$6\mathrm{.}5.$ A $12-$in$.$ type$-$A globe valve $($Fig$.6\mathrm{.}7)$ is operating at $100\%$ open with

$P_u=75,P_{vg}=-12\mathrm{.}4,P_d=42.$ Is the valve cavitating?

Calculate $Q.$

Type$-$B valve

${}_e=0\mathrm{.}59+5\mathrm{.}6C_d-16C_d^2+90C_d^3$

${}_{id}=0\mathrm{.}48-6\mathrm{.}1C_d+53C_d^2-77C_d^3$

Fig. $6\mathrm{.}7$ Critical and incipient damage for $6$ in$.$ globe valves $,$

$\{$:$P_{\text{v}\text{g}\text{o}}=-12).$