BraytonZyklen

BraytonZyklen, commonly known as Brayton cycles, describe a thermodynamic cycle used to convert heat into mechanical work in gas turbine engines and some power plants. The cycle is named after George Brayton and is characterized by compression of a working gas, constant-pressure heat addition, adiabatic expansion in a turbine, and heat rejection at constant pressure. While air is the typical working fluid in open cycles, closed Brayton cycles may use other gases such as helium or CO2.

An open Brayton cycle powers most aircraft and industrial gas turbines, where the working fluid is compressed, heated in a combustor, and expanded through a turbine before being exhausted. In a closed Brayton cycle, the working fluid circulates through a heat source and a turbine, enabling non-air fluids and higher temperatures. Variants include regenerative cycles that recover exhaust heat, intercoolers that cool between compression stages, and reheating that expands the gas in multiple turbine stages.

Performance depends on the compressor pressure ratio and turbine inlet temperature. Ideal cycles assume isentropic steps, while real cycles have irreversibilities. Higher turbine inlet temperatures and pressure ratios improve efficiency but require advanced materials and cooling. Recent developments include supercritical CO2 Brayton cycles, which offer high efficiency in compact layouts and are explored for nuclear and solar-thermal plants.

Applications include aircraft propulsion, stationary power generation, and combined-cycle plants that couple a Brayton turbine with a steam cycle to recover waste heat. The Brayton cycle is contrasted with the Otto cycle for spark-ignition engines and the Rankine cycle for steam systems.