JP2019142385A - Air flow controller, aircraft and air flow control method - Google Patents

Abstract

To freely perform both of reduction of a pressure resistance and reduction of friction resistance, and perform air flow control therefor in a state of having no penalty substantially.SOLUTION: An air flow controller 4 comprises: a sensor 5 for detecting a state of a boundary layer on a machine body surface; a removal prevention device 7 which is arranged on the machine body surface, which is operated by high pressure gas, which applies a momentum to the boundary layer for controlling removal; a blowing device 8 which is arranged on the machine body surface, which blows the high pressure gas equally for reducing a turbulent flow frictional resistance; and a control system 9 for, according to a detection result by the sensor 5, switching between supply of the high pressure gas to the removal prevention device 7 and the supply of the high pressure gas to the blowing device 8.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an airflow control device and airflow control method for a boundary layer on an aircraft body surface, and an aircraft including such an airflow control device.

  In general, lift-dependent resistance, wave-forming resistance, and harmful resistance act on aircraft, and 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 a classification when the entire aircraft is observed from a distance, and when observed from the very vicinity of the aircraft, the force exerted by the flow around the aircraft on the aircraft is only through pressure and velocity fields. Therefore, in this sense, the drag acting on the aircraft can be classified into two types, pressure resistance and friction resistance. This pressure resistance was classified into lift dependent resistance, wave resistance, interference resistance and other pressure resistance according to the resulting action, and only the pressure resistance that does not have a special role was called “pressure resistance”. Is the classification of sentence heads (see Non-Patent Document 1).

  Pressure resistance is a type of shape resistance that changes depending only on the shape of the object. is there. If the flow around the airframe can be made difficult to peel off, the pressure resistance becomes small. Generally, when the angle of attack with respect to the airflow of the aircraft is increased, the air around the aircraft is easily peeled off. For an aircraft, it is fatal that the flow around the fuselage, particularly around the main wing, is greatly separated. This is because the phenomenon in which the flow is largely separated is a phenomenon called stall that leads to a crash because not only the pressure resistance increases explosively but also the lift force decreases. In order to avoid this, a method called a vortex generator (refer to Patent Document 1) is arranged on the airframe surface so that the flow is not easily separated, and the boundary layer (described later) is forced to transition to turbulent flow. There are many cases. A method of increasing the momentum in the vicinity of the surface by blowing a jet along the surface of the airframe may be used (see Non-Patent Document 2 and Non-Patent Document 3). When the flow is peeled off from the periphery of the aircraft, a weak backflow is generated in the vicinity of the surface in the wake after the peeled position in order to compensate for the peeling. This is because if the flow in a region called the boundary layer near the surface has a large momentum in the forward direction, no backflow occurs and the flow does not peel off.

  On the other hand, frictional resistance is a force that makes the flow of the airframe surface difficult to flow due to the influence of viscosity in an area called the boundary layer that develops on the airframe surface, and is small when the boundary layer is called laminar flow, and is called a turbulent state Big in condition. 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 perform natural laminar flow blade design (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) There is also laminar flow control (so-called boundary layer control) using devices such as Document 6), DBD plasma actuator (Non-patent Document 7), 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 when the boundary layer maintains the turbulent state. Well-known techniques for reducing the frictional resistance of the turbulent boundary layer are turbulent flow control techniques such as riblets (Non-patent Document 9) and uniform blowout (Non-patent Documents 10 and 11). .

U.S. Pat. No. 2,740,596 Japanese Patent No. 5747343 JP 2017-222188 A

Wataru Yamazaki, Kisa Matsushima, Kazuhiro Nakahashi, "Verification of resistive 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. Ken Ushiyama, Takaki Ishikawa, Naoko Tokugawa, Toshiyoshi Koike, “Natural Laminar Airfoil Design of Small Supersonic Airliner” (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, Ryoin Ueda, Masayoshi Noguchi, “Boundary Layer Control of Wings with Large Retraction Angle by Plasma Actuator”, Journal of Japan Aerospace Society, 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 two resistances mentioned above, that is, the pressure resistance and the frictional resistance at the same time. Because the boundary layer should be turbulent in order to suppress stall (separation), that is, to reduce pressure resistance, and to reduce frictional resistance, the boundary layer should be laminar rather than turbulent That's why.

