Calculate the thermal efficiency of a cycle that is the same as the diesel cycle but with two polytropic processes instead of adiabatic and with mass of air=1 kg r=287 J/kgK gamma=1.4 and plot its TS diagram. Given: P1=0.9 bar, P2=4 bar, t1=85 c, t2=600 c, n=1.2

1->2: polytropic

2->3:isobaric

3->4:polytropic

4->1:isochoric

 

A piston–cylinder assembly contains air modeled
as an ideal gas with a constant specific heat ratio, k =
1.4. The air undergoes a power cycle consisting of
four processes in series: Process 1–2: Constanttemperature expansion at 600 K from p1 = 0.5 MPa to
p2 = 0.4 MPa. Process 2–3: Polytropic expansion with
n = 1.35 to p3 = 0.3 MPa. Process 3–4: Constantpressure compression to V4 = V1. Process 4–1:
Constant-volume heating. Determine (a) the work and
heat transfer for each process, in kJ/kg, and (b) the
thermal efficiency. 

A regenerative gas turbine power plant is
shown in Fig. P1. Air enters the compressor at 1
bar, 27ºC with a mass flow rate of 0.562 kg/s and
is compressed to 4 bar. The isentropic efficiency of
the compressor is 80%, and the regenerator
effectiveness is 90%. All the power developed by
the high-pressure turbine is used to run the
compressor. The low-pressure turbine provides the
net power output. Each turbine has an isentropic
efficiency of 87% and the temperature at the inlet
to the high-pressure turbine is 1200 K. Sketch the
corresponding T – s diagram and determine: (a) The net power output, in kW. (b) The thermal
efficiency. (c) The temperature of the air at states
2, 3, 5, 6, and 7, in K. 

An ideal Otto cycle with Argon as the working fluid has a compression ratio of 6.8. The minimum and maximum temperatures in the cycle are 450 R and 2,260 R. Assuming constant specific heats, determine

(a) the amount of heat transferred to the argon during the heat-addition process

(b) the thermal efficiency

(c) the thermal efficiency of a Carnot cycle operating between the same temperature limits