Author: haroonkhan
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Nomenclature
There are various terms which are frequently used in an IC engine and are discussed below.
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BASIC STRUCTURE OF IC ENGINES
Even though reciprocating internal combustion engines look very simple in appearance, they are highly complex machines. There are a large number of components which have to perform their functions to produce power. Before going through the working principle of the complex machine, a brief description of the engine components is shown in Figure 6.2. Figure 6.2 The…
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CLASSIFICATION OF IC ENGINES
There are several bases for classification of IC engines, some of the important bases can be explained as Number of Strokes per Cycle: IC engines can be classified as four stroke engines (4S) and two stroke engines (2s). In four stroke engines, the thermodynamic cycle is completed in four strokes of the piston or two revolutions…
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INTRODUCTION
“The heat engine, in which the combustion takes place inside the cylinder or the product of combustion (flue gas) directly goes to the cylinder and the heat energy of the flue gas is converted into mechanical energy, is known as Internal Combustion Engine (IC Engine).” The combustion may take place either inside or outside the…
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Gas Turbine Cycle with Reheating and Intercooling
Intercooling is added to reduce the compressor work. If multistage compressor is used, the air is cooled to initial temperature between each stage. Reheater is used to increase the temperature to initial inlet temperature between each expansion in turbines. Thus, intercooler and reheater are used to increase the work output of turbines. The flow diagram…
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Gas Turbine Cycle with Regenerator
Regenerator is a heat exchanger which is used to exchange the waste heat of gases exhausted from turbine to air after compression but before combustion as shown in Figure 5.25. Due to this fuel economy, the efficiency of plant increases. Figure 5.25 Gas Turbine with Regenerator It is theoretically possible to raise the temperature of the compressed air…
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Optimum Pressure Ratio for Maximum Specific Output
In the T–s diagram (Figure 5.22), Figure 5.22 Actual Brayton Cycle For maximum work done, Wnet should be differentiated with respect to c and equating to zero. Example 5.5: In a gas turbine plant, air is compressed from 1 bar and 15°C through a pressure ratio 6:1. It is then heated to 600°C in a combustion chamber and expanded back to atmospheric pressure…
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Actual Brayton Cycle
The actual turbine cycle differs from the theoretical cycle in the following manner. A T–s diagram for an actual Brayton cycle is shown in Figure 5.21. Figure 5.21 Actual Brayton Cycle 1 – 2 Isentropic compression 1 –2′ Actual compression 3 – 4 Isentropic expansion 3 – 4′ Actual expansion The compressor efficiency, where WT = Work done by turbine WC =…
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Joule or Brayton Cycle
The air standard Brayton cycle or Joule cycle is most ideal thermodynamic cycle for a simple gas turbine plant. Its working is shown in Figure 5.19. Atmospheric air is compressed from pressure P1 to a high pressure P2 in the compressor and delivered to the combustion chamber where fuel is injected and burnt. The combustion process occurs nearly at constant pressure.…
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Applications of Gas Turbines
Gas turbines are used for the following purposes: