Gas Turbines and Its Types Report

Introduction

The earliest gadget for built for the purposes of generating mechanical power from the air was the windmill which was followed by the smoker jack that was designed and described by Leonardo da Vinci and John Wilkins respectively (Encyclopaedia Britannica, 2013). The original gadget contained several horizontal sails built on an axial piston and moved by hot gas coming from a chimney (Encyclopaedia Britannica, 2013).

The first modern gas turbine sketch came into being in 1791 courtesy of John Barber of England but would not construct because the model could not have operated as much as it made use of the chief components of the current gas turbine (Encyclopaedia Britannica, 2013). In 1872, Stolze of Germany received the first patent marking a milestone in the development of the gas turbine. However, his model was short of the required necessities to maintain an operation (Encyclopaedia Britannica, 2013).

The initial successful gas turbine, made in Paris in 1903, consisted of the three major components as they are today. These include the compressor, the combustion chamber, and the turbine. The machine achieved three percent efficiency and proved that it was possible to design a practical gas turbine engine (Encyclopaedia Britannica, 2013).

The gas turbine is one of the most flexible machines in the class of turbomachinery. It finds utility in various modes in crucial industries like the generation of power, oil and gas exploration, process plants, airports, and domestic purposes as well. This essay seeks to look at different types of applications and gas turbines using sketches and descriptions.

Single-shaft, simple cycle gas turbine

This type of turbine contains one or several compressors with a combustor as well as one or several turbines that drive the compressors (Soares, n.d.). The aero engines produce propulsion either through a hot gas jet, a moving fan or a combination of the two. Industrial gas turbines produce mechanical force through the utilization of turbines driven by hot air (Soares, n.d.).

Typical applications in these turbines include the direct drive and mechanical drive (Soares, n.d.). Concerning power production, the gas turbine piston is fixed to the generator piston either directly or through a gearbox application (Soares, n.d.). Power production applications include offshore gas turbines, which normally arise from gas turbines meant for aircraft utility. Mechanical drive applications have a different turbine system. They have a gas producer system, which is a combination of compressor component, combustor component, and turbine component. They have a rotating turbine, which at the end of the gas producer system, which moves freely (Soares, n.d.).

Single shaft simple cycle gas turbine has various advantages. It is relatively cheap, occupies less space due to its small footprint and has a simple unit control application (Site Ge Energy, 2013). Also, single-shaft turbines simplify the ignition and steam bypass systems that are well set for heat recovery (Site Ge Energy, 2013). Single-shaft simple cycle gas turbines are cheap to maintain. However, it is disadvantageous because it needs a large ignition gadget, has a limited range of speed and its efficiency is relatively lower.

Two-shaft, simple cycle gas turbine

This type of turbine is quite similar to the single-shaft turbines in that it contains one or several compressors with a combustor as well as one or several turbines that drive the compressors (Soares, n.d.). The aero engines produce propulsion either through a hot gas jet, a moving fan or a combination of the two. Industrial gas turbines produce mechanical force through the utilization of turbines driven by hot air (Soares, n.d.). The difference lies in the determination of the machine force ratios and the fact that it has two shafts or turbines. The two turbines share the force rise generated by the compressor (Soares, n.d.).

The two-shaft, simple cycle gas turbine has several advantages compared to the single shaft cycle gas turbine. It has higher efficiency and a large range of speed. Overall, it needs a smaller ignition gadget compared to the single-shaft turbine. However, it has its disadvantages too in that it has a very intricate control mechanism and requires specialized and higher maintenance.

Single-shaft, regenerative cycle turbine

The basics concept in this type of turbine lies in the use of high temperatures exhaust air in the calefaction of the gas as it leaves the compressor (Boyce & Chen, n.d.). The effectiveness of a regenerative cycle turbine is forty percent higher than that of the simple cycle while the point of optimum efficiency takes place at a relatively lower force ratio than in basic cycle (Boyce & Chen, n.d.). Other than the optimum efficiency, the regenerative model has the same advantages particular to the single and two-shaft simple cycle turbines. These include the fact that it is relatively cheap, occupies less space due to its small footprint and has a simple unit control application (Site Ge Energy, 2013).

Two- shaft, regenerative cycle turbine

This type of turbine is similar to the single-shaft regenerative turbine. As such, there is heating of the gas, leaving the compressor at high temperatures. The only difference is that the two-shaft regenerative cycle has two pistons, which dictates the sharing of pressure (Boyce & Chen, n.d.).

In most cases, the two- shaft regenerative cycle turbines use less space and require minimum maintenance with very high efficiency (Soares, n.d.). The most distinct disadvantage is its relatively high cost of installation. Also, the two-shaft regenerative cycle requires high maintenance and expertise (Soares, n.d.).

Typical applications for gas turbines

The most significant use of gas turbines is in the aviation industry (Encyclopaedia Britannica, 2013). The gas turbines provide the motive force for aircraft energy. Also, gas turbines are used in the production of electric power. They are widely utilized as average quantified peak load machines to run when there is a high demand for power on an electric mechanism (Encyclopaedia Britannica, 2013).

