Question

Water at 160° Fis drawn at the rate of 400 gal/min from a vented tank into the 2-in Sch 40 suction line of the pump made of steel. The suction line has a total length of 10 ft. the discharge line elevates the water 30 ft to the level of the large heat exchanger. The discharge line has a total length of 40 ft. The system contains: 2 standard elbows, 1 swing check valve, and 4 open gate valves. Assuming the pump efficiency is 78%. Find the power Heat exchanger Branch system is in the same horizontal plane 2-in 30 ft Pump Flow 9 ft

Answer 1

Givens - Temperature of water T=168F, [Density bilb] flow rate. = 400 gal/min = 0.8912 ft3c Sagpma 0.00222 f3, Diameter of sch-40 zin pipe , d = 2.067 in = 2006 ft Aleea of Cross-section. A- fix de 4x(2-047)0.0233 1= 0.00222 Soi Velocity of water in pipe, V = 9 _0.8912 = 38.249 1. ft2 Ā 0.023330 Relative Roughness of 2 in Sch-40,€ = 0.00085 ft/s so, friction factor (coolbrook equation) for Renlos fe 0:c19 Now consider fittings in the pipe 2 standered elbow -> KF = 0,3 X2 = 0.6 . 1 swing check valve => Kg =2 . 4 open gate Valve = Kg = 440.2= 0.8

so, Total loss co-efficient. Ek=KEtks ttg = 0.6+2+0.8 so, Total Head Loss, hy = ( EK + f Lpipe žg h = 3,4+ 0.019X501 x 38.2492 = 202.7ft L 2.0672) S 2x32.174 h = 202. 7 ft

so. Using Besenoulli's Equation between Vented - tank and outlet of pipe, pumn AY 9 [Pa = P2 = Pato , because both ace open to atmos-> V, -o , Velocity Inside tank -phere so, Equation become. 2, thpump = 1 + Zthe .. 9 + hpump = 38.2492 +30 +202.7 2x32.174 =) hpump = 246.435 Ft Son Powere required = es ghpump - 61x0.8912x246-495 ХЯ pump 0.78 powerle = 17175.634 lbfofty7 = 34.228 hp