Question

1a. An air-standard cycle consists of the following processes: isentropic compression from 15 ?C, 1.01 bar through a compression ratio of 5:1; heat addition at constant volume of 2600 kJ/kg; isentropic expansion to the initial volume; heat rejection at constant volume. Sketch the cycle on p-v and T-s diagrams, and calculate its ideal efficiency, mean effective pressure and peak pressure.

Answers(0.475, 18.9 bar, 73.0 bar)

b. The cycle is problem (a) is modified so that the heat is added

(a) at constant pressure,

(b) half at constant volume and half at constant pressure. The compression ratio is increased so as to allow the same peak pressure as before. Sketch the two cycles on p-v and T-s diagrams, and calculate their ideal efficiencies and mean effective pressures.

ANSWER ((a) rv = 21.3, 0593, 19.8 bar (b) rv = 8.37, 0.552, 19.9 bar)

Answer #1

1) An ideal gas is contained in a
piston-cylinder device and undergoes a power cycle as follows:
1-2 isentropic compression from an initial
temperatureT1= 20 degree celsius with a compression ratio
r = 5
2-3 constant pressure heat addition 3-1 constant volume heat
rejection
The gas has constant specific heats with cv = 0.7
kJ/kg·K and R= 0.3 kJ/kg·K.
(a) Sketch the
P-v and T-s diagrams for the cycle.
(b) Determine the heat
and work interactions for each pro-cess, in...

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2) An air-standard Otto cycle operates with a minimum
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10) An air-standard Otto cycle has a compression ratio of 9. At
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Find:
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1) A nozzle is a device for increasing the velocity of a
steadily flowing stream of fluid. At the inlet to a certain nozzle
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