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GATE 2022 ME: RAC, PPE & IC Engines Revision Quiz

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Question 1

Which type of boilers are called drum-less boilers ________?

Question 2

A 4-stroke petrol engine at full load delivers 60 kW. It requires 8 kW to rotate it without load at the same speed and mechanical efficiency at full load is 88.51%. If the brake thermal efficiency is 30%, given that calorific value of the fuel is 45 MJ / kg and specific gravity of petrol is 0.80. The indicated thermal efficiency will be

Question 3

In Rankine cycle, the enthalpy of steam entering the turbine is 2800 KJ/Kg. The enthalpy at the end of actual expansion is 2130 KJ /Kg while enthalpy after isentropic expansion is 2000 KJ/Kg. The turbine efficiency is ____ %

Question 4

In an air-conditioning plant, air enters the cooling coil at 27 °C. The coil surface temperature is –5 °C. If the bypass factor of the unit is 0.4, the air will leave the coil at:

Question 5

In which steam cycle, cooling of steam is initially done?
i. Carnot cycle
ii. Rankine cycle
iii. Otto cycle
iv Brayton Cycle

Question 6

A stream of 1 kg of moist air at , specific humidity ry air mixes with another stream of 2 kg of moist air at , specific humidity ry air. The specific humidity of the mixture (in g/kg of dry air) is ______________.

Question 7

Match List-I with List-II and select the correct answer using the codes given below the lists:

Question 8

In an air conditioning process 1-2 as shown in figure. The Sensible heat factor and Latent heat factor respectively are,

Question 9

An ice making plant using refrigerant R-12 is having an evaporator saturation temperature of –25°C  and the condenser saturation temperature of 35°C . The vapour is leaving the compressor at 65°C . Following table shows the properties of the refrigerant.

Calculate the Coefficient of Performance (COP) of this system & Power consumption If the capacity of the plant is 5 kW. 

Question 10

In a simple vapour compression refrigeration cycle, the swept volume for the compressor is 2 litres and its volumetric efficiency is 80%. If the speed of the compressor is 1800rpm. Calculate the mass flow rate, . Take the value of

Question 11

A single cylinder 4-stroke engine if fitted with a rope brake. The diameter of the brake wheel is 600 mm and the diameter of the rope is 26 mm. The dead load on the brake is 200 N and the Spring balance reads 30 N. If the engine runs at 450 rpm, the brake power of the engine in kW is __________

Question 12

In order to control the temperature of steam in a steam generator, a spray type desuperheater is used. It is fed with water at 60 °C. Steam at 90 bar and 500 °C with flow rate 300 tons/hr enters the desuperheater. Neglect any pressure drop due to mixing and heat loss to the surrounding. Also given
hg (at 90 bar and 500 °C) = 3386.1 kJ/kg
hf (at 60 °C) = 251.11 kJ/kg
hg (at 90 bar and 450 °C) = 3256.6 kJ/kg
Amount of water that must be sprayed to maintain steam at 450 °C, is ___________ kg/s.

Question 13

A thermal plant is operating on Rankine cycle. Steam having enthalpy 3000 kJ/kg and entropy 5.4 kJ/kgK is produced at 3.5 MPa and 573K. This steam is fed to the turbine where it expands to a condenser pressure of 5kPa where hf = 138 kJ/kg, hg = 2561.6 kJ/kg, Sf = 0.4323 kJ/kg-K, Sg = 8.3960 kJ/kg-K. Calculate the enthalpy of steam at the exit of turbine _____kJ/kg

Question 14

Air is approaching a converging-diverging nozzle with a low velocity at 126ºC and 200 kPa, and it leaves the nozzle at a supersonic velocity. The velocity of air at the throat of the nozzle is

Question 15

Following data is obtained from a Rankine power plant:

Enthalpy at turbine inlet = 2765kJ/kg

Enthalpy after expansion = 1560kJ/kg

Heat addition = 2700kJ/kg

Pump work = 20KJ/kg

Generator efficiency = 95%

Calculate the overall plant efficiency (%) for the above data.

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