Brayton Cycle Calculator
Ideal Brayton efficiency depends only on the pressure ratio: rp = 10 with γ = 1.4 gives η = 48.2053 %.
48.2052532076879 %
Full answer, then cut to fewer decimals (not rounded):
- 48.2052532076879 %
- 48.205253207687 %
- 48.20525320768 %
- 48.2052532076 %
- 48.205253207 %
- 48.20525320 %
- 48.2052532 %
- 48.205253 %
- 48.20525 %
- 48.2052 %
- 48.205 %
- 48.20 %
- 48.2 %
- Ideal efficiency 1 − 1/rp^((γ−1)/γ)
- 48.2053 %
- Compressor outlet T₂
- 579.209 K
- Turbine outlet T₄
- 621.537 K
- Compressor work
- 280.605 kJ/kg
- Turbine work
- 581.355 kJ/kg
- Net work
- 300.75 kJ/kg
- Back work ratio wc/wt
- 0.482674
- Pressure ratio for maximum work (ideal)
- 11.3137
Step-by-step solution
- rp^((γ−1)/γ) = 10^0.2857 = 1.9307
- T₂ = 579.209 K, T₄ = 621.537 K
- η = (wt − wc)/qin = (581.355 − 280.605) ÷ 623.895 = 0.482053
Brayton Cycle Formula
η = 1 − 1/rp^((γ−1)/γ)
rp pressure ratio; optimum rp = (T₃/T₁)^(γ/2(γ−1)) for maximum work
Worked Example
rp = 10, T₁ = 300 K, T₃ = 1200 K, ideal compressor and turbine:
- rp^((γ−1)/γ) = 10^0.2857 = 1.9307
- T₂ = 579.209 K, T₄ = 621.537 K
- η = (wt − wc)/qin = (581.355 − 280.605) ÷ 623.895 = 0.482053
Compressor outlet T₂: 579.209 K · Turbine outlet T₄: 621.537 K · Compressor work: 280.605 kJ/kg · Turbine work: 581.355 kJ/kg · Net work: 300.75 kJ/kg · Back work ratio wc/wt: 0.482674 · Pressure ratio for maximum work (ideal): 11.3137
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Example: r = 8, γ = 1.4, intake 300 K and 100 kPa, peak 2000 K: Air-standard efficiency η = 56.4725 %.
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Diesel Cycle Calculator
η = 1 − [1/r^(γ−1)] × (ρ^γ − 1)/[γ(ρ − 1)]
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Example: r = 18, cut-off ratio 2, γ = 1.4, intake 300 K and 100 kPa: Air-standard efficiency η = 63.1578 %.
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Polytropic Process Calculator
W = (p₁V₁ − p₂V₂)/(n − 1), Q = W(γ − n)/(γ − 1)
pVⁿ = constant; n = 1 isothermal W = p₁V₁ ln(V₂/V₁)
Example: Air compressed from 100 kPa, 0.1 m³, 300 K to 800 kPa with n = 1.3: Work done by the gas W = -20.5289 kJ.
Frequently asked questions
What is the back work ratio?
Compressor work divided by turbine work, often 40–80 % in gas turbines, which is why component efficiencies matter so much.
What pressure ratio gives maximum net work?
For the ideal cycle, rp = (T₃/T₁)^(γ/2(γ−1)), where T₂ = T₄ = √(T₁T₃).
Sources
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
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APA
Scientific Converters. (2026, October 15). Brayton Cycle Calculator. Retrieved October 25, 2026, from https://scientificconverters.com/calculators/brayton-cycle-calculator/
IEEE
Scientific Converters, "Brayton Cycle Calculator," scientificconverters.com. Accessed: Oct. 25, 2026. [Online]. Available: https://scientificconverters.com/calculators/brayton-cycle-calculator/