Heat Engine


Also found in: Dictionary, Thesaurus, Wikipedia.
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 ?
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.
Technologically it is impossible to develop a heat engine with a small difference in temperatures.
We successfully decreased the size of the essential parts of a heat engine, such as the working gas and piston, to only a few micrometres and then assembled them to a machine," stated another researcher called Valentin Blickle.
Wu; The Universal Power and Efficiency Characteristics for Irreversible Reciprocating Heat Engine Cycles.
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.
It is thus possible to turn on this hypothetical little heat engine and to start releasing heat inside our solid.
Think about our atmosphere as the heat engine whose role it is to seek a globally balanced distribution of energy, heat and moisture.
An actual heat engine might have only 5-10 percent efficiency, but huge amounts of renewable energy are available at no cost other than the capital cost of the engine and the energy storage system.
Fuel cells currently are a hot topic because they are more efficient at converting chemical energy into work than a heat engine, are simple in design, and don't pollute the environment.
The physics of the universe sets limits to the energy you can extract from a heat engine," says Bruckner.
Each can contains an internal heat engine and, once activated, heats the coffee in just three minutes, providing a 210ml serving of Nescafe Original.