RU2645863C2 - Turboprop engine - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: turboprop engine comprises turbo-gas turbine engine and propeller-type reduction gear. Output shaft of the turbo-gas turbine engine is connected to the gearbox of the propellers by means of a mechanical transmission. Gearbox has output shafts for driving the coaxial propellers and the gearbox axis is displaced relative to the axis of the turbo-gas turbine engine by a value, allowing to place the air intake of the gas turbine engine in the middle zone of the radius of the propellers.

EFFECT: invention is aimed at increasing power of turboprop engine by boosting the air intake without forcing the base turbo-gas turbine engine included in its composition, the elimination of balancing losses of energy on aircraft, associated with the compensation of the total reactive torque, equivalent to additional increase in engine power, as well as reduction of engine mass and aircraft structural elements.

1 cl, 2 dwg

Description

The invention relates to the field of aviation technology and can be used in the design of aircraft engines and power plants.

Known NK-12 turboprop engine for the TU95 aircraft (1944-2000 aircraft, rocket, marine, industrial engines. M: AKS-Conversalt, 2000. S. 187-190), containing a coaxial propeller gearbox and a gas turbine turbo engine, an output shaft which is connected to the gearbox of coaxial propellers.

The axis of the NK-12 engine propeller reducer is located coaxially with the engine output shaft; the air intake is circular. The air intake is located in the area of the air flow formed by sections of propeller blades close to their root part. These design features do not allow the efficient use of the energy of the air flow generated by the propellers, since in this zone the boost is practically absent.

Closest to the proposed invention is the prototype TV3-117SBM1 turboprop engine adopted for the AN-140 aircraft (HIS Janes's Aero-Engines 2013-2014, p. 268), comprising a propeller gearbox and an air intake located in the root portion of the propeller blade, moreover, the output shaft of the gas turbine turboshaft engine is connected to the propeller gearbox by a mechanical transmission, and the exhaust pipe is made with flow rotation.

The disadvantages of this engine are:

- the use of a “single” propeller creates reactive torque on the engine and, as a result, balancing power losses on the plane, the need to compensate for the torque leads to significant power costs;

- insufficient displacement of the axis of the propeller relative to the axis of the engine, not allowing to increase the effective power due to the boost of the air intake.

The displacement of the axis of the propeller relative to the axis of the engine by an amount that does not allow the engine air intake to be placed in the middle part of the radius of the propeller excludes the possibility of efficiently pressurizing the air intake with the air flow behind the propeller and, as a result, eliminates the increase in engine power due to this, as well as the possibility of using direct air intake with low aerodynamic energy losses. In addition, the air intake of an engine with a flow rotation has significantly greater aerodynamic losses in flight than a direct air intake without rotation. An exhaust pipe with a flow turn also causes additional aerodynamic losses.

The problem to which the invention is directed, is to eliminate the above disadvantages.

The technical result of the invention is to increase the power of a turboprop engine by boosting the air intake without forcing the base turboshaft engine included in it, and eliminating balancing energy losses on the plane associated with compensation of the total reactive moment, as well as reducing the mass of engine structural elements.

The solution of the technical problem is achieved by the fact that the turboprop engine contains a turboshaft gas turbine engine, the output shaft of which is connected to the propeller gearbox using a mechanical transmission, and according to the invention, the gearbox has output shafts for driving coaxial propellers, and the gearbox axis is offset relative to the axis of the engine by a value that allows you to place the air intake of the gas turbine engine in the middle zone of the radius of the propellers. The direct, without turns of an air stream air intake minimizes aerodynamic losses of an air stream. The exhaust pipe is also made straight, without turning the flow.

The use of coaxial propellers eliminates jet moment on the engine and balancing energy losses on the plane (which, in turn, is equivalent to an increase in engine power). In addition, the efficiency of coaxial propellers is higher than that of a single propeller. Reducing the loss of total air pressure in the direct air intake of the gas turbine engine, reducing the aerodynamic energy loss at the outlet of the gas turbine engine due to the direct and short output device also leads to an increase in engine efficiency. The reduction in the mass of the structural components of the engine mount and aircraft suspension elements is ensured by the absence of reactive moments.

The invention is illustrated by drawings:

FIG. 1 - General view of a turboprop engine,

FIG. 2 - layout of a turboprop engine on a pylon on an airplane wing, where

1 - base turboshaft engine;

2 - mechanical transmission;

3 - gearbox coaxial propellers;

4 - air intake;

5 - exhaust pipe;

6 - propellers.

The base turboshaft engine 1 has a power output shaft, which is connected through a mechanical transmission 2 to the gearbox 3 of the drive of the coaxial propellers 6, located behind the straight screws, without flow turns, the air intake 4 of the engine 1, offset relative to the axis of the engine 1 in the middle zone of the radius of the propellers 6 located on the axis of the engine behind a straight short exhaust pipe 5 of the engine 1.

The base turboshaft engine 1 transmits the mechanical power of rotation of the output shaft through a mechanical transmission 2 to the gearbox 3 of the drive coaxial propellers 6, which rotate in different directions. In this case, the reactive moments from each screw are equal and directed towards each other, and the total reactive moment on the engine is absent. The propellers 6, rotating, effectively additionally inflate the air intake 4 of the engine located in the middle zone of the radius of the propellers 6, where the boost is most effective.

Thus, the present invention allows to significantly increase the power of a turboprop engine due to boosting the air intake without forcing the base turboshaft engine included in it, and the exclusion of balancing losses on the plane associated with compensation of the total reactive moment is equivalent to an additional significant increase in engine power. The absence of a reactive moment also reduces the weight of the aircraft by reducing the weight of the structural components of the engine mount. Reducing the overall level of aerodynamic losses in the direct air intake and in the short straight exhaust pipe also leads to increased engine efficiency.

Claims (1)

A turboprop engine comprising a turboshaft gas turbine engine and a propeller gearbox, wherein the output shaft of the turboshaft gas turbine engine is connected to the propeller gearbox using a mechanical transmission, characterized in that the gearbox has output shafts for driving coaxial propellers, and the gearbox axis is offset relative to the axis of the turboshaft gas turbine engine by an amount that allows you to place the air intake of the gas turbine engine in the middle zone of the radius of the propellers.

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