Gas Turbine Power Output Calculator

Analyze Brayton cycle performance using practical operating inputs. See shaft, net, and electrical output clearly. Create dependable results for design reviews and feasibility studies.

Enter operating data

Use consistent values for compressor, turbine, fuel, and losses. The calculator applies a simplified Brayton cycle with constant specific heat.

Air entering the compressor.
Compressor inlet absolute pressure.
Ambient compressor inlet temperature.
P2 divided by P1.
Isentropic compressor efficiency.
Temperature entering the turbine.
Isentropic turbine efficiency.
Pressure drop across combustion chamber.
Shaft transmission efficiency.
Electrical conversion efficiency.
Average working fluid specific heat.
Specific heat ratio.
Lower heating value of fuel.
Useful heat transfer from fuel.
Reset

Example data table

Use this sample set to test the calculator and compare your own values.

Parameter Sample Value Unit
Air Mass Flow25kg/s
Inlet Pressure101.325kPa
Inlet Temperature15°C
Pressure Ratio10ratio
Compressor Efficiency82%
Turbine Inlet Temperature1100°C
Turbine Efficiency87%
Combustor Pressure Loss4%
Mechanical Efficiency98%
Generator Efficiency96%
Specific Heat Cp1.005kJ/kg·K
Gamma1.4ratio
Fuel LHV43MJ/kg
Combustion Efficiency99%

Formula used

This model follows a simplified Brayton cycle. It assumes constant specific heat and gamma, equal inlet and exhaust pressure levels, and one combustor pressure loss term.

1. Compressor ideal outlet temperature:
T2s = T1 × rp(γ - 1) / γ

2. Compressor actual outlet temperature:
T2 = T1 + (T2s - T1) / ηc

3. Turbine ideal outlet temperature:
T4s = T3 × (P4 / P3)(γ - 1) / γ

4. Turbine actual outlet temperature:
T4 = T3 - ηt × (T3 - T4s)

5. Specific compressor work:
wc = Cp × (T2 - T1)

6. Specific turbine work:
wt = Cp × (T3 - T4)

7. Specific heat added:
qin = Cp × (T3 - T2)

8. Fuel-air ratio:
f = qin / (ηcomb × LHV)

9. Net cycle power:
Pnet = (ṁgas × wt) - (ṁair × wc)

10. Shaft and electrical power:
Pshaft = Pnet × ηm
Pelectric = Pshaft × ηg

How to use this calculator

  1. Enter the air mass flow reaching the compressor.
  2. Provide inlet pressure and inlet temperature as absolute operating conditions.
  3. Add the compressor pressure ratio and isentropic compressor efficiency.
  4. Enter the turbine inlet temperature and turbine efficiency.
  5. Set combustor pressure loss, mechanical efficiency, and generator efficiency.
  6. Confirm Cp, gamma, fuel LHV, and combustion efficiency.
  7. Click Calculate Power Output to view the summary above the form.
  8. Use the CSV or PDF buttons to export the result table.

FAQs

1. What does this calculator estimate?

It estimates gas turbine electrical output, shaft power, fuel use, turbine work, compressor work, net cycle power, efficiency, and key temperatures using Brayton cycle assumptions.

2. Why does pressure ratio matter so much?

Pressure ratio strongly affects compressor work and turbine expansion. A better ratio can improve net output, but very high values may also raise compressor losses.

3. Is the model suitable for detailed plant guarantees?

No. It is best for screening, comparison, and preliminary studies. Detailed guarantees need manufacturer maps, cooling flows, humidity effects, and part-load corrections.

4. Why does the calculator use constant Cp and gamma?

Constant values simplify the Brayton cycle math. Real gas properties vary with temperature and composition, so this method trades some precision for speed and clarity.

5. What happens if turbine inlet temperature increases?

Higher turbine inlet temperature usually increases turbine work and net power. It can also improve efficiency, provided material limits and cooling needs remain acceptable.

6. Why is there a combustor pressure loss input?

Pressure drops in the combustor reduce turbine expansion potential. That lowers turbine work and, in turn, reduces net cycle output and efficiency.

7. What is specific fuel consumption?

Specific fuel consumption shows how much fuel is needed for each kilowatt-hour of electricity. Lower values generally indicate better operating performance.

8. Can I use this for natural gas only?

No. You can use other fuels too, as long as you enter a suitable lower heating value and combustion efficiency for that fuel.

Related Calculators

gas pressure regulatornatural gas flow rategas pipeline sizingnatural gas expansionnatural gas pipeline diametergas flow factornatural gas burn rategas flow coefficientcompressor efficiency factorpipeline heat transfer

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.