a$)$ A centrifugal pump is situated $12\mathrm{.}5m$ vertically above the surface of liquid toluene in

a tank which is open to atmosphere and at $30C.$ Show that even if primed, the pump could

not lift liquid toluene from the tank under this condition.

If the minimum NPSH of the pump is $0\mathrm{.}65m$ of water under this condition and inside pipe

diameter is $2\mathrm{.}3cm,$ calculate

i$)$ the maximum height at which the pump could be located above the toluene surface

to deliver the liquid at $0\mathrm{.}002\frac{m^3}{sec}$ after priming, without risk of cavitation and if the

suction pipe just dipped into the toluene in the tank. The pipe may be considered smooth.

ii$)$ The maximum delivery rate after priming which could be obtained without the risk

of cavitation if the pump were located $9m$ above the liquid surface with suction pipe just

dipping into the liquid $($friction factor has same value as in section i$).$

Saturated vapour pressure of toluene at $30C$:$4\mathrm{.}535$kPa

Density of toluene at $30C$:$867k\frac{g}{m^3},$ Viscosity of toluene at $30C$:$5\mathrm{.}26{10}^{-4}k\frac{g}{m}-s$

Density of water: $867k\frac{g}{m^3}$

For turbulent flow in smooth pipe, $f=0\mathrm{.}0390NR{e}^{-}\mathrm{.}25$