Gas Turbine Engine Components Design, Configuration And Performance Characteristics

You have recently been employed as an Aircraft Gas Turbine Engine Technician in Trans-Canada Turbines Ltd, which is a maintenance service provider for aeroderivative industrial gas turbines, serving an expanding international client base.
Your basic duties and responsibilities include evaluating the design and performance of aircraft gas turbine engine turbo machinery, engine intake, combustion and exhaust modules.

You would also need to investigate the factors affecting the design and performance, in addition to environmental impact of gas turbine powered aircraft operations. For this, you need to do the following tasks: -

• Discuss and Illustrate the design , configuration, aerodynamic operation and performance characteristics of axial flow and contrifugal compressors and fan modules.

• Analyse the above design and suggest ways to improve performance of the turbo machinery modules of Trans-Canada Turbines Ltd.

• Explore and compare the types, mechanical design, operation and performance characteristics of different turbine modules

• Discuss and illustrate the design features and aerodynamic and thermofluid operation of air intake, combustion and exhaust modules and their components. Also explain the types of combustion methods that aid engine performance.

• Critically evaluate the design features and assess areas for improving performance for Trans-Canada's combustion and exhaust cycles.

• Evaluate and Determine how the gas turbine engine performance is measured and improved in thrust production, fuel efficiency and emissions. Also comment on the nature of environmental noise and emissions produced from these engines and the ways used to control it.

• Critically evaluate how engine performance can be improved and noise and reduction emissions could be achieved by Trans-Canada Turbines Ltd. 

Design and Operation of Centrifugal Compressor

A gas turbine which is sometimes denoted to as ignition turbine is an example of internal ignition engine and it has three chief constituents which are ignition chamber, a downstream turbine on the same shaft, upstream rotating gas compressors.  The gas turbine operates when air from atmospheric finds its way through the compressor which makes it attain higher pressure then the spraying fuel adds energy into the air and igniting it so the ignition produces a high-temperature flow. The gas with high temperature gets into the turbine where it is expanding down to the exhaust pressure leading to the creation of shaft work output in the process.

The compressor drives the compressor and the energy which is not used for the shaft work comes out in the exhaust gases that generate thrust. The gas turbines assist in driving the trains, aircraft, electrical generators, pumps, and tanks. The conversion of mechanical energy into pressure and thermal energy in the gas turbine after the compression of the gas. Example of gas turbine engines include;

A turboprop engine which is a turbine engine that drives an aircraft propeller using a reduction gear. These type engines are used on small aircraft. Turboshaft engines are also another type of engine which is often used in driving compression trains modern helicopters and almost

Discuss and illustrate the design, configuration, operation, and performance of axial flow and centrifugal compressors and fan modules.                       

The centrifugal compressor as referred to as the radial compressors are a sub-class of dynamic axisymmetric work-absorbing turbomachinery. The attain a rise in pressure through the addition of kinetic velocity to a unceasing liquid flow via the impeller or rotor. The flow is slowed down by the diffuser in order to allow the conversion of kinetic energy to static pressure or potential energy (Francis, 2008, p. 78).

The flow leaving the centrifugal impeller is traveling at a speed almost equivalent to the speed of sound after which it flows it then flows through a stationary compressor is ducting with increasing flow area where energy transformation takes place. Examples of turbomachinery that uses the centrifugal compressors include turboshaft, turboprop, turbocharger, centrifugal type supercharger, and gas turbine.

There are four components found in the compressor mentioned above which include the rotor/impeller, inlet, collector, and diffuser. The inlet of centrifugal compressor entails regulator, fixed vanes/airfoils which are used to aid swirl the flow while the impeller is the chief constituent that makes the centrifugal and it comprises a spinning set of vanes that increase the energy of the functioning gas gradually. The diffuser is also a key component of the compressor and it is responsible for the conversion of dynamic energy or high velocity of the gas into pressure by progressively diffusing or slackening the rapidity of the gas (Treager, 2009, p. 65). The collector is also a component which is found in the in the centrifugal compressor which assists in flow gathering from the diffuser. The pipe or the collector also contain instrumentation and valves which control the compressor.

Design and Operation of Axial Compressor

This is a type of compressor which can endlessly pressurize gases. It is a spinning airfoil where the functioning liquid flowing parallel to the axis of spin, or axially. As the fluid streams through the compressor, its level of energy increases as a result of rotor blade action employing a rotating force on the fluid. The fluid is slowed down by the stationary blades transforming the circumferential component of flow into pressure (Treager, 2009, p. 164).

