Hot air engine



 

hot air engine (historically simply 'air engine' or 'phase change. Also excluded are conventional internal combustion engines in which heat is added to the working fluid by combustion of fuel within the working cylinder - continuous combustion types such as George Brayton's Ready Motor and the related gas turbine could be seen as borderline cases.

In a typical implementation, air is repeatedly heated and cooled in a cylinder and the resulting expansion and contraction is used to move a piston and produce useful mechanical work. [1] [2]

History

The expansive property of heated air was known to the ancients and Hero of Alexandria's Pneumatica contains descriptions of devices which might be used to automatically open temple doors when a fire was lit on a sacrificial altar. Devices called hot air engines, or simply 'air engines', have been recorded from as early as 1699, around the time when the Coalbrookdale Shropshire (English patent 739 of 1759) [3] and Thomas Mead, an engineer from Sculcoats Yorkshire (English patent 979 of 1791) [4], the latter in particular containing the essential elements of a displacer type engine (Mead termed it the transferrer). It is unlikely that either of these patents resulted in an actual engine and the earliest workable example was probably the open cycle furnace gas engine of the English inventor Sir George Cayley c.1807 [5] [6] [7]

It is likely that Robert Stirling's air engine of 1818 which incorporated his innovative Economiser patented in 1816 was the first to be put to practical work. The economiser, now known as the Stirling engine. A full description is available at that article.

Thermodynamic cycle

Main article: Thermodynamic cycle

A hot air engine processes (typical 4). The processes can be any of these:

Some examples are as follows:

Cycle\Process Compression Heat Addition Expansion Heat Rejection
Power cycles with external combustion - or heat pump cycles
Brayton adiabatic isobaric adiabatic isobaric
Bell Coleman
(Reverse Brayton) 		adiabatic isobaric adiabatic isobaric
Carnot isentropic isothermal isentropic isothermal
Stoddard adiabatic isometric adiabatic isometric
Stirling isothermal isometric isothermal isometric
Ericsson isothermal isobaric isothermal isobaric

Yet another example is Vuilleumier refrigeration. [8]

See also

References

  1. ^ Sterling (or Hot air) engine
  2. ^ Theodor Finkelstein and Allan J. Organ (2001). Air Engines: The History, Science, and Reality of the Perfect Engine, 1st Edition, ASME Press. ISBN 0791801713. 
  3. ^ Robert Sier (1999). Hot air caloric and stirling engines. Vol.1, A history, 1st Edition (Revised), L.A. Mair. ISBN 0-9526417-0-4. 
  4. ^ Robert Sier (1999). Hot air caloric and stirling engines. Vol.1, A history, 1st Edition (Revised), L.A. Mair. ISBN 0-9526417-0-4. 
  5. ^ Stirling engine history
  6. ^ Robert Sier (1999). Hot air caloric and stirling engines. Vol.1, A history, 1st Edition (Revised), L.A. Mair. ISBN 0-9526417-0-4. 
  7. ^ Detailed contents of the book Hot air caloric and stirling engines. Vol.1, A history
  8. ^ Wurm, Jaroslav (1991). Stirling and Vuilleumier heat pumps: design and applications. McGraw-Hill. ISBN 0-07-053567-1. 

More references

v • d • e
Thermodynamic cycles
Cycles normally with
external combustion
Gas cycles without phasechange -
hot air engine cycles		 Bell Coleman cycle · Carnot cycle  · Stoddard cycle · Ported constant volume cycle[3]  · Vuilleumier cycle
Cycles with phasechange Rankine cycle · Regenerative cycle · Two phased Stirling cycle[4]
Cycles normally with
internal combustion		Mixed/Dual Cycle
Not categorizedClaude cycle [7] · Fickett-Jacobs cycle · Gifford-McMahon cycle [8] · Hirn cycle · Homogeneous Charge Compression Ignition · Humphrey cycle · Linde-Hampson cycle
v • d • e
Rocket engine nozzles · Sleeve valve
Different pistons layoutsBourke engine · Delta engine · Double acting/differential cylinder · Opposed piston engine · Radial engine · Rotary engine · Single cylinder engine · Stelzer engine · Straight engine
Different main rotational motion
mechanisms or arc to (or even
almost) pistons back-and-forth.		Cam · Connecting rod · Coomber Rotary Engine [9] · Crank substitute engine [10] · Crankshaft · Evans linkage [11] · Parallel motion · Peaucellier-Lipkin linkage · Piston rod · QRMC Stirling/HydraLink [12] · Revolving cylinder engine · Rhombic drive · Scotch yoke · Sector straight-line linkage [13] · Swashplate · Swashplate engine · Watt's linkage
One-way stop-and-go like rotational
motion mechanisms to rotation.		Toroidal engine · Trochilic engine
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Hot_air_engine". A list of authors is available in Wikipedia.