GATE ME: Thermal Science Champion Quiz 5 for ESE & GATE ME Exams

Question 1

A p-v diagram has been obtained from a test on a reciprocating compressor. Which of the following represents that diagram?

Question 2

In a 3-stage air compressor, the inlet pressure is p₁, discharge pressure is p₄ and the intermediate pressure are p₂ and p₃ (p₂ < p₃). The total pressure ratio of the compressor is 10 and the pressure ratios of the stages are equal. If p₁= 100 kPa, the value of the pressure p₃ (in kPa. is_____

Question 3

In a Rankine cycle, regeneration results in higher efficiency because

Question 4

The INCORRECT statement about regeneration in vapor power cycle is that

Question 5

The vapor compression refrigeration cycle is represented as shown in the figure below, with state 1 being the exit of the evaporator. The coordinate system used in this figure is
$Description: D:\GradeStack Courses\GATE Tests (Sent by Ravi)\GATE ME 18-Mar\GATE-ME-2005_files\image186.jpg$

Question 6

A reciprocating compressor is to be designed to compress 4.5 kg/min of air from 100 kPa and 27C through an overall pressure ratio of 9. The law of compression is pV^1.3 = constant. Calculate the savings in power consumption , when a two-stage compressor with complete inter-cooling is used in place of a single stage compressor. Assume equal pressure ratio in both the stages of the two stage compressor. (Gas Constant = 0.287 kJ/kg-K).

Question 7

An ideal, air standard regenerative Brayton cycle is working between minimum and maximum temperatures of 300 K and 1200 K respectively.
(a) Find out the value of critical pressure ratio where the degree of regeneration becomes zero.
(b) Calculate the efficiency of the cycle when the operating pressure ratio is 60% of the critical pressure ratio.

Question 8

An ideal Brayton cycle, operating between the pressure limits of 1 bar and 6 bar, has minimum and maximum temperatures of 300 K and 1500 K. The ratio of specific heats of the working fluid is 1.4. The approximate final temperatures in Kelvin at the end of the compression and expansion processes are respectively

Question 9

In a Rankine cycle, the enthalpies at turbine entry and outlet are 3159 kJ/kg and 2187 kJ/kg respectively. If the specific pump work is 2 kJ/ kg. The specific steam consumption (in kg/kW-h) of the cycle based on net output is _________

Question 10

Steam at 300 kPa and 500 °C (h = 3486.0 kJ/kg) enters a steam turbine and exits at atmospheric pressure and 350 °C (h = 3175.8 kJ/kg). Heat losses in the turbine are 50 kW and the mass flow rate is 0.25 kg/s. Determine the power output of the turbine if kinetic energy losses are negligible.