Question

In an ideal Brayton cycle, operating with air, the maximum and minimum cycle temperature are 298 K and 850 K respectively. For an optimum pressure ratio corresponding to maximum work output, the thermal efficiency (%) of cycle is, a) 41 b) 65 c) 51 d) 47

Answer 1

a)The efficiency =40.78 % or nearly 41%.

Step-by-step explanation:

Given that

maximum temperature = 850 K

minimum temperature = 298 K

We know that condition for optimum pressure for maximum work out put is given as

`T_2=T_4=√(T_1* T_3)`

So

`T_2=T_4=√(298* 850)`

`T_2=T_4=503.28 K`

We also know that efficiency of Brayton cycle given

`\eta =1-(T_1)/(T_2)`

So now by putting the values

`\eta =1-(298)/(503.28)`

`\eta =0.4078`

So the efficiency =40.78 % or nearly 41%.