JP7012226B2 - Airflow control device, aircraft and airflow control method - Google Patents

Description

The present invention relates to an airflow control device and an airflow control method for a boundary layer on the airframe surface of an aircraft, and an aircraft equipped with such an airflow control device.

It is generally said that lift-dependent resistance, wave-making resistance, and harmful resistance act on aircraft, of which harmful resistance is classified into interference resistance and shape resistance, and shape resistance is classified into friction resistance and pressure resistance. However, this classification is for observing the entire aircraft from a distance, and when observing from the very vicinity of the aircraft, the force exerted by the flow around the aircraft on the aircraft is only through the pressure and velocity fields. Therefore, in this sense, the drag force acting on the aircraft can be classified into two types: pressure resistance and frictional resistance. This pressure resistance is classified into lift-dependent resistance, wave-making resistance, interference resistance and other pressure resistance according to the resulting action, and only the pressure resistance that has no special role is called "pressure resistance" again. Is the classification at the beginning of the sentence (see Non-Patent Document 1).

Of these, pressure resistance is a type of shape resistance that changes depending only on the shape of the object, as it is a force that pulls the airframe backwards by creating a vortex behind the airframe and reducing the pressure. be. If the flow around the airframe can be made difficult to peel off, the pressure resistance will be small. Generally, if the angle of attack of the airframe is increased, the air around the airframe tends to be separated. It is fatal for an aircraft to have such a large separation of flow around the airframe, especially around the main wing. This is because the phenomenon of large flow separation is a phenomenon called stall that leads to a crash because not only the pressure resistance increases explosively but also the lift decreases. In order to avoid this, a device called a vortex generator (see Patent Document 1) is placed on the surface of the airframe so that the flow does not easily come off, and a method is adopted in which the boundary layer (described later) is forcibly transitioned to turbulent flow. Often. A method of increasing the momentum near the surface by blowing a jet along the surface of the airframe may be adopted (see Non-Patent Document 2 and Non-Patent Document 3). When the flow is peeled off from around the fuselage, a weak backflow occurs near the surface to compensate for the peeling in the wake from the peeled position. This is because if the flow in the region called the boundary layer near the surface has a large momentum in the forward direction, no backflow occurs and the flow does not separate.

On the other hand, frictional resistance is a force that makes it difficult for the flow on the surface of the airframe to flow due to the influence of viscosity in the region called the boundary layer that develops on the surface of the airframe. Large in state. Therefore, if the process of transition of the boundary layer from the laminar flow state to the turbulent flow state can be delayed, the frictional resistance becomes small. The most robust method is to design a natural laminar flow wing (see Patent Document 2, Patent Document 3, Non-Patent Document 4, Non-Patent Document 5, etc.) to obtain a shape that is difficult to transition, but DRE (Non-Patent Document 5) There is also laminar flow control (so-called boundary layer control) using devices such as Document 6), DBD plasma actuator (Non-Patent Document 7), and uniform suction (Non-Patent Document 8). In addition to delaying the transition, it is known that the frictional resistance can be reduced by applying some control even if the boundary layer maintains a turbulent flow state. Well-known techniques for reducing the frictional resistance of the turbulent boundary layer are turbulence control techniques such as riblets (Non-Patent Document 9) and uniform blowouts (Non-Patent Document 10 and Non-Patent Document 11). ..

US Pat. No. 2,740,596 Japanese Patent No. 5747343 Japanese Unexamined Patent Publication No. 2017-222188

