What is an Open Cycle Gas Turbine & Its Working

An internal burning engine like a gas turbine works by rotating rather than responding to the motion. This type of turbine includes three essential components like the compressor, power turbine & combustor. In the first component, the air is occupied as well as thirty times compressed through ambient pressure & heading for the combustor section wherever fuel is used by igniting and burning. The combustor is either annular or can-annular or silo, where these two works with aircraft turbine technology to use in small scale applications. A silo type combustor includes single or several combustion chambers placed outside of the body of the gas turbine. These combustors are normally bigger as compared with annular otherwise can-annular, so these are applicable in a larger-scale process. Gas-turbine works with the gas used to rotate a turbine. Usually, this is also used to explain a whole internal-combustion engine that includes a compressor, a burning chamber & a turbine. This article discusses an overview of an open cycle gas turbine.

What is the Open Cycle Gas Turbine?

An open cycle gas turbine can be defined as a combustion turbine plant that is fired up using liquid fuel for rotating a generator so that electricity can be produced. The residual heat can be worn out to the environment at 550o Celsius. The generators and turbine are enclosed to decrease the levels of noise & occupies an approximate area like 75m X 25m for each unit. The height of the exhaust stack can be 30m approximately through the intake structure 20m height.

Open Cycle Type Gas Turbine
Open Cycle Type Gas Turbine

The major components used in the open cycle gas turbine include a compressor, combustion chamber, turbine, control & start-up. A compressor uses the air from the environment & reduces it throughout several stages within the compressor. The liquid fuel can be supplied to a combustion chamber where the chamber includes compressed air. After that, the mixture of both air and fuel can be ignited to form gas with high velocity.

This gas can be supplied using the blades of turbine blades to make the shaft ON that is connected to the rotor within the generator. The rotation of the rotor can be done within a stator so that electricity can be generated. After that, this electricity can be supplied through the network of high voltage wherever it is required

The classification of the gas turbine can be done based on three main events like the process of combustion, working substance path, and combustion gases action within the turbine.

Open Cycle Gas Turbine Working Principle

The open cycle gas turbine diagram is shown below. The working principle of OCGT is when the fresh air enters at ambient temperature into the compressor wherever both the temperature as well as temperature is amplified. The air with high force can be entered into the chamber of combustion where the liquid fuel can bur at stable force. The gas with high temperature can enter into the turbine wherever it increases to ambient force and generates electricity.

Gas Turbine Working
Gas Turbine Working

The main features of open-cycle gas turbines include the following.

  • It is applicable for combined cycles
  • Open cycle gas turbine efficiency is high thermal up to 44%.
  • Long life and reliability is high
  • It is used to generate electric power as well as in aircraft propulsion
  • The start-up time for the turbine is fast like 2 mins as compared with steam-propulsion systems because it takes four hours.
  • The back work ratio is high up to 50% as compared with less percent within steam power plants.


The advantages of open cycle gas turbine include the following.

  • This gas turbine working doesn’t depend on the pressure of the atmospheric, so therefore any type of force can be used so that specific plant output can be improved. Once the pressure is applied to the turbine, the size of components used in this can be decreased.
  • The gas used in this turbine can be any type. For instance, helium and the combination of helium & carbon dioxide can give high efficiency, so it is used in nuclear plants.
  • Simplicity, less weight, and cost
  • The blades of the turbine are not contaminated through the combustion products.
  • The turbine regulation is very simple
  • Low thermal stresses can be present at different loads due to the stable temperatures


The disadvantages of open cycle gas turbine include the following.

  • Whenever high forces are applied at the input of the compressor then exchanger with strong heat is necessary.
  • The results of poor heat transfer and efficiency of poor combustion is mainly because of the heat exchanger based on the indirect type
  • In this type of turbine, the combustion room is more efficient & applicable to a huge quantity of air.
  • These are sensitive
  • The part-load efficiency of this turbine is poor.


The applications of open-cycle gas turbines include the following.

  • Generally, gas turbines are used in aviation to provide motive power, especially for jet propulsion.
  • Generation of Electric Power
  • Certain Industrial Processes
  • Industries
  • Propulsion of Marine, Automotive & Locomotive
  • Used in the application of mechanical drive

Thus, this is all about an overview of the open cycle gas turbine, working principle, advantages, disadvantages, and applications. This is one kind of engine used to rotate the turbine by using gas as the working fluid. Usually, this is also used to explain an entire internal-combustion engine that includes three components like a compressor, a turbine, and a combustion chamber. Here is a question for you, what are the different types of gas turbines available in the market?