How Does A Gas Turbine Function? The Basics

gas Turbinefunctionalityhow A Gas Turbine Functionsthe Basic Function

The basic functioning of the gas turbine resembles that of the steam power plant. The only difference is that gas turbine uses air while the steam power plant uses water. In the turbine engine, the four steps take place at the same time, but in different areas. The existing fundamental difference means that the turbine has various engine sections referred to as the inlet section, the compressor section, the combustion section, and the exhaust or turbine section. In most cases, people focus on the three parts that include the compressor, the combustion area and the turbine (Office of Fossil Energy, n.d).

The basic functioning of a gas turbine involves intake of air and addition of fuel. The process proceeds to compression of the air plus the fuel. The third step is the combustion, which involves fuel injection in case the addition did not take place with the intake air. During combustion, the fuel burns and converts the stored energy. Finally, expansion and exhaust process takes place. This stage puts the converted energy into use. The compressor has the function of compressing the incoming air to high pressure. Combustion area is the place for burning the fuel and producing high-velocity and high-pressure gas (Brain, 2014). This process involves converting mechanical energy from the turbine into gaseous energy that takes the form of temperature and pressure. Spraying fuel into the fresh, inflowing, atmospheric air by ring of fuel injectors adds energy.

This helps in creating ignition to enable combustion to enhance high-temperature flow. The turbine functions to extract the energy from the high-velocity, high-pressure gas that flows from the combustion chamber (Office of Fossil Energy, n.d). The turbine section performs the task of producing utilizable output shaft power, which helps in driving the propeller. In addition, the turbine section also provides power for driving the compressor, as well as all engine accessories. The turbine has special engineered blades, which attach to a central shaft.

As the high-pressure gas moves through, the shaft rotates and spins with considerable force. This shaft connects to a generator that creates electric power. Therefore, the high-pressure, high-temperature gas enters a turbine. At this point, it expands, as it moves downward to the exhaust pressure (Brain, 2014). The process leads to the production of a shaft work output at the far left of the system. The formation of a shaft power takes place through the conversion of gaseous energy into mechanical energy. In other cases, the shaft connects to a compressor, which compresses vapor or gas for various industrial and commercial applications. The compressor, which is a cone-shaped cylinder, has small fan blades appended in various rows. It sucks air from the right side of the engine. The high-pressure gas produced by a compressor can increase by a factor of 30.

Basic Principles for Change in Pressure and Velocity During the process when air rises through a gas turbine, energy and aerodynamic requirements prompt the need for changes in the air’s pressure and velocity (Brain, 2014). The compression process requires a rise in air pressure, but not a rise in velocity. An increase in velocity is crucial after the compression and combustion have heated the air (Edison Tech Center, n.d). This increase in velocity enables turbine rotors to generate power. The shapes and size of the ducts, which allow the airflow, determine the need for such changes. The passages are divergent where there is a requirement for conversion from velocity to pressure. However, a convergent duct is applicable where there is a need to convert pressure into velocity.

Determinants of Performance and Efficiency Several factors affect both the performance and the efficiency the gas turbine engine. The mass rate of airflow through the gas turbine engine determines engine performance. Therefore, any element that impedes the smooth flow of air through the gas turbine engine will limit its performance (Brain, 2014). Other factors that influence performance and efficiency of the overall engine include the turbine inlet temperatures or engine operating temperatures, pressure ratio of the compressor, as well as the efficiencies and performance of individual parts or sections of the gas turbine (Edison Tech Center, n.d). Therefore, the selection of turbine inlet temperature, an optimum pressure ratio, and air mass flow rate are crucial for obtaining the requisite performance through the most efficient process. This also requires designing the individual engine components in a way that minimizes flow losses, thereby maximizing component efficiency.

Importance Positive Aspects The gas turbine is highly fundamental in contemporary world. It is helpful in meeting the needs of a diverse range of industrial and commercial applications. Various uses include driving tanks, propelling jets and helicopters (Kay, 2002), generation of power, as well as various industrial power uses. The machine has a relatively compact size and generates a lot of power (Edison Tech Center, n.d.). This feature makes it smaller than most reciprocating engines working with the same power rating. It is also flexible and efficient.