Wataru Yamazaki, Kisa Matsushima, Kazuhiro Nakahashi, "Verification of Resistance Element Decomposition Method in CFD", Nagare, 24, (2005), pp. 525-533. D. C. McCormick, "Boundary Layer Separation Control with Directed Synthetic Jets", (2000), AIAA Paper 2000-0519. Jesse Little, Keisuke Takashima, Munetake Nishihara, Igor Adamovich and Mo Samimy, "Separation Control with Nanosecond-Pulse-Driven Dielectric Barrier Discharge Plasma Actuators", AIAA JOURNAL, 50, (2012), pp. 350-365. Hiroaki Ishikawa, Yoshine Ueda, Naoko Tokugawa, Michelle N. Lynde, Richard L. Campbell and Meelan M. Choudhari, "Natural Laminar Flow Wing Design for a Low-Boom Supersonic Aircraft", (2017), AIAA Paper 2017-1860. Kengo Ushiyama, Keiki Ishikawa, Naoko Tokugawa, Toshiyoshi Koike, "Natural Laminar Flow Wing Design for Small Supersonic Passenger Airplanes", (2016), JAXA-RR-16-001. Andrew Carpenter, William S. Saric, and Helen L. Reed, "Laminar Flow Control on a Swept Wing with Distributed Roughness", (2008), AIAA Paper 2008-7335. Jun Guo, Ryoina Ueda, Masayoshi Noguchi, "Boundary layer control of wings with large receding angle by plasma actuator", Proceedings of the Japan Society for Aeronautics and Astronautics, 63, (2015), pp. 233-240. Ronald D. Joslin, "Overview of Laminar Flow Control", (1998), NASA / TP-1998-208705. M. J. Walsh, "Turbulent Boundary Layer Drag Reduction Using Riblets", (1998), AIAA Paper 82-0169. Kametani, K., Fukagata, K., "Direct numerical simulation of spatially developing turbulent boundary layers with uniform blowing or suction," J. Fluid Mech., 681, (2011), pp. 154-172. Noguchi, D., Fukagata, K., Tokugawa, N., "Friction drag reduction of a spatially developing boundary layer using a combined uniform suction and blowing," J. Fluid Sci. Technol. 11, JFST0004 (2016). Y. Ito, K. Yamamoto, K. Kusunose, S. Koike, K. Nakakita, M. Murayama and K. Tanaka, "Effect of Vortex Generators on Transonic Swept Wings", Journal of Aircraft. 53, (2016), pp .1890-1904. K. Eto, Y. Kondo, K. Fukagata and N. Tokugawa, "Wind-Tunnel Experiment of a Friction Drag Reduction on a Clark-Y Airfoil Using Uniform Blowing", Proceedings of 9th JSME-KSME Thermal and Fluids Engineering Conference, ( 2017), TFEC9-1345.

By the way, it is difficult to reduce the above-mentioned two resistances, that is, pressure resistance and frictional resistance at the same time. This is because the boundary layer should be in a turbulent state to suppress stall (peeling), that is, to reduce pressure resistance, and the boundary layer should be laminar rather than turbulent to reduce frictional resistance. That is why.

In view of the above circumstances, an object of the present invention is to provide an airflow control device, an aircraft, and an airflow control method capable of freely reducing both pressure resistance and frictional resistance.

A further object of the present invention is to provide an airflow control device, an aircraft, and an airflow control method capable of performing airflow control for that purpose substantially without penalty, that is, airflow control can be performed with almost no energy required. It is in.

In order to achieve the above object, the airflow control device according to one embodiment of the present invention has a sensor for detecting the state of the boundary layer on the surface of the machine, and is arranged on the surface of the machine and operated by a high-pressure gas to form the boundary layer. A peeling prevention device that controls peeling by giving momentum, a blowing device that is placed on the surface of the machine and reduces turbulent frictional resistance by uniformly blowing out the high-pressure gas, and a detection result by the sensor. Further, it is provided with a control system for switching whether the high-pressure gas is supplied to the peeling prevention device or the blowing device.

In the present invention, since the operation of the peeling prevention device and the blowing of high-pressure gas by the blowing device are switched according to the state of the boundary layer, both the pressure resistance reduction and the friction resistance reduction can be freely performed.
In addition, the anti-peeling device and the blowing device are configured to be driven by high-pressure gas, and since it is not necessary to generate high-pressure gas in an aircraft, airflow control is performed virtually without penalty, that is, Airflow control can be performed with almost no energy required.

The airflow control device according to one embodiment of the present invention may further include a suction device that sucks the high-pressure gas from the surface of the machine body. This makes it possible to obtain the high-pressure gas required for the above-mentioned driving with a simpler configuration.

In the airflow control device according to one embodiment of the present invention, the suction device is arranged so as to be located in a high pressure region of gas on the surface of the airframe, and the anti-peeling device is located in an acceleration region of gas on the surface of the airframe. Arranged to be located or located in the deceleration start region of the gas on the airframe surface, the blowout device is located in the low pressure and boundary layer development region of the gas on the airframe surface. It may have been done. As a result, both the pressure resistance reduction and the friction resistance reduction can be freely and effectively performed without causing turbulence of the air flow on the suction side.

In the air flow control device according to one embodiment of the present invention, the control system includes a solenoid valve and a controller that inputs a detection result by the sensor and controls switching of the solenoid valve according to the detection result. A first high-pressure gas flow path connecting the suction device and the input side of the solenoid valve, and a second high-pressure gas flow path connecting the first output side of the solenoid valve and the peeling prevention device. A third high-pressure gas flow path connecting the second output side of the solenoid valve and the blowing device may be further provided. As a result, the control device can be realized with a simple configuration.

In the airflow control device according to one embodiment of the present invention, the sensor can detect whether or not the sensor is likely to peel off and whether it is a laminar flow or a turbulent flow, and the controller detects that the sensor is likely to peel off. When the sensor detects turbulence, the solenoid valve is switched so as to send the high-pressure gas to the peeling prevention device. May be good. As a result, the sensor can be easily configured, and both pressure resistance reduction and friction resistance reduction can be freely and effectively performed.

The aircraft according to one embodiment of the present invention includes an airflow control device having the above configuration.
The airflow control method according to one embodiment of the present invention detects the state of the boundary layer on the surface of the machine, and gives momentum derived from a high-pressure gas to the boundary layer according to the detection result to peel off the surface of the machine. The turbulent friction resistance is reduced by uniformly blowing out the high-pressure gas.

According to the present invention, both pressure resistance reduction and friction resistance reduction can be freely performed, and airflow control for that purpose can be performed substantially without penalty, that is, airflow control can be performed with almost no energy required. can.

It is a schematic perspective view which shows the aircraft which concerns on one Embodiment of this invention. It is a figure for demonstrating each part of the wing of an aircraft, and shows only the surface of the longitudinal section of a wing. It is a schematic vertical sectional view of the wing of the aircraft which concerns on one Embodiment of this invention. It is a three-dimensional view of the suction device shown in FIG. It is a side view of the suction device shown in FIG. It is a side view of the peeling prevention device shown in FIG. It is a side view of the peeling prevention device which concerns on other forms. It is a three-dimensional view of the balloon device shown in FIG. It is a side view of the balloon device shown in FIG. It is a figure for demonstrating the peeling prevention process which concerns on one Embodiment of this invention. It is a figure for demonstrating the peeling prevention process which concerns on one Embodiment of this invention. It is a figure for demonstrating the peeling prevention process which concerns on one Embodiment of this invention. It is a figure for demonstrating the peeling prevention process which concerns on one Embodiment of this invention. It is a figure for demonstrating the peeling prevention process which concerns on one Embodiment of this invention. It is a figure for demonstrating the peeling prevention process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent friction resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent friction resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent friction resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent friction resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent friction resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent friction resistance reduction process which concerns on one Embodiment of this invention. It is a timing chart explaining the control example which concerns on one Embodiment of this invention. It is a graph which shows the experimental result performed in order to confirm the effect of the peeling prevention which concerns on this invention. It is a graph which shows the experimental result performed in order to confirm the effect of the turbulent friction resistance reduction which concerns on this invention. It is a graph which shows the experimental result performed as a reference for confirming the effect of the turbulent friction resistance reduction which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic perspective view showing an aircraft according to an embodiment of the present invention.
The aircraft 1 has wings 3 and the like on the fuselage 2.
FIG. 2 is a diagram for explaining each part of the wing 3 of the aircraft 1, and shows only the surface of the vertical cross section of the wing 3. FIG. 3 is a schematic vertical sectional view of a wing 3 of an aircraft 1 according to an embodiment of the present invention.