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

  A further object of the present invention is to provide an air flow control device, an aircraft, and an air flow control method capable of performing air flow control substantially without penalty, that is, performing air flow control with substantially no energy required. It is in.

  In order to achieve the above object, an airflow control device according to an aspect of the present invention includes a sensor that detects a state of a boundary layer on a body surface, and is disposed on the surface of the body and operates with a high-pressure gas. Depending on the detection result by the sensor, the peeling prevention device that controls the peeling by giving momentum, the blowing device that is arranged on the surface of the body and that reduces the turbulent frictional resistance by blowing out the high-pressure gas uniformly. And a control system for switching whether to supply the high-pressure gas to the delamination prevention device or to the blowing device.

In the present invention, since the operation of the peeling prevention device or the high-pressure gas blowing by the blowing device is switched according to the state of the boundary layer, both the pressure resistance reduction and the frictional resistance reduction can be performed freely.
In addition, the peeling prevention device and the blowing device are configured to be driven by high-pressure gas, and it is not necessary to generate high-pressure gas specially in an aircraft. Airflow control can be performed with almost no energy required.

  The airflow control apparatus according to an aspect of the present invention may further include a suction device that sucks the high-pressure gas from the body surface. Thereby, the high-pressure gas required for the above driving can be obtained with a simpler configuration.

  In the airflow control device according to an aspect of the present invention, the suction device is disposed so as to be positioned in a high pressure region of the gas on the surface of the airframe, and the separation preventing device is disposed in an acceleration region of the gas on the surface of the airframe. Positioned to be located or located in a gas deceleration start region on the airframe surface, and the blowing device is located in a gas low pressure and boundary layer developing region on the airframe surface May be. Thereby, it is possible to freely and effectively perform both the pressure resistance reduction and the frictional resistance reduction without causing the turbulence of the airflow on the suction side.

  In the airflow control device according to an aspect of the present invention, the control system includes an electromagnetic valve, and a controller that inputs a detection result by the sensor and controls switching of the electromagnetic 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 delamination prevention device; You may further comprise the 3rd high pressure gas flow path which connects the 2nd output side of the said solenoid valve, and the said blowing device. Thereby, the control device can be realized with a simple configuration.

  In the airflow control device according to an aspect of the present invention, the sensor can detect whether or not the sensor is likely to separate and whether it is a laminar flow or a turbulent flow, and the controller detects that the sensor is likely to separate. The solenoid valve is switched to send the high-pressure gas to the peeling prevention device, and when the sensor detects turbulence, the solenoid valve is switched to send the high-pressure gas to the blowing device. Also good. As a result, the sensor can have a simple configuration, and both pressure resistance reduction and frictional resistance reduction can be performed effectively and freely.

An aircraft according to an aspect of the present invention includes the airflow control device configured as described above.
An airflow control method according to an aspect of the present invention detects a state of a boundary layer on a surface of an airframe, and applies a momentum derived from a high-pressure gas to the boundary layer according to the detection result, thereby peeling the surface of the airframe. Or whether to reduce the turbulent frictional resistance by blowing out the high-pressure gas uniformly.

