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Elite Engineer

Efficiency: Gas turbine vs. Steam Turbine (with graphics)

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It's a rather dumb question, but here it is:

 

My thought of the major factor in efficiency between the two turbines is the amount of variation of temperature within the engine itself.

 

*Does this hold true?*

 

Here's my theory: The more consistent the temperature, the higher the efficiency.

 

Gas turbine:

 

Combustion of gases would have a slightly more temperature fluctuation due to occurrence of incomplete combustion of gases.

 

Steam turbine:

 

External source of heat constantly maintains gases' kinetic energy, keeping the heat consistent. Also water has a higher specific heat.

 

post-88195-0-71326500-1494043244_thumb.png

 

 

post-88195-0-48330900-1494043271_thumb.png

 

 

Therefore, the steam turbine would theoretically be more efficient

Edited by Elite Engineer

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Efficiency: Gas turbine vs. Steam Turbine (with graphics)

 

The title of this thread looks like a homework question so I am going to treat it as such.

 

Both gasand steam turbines areheat engines.

That is they interconvert between heat and work - in this case they output (useful) work from an input of heat.

 

The thermodynamic efficiency of all heat engines depends mainly upon the temperature difference between the reservoirs.

 

Other measures of efficiency are available such as comapring the energy in the fuel with the output but this is not the thermodynamic efficiency.

 

So your first task must be to decide which efficiency measure you are discussing.

 

Air plus fuel can be heated to a higher temperature than steam so has an inherently higher work generation. Latent heat for steam does not thus enter the calculation.

 

However the gas turbine work also has to power the air compressor which work is then unavailable to output.

 

So you need to look at the cycles for steam and gas turbines - I suspect that is where the diagrams come in and they want you to discuss the differences between the steam cycle and the gas turbine cycle.

 

The Rankine cycle or perhaps the simpler carnot is appropriate to the steam cycle

 

The constant pressure or again perhaps the carnot gas cycle is appropriate for the gas turbine.

 

Here is the sort of diagram I am referring to for thye Rankine cycle.

 

post-74263-0-03210300-1494062517.jpg

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This may seem simple, after all, I am an amateur scientist but, I like this theory on steam engines!

 

So here is my question would A 8 cylinder pressurized air and water turbine engine built with a unique iron and aluminum alloy frame generate enough

 

horsepower to power a car in super compact funneled in air and water energy source , to power the car with a generator for the electric controls such as the wheel of

 

the driver seat the gas and brake pedal and radio etc?

Edited by Wartec

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But it would only work on Sundays.

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?

 

That's the day Marvel Comics allows Batman to take the post#3 hotrod for a spin.

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