Concept of gas thermal engines

Gas thermal engines are devices that transform the chemical energy contained in a fuel gas into mechanical energy through thermal processes of combustion and expansion. These machines operate under thermodynamic principles that allow the energy released in combustion to be used to perform useful mechanical work.

Generally, these engines use gases such as air combined with gaseous fuels, for example natural gas, propane or hydrogen. The generation of work occurs by the expansion of hot gases inside the engine, which drives a piston or a rotor, transforming thermal energy into mechanical energy with industrial, transportation and electrical generation applications.

Basic thermodynamic cycles

Gas heat engines operate mainly through thermodynamic cycles that describe the energy transformation within the engine. Among the most common are the Otto cycle, the Diesel cycle and the Brayton cycle. Each one has particular characteristics in terms of the way the fuel is introduced, combustion occurs and expansion takes place.

The Otto cycle, typical in gasoline engines, is based on constant volume combustion, while the Diesel cycle uses constant pressure combustion. The Brayton cycle, typical of gas turbines, operates with a continuous flow of gases and constant combustion. The efficiency and performance of these motors depend largely on how these cycles are optimized.

The thermodynamic analysis of these cycles allows us to determine key parameters such as thermal efficiency, net work produced and energy losses, fundamental for the design and improvement of gas thermal engines.

Heat transfer and energy conversion

Energy conversion in gas heat engines involves complex heat transfer processes, where the chemical energy of the fuel is converted into thermal energy through combustion. Subsequently, this thermal energy is transformed into mechanical energy through the expansion of hot gases.