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

1 is a schematic perspective view showing an aircraft according to an embodiment of the present invention. It is a figure for demonstrating each part of the wing | blade of an aircraft, and has shown only the surface of the longitudinal cross-section of a wing | blade. 1 is a schematic longitudinal sectional view of an aircraft wing according to an embodiment of the present invention. FIG. 4 is a three-dimensional view of the suction device shown in FIG. 3. FIG. 4 is a side view of the suction device shown in FIG. 3. 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 another form. FIG. 4 is a three-dimensional view of the balloon device shown in FIG. 3. FIG. 4 is a side view of the blowing device shown in FIG. 3. 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 frictional resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent frictional resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent frictional resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent frictional resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent frictional resistance reduction process which concerns on one Embodiment of this invention. It is a figure for demonstrating the turbulent frictional resistance reduction process which concerns on one Embodiment of this invention. It is a timing chart explaining the example of control concerning one embodiment of the present invention. It is a graph which shows the experimental result performed in order to confirm the effect of peeling prevention which concerns on this invention. It is a graph which shows the experimental result done in order to confirm the effect of the turbulent frictional resistance reduction which concerns on this invention. It is a graph which shows the experimental result done as a reference in order to confirm the effect of turbulent frictional 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 a wing 3 and the like on a fuselage 2.
FIG. 2 is a view for explaining each part of the wing 3 of the aircraft 1, and shows only the surface of the longitudinal section of the wing 3. FIG. 3 is a schematic longitudinal sectional view of the wing 3 of the aircraft 1 according to the embodiment of the present invention.

  In FIG. 2, reference numeral 11 denotes a leading edge, and 12 denotes a trailing edge. A line segment connecting the leading edge 11 and the trailing edge 12 is a chord line 13, the upper side is an upper surface 14 of the wing 3, and the lower side is a lower surface 15. The length of the chord line 13 is the chord length 16, and the angle formed by the chord line 13 with respect to the direction of the airflow is the angle of attack 17. Reference numeral 18 denotes a stagnation point, 19 denotes an upper surface crest, and 20 denotes 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 on which the airflow is placed, and is located in the vicinity of the leading edge 11 in a viscous actual flow. The crest is a position where the z coordinate is maximum or minimum on the wing 3, and the maximum position is called an upper surface crest 19 and the minimum position is called a 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 blowing device 8, and a control system 9, which are mainly disposed 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 delaminate, that is, whether it is likely to delaminate or not to be delaminated, and whether it is laminar or turbulent Detect. The sensor 5 is typically arranged robustly on the upper surface 14 of the wing 3. The sensor 5 may be, for example, a hot film sensor, a Preston tube, a Stanton tube, a floating element, or an existing stall alarm device that changes the surface shape of the body and does not become an additional resistance. Depending on the airframe shape (for example, airfoil), that is, the pressure gradient and size, and the position of the peeling prevention device 7 or the blowing device 8, not only one sensor 5 but two or more sensors 5 may be installed.

  The suction device 6 uniformly sucks high-pressure gas from the surface of the blade 3 into the boundary layer. The suction device 6 is typically arranged in the high pressure part on the airframe surface, in the case of the wing 3, the region from the leading edge 11 to the lower surface 15, for example near the stagnation point 18 instead of the stagnation point 18 of the wing 3. . By arranging the suction device 6 at such a position, the boundary layer transition of the high-pressure portion on the body surface is delayed, and a reduction in the frictional resistance of the lower surface 15 is expected. That is, the suction device 6 is intended to capture the high-pressure gas that drives the delamination prevention device 7 and the blowing device 8, and suppresses its development by sucking the boundary layer, thereby delaying the boundary layer transition and causing friction. The resistance is reduced.

  The delamination prevention device 7 is arranged on the surface of the airframe, operates by the high-pressure gas sucked by the suction device 6, and controls the delamination by giving momentum to the boundary layer. That is, the delamination prevention device 7 is a device that increases the momentum near the wall surface for the purpose of preventing separation of the boundary layer flow. Typically, the gas acceleration region or the deceleration start position on the airframe surface is used. In the case of the wing 3, it is disposed on the upper surface 14.

