# Mechanical Engineering - Thermodynamics - Discussion

Discussion Forum : Thermodynamics - Section 1 (Q.No. 3)
3.
The efficiency and work ratio of a simple gas turbine cycle are
low
very low
high
very high
Explanation:
No answer description is available. Let's discuss.
Discussion:
34 comments Page 2 of 4.

Chauhan Hardik N. said:   8 years ago
I think that, since the specific volume (reciprocal of density) of air is high, the compression of air requires more work.

Hence, the major fraction of the work developed by the turbine is utilized in driving the compressor.

Therefore, the efficiency of the simple gas turbine plant is too low.
(1)

YOGESH GAYAKE said:   9 years ago
But my question is that turbine is used to rotate the generator for generating the electricity & its rotate with the help of steam pressure. Then how we can calculate its efficiency & work ratio. But still we assure that the 70% of power from turbine is used to run the compressor itself. So it's correct but, how we can say its very low. Please suggest answer.

Soham Mitra said:   9 years ago
Rankine cycle used in thermal power plants deals on heating up water in constant pressure while changing its phase. The process will has greater thermal efficiency compared to any other cycles. Otto cycle can't be used because heat supplied to the system is in constant volume process, not allowing steam to expand properly.

If Otto cycle forced to used, the pressure will be too high for any material (vessel) to withstand. Diesel also can't be used, because while heat supplied to the system, the fluid deliver work to the surrounding. This not applicable because the work should be extracted by steam turbine.

Krishna said:   9 years ago
Nothing understood. Post the explanations clearly.

DK SINGHGUPTA said:   9 years ago
We all know that work ratio-turbine work /net work that means turbine work means positive work so the answer is low but how the answer is very low.

Kunwar singh said:   9 years ago
Turbine is mostly energy waste in rotating compressor.

Biswaranjan Biswal said:   10 years ago
It is the ratio of net work/turbine work. Net work equal to turbine work-comp work.

Abhay singh said:   10 years ago
Gas turbine's efficiency and work is minimum because less of friction but turbine fan and air.

Sumit said:   10 years ago
Due to compressor EFF is less.

DHMS said:   10 years ago
The efficiency is very low because, turbine is rotating device due to that it haves high losses.