What Are Different Types of Gas Turbines?

A gas turbine, commonly known as an engine with internal combustion, is a mechanical device that converts chemical power into mechanical power. 

The term “combustor” denotes a constituent of a combustion engine that assumes the responsibility of facilitating the efficient and regulated combustion of fuel. The name “turbine” denotes a mechanism that transforms the kinetic energy of a fluid in motion, such as water or steam.

The essential constituents of the propulsion system in various gas turbine variants encompass the air compressor, the combustor, and turbine. In general, these components are consolidated into a unified entity and operate as a comprehensive primary driver inside an open cycle system. Within this particular system, the intake of atmospheric air occurs, thus leading to the generation of combustion byproducts that are finally discharged again into the atmosphere.

Different Types of Gas Turbines

The types of Gas turbines are broadly classified according to the specific compressors they make use of. There are three major classifications of compressors, specifically centrifugal flow, vertical flow, and rotational-axial flow.

Gas Turbine Types Based on Compression

Centrifugal Flow

The compression process of a centrifugal flow engine entails the acceleration of incoming air in a direction outward that is perpendicular with the longitude of the apparatus.

Axial Flow

The axial-flow engine employs a series of rotational and static airfoils to achieve air compression, resulting in a parallel movement along the axis of longitudinal motion.

Centrifugal-axial Flow

The centrifugal-axial flow arrangement utilizes a hybrid design incorporating both centrifugal and axial compressor to achieve the required level of compression.

Turbojet

The turbojet engine, among the different types of gas turbine, consists of four distinct sections, namely the compressor, combustion chamber, turbine section, and exhaust. The compressor portion facilitates the rapid flow of input air towards the combustion chamber. The turbine is propelled by the expanding air, and it is mechanically linked to the compressor through a shaft, ensuring the continuous functioning of the engine. 

The high-velocity exhaust gasses emitted from the engine generates a strong propulsion. This represents a fundamental utilization of air compression, combustion of the fuel-air amalgamation, generation of power to autonomously sustain engine functionality, and expulsion of exhaust gasses to facilitate propulsion.

Air Compressor

The air compressor is a mechanical device used to convert power from a primary energy source, such as an electric motor or internal combustion engine

Located in the intermediary space connecting the combustion chamber and the turbine, the air compressor and the turbine are affixed to a shared shaft. Gas turbines necessitate the presence of a starting motor due to their inherent absence of self-starting capabilities. The primary function of an air compressor is to intake and compress air, therefore increasing its pressure. The utilization of axial design compressors comprising many stages is favored in the context of modern and big gas turbines.

Aeroderivative Gas Turbine

It is a variant of the gas turbine that draws its design principles from jet engines. It is specifically engineered to possess a compact and lightweight structure, rendering it highly ideal for deployment in mobile and marine settings. Aeroderivative gas turbines find widespread application in airplane propulsion, marine propulsion, and mobile electric power generation.

Combustion Chamber

It is a crucial component in internal combustion engines among the various gas turbine types, where the combustion of fuel and air takes place.

Within this particular constituent, the process involves the amalgamation of compressed air and fuel, thereby generating a fuel-air amalgam that subsequently experiences the process of combustion. The resultant combustion byproducts are then sent into the gas turbine. The presence of elevated air pressure facilitates the optimal burning of the fuel combination. 

Microturbine

The microturbine is a compact gas turbine that has been specifically engineered for the purpose of decentralized power generation, catering to scenarios such as rural areas or as a contingency power source. Microturbines find widespread utilization throughout a range of settings, encompassing residential, commercial, and industrial domains.

Turbine

The multistage gas turbine is an apparatus in which high-temperature gases pass through a sequence of stages, during which their kinetic energy is converted to mechanical energy produced in the form of shaft hp. Like the steam turbine, a gas turbine is furnished with both fixed and spinning blades. The principal purpose of blades that are stationary is to govern the direction of gas flow towards the blades of the rotor and manage their speed. The turbine’s shaft is connected to a generator using mechanical means.

Final Words

Various forms of fuel are commonly employed in different gas turbine types, encompassing liquid fuel, gaseous fuel, and natural gas. The fuel is introduced into the system at the upstream location in the form of a finely dispersed spray, and the fuel nozzles can be classified as either simplex or dual fuel variants.

Certain gas turbines possess the capability to operate on a dual-fuel basis, enabling them to combust a blend of gaseous and liquid fuels.