A gas turbine is an engine in whichDuring the continuous operation, the main device organ (rotor) converts the internal energy of the gas (in other cases steam or water) into the work of the mechanical plan. In this case, the jet of the working substance acts on the vanes fixed on the circumference of the rotor, causing them to move. In the direction of the gas flow, turbines are divided into axial (gas moves parallel to the axis of the turbine) or radial (perpendicular motion relative to the same axis). There are both single- and multistage mechanisms.
A gas turbine can act on the bladestwo ways. Firstly, it is an active process, when gas is supplied to the working zone at high speeds. At the same time, the gas flow tends to move rectilinearly, and the curved blade member standing in its way deflects it, turning itself. Secondly, it is a reactive type process where the gas flow rate is low, but high pressures are used. Engines of the reactive type in pure form almost never occur, because in their turbines there is a centrifugal force that acts on the blades together with the reaction force.
Where is the gas turbine currently used?The principle of operation of the device makes it possible to use it for the drives of electric generators, compressors, etc. The turbine of this type is widely used in transport (ship gas turbine units). In comparison with the steam analogs, they have a relatively small weight and dimensions, they do not need the arrangement of a boiler house, a condensation unit.
The gas turbine is quickly ready for operationafter start-up, develops full capacity in about 10 minutes, easy to maintain, requires a little water for cooling. Unlike internal combustion engines, it does not have inertial effects from the crank mechanism. The gas-turbine plant is one and a half times shorter than diesel engines and more than twice as light. The devices have the ability to work on low-quality fuels. The above qualities make it possible to consider engines of such a plan of particular interest for hovercraft and hydrofoils.
Gas Turbine as the main component of the enginehas a number of significant drawbacks. Among them there is a high noise level, which is lower than that of diesel engines, economical, a short working life at high temperatures (if the gas medium used has a temperature of about 1100 aboutC, then the use of the turbine can be up to 750 hours on average).
The efficiency of a gas turbine depends on whichsystem it is used for. For example, devices used in power engineering with an initial temperature of gases above 1300 degrees Celsius, with a compression ratio of air in the compressor of not more than 23 and not less than 17 have a coefficient of about 38.5% for autonomous operations. Such turbines are not very widespread and are used mainly to overlap the load peaks in electrical systems. Today, about 15 gas turbines with a capacity of up to 30 MW are operating at a number of thermal power plants in Russia. At multi-stage plants, a much higher efficiency (about 0.93) is achieved due to the high efficiency of the structural elements.
