The pressure ratio and maximum temperature of a Brayton cycle are 5:1 and 928 K respectively. Air enters the compressor at 1 bar and 300 K. What will be the network output of the cycle per kg of air flow?

[\(C_p = 1.0 \, \text{kJ/kg-K}, \gamma = 1.41, 5^{\frac{(0.41)}{(1.41 ) }} = 1.6\) ]

This question was previously asked in
SJVN ET Mechanical 2019 Official Paper
View all SJVN Executive Trainee Papers >
  1. 256 kJ/kg
  2. 205 kJ/kg
  3. 120 kJ/kg
  4. 168 kJ/kg

Answer (Detailed Solution Below)

Option 1 : 256 kJ/kg
Free
SJVN ET General Awareness Mock Test
0.8 K Users
20 Questions 20 Marks 12 Mins

Detailed Solution

Download Solution PDF

Concept:

The Brayton cycle is an ideal gas turbine cycle that consists of isentropic compression, constant-pressure heat addition, isentropic expansion, and constant-pressure heat rejection. The net work output is the difference between turbine and compressor work.

Given:

Pressure ratio, \( r_p = 5 \)

Inlet temperature, \( T_1 = 300~K \)

Maximum temperature, \( T_3 = 928~K \)

\( C_p = 1.0~\text{kJ/kg·K},~\gamma = 1.41 \)

Calculation:

\( T_2 = T_1 \times r_p^{\frac{\gamma - 1}{\gamma}} = 300 \times 5^{\frac{0.41}{1.41}} \approx 300 \times 1.6 = 480~K \)

\( T_4 = T_3 \times r_p^{-\frac{\gamma - 1}{\gamma}} = 928 \div 1.6 = 580~K \)

Net work output per kg of air:

\( W_{net} = C_p \left[ (T_3 - T_4) - (T_2 - T_1) \right] \)

\( W_{net} = 1.0 \times \left[ (928 - 580) - (480 - 300) \right] = 348 - 180 = 168~\text{kJ/kg} \)

 

Latest SJVN Executive Trainee Updates

Last updated on Jul 15, 2025

-> SJVN Executive Trainee Written Exam date is out, The computer based exam will be held on 10th, 14th August 2025.

->SJVN Executive Trainee recruitment 2025 application form has been released. Applicants can apply for the SJVN recruitment 2025 Executive Trainee till May 18.

->SJVN Limited has announced the recruitment notification for the position of Executive Trainee 2025.

->A total of 114 vacancies are available for the SJVN Executive Trainee Recruitment across various disciplines such as Civil, Mechanical, Electrical, Environment, Electronics & Communication, and more.

->The selection process of SJVN Executive Trainee recruitment 2025, as per the previous notification, includes a Computer-Based Test, Group Discussion, and Personal Interview.

->Once selected, candidates will be required to sign a service agreement bond of Rs. 10,00,000/- (Rs. 7,50,000/- for SC/ST/PWD candidates), committing to complete the prescribed training and serve the company for a minimum of 3 years.

->Candidates must refer to the SJVN Executive Trainee Previous Year Papers and boost their preparation for the exam.

Get Free Access Now
Hot Links: teen patti club apk teen patti master golden india teen patti lucky