In FIG. 2, reference numeral 11 indicates a leading edge, and reference numeral 12 indicates a trailing edge. The line segment connecting the leading edge 11 and the trailing edge 12 is the chord line 13, the upper surface of the chord line 13 is the upper surface 14 of the wing 3, and the lower surface is the lower surface 15. The length of the chord line 13 is the chord length 16, and the angle of attack of the chord line 13 with respect to the direction of the airflow is the angle of attack 17. Reference numeral 18 is a stagnation point, 19 is an upper surface crest, and 20 is a lower surface crest. The stagnation point 18 is a position where the flow velocity becomes zero on the surface of the two-dimensional element in which the air flow is placed, and is located in the vicinity of the leading edge 11 in the actual viscous flow. The crest is a position on the wing 3 where the z coordinate is the maximum or the minimum, and the maximum position is called the upper surface crest 19 and the minimum position is called the lower surface crest 20.

As shown in FIG. 3, the aircraft 1 has an airflow control device 4.
The airflow control device 4 includes a sensor 5, a suction device 6, a peeling prevention device 7, a blowout device 8, and a control system 9, which are mainly arranged on the wing 3.

The sensor 5 determines the state of the boundary layer on the surface of the wing 3 of the aircraft 1, typically whether it is likely to peel off, that is, whether it is likely to peel off, or whether it is likely to peel off, and whether it is laminar or turbulent. Detect. The sensor 5 is typically robustly located on the top surface 14 of the wing 3. The sensor 5 corresponds to, for example, a hot film sensor, a Preston tube, a Stanton tube, a floating element, or the like, or an existing stall warning device that changes the surface shape of the machine body and does not become an additional resistance. Depending on the shape of the airframe (eg, airfoil), i.e., the pressure gradient and size, and the position of the anti-peeling device 7 or the blowout device 8, two or more sensors 5 may be installed instead of just one.

The suction device 6 sucks high-pressure gas uniformly from the surface of the blade 3 to the boundary layer. The suction device 6 is typically located near a high pressure portion on the surface of the fuselage, a region of the wing 3 from the leading edge 11 to the bottom surface 15, for example, near the stagnation point 18 rather than the stagnation point 18 of the wing 3. .. By arranging the suction device 6 at such a position, the transition of the boundary layer of the high pressure portion on the surface of the machine body is delayed, and it is expected that the frictional resistance of the lower surface 15 is reduced. That is, the suction device 6 aims to capture the high-pressure gas that drives the peeling prevention device 7 and the blowout device 8, and also suppresses the development of the boundary layer by sucking the boundary layer, delays the boundary layer transition, and causes friction. It reduces resistance.

The peeling prevention device 7 is arranged on the surface of the machine body, is operated by an operation by a high-pressure gas sucked by the suction device 6, and controls peeling by giving momentum to the boundary layer. That is, the peeling prevention device 7 is a device that increases the momentum near the wall surface for the purpose of preventing the peeling of the boundary layer flow, and is typically an acceleration region or deceleration start position of the gas on the surface of the machine body. , If it is a wing 3, it is arranged on the upper surface 14.

The blowing device 8 is arranged in a region on the surface of the machine body through which the turbulent flow passes, and the turbulent friction resistance is reduced by uniformly blowing out the high-pressure gas sucked by the suction device 6. That is, the blowout device 8 is a device for the purpose of reducing the frictional resistance of the turbulent boundary layer developed on the surface of the airframe, and is typically a low-pressure and developed boundary layer portion on the surface of the airframe. If it is a wing 3, it is arranged so as to be located in a region near the trailing edge 12 of the upper surface 14.

The control system 9 switches between supplying the high-pressure gas sucked by the suction device 6 to the peeling prevention device 7 and the blowing device 8 according to the detection result of the sensor 5. The control system 9 typically includes a solenoid valve 91 and a controller 92 that inputs a detection result by the sensor 5 and controls switching of the solenoid valve 91 according to the detection result.

The solenoid valve 91 is intended to rectify the control fluid and is typically arranged within the blade 3. When one or more of the suction device 6, the peeling prevention device 7, and the blowout device 8 are installed, two or more solenoid valves 91 may be installed.

