Question

Slalludlu basis with a n 9.36 Solve Problem 9.35 on a cold d specific heats evaluated at 298 K. (0.37 Consider an ideal air-standard Brayton cycle wit minimum and maximum temperatures of 298 K and 1400 respectively. The pressure ratio is that which maximizes the net work developed by the cycle per unit mass of air flow On a cold air-standard basis, calculate (a) the compressor and turbine work per unit mass of air flow, each in kJ/kg. (b) the thermal efficiency of the cycle. (c) Plot the thermal efficiency versus the maximum cycle temperature ranging from 1200 to 1800 K. 9.38. On the basis of a cold air-standard analysis, show that the

Answer 1

Soln Civen! - Ti =290k T3 = 1400k ble know that Pressure ration het wook - for maximum Port = Seman) s Imax = Tmax airn 1.4 Process 1-2 290 T2 = 7, (op) = 290 (15) itu = 14.99 import = 15 Ta = 645.9k fx mum power Tq Tq= 137 645.9* Tq=298x1400 Compress of work- Using SFEE> wth, to= hato he Cpl Tg-T) = 1.0051645.9 – 290) Tq = 645.9k The = 349.66 kJ/kg / Compressor klook

Turtone work- Using SFEE- hz = hqthly klep Cpl Tz-TA) = 1005( 1400–645.9) 1 kly = 757.07 kolky Turbine blosk ② Heat supplied - Heat supplied during process 2 to 3. Ps = G(T3-T) = 1.005 (1400 – 645.9) as = 757.07 kJ/kg and What = Wp- hle s 757.07 – 349166 What = 400. 2 kilkg Hence Thermal efficiency = 7 kluet Heat supplied - 4 = 4od. 2 757.07 Y=1538 Efficiency, Y = 538641

po 1 Dook Yoohl 12001 Efficiency Pressure Ration