Let us begin somewhat unconventional and recall the hum of the turbines. This is a fairly common phrase, usually used by inexperienced authors in the media when describing the operation of powerful aircraft. Here we can also add “rumble, whistle” and other loud definitions for the same “airplane turbines”.

Quite familiar words for many people. However, people who understand well know that in fact all these “sound” epithets often describe the work of jet engines as a whole or its parts, having very little to do with turbines, as such (except, of course, the mutual influence in their joint work in the overall cycle of turbofans).

Moreover, in a turbojet engine (just such are the object of enthusiastic reviews), as a direct reaction engine, which creates thrust by using the reaction of the gas jet, the turbine is only part of it and to the “roaring roar” has rather indirect relation.

On those engines, where it, as a unit, plays, in some way, the leading role (these are indirect reaction engines, and they are not called gas turbines for nothing), there is no such impressive sound, or it is created by completely different parts of the power plant of the aircraft, for example, the propeller.

That is, neither the hum nor the rumble, as such, are actually related to the aircraft turbine. However, despite such sound inefficiency, it is a complex and very important unit of a modern turbine, which often determines its main performance characteristics. No GTE can do without a turbine, simply by definition.

History and Theory

And even a very long time ago. Since the time when mechanisms were invented that converted the energy of the forces of nature into useful action. The simplest in this respect and therefore one of the first to appear were the so-called rotary engines.

This definition itself, of course, appeared only in our days. However, its meaning just defines the simplicity of the engine. Natural energy directly, without any intermediate devices is converted into mechanical power of rotational motion of the main power element of such an engine – the shaft.

The turbine is a typical representative of the rotary engine. Getting ahead, we can say that, for example, in a piston internal combustion engine (ICE), the main element is the piston. It performs reciprocating motion, and to obtain the rotation of the output shaft, it is necessary to have an additional crank mechanism, which, naturally, complicates and weighs down the design. The turbine is much more advantageous in this regard.

For the rotary-type ICE, as a heat engine, which, by the way, is a turbojet engine, the name “rotary” is usually used.

Some of the best known and oldest applications of the turbine are large mechanical mills, used by man since time immemorial for various economic needs (not only for grinding grain). These include both water and wind mechanisms.

For a long period of ancient history (the first mentions from about the 2nd century B.C.) and the history of the Middle Ages, these were actually the only mechanisms used by man for practical purposes. Possibility of their application with all primitiveness of technical circumstances was in simplicity of transformation of energy of used working body (water, air).

In these, as a matter of fact, real rotary engines the energy of water or air flow is converted into power at the shaft and, eventually, into useful work. This happens when the flow interacts with the working surfaces, which are blades of a water wheel or wings of a windmill. Both of them, in fact, are the prototype of blades of modern blading machines, which are turbines used nowadays (and compressors, too, by the way).

There is another type of turbine, first documented mentioned (apparently invented) by the ancient Greek scientist, mechanic, mathematician and naturalist Heron the Alexandrian (Heron ho Alexandreus, 1st century AD) in his treatise “Pneumatics”. The invention he described was called the aeolipile, which in Greek means “ball of Aeolus” (the god of wind, Αἴολος – Aeolus (Greek), pila – ball (Latin)).

In it, the ball was equipped with two oppositely directed nozzle tubes. Steam came out of the nozzles and entered the ball through the pipes from the boiler located below and thus made the ball rotate. The action is clear from the figure above. It was a so-called inverted turbine, rotating in the opposite direction to the steam outlet. Turbines of this type have a special name – jet turbines (more details below).

It is interesting that Heron himself hardly had any idea what the working body of his machine was. At that time, steam was identified with air; even its name testifies to this, because Aeolus commands the wind, that is, the air.

The Aeolipile was, in general, a full-fledged thermal machine, which converted the energy of the burned fuel into the mechanical energy of rotation on the shaft. It was probably one of the first thermal machines in history. However, its usefulness was still “incomplete”, because the invention did not perform any useful work.

The Aeolipile, among other mechanisms known at that time, was part of the set of the so-called “automata theater”, which had great popularity in the following centuries, and was actually just an interesting toy with an unclear future.

From the moment of its creation and in general from the era when people in their first mechanisms used only “manifestly manifest” forces of nature (wind power or gravity of falling water) to the beginning of confident use of thermal energy of fuel in the newly created thermal machines passed not one hundred years.

The first such machines were steam engines. Real working examples were invented and built in England only by the end of the 17th century and were used for pumping water out of coal mines. Later, steam machines with a piston mechanism appeared.

In the future, as technical knowledge developed, piston internal combustion engines of various designs, more perfect and more efficient mechanisms, “came on the scene”. They already used gas (combustion products) as a working body and did not require cumbersome steam boilers for its heating.

Turbines, as the main units of heat machines, also passed a similar path in their development. Although there are separate mentions of some specimens in history, but noteworthy and documented, including patented, units appeared only in the second half of the 19th century.