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InterviewSolution
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In an internal combustion engine, during the compression stroke the heat rejected to the cooling water is 50 kJ/kg and the work input is 100 kJ/kg. Calculate the change in internal energy of the working fluid stating whether it is a gain or loss. |
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Answer» Heat rejected to the cooling water, Q = – 50 kJ/kg (–ve sign since heat is rejected) Work input, W = – 100 kJ/kg (–ve sign since work is supplied to the system) Using the relation, Q = (u2 – u1) + W – 50 = (u2 – u1) – 100 or u2 – u1 = – 50 + 100 = 50 kJ/kg Hence, gain in internal energy = 50 kJ/kg. |
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