Head at the base of the nozzle 80 m Diameter of the jet 100

Head at the base of the nozzle: 80 m Diameter of the jet: 100 mm Discharge of the nozzle: 0.30 m^3/s Power at the shaft: 206 Kw Power absorbed in mechanical resistance: 4.5 kW Determine Power lost in nozzle?

Solution

Area of jet =/4 d2 = /4 (0.1)2 = 0.007854m2

Calculate the velocity of fluid Q= AV

0.3 = 0.007854 x v

V = 38.197 m/s

Calculate power at base of nozzle

P = rho Qgh / 1000

P = 1000x9.81x0.3x80/1000

P = 235.44 kw

Calculate power corresponding to kinetic energy

Pkinetic = 1/2 mv2

m = rho x Q

Pkinetic = 1/2 x1000x0.3x38.1972

Pkinetic = 218.85 kw

Now

Power at base of nozzle = power of jet + power lost in nozzle

Power lost in nozzle =235.44-218.85

= 16.59kw