-ic-engines-and gas turbine presentation.pptx

It is about IC engine and gas turbine

1. Heat Engine A heat engine is a system that converts heat or thermal energy ( and chemical energy ) to mechanical energy, which can then be used to do mechanical work. It does this by bringing a working substance from a higher state temperature to a lower state temperature. A heat "source" generates thermal energy that brings the working substance to the high temperature state. The working substance generates work in the "working body" of the engine while transferring heat to the colder "sink" until it reaches a low temperature state. •

2. IC Engine The Internal Combustion (IC) engines are those engines in which the combustion of fuel takes place inside the engine cylinder. These are Petrol, Diesel and Gas engines . External Combustion Engine: Steam engines or Steam turbines.

3. Transport Vehicles

4. Engine

5. Power Plant

6. Steam engines

7. Classification of IC Engine According to the type of fuel used: (a) Petrol engines, (b) Diesel engines, and (c) Gas engines. According to the method of igniting the fuel: (a) Spark Ignition (SI) engines, (b) Compression Ignition (CI) engines, and (c) Hot spot ignition engines. According to the number of stroke per cycle: (a) Four stroke cycle engines, (b) Two stroke cycle engines. According to the cycle of operation: (a) Otto cycle engines, (b) Diesel cycle engines, and (c) Dual combustion cycle engines. According to the speed of the engine: (a) Slow speed engines, (b) Medium speed engines, and (c) High speed engines.

8. Classification of IC Engine According to the Cooling system: (a) Air- cooled engines, (b) Water- cooled engines, and (c) Evaporative cooling engines. According to the method of fuel injection: (a) Carburetor engines, (b) Air injection engines, and (c) Airless or solid injection engines. According to the number of cylinder: Single cylinder engines, (b) Multi-cylinder engines. According to the arrangement of cylinders: (a) Vertical engines, (b) Horizontal engines, (c) Radial engines, (d) In- line multi- cylinder engines, (e) V- type multi- cylinder engines, (f) Opposite- cylinder engines, and (g) Opposite- piston engines. According to the valve mechanism: Overhead valve engines, and (b) Side valve engines. According to the method of Governing: Hit and miss governed engines, (b) Quantitatively governed engines, and (c) Qualitatively governed engines .

9. Main components of IC engines Cylinder Cylinder Head Piston Piston rings Connecting rod Crankshaft Crank case Flywheel Carburetor (in Petrol engine) Spark plug (in Petrol engine) Fuel injector (in Diesel engine)

10. Main components of IC engines

11. Working Principle of 4 Stroke IC (Petrol and Diesel) Engines Petrol Engine Diesel Engine Suction Compr ession Exhaust Expansion 1. Suction or Charging stroke, 2. Compression stroke, 3. Expansion or Working stroke and 4. Exhaust stroke

12. Actual Indicator Diagram of IC Engines

13. Valve Timing Diagram

14. Valve Timing Diagram

15. Working Principle of Two stroke Petrol Engines

16. Working Principle of Two stroke Diesel Engines

17. Indicator Diagram of Two stroke Petrol Engines

18. Scavenging It is a process of removing the burnt gases from the cylinder after combustion. Cross- flow Back flow/ Loop Uniflow

19. Comparison of/ Difference between Petrol and Diesel engines 15 to 25

20. Detonation in IC Engine The loud pulsating noise heard within the engine cylinder is known as detonation (also called knocking or pinking). It is caused due to the propagation of a high speed pressure wave created by the auto ignition of end portion of unburnt fuel. The blow of this pressure wave may be of sufficient strength to break the piston. Thus, the detonation is harmful to the engine and must be avoided. Factors which causes detonation: The shape of the combustion chamber, The relative position of the sparking plugs in case of SI engines, The chemical nature of the fuel, The initial pressure and temperature of the fuel, and The rate of combustion of that portion of the fuel which is the first to ignite. This portion of fuel in heating up, compresses the remain unburnt fuel, thus producing the condition for auto ignition to occur.

21. The detonation in petrol engines can be suppressed or reduced by the addition of a small amount of lead ethide or ethyl fluid to the fuel. This is called doping. Effects due to detonation: A loud pulsating noise which may be accompanied by a vibration of the engine. An increase in the heat lost to the surface of combustion chamber. An increase in carbon deposits. Detonation in IC Engine

22. Detonation & Knocking

23. Octane Number The knocking tendency of a fuel in SI engines is generally expressed by its octane number. The percentage, by volume, of iso- octane in a mixture of iso- octane and normal heptane, which exactly matches the knocking intensity of a given fuel, in a standard engine. Cetane Number The property of ignition lag is generally measured in terms of ocetane number. It is defined as the percentage, by volume, of ocetane in a mixture of cetane (straight chain paraffin) and alpha- methyl- napthalene that produce the same ignition lag as the fuel being tested, in the same engine and under the same operating conditions. Rating of Engine Fuel

24. Carburetor Carburetor is a device for atomizing and vaporizing the fuel and mixing it with the air in varying proportions to suit the charging operating conditions of the engine. The process of breaking up and mixing the fuel with the air is called carburetion.

25. Self Study Lubrication System (26.33, Page: 602) Cooling System (26.32, Page: 601)

26. Gas Turbine In a gas turbine, first of all, the air is obtained from the atmosphere and compressed in an air compressor. The compressed air is then passed into the combustion chamber, where it is heated considerably. The hot air is then made to flow over the moving blades of the gas turbine, which imparts rotational motion to the runner. During the process, the air gets expanded and finally it is exhausted into the atmosphere. A major part of the power developed by the turbine is consumed for driving the compressor. The remaining power is utilized for ding some external work.

27. Gas Turbine

28. Comparison of Gas turbine and IC engines Gas turbine IC engines The mass of gas turbine per kW developed is less. The installation and running cost is less. Its efficiency is high. The balancing of gas turbine is perfect. Torque produced is uniform. Lubrication and ignition system are simple. It can be driven at very high speed. The pressure used are very low. Exhaust from gas turbine is free from smoke and less polluting. Starting is not simple. The mass of an IC engine per kW developed is more. The installation and running cost is more. Its efficiency is less. The balancing of an IC engine is not perfect. Torque produced is not uniform. Lubrication and ignition system are difficult. It can not be driven at very high speed. The pressure used are high. Exhaust from IC engine is more polluting. Starting of an IC engine is simple.

29. Gas Turbine Classification Gas turbine may be classified as According to path of the working substance: Closed cycle gas turbines, b) Open cycle gas turbines, and c) Semi- closed gas turbine. According to process of heat absorption Constant pressure gas turbines, and b) Constant volume gas turbines.