Question

In a gas turbine based on Brayton cycle, maximum and minimum temperature are ${900}^{\circ }C$ and ${20}^{\circ }C$ respectively The pressure ratio for maximum work output is

• A. 781.85
• B. 128.38
• C. 1.486
• D. 11.33

Answer 1

The correct option is D 11.33

$T_1=20+273=293K$

$T_3=900+273=1173K$

For maximum work output,

$r_{p,opt}={\left(\frac{T_3}{T_1}\right)}^{\frac{\gamma }{2(\gamma -1)}}={\left(\frac{1173}{293}\right)}^{\frac{1.4}{2(1.4-1)}}=11.33$