The controller 92 may be located in the wing 3, or may be arranged in the fuselage 2, or the like. The controller 92 may be used together by, for example, another control system of the aircraft 1.

The suction device 6 and the input side 91a of the solenoid valve 91 are connected to each other via a pipe 93 which is a first high-pressure gas flow path. The first output side 91b of the solenoid valve 91 and the peeling prevention device 7 are connected to each other via a pipe 94 which is a second high-pressure gas flow path. The second output side 91c of the solenoid valve 91 and the blowing device 8 are connected to each other via a pipe 95 which is a third high-pressure gas flow path. In order to minimize the pressure loss, the pipes 93, 94 and 95 are preferably made as thick as possible and the bending and the change in diameter are minimized. Further, when one or more devices of any one or more of the suction device 6, the peeling prevention device 7 and the blowout device 8 are installed, two or more solenoid valves 91 are also installed, so that the piping is located at the chamber position. The optimum connection method may be selected and connected according to the type and type.

When the controller 92 detects that the sensor 5 is about to peel off, the solenoid valve 91 is switched so as to send a high-pressure gas to the peeling prevention device 7, and when the sensor 5 detects a turbulent flow, the high pressure is applied to the blowout device 8. The solenoid valve 91 is switched so as to send the gas of.

<Specific example of suction device 6>
FIG. 4A is a three-dimensional view of the suction device 6, and FIG. 4B is a side view of the suction device 6.
The suction device 6 has, for example, a perforated wall 61 on the surface side 101 of the airframe, and a closed chamber 62 except that the pipe 93 leading to the solenoid valve 91 is provided inside the airframe. The suction device 6 takes in a high-pressure gas flow on the surface side 101 of the machine body and serves to supply the high-pressure gas to the peeling prevention device 7 or the blowout device 8 via the solenoid valve 91.

Depending on the shape of the machine (for example, the airfoil), that is, the pressure gradient, and the size, not only one suction chamber but also two or more suction chambers may be installed.
Further, it is preferable that the pore size of the porous wall 61 is reduced so as not to disturb the flow as much as possible. Further, in order to minimize the pressure loss, it is preferable to make the wall thickness at least in the vicinity of the hole as thin as possible.

<Specific example of peeling prevention device 7>
FIG. 5A is a side view of the peeling prevention device 7.
As the peeling prevention device 7, for example, the tangential direction blowing device shown in FIG. 5A can be used. The peeling prevention device 7 has a closed chamber 71 to which the pipe 94 is connected. The closed chamber 71 has an outlet 72 for blowing a high-pressure gas flow tangentially from the inside of the wing 3 to the airframe surface side 101.

FIG. 5B is a side view showing another form of the peeling prevention device 7.
As shown in FIG. 5B, as the peeling prevention device 7, a vortex generator-like protrusion type device can also be used. The peeling prevention device 7 has a closed chamber 73 to which the pipe 94 is connected. A perforated wall 74 is provided at the tip of the closed chamber 73, and an elastic film 75 capable of projecting on the surface side 101 of the machine body and having sufficiently strong strength and restoring force is attached to the perforated wall 74. When a high-pressure gas is supplied from the pipe 94 to the closed chamber 73, the elastic film 75 protrudes from the machine body surface side 101. The protrusions formed by the elastic film 75 project into the boundary layer, forcibly transitioning the boundary layer to turbulent flow, and mixing a low momentum flow near the wall surface and a high momentum flow away from the wall surface.

Depending on the shape of the machine (for example, the airfoil), that is, the pressure gradient and the size, not only one but also two or more peeling prevention devices 7 may be installed.

<Specific example of the balloon device 8>
FIG. 6A is a three-dimensional view of the blowing device 8, and FIG. 6B is a side view of the blowing device 8.
The blowing device 8 has, for example, a perforated wall 81 on the surface side 101 of the airframe, and a chamber 82 inside the wing 3 except for the airframe surface and the pipe 95 continuing from the solenoid valve 91.

