A bit of history
The historical evolution of thermal engineering begins with the domain of the fire that nothing served to illuminate and heat; and about the year 10,000 a. C. began to be used in smelters.
Later in Crete and Rome, later the first central heating systems are implanted, and later in the century Heron of Alexandria gets build the first heat engine in history, called aeolipile, it was a machine consisting of a tube and a tubes through which the steam is ejected. The force was steam coming out makes start rotating mechanism. And this, it was used as a toy or entertainment.
In 1480, Leonardo da Vinci, draw a machine that works with the warmth of a fireplace. It consisted of a machine coupled to a fireplace around gave a twist to the boar that was brewing.
Grill invented by Leonardo da Vinci aeolipile
Classification:
Heat engines can be classified according to the direction of energy transfer, in:
· Heat Engines motor, in which the energy of the fluid decreases in passing through the machine, obtaining mechanical energy at the shaft.
· Generating thermal machines, in which the energy of the fluid passing through the machine increases, requiring mechanical energy into the shaft.
Following the principle of operation, heat engines are classified as:
Volumetric machines, whose operation is based on mechanical and hydrostatic principles, so that at some point the fluid is contained in a limited by the volume of the machine elements. In such machines the flow is pulsating. Is subdivided into two types according to the movement of the propeller body: Alternative, whose motion is rectilinear; and rotating, whose movement is circular.
Turbomachinery, whose operation is based on the exchange of momentum between the fluid and an impeller. In these machines the flow is continuous.
According to its constitution:
● Rotary Machines: whose main feature moving parts
rotate the same.
● Alternative machines:
It has to make a linear movement conversion describing plungers
rotating the cylinders by Crank mechanisms.
How a heat engine works?
There are three types of heat engine:
· Steam engines: When water turns to steam, expands occupying a volume 1700 times greater than in its liquid state. The steam used the enormous energy produced by this expansion to generate a job. steam engine is an external combustion if it burns outside heating the boiler producing steam that feeds it.
· Internal combustion engines: An internal combustion engine is a type of machine that obtains mechanical energy directly from chemical energy produced by burning fuel in a combustion chamber, the main part of an engine.
Internal combustion engines are used four types:
· The Otto cyclic engine: who invented Nikolaus August Otto, is the conventional gasoline engine that is used in automotive and aeronautics.
· The diesel engine: works on a different principle and usually consumes diesel. It is used in electricity generators, marine propulsion systems in trucks, buses and some cars.
· Heavy combustion engines or engines of heavy oils: are characterized because they have no ignition system or carburetor.
· The rotary or Wankel engine: what created the Dr. Felix Wankel, works in a completely different way than conventional engines.
In a reciprocating engine, the same volume (cylinder) made on four different jobs - intake, compression, combustion and exhaust. In a Wankel engine 4 stroke develop the same but in different places; that is, it's like having a dedicated cylinder each time, with the piston moving continuously from one to another.
· Reaction Engines:
Jet engines are based on the principle of action and reaction.
There are two types:
· The turbojets: consist of a hot gas generator and a nozzle that expels back in a jet (action) and drives the motor and mobile in which it is installed forward (reaction).
· The rocket engine: generates thrust by expelling the atmosphere of gases from the combustion chamber. The hot gases produced in the combustion chamber are expelled with great force back (action), thus driving the ship forward (reaction). Rocket engines incorporate both the fuel, usually liquid ohidrógeno kerosene, as the oxidant (oxygen in gaseous or liquid state generally)
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