What is Gas turbine: Definition and 63 Discussions

A gas turbine, also called a combustion turbine, is a type of continuous and internal combustion engine. The main elements common to all gas turbine engines are:

an upstream rotating gas compressor
a combustor
a downstream turbine on the same shaft as the compressor.A fourth component is often used to increase efficiency (on turboprops and turbofans), to convert power into mechanical or electric form (on turboshafts and electric generators), or to achieve greater thrust-to-weight ratio (on afterburning engines).
The basic operation of the gas turbine is a Brayton cycle with air as the working fluid: atmospheric air flows through the compressor that brings it to higher pressure; energy is then added by spraying fuel into the air and igniting it so that the combustion generates a high-temperature flow; this high-temperature pressurized gas enters a turbine, producing a shaft work output in the process, used to drive the compressor; the unused energy comes out in the exhaust gases that can be repurposed for external work, such as directly producing thrust in a turbojet engine, or rotating a second, independent turbine (known as a power turbine) that can be connected to a fan, propeller, or electrical generator. The purpose of the gas turbine determines the design so that the most desirable split of energy between the thrust and the shaft work is achieved. The fourth step of the Brayton cycle (cooling of the working fluid) is omitted, as gas turbines are open systems that do not reuse the same air.
Gas turbines are used to power aircraft, trains, ships, electrical generators, pumps, gas compressors, and tanks.

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  1. J

    I Trying to wrap my head around gas turbine thermodynamics

    I created a crayon drawing to aid the discussion below: Basically if you have a blower of low pressure, and you blow it through a tube which has a very hot center, when the heat is added to the air, does the pressure of the air increase after passing by the fire, or is that impossible since...
  2. W

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    Hello, I am trying to solve a problem about an open Gas Turbine. The given information would be: - An open gas turbine draws in air from the surroundings having the m, cp, T1 and constant kL with the next values: , - The air flow is heat over natural gas supplied: - The pressure ratio is 𝜋...
  3. PaxFinnica96

    Engineering Steam Turbine with Open Regenerative Feed Heater

    I would very much appreciate anyone to cast their eye over my attempt at solving this problem which I've been struggling with the past few days. Many thanks in advance. Assuming that: energy input from open-type regenerative feed heater pump is negligible no energy is lost the heater pressure...
  4. S

    Confusion about energy conversion mechanisms in gas turbines

    Hello Gents, I am very confused about the working principle of gas turbines. I understand that air is first compressed in a compressor to obtain high pressure air at the inlet of turbine, but before air is introduced to the turbine, first it has to be heated to very high temperatures through...
  5. M

    Engineering Gas turbine (mean line) analysis question

    Hi, I was attempting another turbomachinery question and am struggling with a few concepts. The question is: "A single stage gas turbine for power generation is designed for the following overall duty: - Power output is 4.2 MW, and mass flow rate is 70 kg/s - Inlet stagnation pressure = 3 bar...
  6. C

    Thermodynamics help please -- Air passing through a gas turbine system

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  7. J

    Power required to compress air in a gas turbine

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  8. M

    Gas Turbine Engines: Expansion Away From Compressors

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  9. A

    How mass flow and pressure ratio is related in case of a Gas Turbine

    Hi, As per my observation and experience, when we use evaporative cooler to cool the inlet air to the gas turbine, the compressor discharge pressure (i.e PCD or P3) rises. As, the temp. of the inlet air drops and the mass flow increases due to the increase in density, I believe the discharge...
  10. R

    Gas Turbine Performance

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  11. S

    Turbine Work - Can I assume ideal gas?

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  12. S

    Water injection improves or reduces gas turbine power?

    Hello, I am currently working on a storage project which allows me to decouple the compressor from the expander of a gas turbine. (see image link below) The reason I use a gas turbine is to reheat the air which was cooled after being compressed. As you can imagine there is a efficiency loss...
  13. Seth Allen

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  14. M

    How to do failure analysis of gas turbine blade ?

    I want do thermal and structural analysis (Failure) on gas turbine blade. So what how to begin. Kindly help me.
  15. I

    Gas turbine TS cycle question

    Homework Statement Homework Equations N/A The Attempt at a Solution I am confused what 5-5b and 5b-6 represent in the above TS diagram. I know that 1-2 is compression, 2-3 is cooling, 3-4 is compression and 4-5 is regeneration (since these are indicated in the block diagram) but as for 5-5b...
  16. M

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    Hi Everyone, So I seem to have many problems understanding the Psychrometric chart and its physical meaning. First of all, I would be so thankful if you could introduce me a source which can be useful to physically and fundamentally understand the dew point, effect of pressure, humidity... and...
  17. voltech444

    Gas Turbine Afterburner Water Injection

    Hey I've been thinking of this idea for a while, If I had a small boat with a home made gas turbine engine on it to power it solely with thrust. If I put an afterburner on it and nozzle; and had a small intake for water that filtered out all of the crud. Would it be possible to generate more...
  18. A

    Acceleration of gas turbine?

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  19. A

    The second law efficiency of compressor in gas turbine cycle

    hi friends, I've used the following equation in Thermodynamics: an engineering approach(Cengel) for calculating exergy efficiency of compressor. In fact, for an adiabatic compressor with negligible kinetic and potential energies, the second-law(exergy) efficiency becomes...
  20. A

    Exergy analysis gas turbine cycle For EEs

    hi friends, I am working EES software for thermodynamic lesson,I am analyzing second law efficiency(exergy efficiency) and exergy analysis for all components of gas turbine cycle. Now I have a problem,exergy efficiency of turbine decrease with increasing before temperature,why? As you know...
  21. P

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  22. K

    Gas Turbine: Full Load/Part Load Understanding

    Hi all, I am not able to physically understand the term "load" when we refer to Single Shaft Gas Turbine engines used for power generation purposes. What is causing the torque on the Gas Turbine (GT) to change? Again how the speed is maintained constant while the torque is varied? For a single...
  23. E

    Troubleshooting Alarm Logging on a Gas Turbine

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  24. K

    Gas Turbine: Making Rotor as Stator and vice versa

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  25. K

    Gas Turbine Compressor Stall

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  26. S

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  27. A

    Anyone have experience with gas turbine blade stress analysis?

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  28. C

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  29. M

    Gas Turbine Engine Compressor Discharge Air Temperature Calculation

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  30. Q

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  31. O

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  32. K

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  33. J

    Gas turbine brayton cycle thermodynamic mass flow rate of air

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  34. K

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  35. T

    Compressor maps for mathematical model of a gas turbine

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  36. S

    Gas turbine for peaking power

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  37. Q

    The advantage the constant-volume combustion type gas turbine engine

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  38. C

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  39. A

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  40. A

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  41. E

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  42. B

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  43. B

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  44. H

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  45. J

    Calculating mean radius of a gas turbine rotor (blade and hub)

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  46. G

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  47. B

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  48. M

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  49. K

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