The blowing device 8 uniformly directs the flow of high-pressure gas from the suction device 6 flowing in through the solenoid valve 91 toward the low-pressure flow outside the chamber 82, and is normal to the machine surface side 101. It plays a role of blowing out.

It should be noted that the blowing device 8 may be installed not only one but also two or more depending on the shape of the machine body (for example, the airfoil), that is, the pressure gradient and the size.
Further, as for the porous wall 81, it is preferable to reduce the pore diameter so as not to disturb the flow as much as possible, as in the case of the porous wall 61. Further, in order to minimize the pressure loss, it is preferable to make the wall thickness at least in the vicinity of the hole as thin as possible.

<Specific example of control system 9>
7A to 7F are diagrams for explaining the peeling prevention process, and FIGS. 8A to 8F are diagrams for explaining the turbulent friction resistance reducing process. FIG. 9 is a timing chart for explaining a control example.
The controller 92 periodically receives the detection signal from the sensor 5 (FIG. 9A).

When the detection signal from the sensor 5 exceeds the first level L1 (for example, FIGS. 9A and 9I), the controller 92 considers that the boundary layer is peeled off or there is a risk of peeling off. .. FIG. 7A shows a state in which the boundary layer is peeled off or there is a risk of peeling off (the region shown in FIG. 7A (i)).

In this case, the controller 92 sends a control signal for operating the peeling prevention device 7 to the solenoid valve 91 (FIGS. 9 (b) (ii) and 7B (ii)).

As a result, a high-pressure gas is sent to the peeling prevention device 7 via the solenoid valve 91 (FIG. 7C (iii)), and the peeling prevention device 7 operates (FIGS. 9 (c) (iii) and 7D (iv). ).

When the peeling prevention device 7 operates, the boundary layer becomes turbulent and peeling is suppressed (FIG. 7E (v)).

FIG. 7F shows a state in which the boundary layer is peeled off again after the peeling prevention device 7 is stopped, or there is a risk of peeling, and the same operation as described above is performed thereafter.

On the other hand, when the detection signal from the sensor 5 exceeds the second level L2 (for example, FIGS. 9 (a) and 9 (iv)), the controller 92 considers that turbulence has occurred in the boundary layer. FIG. 8A shows a state in which turbulence is generated in the boundary layer and frictional resistance is large (region shown in FIG. 8A (i)).

In this case, the controller 92 sends a control signal for operating the blowout device 8 to the solenoid valve 91 (FIGS. 9 (d) (v) and 8B (ii)).

As a result, a high-pressure gas is sent to the blowing device 8 via the solenoid valve 91 (FIG. 8C (iii)), and the blowing device 8 operates (FIGS. 9 (e) (vi) and 8D (iv)).

The operation of the blowout device 8 reduces the turbulence in the boundary layer (FIG. 8E (v)).

FIG. 8F shows a state in which turbulence is generated again in the boundary layer after the blowing device 8 is stopped, and the same operation as described above is performed thereafter.

The sensor 5 that detects the state of the boundary layer detects only when the boundary layer is peeled off or there is a risk of peeling, and when the danger of peeling is detected, the high-pressure gas is prevented from peeling off. The peeling prevention device 7 may be operated by flowing it through the device 7, and in other cases, the blowing device 8 may be operated by flowing a high-pressure gas. This simplifies configuration and control.

In this way, a combination of separation control of the boundary layer that develops on the surface of the aircraft body, laminar flow control that delays the laminar-turbulent boundary layer transition, and turbulence control that reduces the frictional resistance of the turbulent boundary layer. Therefore, the power required for driving the sensor 5 for detecting the state of the boundary layer, transmitting a control signal based on the sensor 5, and opening and closing the electromagnetic valve 91 is required, but other than that, a new power for performing them, that is, a penalty is required. Penaltyless control that eliminates the need for

Further, the frictional resistance reducing effect using the present invention contributes differently to the total resistance depending on the blowing speed and the area of the blowing region. Locally, the frictional resistance in the blowing region can be reduced by about 75% by uniformly blowing a high-pressure gas from the blowing device 8 at a speed corresponding to 1% of the cruising speed (see Non-Patent Document 10). On the other hand, when the peeling prevention effect is compared as the maximum lift coefficient, it is expected to increase by a maximum of about 0.12 depending on the presence or absence of the peeling prevention device 7 (see Non-Patent Document 12).

