Fluid Mechanics & Thermal Sciences [GATE (Graduate Aptitude Test in Engineering) Mechanical Engineering]: Questions 45 - 47 of 77

Access detailed explanations (illustrated with images and videos) to 314 questions. Access all new questions- tracking exam pattern and syllabus. View the complete topic-wise distribution of questions. Unlimited Access, Unlimited Time, on Unlimited Devices!

View Sample Explanation or View Features.

Rs. 250.00 -OR-

How to register? Already Subscribed?

Question 45

Fluid Mechanics & Thermal Sciences
Carnot Cycle

Appeared in Year: 2019


Numeric Answer▾

Air of mass 1 kg, initially at 300 K and 10 bar, is allowed to expand isothermally till it reaches a pressure of 1 bar. Assuming air as an ideal gas with gas constant of 0.287 kJ/kg. K, the change in entropy of air (in kJ/kg. K, round off to two decimal places) is________

Question 46

Fluid Mechanics & Thermal Sciences
Turbulent Flow

Appeared in Year: 2020



The values of enthalpies at the stator inlet and rotor outlet of a hydraulic turbo machine stage are and respectively. The enthalpy at the stator outlet (or, rotor inlet) is . The condition indicates that the degree of reaction of this stage is


Choice (4)Response


75 %


50 %


100 %



Question 47

Fluid Mechanics & Thermal Sciences
Rankine and Brayton Cycles with Regeneration and Reheat

Appeared in Year: 2019


Numeric Answer▾

A gas turbine with air as the working fluid has an isentropic efficiency of 0.70 when operating at a pressure ratio of 3. Now, the pressure ratio of the turbine is increased to 5, while maintaining the same inlet conditions. Assume air as a perfect gas with specific heat ratio . If the specific work output remains the same for both the cases, the isentropic efficiency of the turbine at the pressure ratio of 5 is ________ (round off to two decimal places)

Developed by: