Question

A pump running at 840 liters / minute of a liquid with a specific density SG = 1,33 from an underground storage tank with opening to a pressurized reserve tank. Calculate:

a) the horsepower output of the pump if all losses are neglected.

b) pressure at the inlet and outlet of the pump, neglecting the losses.

Air at 825 kPa 15 m Flow 10 m Pump 3 m Suction pipe DN 65 Schedule 40

Answer 1

(a) Apply Bernoulli's Eqn at free surfaces of two tanks. [Datum= Lower surface] 2 + K 21 P2 + #tlp + Za theo zg 7 zg (3+10+15) =) tip 14.5 = + 825 9181 Hp = 98.59 m Discharge Lit 840 min 3 -3 840 x10 11 0.014 m3 60 i Power output of pump = rQ Hp = (-33*981)(0.014) (98.59) - 18 kW Hoose power 18x10 746 - 24.12 HP

(b Pin Pressure - @ inlet - 65mm Diameter of suction pipe velocity in suction pipe = A 0.014 5 (463) 1000) =4,22 m ک Apply. Bernoullis Eqn @ lower surface & pump inlet 2 + . Pin + Vin + Zin the Y Y ag 0 = Pin 1-33(9181) + + 3 3 4.223 249.81) Pin = -50 kPa pump. Pressure head im Pont = Pin + tp. nported by =-50 + 98.59(9181) (1-33). (en) 1236 kPa 1.33x9181 Pont