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Define : i) Tonnage of refrigeration........

i) Tonnage of Refrigeration – is defined as the amount of refrigeration effect produced by uniform melting of one ton (1000Kg) of ice from and at 00 in 24 hours. .

ii) Coefficient of performance- is the ratio of heat extracted in refrigerator to work done on the refrigerant

What are the advantages of multistaging ?

1. The air can be cooled in between two cylinders 2. The power required is less 3. Mechanical balance is good 4. Reduced leakage losses 5. More volumetric efficiency 6. High pressure range 7. Comparatively lighter in construction

Enlist uses of compressed air (any four).

Following are the applications of compressed air 1) To drive air motors in coal mines. 2) To inject fuel in air injection diesel engines. 3) To operate pneumatic drills, hammers, hoists, sand blasters. 4) For cleaning purposes. 5) To cool large buildings. 6) In the processing of food and farm maintenance. 7) In vehicle to operate air brake. 8) For spray painting in paint industry.

Explain the working of window air conditioner with neat sketch.

The low pressure and low temperature refrigerant vapour from evaporator is sucked by compressor. The compressor compresses the vapour to high pressure and high temperature and discharges to the condenser. On the condenser the refrigerant vapour condenses by dissipating heat to the cooling medium (air) the liquid refrigerant coming out of condenser passes through filter, dryer into capillary tube where it is again throated back to the evaporated pressure.

Explain the working principle of jet propulsion with a neat sketch.

Working principle of jet propulsion - Jet propulsion is based on Newton’s second law and third law’s of motion. - Means producing forward axial thrust by means of reaction of jet of gases which are discharged rearward with a high velocity (aircraft, missile & submarine) - As applied to vehicle operating in fluid, a momentum is imparted to a mass of fluid in a such a manner that the reaction of imparted momentum furnishes a propulsive force. The magnitude of this propulsive force is termed as thrust.

Define.............

Define i) Free air delivered (FAD) – It is volume of air delivered under the condition of temperature and pressure existing at compressor intake, i.e. volume of air delivered at surrounding air temperature & pressure. In absence of any given free air conditions these are generally taken as 1.101325 bar and 150 c. ii) Compressor capacity – It is quantity of free air actually delivered by compressor in m3 /min. iii) Swept volume – It is the volume of air taken during sanction stroke. It is expressed in m3 . iv) Pressure ratio – It is defined as delivery pressure to suction pressure.

What is MPFI ? Explain any one MPFI system with neat sketch

The MPFI means multi point injection system. In this system each cylinder has number of injector to supply/ spray fuel in cylinder as compared to one injector located centrally to supply and spray fuel in case of single point injection system

 

 

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