Gas turbines also find utility in the industries with their sizes of between one thousand to fifty thousand horsepower. In the industries, gas turbines drive compressors for pressurizing of natural air through the pipe systems where a bantam part of the pressurized air burns as fuel (Encyclopaedia Britannica, 2013). In addition, the gas turbine finds utility in the Houdry process of oil refining. Here, the compressed air passes over a catalyst to conflagrate residual carbon (Encyclopaedia Britannica, 2013). The hot air pushes a turbine directly in the absence of a combustion compartment and the turbine moves a compressor to push the gas for the process. Gas turbines fitted with spiral compressors find utility in operating pumps (Encyclopaedia Britannica, 2013).

Gas turbines are light and small compared to steam and diesel propelled machines (Encyclopaedia Britannica, 2013). As such, the marine sector utilizes gas turbines. Their use became prominent in the 1970s after a ship propelled by a gas turbine passed the test applied by the U.S. Navy, which has consequently favored them and uses them in most of the vessels (Encyclopaedia Britannica, 2013).

Makers of locomotives have used gas turbines in their vehicles, which utilize dense oil. However, the success of the gas turbine-propelled vehicles compares poorly to diesel locomotives though they still feature in locomotives because of their low maintenance requirement (Encyclopaedia Britannica, 2013).

Car manufacturers have also tested the gas turbines on various vehicles but the size and weight of the gas turbine machines have worked against further use in more cars. Such cars have lofty manufacturing expenses couple with poor thermal efficiency and poor idling performance (Encyclopaedia Britannica, 2013). As such, gas turbine cars are not a practical idea.

Operating principles of a simple gas turbine

The gas turbine is in the class of internal combustion engines and uses gas as the fluid of operation (Encyclopaedia Britannica, 2013). The turbine extracts chemical power from fuel and converts it to mechanical power by utilizing the gaseous power of the air to move the engine. The engine applies the following principles.

As gas goes through a gas turbine engine, aerodynamic and power needs demand changes in the speed of the air and force. An increase in the air pressure during compression is necessary but an increase in its speed is not necessary (Encyclopaedia Britannica, 2013). On compression and burning of the gas, a rise in the speed of gases becomes necessary for the turbine rotors to gain energy. This results in either the use of a divergent duct or a convergent duct (Soares, n.d.).

Gas turbines have three basic components, which coordinate as follows. The compressor is responsible for compressing the gas to high force, which burns in the combustion chamber to produce high-pressure and high-speed gas. The turbine removes the energy from the combustion compartment (Encyclopaedia Britannica, 2013).

Key elements of the typical gas turbine, materials, and functions

A typical gas turbine has three, which include the turbine, the compressor, the generator, auxiliaries and controls, and the combustion compartment.

The turbine

The turbine consists of vanes mounted on a shaft and encased in a compartment (Encyclopaedia Britannica, 2013). The flow of liquid through the engine is usually equidistant and tangential to the rotor in either rising or reducing the radius. There are two kinds of the rotor in all engines: ones that are embedded on the rotor and move with the piston and those that are attached to the compartment. The use of multi-staging increases the energy output of the engine by putting extra sets of attached and moving blades (Encyclopaedia Britannica, 2013).

The casing of the turbine grants the joining of the gas ducts for inlet and outlet as well as the turbine rotor. The turbine and its components consist of iron-base superalloy and udimet.

The compressors

The gadgets supply pressurized gas to the combustion compartment and can be either positive replacement type or the rotodynamic type and further, they may be single stage or multi-stage model (Encyclopaedia Britannica, 2013). Concerning the positive replacement type, consequent volumes of gas compress within a closed area where compression happens by the dynamic performance of revolving vanes. This rotation provides speed and force to the gas as it moves through the compressor. The compressor is designed using titanium alloys (Site Ge Energy, 2013).

The generator

This gadget produces electrical power while being embedded to the same shaft of the engine and moves at the same velocity with the turbine. The basic material is titanium to the tune of around 33 percent in the various alloys. Castings also make up the static components in the generator (Encyclopaedia Britannica, 2013).

The auxiliaries and controls

These consist of the ignition gadget, supporting lubricating oil compressor, the fuel control chamber, coolers, and filters among other things (Encyclopaedia Britannica, 2013). They serve to start the machinery with the controls acting to alert the user in case of any malfunction due to the presence of the safety rings. They are part of the turbine and are made of iron superalloy (Encyclopaedia Britannica, 2013).

The combustion compartment

It is in this compartment that combustion of fuel happens and usually consists of the nickel-super alloy (Encyclopaedia Britannica, 2013).

Typical basic control system for a gas turbine

The gas turbine control system performs various functions that include fuel, gas and fumes control, arranging of fuel and support components for ignition, closing and cool down. In addition, the systems synchronize and match the voltage of the generator and the system (Encyclopaedia Britannica, 2013). They also guard the turbine against the unsafe and unfavorable operating environment. Fuel controls moderate the flow of fuel to feed the generator with the right amount of fuel.

Their control systems include the temperature control function, which moderates the flow of fuel to achieve the right burning temperature (Encyclopaedia Britannica, 2013).

References

Boyce, M. P., & Chen, M.-S. (n.d.). Optimization of Various Gas Turbine Cycles. Web.

Encyclopaedia Britannica. (2013). gas-turbine engine. Web.

Site Ge Energy. (2013). Stage Equipment Configuration. Web.

Soares, C. (n.d.). Simple and Combined Cycles. Web.