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Q1. :A pump running at an efficiency of 70%,, delivers oil at a rate of 4 kg/s with a speed of 3 m/s to an oil, heater. If the vertical distance moved by the oil is 10 m, what, is the power consumption of the pump?, , Solution: Given: n = 70%, m = 4kg/s, v = 3 m/s, h= 10m,, g = 9.81 m/s”,, Power required to raise oil 8 m high, Praise = mgh, 4 (kg/s) x 9. 81 (m/s”) x 10 (m), 392.4 J/s, , Power to produce discharge speed, , 1.2, Puischarge = amv, , 0.5 x 4 (kg/s) x [3 (m/s)]?, 18 J/s, , ul, , Total Power, , Protat = Praise + Puischarge, 392.4 (W) + 18 (W), 410.44 (W), , 410.4 W represents 65% of the power supplied,, , Power Out, Power In, , Power Out, , Power in, n, , The total power consumption of pump =, , 410.4 (W), (70/100), , 586.2857 W, , n, , Power consumption of pump is 586.2857 W (1.d.p.)
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Q2::A Power Plant produces 400 MW. Find overall, efficiency of the plant. Assume Coal Consumption of plant, as 200 Tons per Hour. Calorific Value of Coal is 3800, kcal/kg. Use relation 1 kcal = 4.18 kJ., , Solution: Given Pour = 400 (MW),, Coal Consumption rate, = 200 (Tons /Hour) x 10° (kg/ton), , 1, * 3600 (hr/s), , = 55.56 kg/s, , Calorific Value of Coal = 3800 kcal/kg, = 3800 (kcal/kg) x 4.18 (kJ/ kcal), = 15884 kJ/kg, , Rate of coal consumption of plant, , = CVof coal x m,,, , = 15884 (kJ/kg) x 55.56 (kg/s), = 882444.4444 (kJ/s), , = 882.44 (MW), , The overall efficiency of plant can be obtained as, , _ Output from the plant, Input given to plant, , _ Pout, ~ Coal consumption rate of plant, , _ 400 (MW), N= 982.44 (MW), , 0.45, , Overall efficiency of plant is 45%
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Q 3: A wind farm site is observed to have steady, , winds at a speed of 10.5 m/s. Determine the wind energy (a), , per unit mass (b) for a flow rate of 1200 kg/s for air, and (c), , for a mass of 15 kg., , Solution: Given: winds at a speed V = 10.5 (m/s), , (b), , (o), , (a) The kinetic energy in wind is,, , KE =, , Loui, amv, , The kinetic energy per unit of mass in wind is, , 1, , ke = >V?, , 2, , for wind energy per unit mass, , ke =, , for airm =, , Wind power =, , Wind Energy =, , 1 2, 2 [10.5 (m/s)], , 55.125 (m?/s’), , 55.125 (J/kg), , 1200 (kg/s), , m ke, , 1200 (kg/s) x 55.125 (J/kg), 66150 (J/s), , 66.15 (kW), , 15kg, , m x ke, , 15 (kg) x 55.125 (J/kg), , 826.875 J.
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Q 4:A Toyota Etios liva engine generates a torque, 170 N-m. Capacity of eninge is 1197 cc. Determine the, power transmitted through the shaft of a car when the shaft, rotates at a rate of 4500 revolutions per minute (rpm)., , Solution: Torque = 170 (N-m), Shaft speed = 4500 (rpm), The shaft power is, , Porat = 20NT, , 2m x 4500 (rpm) x (1 min/60 s), x 170 (N-m), 80110.61 (J/s), , = 80.11 (kW)
