RU199016U1 - Subsonic aircraft with a thick wing profile with a drag reduction device - Google Patents

Abstract

The utility model refers to technical means in the field of aerodynamics, in particular, to devices designed to reduce the drag force of aircraft (AC) moving at subsonic speeds. A subsonic aircraft with a thick wing profile with a drag reduction device, which is made in the form of an internal semi-open system of external circulation of the air flow coming from the boundary layer along the aircraft surface into an elliptical cavity located in the area of flow separation from the aircraft surface. Inside the elliptical cavity, a controlled process of air flow circulation is organized due to the placement of an air channel inside the aircraft, made in the form of a pipeline, which has a confuser at one end for sucking air from the cavity, and at the other end - a confuser for blowing air into the cavity. To organize a controlled process of suction-blowing of air from the cavity, an axial fan is located in the pipeline between the confusers, driven into rotation by the drive shaft of the electric motor. The technical result provided by the utility model consists in creating conditions that make it possible to increase the aircraft's payload and ensure the stability of control at various stages of the aircraft's flight, including under high wind loads. 1 ill.

Description

The utility model relates to technical means in the field of aerodynamics, in particular to devices designed to reduce the drag force of aircraft (AC) moving at subsonic speeds.

Known device "Wing with boundary layer control" (RU 149950 [1]). The disadvantage of this device is the technological complexity of manufacturing the air intake duct, combined with the internal cavity, as well as the inability to fit the entire supporting structure of the aircraft.

Another known device is "Aircraft" (RU 192918 [2]). The analysis of the presented solution made it possible to reveal its drawback, which consists in blowing out the air taken from the critical point through the nozzle in the trailing edge of the fuselage and wings, which can contribute to the formation of a vortex zone of the aircraft and lead to an increase in the bottom pressure.

The closest analogue is implemented in an aircraft with an aerodynamically bearing body (RU 85446 [3]) a method for controlling the lift force, which consists in using the energy of compressed gas blown out of tangentially oriented slots on the surface of the aircraft body.

The disadvantage of the given device is the inability to regulate the static pressure along the surface depending on the flight modes of the aircraft, which, under certain conditions, can lead to a repeated separation of the air flow and a violation of the stability of the aircraft control.

The technical result provided by the utility model consists in creating conditions that make it possible to increase the aircraft's payload and ensure the stability of control at various stages of the aircraft's flight, including under high wind loads.

To achieve the specified technical result on the surface of a subsonic aircraft, which has a thick wing profile with a device for reducing the drag, a transverse channel is made in the form of an elliptical cavity located in the area of flow separation from the aircraft surface.

The subsonic aircraft is also distinguished by the fact that a controlled process of air flow circulation is organized inside the elliptical cavity, due to the placement of an air channel inside the aircraft, made in the form of a pipeline having at one end a confuser for sucking air from the cavity, and at the other end a confuser for blowing air into the cavity. To organize a controlled process of suction-blowing of air from the cavity, an axial fan is located in the pipeline between the confusers, driven by the drive shaft of the electric motor.

The essence of the utility model is illustrated by the diagram shown in Fig. 1. On the surface of the aircraft (1) made a transverse channel in the form of an elliptical cavity (2). The generating surfaces of the cavity are perpendicular to the side surface of the aircraft (the plane of the scheme in Fig. 1). FIG. 1 there is a leader showing on an enlarged scale the location of the confuser for blowing out air (6) and the confuser for suction of air (10), having inlet and outlet ducts, respectively, in the form of a slot along the generating surface of an elliptical cavity (2).

The principle of operation of the utility model is explained as follows. The flow of subsonic air running on the aircraft (1) with a velocity V creates a boundary layer along the aircraft surface with a laminar structure and a velocity profile (8). Depending on the geometric features of the external appearance of the aircraft in a certain area, a flow separation forms on the surface, leading to its turbulence and to a decrease in the stability of the aircraft control and an increase in the surface pressure behind the separation point and, as a consequence, an increase in the drag force.

To eliminate the above negative phenomena, it is proposed to make elliptical cavities on the aircraft surface (2), which at the time of takeoff and landing of the aircraft have the ability in their upper part, due to special shutters, to take the shape of the aircraft surface. The left edge of the elliptical cavity (2) is located in such a way that the flow separation region is inside the cavity. Inside the cavity, due to the creation of a low-pressure region, a zone of internal circulation of the flow (9) is formed, the core of which has dimensions smaller than the dimensions of the cavity.

However, for special driving modes, i.e. at certain values of V , angles of attack and flight altitudes of the aircraft, the pressure value can reach a critical level at which a turbulent flow is formed at the right edge of the cavity, which goes beyond the cavity and leads to repeated separation of the flow from the aircraft surface.

To create conditions conducive to compression of the flow core, it is proposed to place a suction-blowing system of the air flow from the cavity inside the aircraft. This system consists of a pipeline (3), an axial fan (4), which allows increasing the pressure of the blown stream at the outlet of the confuser (6). Before leaving the confuser (6), a straightening grate (7) is installed, designed to create a laminar flow of blown air.

The technical and economic efficiency obtained when using the proposed device is ensured by reducing the cost of fuel supplies on board the aircraft, which allows to increase the mass of the brought payload. The electrical energy required to rotate the shaft of the electric motor is generated by an electric generator powered by the turbine of the main power unit of the aircraft, which makes it possible, in cruise flight, not to waste fuel reserves for the operation of the aircraft drag reduction device.

Sources of information adopted in the preparation of the description and claims:

1. Wing with boundary layer control: US Pat. 149950 U1 Rus. Federation / Zhitenev E.A., Zhitenev A.S .; applicant and patentee: Zhitenev E.A., Zhitenev A.S. - No. 2014117879/11; declared 04/30/2014; publ. 01/27/2015, Bul. Number 3.

2. Aircraft: US Pat. 192918 U1 Rus. Federation / Bulat P.V .; applicant and patentee: LLC "Problem laboratory" Turbomachines "- No. 2019119000; declared 06/19/2019; publ. 07.10.2019, Bul. No. 28.

3. Aircraft with aerodynamically bearing body: US Pat. 85446 U1 Rus. Federation / Volchkov O.D., Matvienko A.M .; applicant and patentee: GOU VPO MAI (GTU). - No. 2009112642/22; declared 04/06/2009; publ. 10.08.2009, Bul. No. 22.

Claims (2)

1. A subsonic aircraft having a thick wing profile with a drag reduction device, characterized in that a transverse channel in the form of an elliptical cavity is made on the surface of the aircraft, located in the area of flow separation from the surface of the aircraft, while a controlled process is organized inside the elliptical cavity air flow circulation due to placement inside the aircraft of an air channel made in the form of a pipeline having convergers at both ends for suction of air from the cavity and blowing into it. 2. A subsonic aircraft having a thick wing profile with a drag reduction device according to claim 1, characterized in that an axial fan is located in the pipeline between the convergers in order to organize the controlled suction-blowing of air from the cavity in the pipeline between the convergers, driven by the drive shaft of the electric motor ...

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