  The blowing device 8 is disposed in a region where turbulent flow on the airframe surface passes, and reduces the turbulent frictional resistance by blowing out the high-pressure gas sucked in by the sucking device 6 uniformly. In other words, the blowing device 8 is a device intended to reduce the frictional resistance of the turbulent boundary layer that develops on the airframe surface. Typically, the low pressure and the boundary layer developed portion on the airframe surface. In the case of the wing 3, the wing 3 is disposed so as to be positioned in the vicinity of the rear 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 or supplying the blowing device 8 according to the detection result by the sensor 5. The control system 9 typically includes an electromagnetic valve 91 and a controller 92 that inputs a detection result from the sensor 5 and controls switching of the electromagnetic valve 91 according to the detection result.

  The electromagnetic valve 91 is intended to rectify the control fluid, and is typically disposed in the blade 3. In addition, when one or more of any one of the suction device 6, the peeling prevention device 7, and the blowing device 8 are installed, two or more electromagnetic valves 91 may be installed.

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

  The suction device 6 and the input side 91a of the electromagnetic valve 91 are connected via a pipe 93 that is a first high-pressure gas flow path. The first output side 91b of the electromagnetic valve 91 and the separation preventing device 7 are connected via a pipe 94 that is a second high-pressure gas flow path. The second output side 91c of the electromagnetic valve 91 and the blowing device 8 are connected via a pipe 95 that is a third high-pressure gas flow path. In order to reduce the pressure loss to the minimum, the pipes 93, 94, and 95 are preferably made as thick as possible and bend and change in diameter to a minimum. In addition, when one or more of any one of the suction device 6, the peeling prevention device 7, and the blowing device 8 are installed, two or more electromagnetic valves 91 are also installed. Select the optimal connection method depending on the type and connection.

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

<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 chamber 62 that is sealed except that it has a porous wall 61 on the airframe surface side 101 and a pipe 93 that leads to the electromagnetic valve 91 inside the airframe. The suction device 6 plays a role of taking in a flow of high-pressure gas on the body surface side 101 and supplying high-pressure gas to the separation preventing device 7 or the blowing device 8 through the electromagnetic valve 91.

Depending on the shape of the fuselage (for example, airfoil), that is, the pressure gradient and size, not only one suction chamber but two or more suction chambers may be installed.
Moreover, it is preferable that the porous wall 61 has a small pore diameter so as not to disturb the flow as much as possible. In order to minimize the pressure loss, it is preferable to make at least the wall thickness near 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, a tangential direction blowing device shown in FIG. 5A can be used. This peeling prevention device 7 has a sealed chamber 71 to which a pipe 94 is connected. The sealed chamber 71 has a blowout port 72 that blows out a high-pressure gas flow in a tangential direction from the inside of the blade 3 to the body surface side 101.

FIG. 5B is a side view showing another form of the peeling preventing device 7.
As shown in FIG. 5B, the peeling prevention device 7 may be a vortex generator-like protruding device. This peeling prevention device 7 has a sealed chamber 73 to which a pipe 94 is connected. A porous wall 74 is provided at the tip of the sealed chamber 73, and an elastic film 75 that can protrude from the body surface side 101 and has a sufficiently strong strength and restoring force is attached to the porous wall 74. When high-pressure gas is supplied from the pipe 94 to the sealed chamber 73, the elastic film 75 protrudes from the body surface side 101. The protrusion by the elastic film 75 protrudes into the boundary layer, so that the boundary layer is forced to transition to turbulent flow, and the low momentum flow near the wall surface and the high momentum flow away from the wall surface are mixed.

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

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

  The blowing device 8 is configured so that the flow of high-pressure gas from the suction device 6 flowing in via the electromagnetic valve 91 is uniform toward the low-pressure flow outside the chamber 82 and is normal to the body surface side 101. Play a role to blow out.

Depending on the shape of the fuselage (for example, a wing shape), that is, the pressure gradient and the size, one or more blowing devices 8 may be installed.
Further, as with the porous wall 61, it is preferable that the pore diameter of the porous wall 81 is made small so as not to disturb the flow as much as possible. In order to minimize the pressure loss, it is preferable to make at least the wall thickness near the hole as thin as possible.

