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helicopter Air intakes
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helicopter Air intakes

helicopter Air intakes

 

In all permitted Flight Manual modes of operation of engines and their combinations should be provided dynamic stability collaboration air intakes and engine.

The design and layout of the air intake SU helicopter must be designed in such a way that during taxiing, takeoff and landing is minimized can be sucked from the ground to the engine of foreign objects that may cause unacceptable deviations of the engine. If this requirement is notcan be done, there should be created a protective device (such as dust-proof device - ROM) that provides the necessary degree of cleaning of air entering the engine.

The air intake is equipped with anti-icing system (G10S) to prevent dangerous ice during flight in icing conditions.

The problem of protection from dust solve a motor company and helicopter.

Cleaning the dust can be carried out by gravity sedimentation, inertial separators and centrifuges, leaching, electric wipers, sound agglomeration, etc.

Selection purification method depends on the flow rate, the energy required for operation of the separator, the installation space for disposable separator type, shape, size and concentration of particles, and many other factors.

To protect against erosion helicopter turbine engine primarily used inertial ROM. They separation of particles occurs under the influence of inertial forces that arise due to changes in the direction of motion of dusty air. They have dimensions and minor hydraulic resistance device characteristics constant during operation and a high degree of cleaning dusty air.

Inertia ROM on the principle of action or design features can be divided into the following subgroups IA:

  • - Zhalyuznye (ballistic, with inertial bars);

  • - Cyclone (monocyclone, multicyclones);

  • - Rotation (with rotating blades turbotsiklony, with rotating flaps);

  • - With curved channels;

  • - Separation from directed towards the axis of symmetry;

  • - Separation from the periphery.

Permissible levels of hydraulic losses in the ROM cleaning path can be considered a loss about 2% (200 mm of water..).

 

Two modes are considered for selection of the parameters of the air intake of GTE:

  • - Air purification (testing engines, taxiing, taking off, hovering, moving at low altitude, landing);
  • - Horizontal flight.

Thus, the air intake is necessary to have two channels, and air-bypass.

The air cleaning mode, all the air flows through the purifying tract, thus "bypass" channel must be stopped (valve installed therein). In the case of the presence of ice or snow in the air "bypass" channel opens and the air is supplied to the gas turbine engine through both path. In the first approximation we can assume that in a hover cleaning path goes 33%, and through the "bypass» - 67% air. "Bypass" channel must be provided with the PIC. This mode can be considered acceptable only if there is an intense ice formation on the surface of the cleaning path.

The most promising inertial ROM peripheral dust separation and separation to the symmetry axis of the device. For

increase the degree of purification is fulfilled more perfect form of the input channel and the central body. Develop options for ROM, providing the installation of swirl flow blades.

Initial data for selecting the ROM parameters are:

  • - Dusty flow structure in the helicopter operating area in a ground proximity;
  • - The composition of soil dust and abrasive properties of their constituents;
  • - The nature of the interaction of fast moving abrasive dust particles with structural elements of the GTD materials.

Formation of dust cleaning the channel geometry is performed on the basis of the calculation of the path of movement of solids through the input channels for different initial particle velocities.

 

In terms of increased dust concentration increases the interaction between particles in the dispersed phase, and between different fractions of particulate dust composition.

Perfection of a design team in the area of ​​inertial separation rings considerably reduces energy costs for sucking dust concentrate.

An effective way to increase the life of engines is to arrange air intake from the least dusty zone. This zone is located in the area of ​​the axis of the HB. In particular, in the experimental Boeing-360 helicopter, the air enters the engines from the upper part of the rear HB pylon. With this arrangement of the power plant in the horizontal flight of the helicopter, the energy of the high-speed flow is not used. However, with helicopter speeds achievable, the increase in engine power from the high-speed flow is insignificant. This eliminates the loss of engine power from the ROM, reduces the weight of the power plant and the cost of its operation.

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