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

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Question 45

Fluid Mechanics & Thermal Sciences
Carnot Cycle
Edit

Appeared in Year: 2019

Question

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

Question

MCQ▾

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

Choices

Choice (4)Response

a.

75 %

b.

50 %

c.

100 %

d.

zero

Question 47

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

Appeared in Year: 2019

Question

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)

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