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THERMAL ENGINEERING-1 (UNIT-5)

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UNIT-5 Compressors:  Classification –positive displacement and roto-dynamic machinery – Power producing and power absorbing machines, fan, blower and compressor – positive displacement and dynamic types – reciprocating and rotary types. Reciprocating: Principle of operation, work required, Iso-thermal efficiency, volumetric efficiency and effect of clearance, multi stage compression, under cooling, saving of work, minimum work condition for two stage compression. Classification of Compressors : Positive Displacement Type : In this type of compressors,  air is physically trapped between to relatively moving components and forced to occupy lower volume,  thereby increasing its pressure.  Most notable example would be, a reciprocating compressor. In which air is trapped between piston and cylinder volume and then literally pressed to increase its pressure. Another point of interest is the output of these pumps. Since constant volume is being ...
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THERMAL ENGINEERING-1 (UNIT-3)

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UNIT-3 Combustion in S.I. Engines : Normal Combustion and abnormal combustion – Importance of flame speed and  effect of engine variables – Types of Abnormal combustion, pre-ignition and knocking (explanation of ) – Fuel  requirements and fuel rating, anti knock additives – combustion chamber – requirements, types. Combustion in C.I. Engines : Four stages of combustion – Delay period and its importance – Effect of engine  variables – Diesel Knock– Need for air movement, suction, compression and combustion induced turbulence –  open and divided combustion chambers and nozzles used – fuel requirements and fuel rating. Introduction : Combustion may be defined as a relatively rapid chemical combination of hydrogen and carbon in fuel with oxygen in air resulting in liberation of energy in the form of heat. Following conditions are necessary for combustion to take place:  1. The presence of combustible mixture  2. Some means to initiate m...
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THERMAL ENGINEERING-1 (UNIT-2)

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UNIT-2 I. C. ENGINES : Classification - Working principles, Valve and Port Timing Diagrams, - Engine systems – Fuel, Carburettor, Fuel Injection System, Ignition, Cooling and Lubrication, principle of wankel engine, principles of supercharging and turbo charging. I.C Engines Classification : According to combustion:Internal combustion (I.C) and External Combustion (EC) According to Type of fuel used: Petrol, diesel , gas / Alternative Fuels According to Number of strokes –Two stroke , four stroke  According to Type of ignition such as  Spark Ignition (SI), Compression Ignition (CI) According to Number of Cylinders – From 1 to up to 18 cylinders (in a car) According to Arrangement of cylinders which are Inline, V, W, Horizontal, Radial According to Motion of Pistons which are Reciprocation, Rotary According to Size / Capacity According to Bore-to-Stroke Ratio According to Engine cooling methods such as Air-cooled, Liquid-c...
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