This makes it useful in backup power systems, where they can power up and produce during emergency cases. The turbine has a greater power-to-weight ratio (Giacomazzi, 2014). Because of this, they can generate the same power with smaller engines than is the case with conventional piston or reciprocating engines. Gas turbines have high operating speeds and low operating pressure. Such aspects are fundamental in enhancing the effectiveness of their utilization in various industrial applications.

In oil exploration platforms, gas turbines have been highly essential for making power. It is also applicable in making power for the crack process experienced in oil refineries. They have been useful in offshore gas and oil exploration (DECC, 2014). In most cases, gas turbines consume less lubricating oil. This means that is cost effective given that users have to incur reduced costs. Such an aspect is critical in contributing to enhancing better returns when using the gas turbine engines in various areas. This feature supports the business process given that profit making always anchors heavily on reducing operating costs.

The gas turbines have high levels of interoperability. This feature increases their flexibility given that they can operate on a wide variety of fuel. With such an element, they facilitate meeting various power generation and industrial needs (DECC, 2014). They also have low foundation loads and cooling water requirement. Moreover, the machines generate extremely low toxic emissions of HC and CO because of the excess air (Brain, 2014). It normally ensures complete combustion and averts quench on the flame when operating on cold surfaces. These instances are vital for ensuring environmental protection. They pose limited damage to the damage given the low green house gas emission. This implies that it does not pose overriding global warming effect on the planet. This contributes to enhancing the protection of biodiversity.

The machines are highly reliable, especially when applied in situations requiring sustained high power output. Such a level of reliability is essential for ensuring the achievement of the objectives of the operation processes (Brain, 2014). In other words, it helps in meeting the requisite needs depending on the area of application. Further, it has less moving parts than is the case with reciprocating engines. This means that it faces reduced depreciation rate due to limited surfaces facing friction. In this regard, maintaining the machines is much easier than in other reciprocating engines. This can also take place because of the fact that gas turbines have a unidirectional move. Their movement in one direction results in less vibration than that experienced in a reciprocating engine (DECC, 2014).

This helps to ensure reduced rate of machine degradation. When the machine works, it dissipates almost 100 percent of waste heat in the exhaust. This process prompts the exhaust stream to have high temperatures. That temperature is highly applicable in boiling water in cogeneration or in a combined cycle. Through this process, gas turbines are applicable in performing additional functions to the benefit of the user. The constant high speed and the provision of high-grade heat enable close control of the frequency of electrical output.

Negative Aspects The gas turbine engines have some demerits. Under typical situations, the turbines can rotate at over 10,000 rpm. The speeds of over 100,000 rpm can sometime occur in smaller turbines. Such a speed in conjunction with the high temperatures results in expensive designing and the manufacturing process of the engines (Kurz, 2012). Usually, a gas turbine operates most efficiently when having a constant load. Therefore, when the load fluctuates or during idle times, it uses more fuel than a reciprocating engine. This means that it incurs more costs. The turbine also uses large amounts of air when operating at full power (Kurz, 2012). This amount of air results in a situation where particles of the contaminants like salts, dusts, aerosols and pollens stick to the blades of the compressor.

This process ends up reducing the engine efficiency, and makes the machine less efficient than reciprocating engines. The situation impedes air inflow into the turbine, thereby compromising the performance of the gas turbine. This means that the system will need more energy to maintain power output. This means that making the compressors clean is fundamental.

References

• Brain, M. (2014). How Gas Turbine Engines Work. Available at: https://www.enginebuildermag.com/2014/03/how-gas-turbine-engines-work/
• DECC. (2014). Technology: Gas Turbine Pro & Cons. Available at: https://www.decc.gov.uk/
• Edison Tech Center. (n.d.). Gas Turbines. Available at: https://edisontechcenter.org/
• Giacomazzi, Eugenio. (2014). The importance of operational flexibility in gas turbine power plants. Available at: https://www.power-technology.com/
• Kay, A. (2002). German Jet Engine and Gas Turbine Development. Airlife Publishing.
• Kurz, R. X. (2012). Important Properties for Industrial Gas Turbine Fuels. PGJ, 239(6).
• Office of Fossil Energy. (n.d.). How Gas Turbine Power Plants Work. Available at: https://www.energy.gov/