A steady flow of compressed air is produced by the axial flow compressor and it is beneficial because of high proficiency as well as large mass flow rate and the compressors mentioned are integral to the design of large gas turbines such as jet engines and high-speed ship.  The transformation of the fluid dynamic head into a rising pressure is caused by the diffusing action in the stator. The fluid dynamic head is reduced by the rotor and the rotor impact on the fluid elements upsurges its velocity thereby decreasing the relative velocity between the fluid and the rotor.

There are various types of engines which are used in the turbine which include;

A turboprop engine is a turbine engine that drives an aircraft propeller and it consists of turbine, combustor, thrusting nozzle and compressor. Air is withdrawn from the opening and compacted by the compressor then the addition of fuel to compacted air is carried out in the combustor where the mixing of fuel with air and then combusts is done. The burning ignition gases enlarge through the turbine and some of the generated power is used in driving the compressor while others are driven via the lessening gearing to the propeller. The gases further expand from propeller outlet such that the gases deplete to atmospheric pressure. The driving nozzle delivers a comparatively small amount of the generated thrust by a turboprop. A large volume of air is accelerated because the propeller has a large diameter and the efficiency of the propeller increases as the speed of the aircraft increases and that is the reason why the turboprop is not used in high-speed aircraft since they sail a flight speed impending Mach 0.75. Numerous turboprop nowadays features a unrestricted power turbine on isolated coaxial shaft thus enabling the propeller to revolve liberally, liberated of compressor speed and further expansion of in turbine system helps in avoiding the residual thrust (Fleming, 2011, p. 45).

The turbojet is an air-breathing engine mostly applied in aircraft and it entails of a gas turbine having thrusting nozzle. The fuel in the combustion chamber assist in the heating of compressed air and the permitted to expand through the turbine. The turbine exhaust is then expanded in the propelling nozzle where it is speeded to high speed to provide thrust. Turbojets have been replaced in slower aircraft by the turboprops because they have better range-specific fuel consumption and also they are a quitter. The turbojets have poor efficiency at low speeds.

The turbojet has an air intake at the compressor anterior to assist in directing the entering air easily into the stirring compressor blades (Francis, 2008, p. 67). The supply of air to the engine is done by the intake with an adequately small variation in pressure and the pressure of the ram upsurge in the opening in the inlets involvement to the thrust system whole pressure ratio and thermal effectiveness. And the intake gains prominence at high speeds when it diffuses more thrust to the airframe than the engine does. The pressure and temperature of the air increases as a result of compression. The compressor mostly used by the turbojet is the centrifugal and axial compressor. The turbojet also has nozzle enabling the expansion of gases via the exhaust nozzle producing a high-velocity jet.

Types of Gas Turbine Engines

This is an example of the air-breathing jet engine which is extensively used in aircraft thrust and they were invented to circumvent an awkward feature of turbojet which was inefficient for subsonic flight and it is also used in driving  

          Ways to improve the performance of turbomachinery modules

• Have a regular engine check-up since when they are in a bad condition then one is expected to replace the oxygen sensor, spark plug, air and fuel filters.
• Improving the gas mileage by one to two percent by using the manufacturer grade of oil.
• Evade accelerating the engine, particularly before switching the engine off since this washes away oil down from the inside the cylinder walls.

The types, mechanical design, operations and performance of different turbine modules

The fast moving gas, water, steam or other fluids and converting it into valuable work is done by the turbine which is a rotary mechanical device. A turbine consists of at least one moving part known as rotary assembly known as drum and shaft with attached blades.

The turbine working principle takes place when blades of the turbine is strikes by the fluid, the they are displaced which assist in the production of rotational energy. When the turbine shaft is directly coupled to electric generator mechanical energy is converted into electrical energy and this electrical power is known as hydroelectric power.

There are various kinds of turbines which are; water, steam, gas and wind turbine.                                       

 The turbine mentioned above is a rotary machine which helps in the conversion of water dynamic energy and potential energy into mechanical work. The most areas which water turbine application takes place was industrial power prior to electrical grids and the water turbine set up in dams frequently for generation of electric energy.

The water turbine starts operating when water which was flowing is channeled towards the turbine runner blade thus forming a force on the blades and since the runner is whirling, the force action through a distance and the action of force through a distance is what is referred as work. This is the manner in which the energy is transferred from the water flow to the turbine. The classification of the water turbine is done in two groups which include the reaction and impulse turbine.

The reaction turbines are acted on water which converts the pressure moving through the turbine and gives up its energy. There is a need of encasing them so that they comprise the water pressure or they must be immersed in the water flow. Its application takes place in low 30m or 100 ft and medium 30-300m head applications. There fall in pressure takes place in both moving and fixed blade. Examples of impulse turbine include Pelton turbine and cross-flow turbine.