<Experimental result>
A Clark-Y blade with a chord length of 400 mm and a wingspan of 548 mm, which has no receding angle, was installed in the wind tunnel, and the effects of preventing peeling and reducing frictional resistance were verified.
The suction device and the blowout device were built in −0.072 ≦ X / C ≦ 0.072 and −70 mm ≦ Y ≦ 70 mm of 0.58 ≦ X / C ≦ 0.82, respectively.

In addition, a vortex generator-like protrusion type anti-peeling device was installed on the surface of X / C = 0.6, −20 mm ≦ Y ≦ 20 mm. Here, X is the distance along the chord line from the leading edge, and C is the chord length.

10 and 11 show changes in the boundary layer distribution when the suction device and the balloon device are operated.

In FIG. 10, the wing is installed at a uniform flow velocity U _∞ = 24 m / s (Reynolds number 0.64 × ¹⁰⁶ based on the chord length) with an angle of attack of 11.4 °, and a peeling prevention device is shown. Shows the change in the boundary layer distribution at X / C = 0.9 when is operated.
As shown in FIG. 10, it can be seen that the boundary layer distribution, which was a peeling type when the peeling prevention device was not operated, is approaching the turbulent flow type distribution due to the increase in the flow velocity near the wall surface due to the operation of the peeling prevention device. Therefore, from this result, it can be seen that the prototype peeling prevention device prevents peeling. Further, it can be seen that the peeling is large in a clean state in which the peeling prevention device is not attached. From this result, it can be seen that the prototype peeling prevention device causes roughness on the blade surface even when it is not in operation, and peeling is prevented as compared with the clean state. Therefore, if the peeling prevention device can be improved and a smooth surface equivalent to that in a clean state can be realized when not in operation, the control effect of the peeling prevention device will be greater, and if the maximum effect can be obtained, the maximum lift coefficient will drive the peeling prevention device. Therefore, it is expected to increase by about 0.12.

On the other hand, in FIG. 11, the blade is installed so that the angle of attack is 0 ° in a uniform flow velocity U _∞ = 60 m / s (Reynolds number 1.54 × ¹⁰⁶ based on the chord length), and the peeling prevention device is shown. Shows the change in the boundary layer distribution at X / C = 0.8 when is operated. Here, X is the distance along the chord line from the leading edge, and C is the chord length. The blowing velocity U _blow is about 0.04% of the uniform flow (U _blow / U _∞ = 0.04 × ^10-2 ). As is clear from the figure, when the control is performed by the balloon (indicated as wb in the figure), the average velocity distribution (u (with ￣) /) is compared with the case where the control is not performed (indicated as nb in the figure). It can be seen that the U ∞) and the velocity fluctuation distribution (u'/ U _∞ ) are shifted upward, and the friction on the wall surface is reduced.

For reference, the same test conditions (uniform flow velocity U _∞ = 60 m / s, Reynolds number 1.54 × 106 based on chord length, angle of attack ⁶ °) are used, but the compressor is used instead of the suction chamber. The change in velocity distribution at X / C = 0.75 when controlled with a penalty is shown in FIG. 12 (K. Eto, Y. Kondo, K. Fukagata and N. Tokugawa, "Wind-Tunnel Experiment". See of a Friction Drag Reduction on a Clark-Y Airfoil Using Uniform Blowing ", Proceedings of 9th JSME-KSME Thermal and Fluids Engineering Conference, (2017), TFEC 9-1345.). Due to the use of the compressor, the blowing speed is as large as 0.15% (U _blow / U _∞ = 0.15 × ^10-2 ) of the uniform flow, and the control effect (shift amount of the speed distribution) is obtained accordingly. ) Is large. In this case, the effect of reducing the local frictional resistance at that position by about 26% was confirmed from the quantitative evaluation by fitting with the wall index. In the prototype control device shown in FIG. 11, the blowout speed is lower than that when the compressor is used (FIG. 12), so the control effect is small, but by optimizing the airfoil, suction / blowout position, piping routing, etc. It is possible to obtain a control effect similar to that when a compressor is used. It is expected that the frictional resistance in the blowout region can be reduced by about 75% if the blowout can be performed uniformly at a speed corresponding to 1% (U _blow / U _∞ = 1.0 × ^10-2 ) of the uniform flow velocity.

