Heat Engine


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Related to Heat Engine: heat pump, Stirling engine

heat engine

[′hēt ‚en·jən]
(mechanical engineering)
A machine that converts heat into work (mechanical energy).
(thermodynamics)
A thermodynamic system which undergoes a cyclic process during which a positive amount of work is done by the system; some heat flows into the system and a smaller amount flows out in each cycle.

Heat Engine

 

an engine in which thermal energy is converted into mechanical work. Heat engines, which make up the largest group among prime movers, use natural energy sources in the form of chemical or nuclear fuel.

The basis of operation of a heat engine is a closed or arbitrarily closed thermodynamic cycle. The operating efficiency of an ideal heat engine is determined by its thermal efficiency. The operation of a real heat engine, which has additional losses—for example, heat losses and losses caused by friction and vortex formation—is evaluated by the actual efficiency, which is the ratio of the mechanical work at the output shaft of the engine to the heat energy supplied. The actual efficiency of heat engines ranges from 0.1 to 0.6.

Heat engines are divided into piston, rotary, and jet heat engines according to the type of machine carrying out the working thermodynamic process. Combinations of these types, such as turbojet and Wankel engines, are possible. According to the means of heating the working body, heat engines are subdivided into internal-combustion engines, in which both the combustion of fuel and conversion of heat into mechanical work occur in the same working chambers of the engine (the cylinders), and external-combustion engines, in which the working body is obtained or heated outside the engine proper in special devices (for example, the Stirling engine and the steam engine).

O. N. EMIN

References in periodicals archive ?
The modular heat engines provide flexibility in meeting power requirements because the small scale allows them to be combined to create larger sizes as needed," said GTI's project manager Dr.
In theory, it is assumed that the power of a heat engine can be increased by linking it to a quantum heat bath, thus providing a wealth of possibilities that can be used to move beyond the standard accepted boundaries of classical thermodynamics and construct new types of engines.
Kodal, "Performance analysis of an irreversible Brayton heat engine based on ecological coefficient of performance criterion," International Journal of Thermal Sciences, vol.
The irreversible heat engine, as considered earlier, in [32], was assumed to follow law of radiative heat transfer.
Schematic presentation of the processes occurring in the cavities of the plate makes the investigation easier and enables to prove that in the cavity of the plate there exists a heat engine cycle where mechanical energy is produced.
In the heat engine invented almost 200 years ago by Robert Stirling, a gas-filled cylinder is periodically heated and cooled so that the gas expands and contracts.
The Wankel rotary engine is the most known rotary heat engine, patented in 1954 by Felix Wankel.
Farris [15] then presented his work (1977) on the potential use of rubbery solids as the "working fluid" in heat engine and heat pump applications.
Now, let us imagine that there is a hypothetical little heat engine inside [S.sub.1].
The final narrative chapter outlines Sadi Carnot's description of the working of a perfect heat engine, and William Thomson's use of that heat cycle to develop three theoretical definitions of temperature, the first (1847) grounded in Caloric theory, the second (1851) in the mechanical theory of heat, and the last (1881) in thermodynamics.
Robert Stirling propounded the idea of a heat engine which he termed an 'Economiser' now universally known as a 'Stirling Engine'.