n the centrifugal fan impeller there is a loss by friction of 0.4 times the kinetic head corresponding to the relative outlet velocity, and in the volute there is a gain equivalent to 0.5 times the kinetic head corresponding to the absolute velocity at exit from the runner. The impeller has an inner radius of 250 mm and width of 187.5 mm; the values at exit are 375 mm and 125 mm, respectively. There is no whirl at inlet, and at outlet the blades are backward facing at 70° to the tangent. The discharge of air is 5.7 m3/s when the speed is 13.5 rps, the density of the air is sensibly constant at 1.25 kg/m3 throughout, and mechanical losses account for 220 Watts. Neglecting the thickness of the blades and whirl slip, determine the following:The head gained, in meters, across the fan. The Brake Horsepower required to drive the fan
In the centrifugal fan impeller there is a loss by friction of 0.4 times the kinetic head corresponding to the relative outlet velocity, and in the volute there is a gain equivalent to 0.5 times the kinetic head corresponding to the absolute velocity at exit from the runner. The impeller has an inner radius of 250 mm and width of 187.5 mm; the values at exit are 375 mm and 125 mm, respectively. There is no whirl at inlet, and at outlet the blades are backward facing at 70° to the tangent. The discharge of air is 5.7 m3/s when the speed is 13.5 rps, the density of the air is sensibly constant at 1.25 kg/m3 throughout, and
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