Aircraft Gas Turbine Blade

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   Aircraft Gas Turbine Blade

Section A) Review the function of your selected component and describe how it operates within the system of which it is a part

Function

The aircraft engine has a complex combustion system that applies both air and fuel mixture in a balance that enables the attainment of the required temperatures of about 1350˚C to run the engine (O’Donoghue, 1). To achieve this, there must be an efficient system that enables the appropriate supply of both the air and the fuel that contribute to constant supply of the desired mixture. A Perhaps the most important aspect of the gas turbine variously referred to as the jet engine is this specificity of combustion parameters. A series of blades are aligned along the length of the jet gas turbine in order to facilitate the achievement of the high energy output required for the engine. Aircraft gas turbine blade is a component of the internal combustion engine which plays an important role of turning the air or gas that enters into the engine for mixing with fuel. After turning the gas stream in preparation for mixing with fuel, the gas turbine blade also propels and accelerates the gas into the fuel mixing phase of the engine.

It is therefore important to highlight the functions of the gas turbine blades in the jet engine with the specialized nature of the engine coming into focus. The turning of the air or gas needed in the combustion chamber must be ensured in order to facilitate compression of the air entering into the engine for mixture with the fuel. This set of blades in the series of turbine blades are referred to as compressor blades.

Operation

The gas turbine blades rotate with a high velocity of spinning in order to carry out the above mentioned functions. The air entering the engine from the atmosphere through the sucking force created by the turbine is spun and compressed for mixing with the fuel. In he combustion chamber, the exhaust gas obtained is passed on to the turbine section of the engine and expelled on the turbine blades through a nozzle system. The turbine is powered by the energy obtained from temperature and pressure changes that the end products of combustion experience in form of exhaust gases. Propulsion from the engine is therefore in form of shaft power thrust force as well as compressed air.

Compressor blades are aligned at the entrance of the engine and they also facilitate in the sucking in of air. Positioning of the compressor turbine blades at the entrance of the engine with regard to the flow of materials is important since it enables sucking in of air from the atmosphere without difficulties (O’Donoghue, 1). The other set of turbine blades is the inner blades that facilitate mixture of fuel with gas. The motion of the blades facilitates an even mixture of fuel and gas in order to supply the combustion process with the appropriate raw materials. A different type of such inner blades is also present in the combustion chamber which is turned due to the combustion process. Stator and rotor blades play different roles in the gas turbine.

Section B) Describe both the operational requirements and in-service conditions for your component and relate them to the material properties required

Operational Requirements

In order for the gas turbine blade to be of use in the engine operations, it must meet certain requirements that meet the conditions of the combustion processes environment. While it could be difficult for several parts of a system to remain functional under high speeds of rotation as well as very high temperatures, the gas turbine cannot afford to bend the physical needs in such environment. It is therefore expected that the most appropriate design of a gas turbine blade is capable of overcoming the harsh conditions inside the gas turbine that is almost synonymous with the high efficiency combustion requirement mentioned earlier (about 1350˚C). The blades must be maintained in a good shape to ensure that the functions mentioned earlier are met. Without the expected shape and condition, the various material movements could be compromised and hence the propulsion functions of the engine.

In-Service Conditions

Material used in the manufacture of the various blades needed in the engine must meet the high pressure and temperature that the gas turbine rotation is supposed to operate in. it is expected that material of choice is capable of withstanding deformation likely to occur due to these harsh conditions. Stresses and deformation forces must be anticipated and therefore contemplated during the design and manufacture of the gas turbine blades (Jazayeri, Naeem and Rezamahdi, 2).

Due to the variations in the effective stresses at the different stages of blade series along the turbine, it is important that various types of blades are used at the appropriate instances. Stress types at different stages of the engine usually give different needs for the design shapes and material for improved efficiency. For instance, a different turbine blade is required for the exhaust gas manipulation and maneuver when compared to the rotor blades at the entrance of the engine due to the temperature conditions and roles played.

 

 

Section C): From a consideration of the required material properties outlined in part a), justify a material for your selected component based on maximizing functionality and minimizing weight and cost. Relevant performance indices should be used to justify material selection.

Maximizing Functionality

To ensure that the gas turbine blades meet the highest possible efficiency in dispensation of its expected service, various modifications the most important of which entails material selection. In the earliest days after discovery of the gas turbine, various materials were applied in the manufacture of the blade parts. However, with advancement in technology and knowledge, the most efficient material has been south to deliver maximum performance by the blade obtained from such material.

To meet the high temperature requirement that the gas turbine blade requires, it is important to use materials that can withstand high temperatures for the blades involved in the stages where the turbine involves very high temperatures. High temperature resistant materials such as nickel-based alloys have been applied in the manufacture of the gas turbine blades. However, the upper temperature limits that these alloys can withstand are slightly below the range of temperatures that the jet engine is expected to produce for full operations. For instance, the ordinary temperature that the engine is expected to operate in is around 1350˚C while the range of nickel-based allows resistance to temperatures between 1200˚C and 1315˚C. Generally, there is another challenge that faces the gas turbine blades in form of corrosion due t the harsh conditions of the turbine.

To overcome the corrosion and temperature challenges that the blades experience, there are additional modifications that the nickel-based alloys and other super-alloys used to manufacture the blades are subjected to (Blackford, 15). One of the modifications of the turbine engine is its design such that air is introduced into the turbine and allowed to flow on the blade on specific cooling channels thereby reducing the effective temperatures to below the melting temperatures of the alloy. Other modifications include introduction of specified coatings that can withstand higher temperature than the alloy. Other coatings that can overcome the corrosive conditions that the gas turbine exposes the blade to are effected on the blade to facilitate improved functionality. Various elements have been used to facilitate high temperature and corrosion resistance in gas turbine blades. Aluminades and aluminides are the commonest type of coatings that are applied onto gas turbine blades to improve functionality against oxidation and corrosion. Other coatings are ceramic materials such as zirconia that are used in conjunction with other alloys to reduce heat deformation.

Minimizing Weight and Cost

Perhaps the mos.............


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