<Specific example of control system 9>
7A to 7F are diagrams for explaining a separation preventing process, and FIGS. 8A to 8F are diagrams for explaining a turbulent frictional resistance reduction process. FIG. 9 is a timing chart for explaining a control example.
The controller 92 periodically receives a 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 or there is a risk of peeling. . FIG. 7A shows a state where the boundary layer is peeled off or there is a risk of peeling (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 electromagnetic valve 91 (FIGS. 9B and 9B).

  Thereby, a high-pressure gas is sent to the peeling prevention device 7 through the electromagnetic valve 91 (FIG. 7C (iii)), and the peeling prevention device 7 operates (FIGS. 9C, iii) and 7D (iv). ).

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

  FIG. 7F shows a state in which the boundary layer is peeled again after the stop of the peeling preventing device 7 or there is a risk of peeling. Hereinafter, the same operation as described above is performed.

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

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

  Thereby, a high-pressure gas is sent to the blowing device 8 via the electromagnetic valve 91 (FIG. 8C (iii)), and the blowing device 8 operates (FIGS. 9E, VI, and 8D, iv).

  The operation of the blowing device 8 reduces the turbulent flow in the boundary layer (FIG. 8E (v)).

  FIG. 8F shows a state where turbulent flow is again generated 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. The separation preventing device 7 may be operated by flowing it through the device 7, and in other cases, it may be operated by always flowing high pressure gas through the blowing device 8. This simplifies the configuration and control.

  In this way, combining boundary layer separation control that develops on the aircraft body surface, laminar flow control that delays laminar-turbulent boundary layer transition, and turbulent flow control that reduces frictional resistance of the turbulent boundary layer Therefore, it is necessary to drive the sensor 5 for detecting the state of the boundary layer, to transmit a control signal based on the driving force, and to open / close the electromagnetic valve 91, but in addition to this, new power to perform them, that is, a penalty It is possible to perform penaltyless control that eliminates the need for.

  Further, the frictional resistance reduction effect using the present invention differs in contribution to the total resistance depending on the blowing speed and the area of the blowing area. Locally, by blowing out high-pressure gas uniformly at a speed corresponding to 1% of the cruising speed from the blowing device 8, the frictional resistance in the blowing area can be reduced by about 75% (see Non-Patent Document 10). On the other hand, when the anti-peeling effect is compared as the maximum lift coefficient, it is expected to increase by about 0.12 at maximum with or without the anti-peeling device 7 (see Non-Patent Document 12).

<Experimental result>
A Clark-Y blade having a chord length of 400 mm and a blade width of 548 mm without a receding angle was installed in the wind tunnel, and the effect of preventing separation and reducing frictional resistance was verified.
In addition, the suction device and the blowing device were incorporated in −70 mm ≦ Y ≦ 70 mm where −0.072 ≦ X / C ≦ 0.072 and 0.58 ≦ X / C ≦ 0.82, respectively.

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

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

FIG. 10 shows an anti-separation device in which a blade is installed at a uniform flow velocity U _∞ = 24 m / s (Reynolds number 0.64 × 10 ⁶ with reference to the blade chord length) at an angle of attack of 11.4 °. 6 shows a change in the boundary layer distribution at X / C = 0.9 when the operation is performed.
As shown in FIG. 10, it can be seen that the boundary layer distribution, which was a separation type when the separation preventing device was not in operation, was approaching a turbulent distribution due to an increase in the flow velocity near the wall surface due to the operation of the separation preventing device. Therefore, it can be seen from this result that peeling is prevented by this prototype peeling prevention device. Furthermore, it can be seen that the film is largely peeled in a clean state in which no peeling prevention device is attached. This result shows that this prototype peeling prevention device causes roughness on the blade surface even when not operating, and peeling is prevented compared to the clean state. Therefore, if the peeling prevention device is improved and a smooth surface equivalent to the clean state can be realized when not operating, the control effect by the peeling prevention device will be greater, and if the greatest 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, FIG. 11 shows that 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 × 10 ^{6 based on the} chord length), and the separation preventing device 6 shows the change in the boundary layer distribution at X / C = 0.8 when the is operated. Here, X represents the distance along the chord line from the leading edge, and C represents the chord length. The blowing speed U _blow is about 0.04% of the uniform flow (U _blow / U _∞ = 0.04 × 10 ⁻² ). As is apparent from the figure, the average velocity distribution (u (has a wrinkle)) / when the control by the balloon (indicated as wb in the figure) is compared to the case where the control is not performed (indicated as nb in the figure). U∞) and velocity fluctuation distribution (u ′ / _U∞ ) are shifted upward, and it can be seen that the friction on the wall surface is reduced.

