Closed Gas Turbine It's Working principle, advantages, disadvantages and application of closed gas turbine.

1. PES COLLEGE OF ENGINEERING
MECHANICAL ENGINEERING
PRESENTATION
UNIT : ENERGY CONVERSION SYSTEMS
TOPIC : CLOSED GAS TURBINE

2. WHAT IS CLOSED GAS TURBINE ?
A Closed-cycle gas turbines can be defined as gas turbines that
uses a gas for the working fluid as a part of closed thermodynamic
system.
In this type of turbine, the air is continuously circulated within the
gas turbine with the help of a compressor, heat chamber, gas
turbine, and cooling chamber. It performs a thermodynamic cycle,
which means that the fluid is circulated and used continuously
without leaving the system.

4. Working Principle of Closed Cycle
Gas Turbine
• The closed cycle gas turbine works on the
basis of the Brayton cycle or Joule’s cycle.
• Gas is compressed isentropically in this type
of gas turbine by a compressor, which then
flows into a heating chamber
• . An external heat source is used to heat the
compressed air before it is passed over the
turbine blades.
• As the gas streams over the turbine blades, it
expands and enters the cooling chamber,
where it is cooled down. Through the
circulation of water at constant pressure, the
gas is cooled to its initial temperature.
Continuing the process, the gas is again
passed into the compressor.

5. Advantages of Closed Cycle Gas Turbine
Closed cycle gas turbines have the following advantages:
• Excellent thermal efficiency at all temperatures and pressure ratios
• Use of any working fluid with low caloric value, such as helium
• Corrosive-free
• No need to clean the inside
• The small size of the gas turbine
• The higher the pressure, the better the heat transfer coefficient in the
exchanger
• Less fluid friction loss

6. Disadvantages of closed-cycle gas turbines:
• The entire system is working under high pressure with a working
fluid (medium), which increases the cost.
• The combustion chamber, when used in the open cycle, is not
enough to heat the air, which here the closed cycle needs a very large
air heater.
• This type of gas turbine is not suitable for aeronautical engines because
it uses water for cooling.
• A complex system is needed to be able to withstand high pressures.

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8. Types of Closed Cycle Gas Turbine
Initially, closed cycles are classified based on working fluid and heat source.
Working Fluid
Gases that can be used as the working fluid are:
• Air
• Helium, along with other noble gases
• Nitrogen
• S-CO2
Heat Source
Heat sources are classified as:
• Solar
• Nuclear
• Fossil
• Biomass