<others>
The best form of the present invention is application to the airframe surface, especially the main and tail wings. Furthermore, it is most suitable for application to the main wing and tail wing of transonic aircraft, which are large passenger aircraft currently in operation. Further, the aim of the present invention is to suppress stall (peeling), that is, to reduce pressure resistance and frictional resistance, and to reduce the penalty of the boundary layer on the surface of the aircraft body, which does not require the power required for control. Control is not only a major research theme not only in Japan but also in overseas aviation-related laboratories and universities, and its industrial utility value for aircraft manufacturers and airlines is extremely high.

The present invention is not limited to the above embodiment, and various modifications and applications are possible within the scope of the technical idea. The scope of such modifications and applications also belongs to the technical scope of the present invention.

For example, the present invention can be applied to other airframe surfaces other than aircraft wings. Of course, the present invention can be applied even if the aircraft is an unmanned aerial vehicle.

Further, in the above embodiment, the high-pressure gas is obtained from the suction device, but the high-pressure gas may be obtained from, for example, the jet engine side of the aircraft.

1: Airflow 4: Airflow control device 5: Sensor 6: Suction device 7: Peeling prevention device 8: Blow-out device 9: Control system 91: Solenoid valve 91a: Input side 91b: First output side 91c: Second output side 92: Controller 93: Piping 94: Piping 95: Piping

Claims (7)

Sensors that detect the state of the boundary layer on the surface of the aircraft, and
A peeling prevention device placed on the surface of the airframe, operated by a high-pressure gas, and controlling peeling by giving momentum to the boundary layer.
A blowout device that is placed on the surface of the machine and reduces turbulent frictional resistance by uniformly blowing out the high-pressure gas.
An airflow control device including a control system for switching between supplying the high-pressure gas to the peeling prevention device and supplying the blowing device according to a detection result by the sensor. The airflow control device according to claim 1.
An airflow control device further comprising a suction device for sucking the high-pressure gas from the surface of the airframe. The airflow control device according to claim 2.
The suction device is arranged so as to be located in a high pressure region of gas on the surface of the airframe.
The delamination prevention device is arranged so as to be located in the acceleration region of the gas on the surface of the airframe or in the deceleration start region of the gas on the surface of the airframe.
The blowout device is an airflow control device arranged so as to be located in a region where a low pressure gas and a boundary layer develop on the surface of the airframe. The airflow control device according to claim 3.
The control system includes a solenoid valve and a controller that inputs a detection result by the sensor and controls switching of the solenoid valve according to the detection result.
A first high-pressure gas flow path connecting the suction device and the input side of the solenoid valve,
A second high-pressure gas flow path connecting the first output side of the solenoid valve and the peeling prevention device, and
An airflow control device further comprising a third high-pressure gas flow path connecting the second output side of the solenoid valve and the blowing device. The airflow control device according to claim 4.
The sensor can detect whether or not it is likely to peel off and whether it is laminar or turbulent.
When the controller detects that the sensor is about to peel off, the solenoid valve is switched so as to send the high-pressure gas to the peeling prevention device, and when the sensor detects turbulence, the blowout device is sent to the blowout device. An airflow control device that switches the solenoid valve to send the high-pressure gas. An aircraft provided with the airflow control device according to any one of claims 1 to 5. Detects the state of the boundary layer on the surface of the aircraft and
Whether to control the peeling of the airframe surface by giving momentum derived from the high-pressure gas to the boundary layer according to the detection result, or to reduce the turbulent friction resistance by uniformly blowing out the high-pressure gas. Airflow control method to switch.

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