What is the Brayton Cycle?

The Brayton cycle is a type of thermodynamic cycle typically used to depict the way gas turbine engines, jet aircraft engines, and other turbine engines work. The Brayton cycle can be used in both internal combustion engines as well as external combustion engines. The original Brayton cycle engine consisted of three basic components: a gas compressor, a mixing chamber, and an expander. Today, the Brayton cycle is used almost exclusively in gas turbine engines, which typically consist of a gas compressor, a burner, and an expansion turbine. The two primary uses of gas turbine engines are electrical power generation and jet aircraft propulsion.

American engineer George Brayton, who gave his name to this cycle, developed a type of engine called a "Ready Motor" in the early 1870s. These motors were produced to perform such tasks as mill operation and water pumping. These early Brayton cycle engines operated smoothly and were also relatively efficient as well.

Brayton’s original engine produced energy by drawing air into a piston compressor, where it was heated by compression before proceeding to a mixing chamber. Once it reached the mixing chamber, the hot compressed air was mixed with fuel and sent to an expansion cylinder where it was ignited. The ignition of the fuel and air mixture in the expansion cylinder would cause the compressed air to expand and produce enough energy to turn a piston and crankshaft assembly. A portion of the energy produced by this process was used to operate the compressor piston as well.

The Brayton cycle was the basis for the first continuous ignition two-stroke combustion engine. This continuous combustion process was later used in the development of the gas turbine engine used in modern jet aircraft. The Brayton cycle demonstrated that introducing fuel at a controlled rate during the combustion cycle would ultimately produce more energy per unit of fuel consumed. Brayton’s Ready Motor was considered by many to be the first practical and safe oil engine. A Brayton engine is preserved in the American History Museum of the Smithsonian Institute in the U.S.