Impulse turbines convert the water velocity and the first moving fluids are ablaze via a slender nozzle at the blades to enable the spin around. The turbine curved blades are pushed by the jet thus changing the direction of the flow and a force on the blade is caused by the resulting momentum. The force acts through a distance as a result of spinning turbine thus parting distracted water flow with lessened energy. An impulse turbine is one with the fluid pressure running over the rotor blades is constant and all the work output is as a result of the alteration in kinetic energy of the fluid. The conversion of potential energy or water pressure to kinetic energy by a nozzle is done by the nozzle after hitting the turbine blades and no change in pressure takes place. Examples of reaction turbines Francis turbine, Francis turbine and Kinetic turbine.

Design and Operation of Combustion and Exhaust Modules

Turbines are selected depending on the availability of water heads and also rate of flow. The use of a turbine for low head sites is the reaction while the impulse is applied to high head sites. Kaplan turbines with changeable blade pitch are well-adapted to a wide range of flow or head condition since their peak efficiency can attain over a wide range of flow conditions. On the environmental impact, the water turbine has no effect on water since they make use source of energy which can be renewed and are designed to carry out operation for decades.

The steam turbine is an example of a heat engine which helps in the conversion of steam into mechanical work. The maintenance and construction of steam turbine are very easy since it does not contain slide valves or flywheel and piston rod. The mechanical energy from the shaft is converted into electrical energy since this type of turbine has a steam turbine generator which also improves the efficiency of the turbine.  Steam turbine starts operating when a great velocity steam originating from control valve and attacks the spinning blades, snug on a disc attached on a shaft. A vibrant pressure on the blades in which blades and the shaft both start spinning in a similar direction is produced by high-velocity steam. The extracted pressure is converted into kinetic energy by permitting the flowing of the steam via nozzles. The transformation of dynamic energy takes place in the rotor blade linked to the steam initiator acting as a facilitator. The mechanical energy is collected and converted into electrical energy by the turbine generator. This type of turbines is made in numerous sizes ranging from small to large, used as mechanical drives for pumps, compressors, and shaft driven apparatus used for electricity generation.

This is just a device which helps in the conversion of wind dynamic energy into electrical power. This energy releases electricity when two or three propellers such as blades are turned by the wind nearby a rotor. The connection of the motor is at the key shaft which create electricity after spinning a generator. The blowing of wind past, moves them upwards with a force called the lift and when it blows past turbine blades, it spins them around causing the wind to lose some dynamic energy as the turbine gains. The quantity of energy generated by the turbine is proportional to the area that the rotor blades sweep out. The longer the rotor blade, the more energy a turbine will generate.

Design features, thermofluid operations of the air intake, combustion and exhaust modules. Also, combustion methods that aid engine performance

The thermodynamic principle is applied in an aircraft gas turbine engine since it entails energy conversion involving heat and other forms of energy. The ignition is the order of exothermic reaction of chemicals involving the fuel and an oxidant escorted by the creation of heat and transformation of chemical species (Fleming, 2011, p. 239).

A combustor is an area in a gas turbine where the process of ignition takes place and it is recognized as the flame holder or ignition chamber. This particular chamber in the gas turbine is nourished with an air of elevated pressure by the compression system then the air is heated at an endless pressure by the combustor (Fleming, 2011, p. 98). The nozzle guide vanes allow the passage of air from the combustor to the turbine after the heating process.

Measuring and Improving Gas Turbine Engine Performance

A combustor also plays an important part in determining many of engines operating characteristics for example emission level, fuel efficiency as well as a transient response which is the response to changing conditions such as airspeed and flow of fuel. They are various types of combustors for example;                                

These are combustors with cylindrical combustion chambers and has petrol injector, casing, liner, and igniter. The prime air leaving compressor is directed into every separate can where it is slowed, mixed with fuel and then ignited (Adwera, 2008, p. 97). The subordinate air comes from the compressor where the feeding is done outside the liner. The feeding of secondary air is normally done using the liner slit into the ignition region in order to calm the liner via thin film cooling. This type of combustors is stress-free to uphold since only a single can need to be detached.

This type of combustor has separate ignition regions found in detached liners having their own fuel injectors and all ignition sectors share a mutual ring or annulus casing. The exit flow from the cannula generally has a more even temperature and it also eradicates the requirement for each chamber to have its own igniter. When compared to can combustor, a cannular combustor is more difficult to maintain (El-Sayed, 2017, p. 137).

An annular combustor is the most widely used combustor and they get rid of isolated ignition zone and having unceasing casing and liner in a ring (Fleming, 2011, p. 65). An annular combustor is advantageous since they are shorter in size, they have the lowest pressure drop and have a uniform combustion. The double annular combustor is one variation of the annular combustor and it is a continuous ring without separate combustion zones around the ring.

