2g(∆h)}$

$=\sqrt{2*9.81*16.087}$

$=\sqrt{315.62694}$

$=17.7659m/s$