Question

Please answer question 7:

QUESTION 7 A centrifugal pump discharges 500 GPM through a 12-inch diameter impeller. The fluid leaves the impeller with a tangential velocity of 17 ft/sec. If water, @ 68°F, enters the impeller via radial flow (I.E. no whirl), and the inner radius and thickness of the impeller are 1.75-inches. (Assume a constant thickness of the impeller) and if the pump speed is 1775 rpm, with a head loss of 4.5-feet. What is the horsepower input to the flow by the pump? a. 4 HP b.1.25 HP OC. 2.5 HP od.4.4 HP e. 6 HP

A centrifugal pump discharges 500 GPM through a 12-inch diameter impeller.  The fluid leaves the impeller with a tangential velocity of 17 ft/sec.  If water, @ 68°F, enters the impeller via radial flow (I.E. no whirl), and the inner radius and thickness of the impeller are 1.75-inches.  (Assume a constant thickness of the impeller) and if the pump speed is 1775 rpm, with a head loss of 4.5-feet.  What is the horsepower input to the flow by the pump?

Answer 1

N . Given, Discharge Q = 500 GPM 1 = 1.114 t/sec Diameter of impeller d = gets 12" = 1' Diesen Tangential velocity (42) = 17 Ht/sec Diameter of impeller at radial flow D=175x2 -3.5" Rotation made by the pump = 1775 rpm = 4:5' Wikilo, Ue = D = **3*1775 -27-106 #/sec TN TX 35 12*1775 60 -27.106 60 Now , m = = (27.106)2 - 117) +4.5 2132.2) = 9.8856 Imput to the flow of Pump = 99 Q Hom Now, o 3

= na Mm = 162.43) (1114) (9.8856) = 687-514 lb . int-sec = 687.514 550 = 1:25002 ~ 1.25HP (b)