How gas performance is measured and improved in thrust production and fuel efficiency.

The engine operation is assessed based on the succeeding foundation;

1. Exact Fuel Intake
2. Brake Mean Operative Pressure
3. Exact Power Output
4. Exact Weight
5. Exhaust smoke and other emissions.

Speed is using varieties of speed measuring devices commencing by mechanical tachometer to digital and generated electrical tachometers. The finest technique of gauging the velocity is through counting the number of revolts in a specified time since it is a correct method and engines are also equipped with revolution counters.

The fuel intake of an engine is gauged by finding the volume flow in a specified time interval and times the exact fuel gravity. An alternative method is through measuring the time needed for consumption of a given mass of fuel.

The assessing of brake entails the torque determination and the angular speed of the engine output shaft. The device used in measuring the torque is the dynamometer which is also classified into two that is power absorption dynamometers and transmission dynamometer (Adwera, 2008, p. 89).

The friction power is simply the alteration between the designated power and the brake power output. The frictional losses cause a variance between a good and a bad engine and the losses frictionally are mostly degenerate to the freezing system. Lesser friction means that obtainability of more brake power thus brake specified fuel intake is lower.

Emissions Reduction from Gas Turbine Engines

The environmental occurs since an aircraft engine emits noise, gases and warmth which result in climatic alteration and global darkening. The gas turbine engine emits elements as well as gases such as the carbon dioxide, black carbon, sulfur oxide, lead and nitrogen oxides intermingling amongst themselves in the air (Treager, 2009, p. 341).

The aircraft produce noteworthy water contamination due to widespread use and usage of jet fuel, lubricants and other chemicals and that is the reason why airports install the void trucks, moveable berms to avoid chemical pilings and lessen the impact of pills which usually befall. Water pollution is also caused by the use of deicing fluids and most of the fluid which is applied to the fluids normally drop to the surface and swapped by running water to nearby streams and rivers. Aircraft apply melting fluids grounded in propylene ethyl glycol and they are recognized for exerting producing large concentration of biochemical oxygen request throughout deprivation in waters surface.

The aircraft causes air pollution since ultrafine elements are released by aircraft engines during near surface level operation such as landing. Lead is also emitted and is an environmental threat such if ingested or inhaled cause adverse impacts on body system, red blood cells, immune system and also the cardiovascular. People in the aircraft stay unprotected ten times the cosmic rays dose that people at sea level receive when they fly 12 kilometers high.

 Setting up of Regulations

As a solution to environmental degradation by the aircraft, regulation of the industry is needed for example the Carbon Offsetting and Reduction Scheme which gives the airlines restrictions on carbon emissions. The issue of regulating the aviation industry should, therefore, be treated as other transport policy and maintenance of its consistency so that environment to be protected. International cooperation should be enhanced in order for policies and regulations to take place.

The technology can be used in designing the systems of a gas turbine engine to make them more efficient in order to deal with the problem of climate impact. A breakthrough in use of another type of fuel that is greener like biofuels, solar panels, batteries, and hydrogen to save the world from environmental degradation.

Environment effect caused by charging the number of greenhouses emitted into the aircraft should be payable such that pay for every ton of greenhouses emitted. The government can also add social and environmental cost thus allowing the companies to start the projects that protect the environment.

The computer can be used to reduce the noise caused by the aircraft such that computer programs are used to simulate aircraft operations to identify areas that are prone to such disturbance. The use of International Noise Model for predicting the noise extent level can be used to address these issues of environmental effects.

The technological advancement in the sector might lead to electric planes that emit less and are more fuel efficient.

Optimizing flight route can decrease undesirable impacts in the air such that taking a flight plan that evades weather circumstances which result to the making of clouds is among the best approach (Francis, 2008, p. 67). By limiting clouds formation, it aids in releasing the radiation from the earth up to space bringing about a cooling effect.

• Have a regular engine check-up since when they are in a bad condition then one is expected to replace the oxygen sensor, spark plug, air and fuel filters.
• Improving the gas mileage by one to two percent by using the manufacturer grade of oil.
• Evade accelerating the engine.

Adwera, P., 2008. Aircraft Propulsion and Gas Turbine Engines. s.l.:Adventure Works Press.

El-Sayed, A. F., 2017. Aircraft Propulsion and Gas Turbine Engines. s.l.:China Publishing Company.

Fleming, W., 2011. The History of North American Small Gas Turbine Aircraft Engine. s.l.:Media Participation.

Francis, T., 2008. Aircraft Propulsion and Gas Turbine Engine. s.l.:Scholastic.

Treager, I., 2009. Gas Turbine Engine Technology. s.l.:OLMA Media Group.