Question

Combined Head Loss in Systems ($10.8) A heat exchanger consists of 15 m of copper tubing with an internal diameter of 15 mm. There are 14 return elbows in the system with a loss coefficient of 2.2 for each elbow. The pump in the system has a pump curve given by hp = hp0|1 - 21 Qmax where hpo is head provided by the pump at zero discharge and Qmax is 10-3 m/s. Water at 40°C flows through the system. Find the system operating point for values of hpo of 2 m, 10 m, and 20 m. Pump PROBLEMS 10.75, 10.76

Answer 1

b = \(\- given data d=15mm L= 15m K= 2.2 n= 14 Smay = \s 3 mºl & ac. Let us assume the value of friction factor is for Forhipo-am for mulet tot To Calculate head the is tot mix) & av Loolsx 156 +14%8-8) Q. O'015 39.24 = 12x45.8 ve - 0.9256 Q=XV = I x 0:015)*80.9256 Q. = 1.6356 8 10-04 m3/sec. tup= [-(.]

S6 X 1094321 RO Thp = ligga Thus the system the System operating point for values ho am is 1.99m For hp = lom Formula to calculate head is, lo a enten ( 0015 Mesos + 19789) 1916..2 = 12x 45.8 10=2.069 misec QE TI de xv X0.0152X20694 Q. - 3.6575X10-4 m3/sec the = 9.510725ml the System operating point for lom is 9.510725 m Thus the System of

for horaom Formula to calculate themel the way by 48K) 20 V2 10.015x15 - 14X98) 2x9.811 0015 592.4 = 12 x 45.8 V=2.997 mesec 45 x 10.013)?x2927 = 5.17.24 35 x10*4 thp = hro (1-4)") 6442935 X10:41 11-05:19.2935X/0-413 20 (10 3 p = 17.252 m ) Thus the System operating point for value 20 m is 11-1327