A new engineer who just joined Air Selangor operates a self$-$priming centrifugal pump at

volume flow rate, V $=70$ LPM$.$ The centrifugal pump is used to pump water at $25\backslash$deg C

from a reservoir whose surface is $2\mathrm{.}2$ m above the centreline of the pump inlet $($Figure

$1).$ The reservoir is open to the atmosphere. The pipe is PVC with an ID of $24\mathrm{.}0$ mm and

negligible average inner roughness height. The pipe length from the submerged pipe

inlet to the pump inlet is $2\mathrm{.}8$ m$.$ There are only two minor losses in the piping system,

from the pipe inlet to the pump inlet: a sharp$-$edged re$-$entrant inlet $($KL $=0\mathrm{.}85)$ and a

flanged smooth $90\backslash$deg regular elbow $($KL $=0\mathrm{.}3).$ The pump is to supply a minimum

pressure of $5$ bar to the pipe outlet Obtain the pump power needed if the overall

efficiency of the pump is $85\%.$ At T$=25\backslash$deg C$,$ take p$=999\mathrm{.}7$ kg$/$m$^3$ h $=8\mathrm{.}91$x$10$~$4$ kg$/$

ms and Patm$=101\mathrm{.}325$kPa