Heat Engine

(redirected from Heat engines)
Also found in: Dictionary, Thesaurus.
Related to Heat engines: Internal combustion 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 ?
An article in the latest edition of the journal Science describes an innovative form of heat engine that operates using only one single atom.
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.
White; Optimization of Heat Engines Including the Saving of Natural Resources and the Reduction of Thermal Pollution.
The main goal of the present paper is to study specific parameters related to certain heat engine for nonconventional motor vehicles.
Rubber heat engines utilize the property that a stretched rubber shows a positive coefficient of force with temperature.
Now, let us imagine that there is a hypothetical little heat engine inside [S.
A diesel prime mover, or CDI heat engine, is used by both PNGV models.
Some will focus on increasing the energy efficiency of buildings, electric motors, and heat engines (including alternatively fueled gas turbines).
The Stirling engine, like most heat engines, cycles through four main processes: cooling, compression, heating and expansion.
The energy and power densities of the proposed metal-fueled heat engines are predicted to be close to current fossil-fueled internal combustion engines, making them an attractive technology for a future low-carbon society.