For reference, the same test conditions (uniform flow rate U _∞ = 60 m / s, Reynolds number 1.54 × 10 ⁶ , angle of attack 6 ° based on chord length), but not from the suction chamber, Fig. 12 shows the change in velocity distribution at X / C = 0.75 when penalized control is used (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.). Due to the use of a 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 (speed distribution shift amount) accordingly ) Is large. In this case, the quantitative evaluation by fitting with the wall index confirmed the effect that the local frictional resistance at the position was reduced by about 26%. In the prototype control device shown in FIG. 11, the control speed is small because the blowing speed is lower than when the compressor is used (FIG. 12), but by optimizing the airfoil shape, the position of the suction / blowing, the piping handling, A control effect close to that when a compressor is used can be obtained. It is expected that the frictional resistance in the blowing region can be reduced by about 75% if it can be blown uniformly at a speed corresponding to 1% of the uniform flow velocity (U _blow / U _∞ = 1.0 × 10 ⁻² ).

<Others>
The best mode of the invention is the application to aircraft fuselage surfaces, especially the main and tail wings. Furthermore, application to the main wing and tail wing of a transonic aircraft, which is a large passenger aircraft currently in operation, is optimal. Further, the present invention aims to suppress stall (peeling), that is, to reduce both pressure resistance and frictional resistance, and to reduce the penalty on the aircraft body surface boundary layer that 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 research laboratories and universities, and the industrial utility value for aircraft manufacturers and airlines is extremely high.

  The present invention is not limited to the above-described 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 body surfaces other than aircraft wings. Of course, the present invention can be applied even if the aircraft is an unmanned aircraft.

  In the above embodiment, the high pressure gas is obtained from the suction device. However, the high pressure gas may be obtained from, for example, the jet engine side of the aircraft.

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

Claims (7)

A sensor that detects the state of the boundary layer on the aircraft surface;
An anti-peeling device disposed on the surface of the fuselage, operating with high pressure gas and controlling the delamination by imparting momentum to the boundary layer;
A blowing device that is disposed on the surface of the airframe and reduces turbulent frictional resistance by blowing out the high-pressure gas uniformly;
An airflow control apparatus comprising: a control system that switches whether to supply the high-pressure gas to the peeling prevention device or to 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 machine body. The airflow control device according to claim 2,
The suction device is positioned to be in a high pressure region of gas on the airframe surface;
The delamination prevention device is disposed so as to be located in a gas acceleration region on the airframe surface or in a gas deceleration start region on the airframe surface,
The blowout device is disposed 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 delamination prevention device;
An airflow control device further comprising: a third high-pressure gas flow path connecting the second output side of the electromagnetic valve and the blowing device. The airflow control device according to claim 4,
The sensor can detect whether it is likely to peel and whether it is laminar or turbulent,
When the controller detects that the sensor is about to peel off, the controller switches the solenoid valve to send the high-pressure gas to the peeling prevention device, and when the sensor detects turbulence, An airflow control device that switches the solenoid valve to send the high-pressure gas.   An aircraft comprising the airflow control device according to any one of claims 1 to 5. Detect the boundary layer condition on the aircraft surface,
Depending on the detection result, whether the surface of the airframe is controlled by applying momentum derived from high-pressure gas to the boundary layer, or whether turbulent frictional resistance is reduced by blowing out the high-pressure gas uniformly Switch airflow control method.