RU2443892C1 - Method of turning gas flow in deflecting grids of gas turbine engine reversing device - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: proposed method consists in selecting required reversing flow turn angle in reversing device relative to engine lengthwise axis in the range of φ=90°…135°. Then, selected angle is used to define angles of deflecting grid vane front and rear angles at preset curvature of vanes. Then, reversing device deflecting grid is dissected by cylindrical surface passing through deflecting grid vanes and located concentrically with engine axis. Then, the vanes of formed inner deflecting grid are shifted relative to outer deflecting grid vanes along engine axis streamwise for distance smaller than vane pitch. Angles of the vane exit edges on said inner deflecting grid are set equal to those of outer deflecting grid.

EFFECT: higher efficiency of reversing device.

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Description

The invention relates to aviation, in particular to a method for creating reverse thrust of an aircraft gas turbine engine.

There is a method of creating a reverse thrust of aircraft gas turbine engines, in which in reverse devices the reverse thrust is created due to the kinetic energy of the gas stream, which is deployed and sent in the direction of movement of the aircraft (AC). An example of such a method of creating reverse thrust is a lattice-type reversing device in which deflecting grids and flaps are installed that block the engine flow path (PS-90A Aircraft Engine, M., Libra-K, 2007, p. 105; "Aerodynamics of the TU-154 aircraft", Moscow, "Transport", 1977, p. 70). On the flaps, the main rotation of the gas flow in the direction of the deflecting gratings occurs. In the deflecting gratings, the final rotation of the gas stream flowing from the reversing device to the side of the aircraft occurs.

The disadvantage of this method is the decrease in the efficiency of the reversing device due to the possibility of disruption of the gas stream from the backs of the blades of the deflecting gratings.

The aim of the invention is to increase the efficiency of the reversing device by improving the flow around the blades of the deflecting grates with a gas stream.

The goal is achieved by the fact that:

- choose the required angle of rotation of the reverse jet in the reversing device relative to the longitudinal axis of the engine within φ = 90 ° ... 135 °;

- the selected angle of rotation determines the installation angles of the front and rear edges of the blades of the deflecting grating for a given curvature of the blades;

- "dissect" the deflecting lattice of the reversing device with a cylindrical surface passing through the blades of the deflecting lattice and located concentrically relative to the axis of the engine;

- the blades of the formed internal deflecting grating are shifted relative to the blades of the external deflecting grating along the axis of the engine downstream by a distance less than the pitch of the blades t (t is the distance between the same points of adjacent blades of the deflecting grating);

- the installation angles of the output edges of the blades of the internal deflecting grating are chosen equal to the angles of installation of the input edges of the blades of the external deflecting grating.

The proposed method of turning the gas flow in the grids of a reversing device of a gas turbine engine is as follows.

Select the angle of rotation of the reverse jet 3 relative to the longitudinal axis of the engine within φ = 90 ° ... 135 °, necessary to create the required value of reverse thrust (Fig. 1). The maximum angle of rotation of the reverse jet 4 is limited by an angle of the order of 135 °. An increase in the angle of rotation of the reversible jet leads to the “sticking” of the jet to the surface of the engine nacelle and its getting into the engine, which can cause unstable engine operation (“Aerodynamics of the TU-154 aircraft”, M., “Transport”, 1977). A decrease in the angle of rotation of the reverse jet leads to a decrease in the magnitude of the reverse thrust. The rotation of the flow in the reversing device is carried out mainly by the shutters 1, overlapping the engine duct and which are installed both at an angle of 90 ° to the axis of the engine, and at an angle exceeding 90 °. The angle of installation of the trailing edges of the blades of the deflecting grating 2 is determined by the selected value of the angle of rotation of the reversible jet flowing from the reversing device (φ = 90 ° ... 135 °). For a given curvature of the blades, the angle of installation of the leading edges of the blades of the deflecting grating is determined.

"Dissect" the deflector lattice of the reversing device with a cylindrical surface 1 passing through the blades of the deflector lattice and located concentrically relative to the axis of the engine, thereby forming an internal deflector lattice 2 and an external deflector lattice 3 (Fig. 2).

The resulting internal deflecting grate 2 is shifted relative to the external deflecting grating 3 along the axis of the engine in the direction of gas flow by a distance less than the pitch of the blades of the deflecting gratings (t) (Fig. 2 and Fig. 3). The profile of the blades of the deflecting grating is chosen so that the installation angles of the outlet edges of the blades of the internal deflecting grating 2 are equal to the angles of installation of the input edges of the blades of the external deflecting grating 3.

Claims (1)

The method of rotation of the gas flow in the deflecting grids of the reversing device of the gas turbine engine, based on the rotation of the gas flow and its direction in the direction of movement of the aircraft, characterized in that, in order to increase the efficiency of the reversing device due to the improvement of the flow around the blades of the deflecting grids with a gas stream: select the necessary angle of rotation of the reverse jet in the reversing device relative to the longitudinal axis of the engine within φ = 90 ° ... 135 °; the selected angle of rotation determines the installation angles of the front and rear edges of the blades of the deflecting grating for a given curvature of the blades; "dissecting" the deflecting grate of the reversing device with a cylindrical surface passing through the blades of the deflecting grating and located concentrically relative to the axis of the engine; the blades of the formed internal deflecting grating are shifted relative to the blades of the external deflecting grating along the axis of the engine downstream by a distance less than the pitch of the blades t; the installation angles of the output edges of the blades of the internal deflecting grating are chosen equal to the angles of installation of the input edges of the blades of the external deflecting grating.

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