An air-standard cycle consists of the following processes: (i) isentropic compression from 15C, 1.01 bar through a compression ratio of 5:1. (ii) heat addition at constant volume of 2600 kJ/kg. (iii) reversible adiabatic expansion to the initial volume. (iv) heat rejection isochorically. For air take R = 0.287 kJ/(kg·K) and cP = 1.005 kJ/(kg·K). Sketch the cycle on P-v and T-s diagrams, and calculate its ideal efficiency, mean effective pressure and peak pressure. Take the start of isentropic compression as state point 1.
Q#01
An air-standard cycle consists of the following processes:
(i) isentropic compression from 15C, 1.01 bar through a compression ratio of 5:1.
(ii) heat addition at constant volume of 2600 kJ/kg.
(iii) reversible adiabatic expansion to the initial volume.
(iv) heat rejection isochorically.
For air take R = 0.287 kJ/(kg·K) and cP = 1.005 kJ/(kg·K). Sketch the cycle on P-v and
T-s diagrams, and calculate its ideal efficiency, mean effective pressure and peak pressure. Take the start of isentropic compression as state point 1.
Now the cycle above is modified in two ways so the heat is added, i.e.,
(a) isobarically, and
(b) half isochorically and half isobarically.
Take the start of isentropic compression in both the cases as state point 1. Compression
ratio is increased so as to follow the same peak pressure as before. Now sketch these two
cycles on both P-v and T-s diagrams, and calculate their ideal efficiencies and mean effective pressures. The values of R and cP remain the same.
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