Design and Construction of Turbine Engines †MyAssignmenthelp.com

Question: Discuss about the Design and Construction of Turbine Engines. Answer: Design and Construction of Turbine Engines: A Review In a turbine engine the entire process of intake, compression, combustion and exhaust takes place inside the combustion chamber simultaneously without any interruption as separate sections are provided for carrying out each function inside the chamber. Major parts of a gas turbine are more or less the same and consists of exhaust section, turbine section, combustion section, compressor section, air inlet, accessories section, sections for fuel supply, lubrication and starting purposes and sections for pressurization, cooling and anti-icing (Anderson, 2009). The main difference between turbine engines are the terminology used by different manufacturers and the type of compressor used. Commonly available types of turbine engine are the high by-pass fan jet, turbo-fan, turbo-prop and turbo-jet (Hunecke, 2010). Based on the type of compressor turbo-jet engines can be divided into two types namely, centrifugal and axial flow turbo-jet engines. The centrifugal flow turbo-engine picks up the air flowing inwards and applies centrifugal action to accelerate it outwards, thereby converting velocity into pressure. The power required by this type of engine could be provided only if the compressor had very large diameter. Both double and single stage impellors have been used to design the compressors. In axial flow turbo-jet engine the flow of air is along its longitudinal axis using a turbine assembly and an axial flow compressor. The pressure of the air taken in by the compressor is increased substantially by passing it through several stages of compression and then passed into the combustion chamber. The compressed air is then mixed with the fuel and ignited which raises the temperature. The by-products expand through the turbine and leave the compressor, in-turn driving it. As the by-products leave the compressor the temperature and pressure falls to reach ambient pressure, producing a high velocity jet as the gas flows through the propelling nozzle. The difference between turboprop and turbojet engines is that there are more stages in turboprop engines and generates more forward power through the gear train and shaft in order to drive the propeller. The exhaust gases which pass through the extra stages help the turbine to provide extra power. Coaxial shafts are used in case of multiple rotor turbines so as to drive the propeller and compressor independently. The turboprop configuration is available in the gear reduction or gearbox assembly which is connected to the torque meter assembly so as to transmit the torque. If the propeller in a turboprop engine is replaced using a duct enclosed axial flow fan, then it is a turbofan turbine (Kroes and Wild 2010). The fan is either mounted on a separate set of blades or on the first stage of compressor blades. Whereas the blades are mounted aft of the turbine wheel or forward of the compressor. This converts more fuel energy to pressure and consequently saves more fuel and in order to provide more power for driving the fan an extra stage has to be added in the turbine and the jet nozzle requires to have a larger area. Forward fan engines use two different duct designs one ducted along the outer case of the engine and the other ducted overboard. Thus the exhaust gases are either directly passed without mixing with the air or are mixed with air and then discharged. References Anderson, K. (2009). Propulsion Plant Accident Investigation. Embry-Riddle Aeronautical University. Hunecke, K. (2010). Jet Engines: Fundamentals of Theory, Design and Operation. Marlborough: The Crowood Press Kroes, M.J. and Wild, T.W. (2010). Aircraft Powerplants (Aviation Technology Series). New Delhi, new Delhi: McGraw-Hill Higher Education.