Air guiding device for controlling air flow at outlet

Abstract

The invention relates to an air guiding device (8) for controlling an air flow at a cabin outlet (2e) of a fuselage of a rotorcraft. The air guiding device (8) comprises: a continuous surface (9) covering the cabin outlet (2e) outside the fuselage and forming a flow channel (17) for guiding the air flow at the cabin outlet (2e); a first flow opening (9a) formed at a first location (8a) of the flow channel (17), where the first flow opening (9a) forms an air inlet region; and a second flow opening formed at a second location (8b) of the flow channel (17), where the second flow opening is arranged downstream of the first flow opening (9a) in the predetermined flow direction, and where the second flow opening forms an air outlet region; wherein the air inlet region is smaller than the air outlet region.

Description

Technical Field

[0001] The present invention relates to an air guiding device for controlling the flow of air in a predetermined flow direction at a cabin outlet of a fuselage of a rotary-wing aircraft. The present invention also relates to a rotary-wing aircraft having such an air guiding device. Background Art

[0002] In general, a plurality of air inlets and outlets are foreseen on the fuselage of a rotorcraft. Such air inlets and outlets are usually used to provide cooling for oil coolers on the fairing, air conditioning systems, avionics bays or simply to ensure cabin ventilation. Usually, the inlets are located in stagnant areas and the outlets are located in negative pressure areas on the rotorcraft. Thus, during cruising flight, air is forced into the inlets and sucked out of the outlets without implementing any fans and therefore without any additional energy consumption.

[0003] Most outlets implemented on rotorcraft are of two types. The first type of outlet is made of a simple sheet of metal that is cut and bent to form a grille. The grille usually ensures a specific flow direction at the outlet section, which is usually between 30° and 50° compared to the outer surface of the fuselage. The second type of outlet implements a rearward scoop on the outlet section, which can ensure that the flow direction around the outlet is almost tangential to the fuselage. The first type of outlet is usually lighter, simpler and cheaper to make and implement - or even modify - on the fuselage surface, but may be more likely to trigger airflow separation by destabilizing the surface airflow. The second type of outlet is usually slightly heavier than the first type of outlet and more difficult to install on the fuselage, but can better align the outlet airflow with the fuselage surface.

[0004] For example, document RU 203671 U1 describes an exhaust system housing with an air inlet device for reducing the exhaust gas temperature.

[0005] Similar air intake structures are described in documents CN202624638U and US2362552A. A boundary layer suction system is described in document US2012 / 0273609A1.

[0006] The described prior art solutions for air inlets and outlets often result in localized flow separations, which usually occur when the outlet is located in a negative pressure region, shortly before pressure recovery begins. These localized flow separations may trigger larger flow separations, which are often of an unstable nature, and which interact with the lifting surfaces and may cause strong vibrations. In the best case, these aerodynamic excitations may impair comfort, and in the worst case may jeopardize structural integrity due to fatigue.

[0007] Furthermore, none of the prior art documents describes an air guiding device at the cabin outlet which avoids or at least reduces a flow separation which may occur downstream of the outlet portion. Summary of the invention

[0008] Therefore, the object of the present invention is to provide a new air guiding device for controlling the flow of air at the cabin outlet of the fuselage of a rotorcraft in a predetermined flow direction in order to reduce air flow separation. This object is solved by an air guiding device having the features of claim 1.

[0009] More specifically, according to the present invention, there is provided an air guiding device for controlling the flow of air at a cabin outlet of a rotorcraft fuselage in a predetermined flow direction. The air guiding device comprises a continuous surface, a first flow opening and a second flow opening. The continuous surface has a longitudinal direction and covers the cabin outlet outside the fuselage. The continuous surface forms a flow channel for guiding the air flow at the cabin outlet. The first flow opening is formed at a first position of the flow channel between the continuous surface and the fuselage. The first flow opening forms an air inlet area. The second flow opening is formed at a second position of the flow channel between the continuous surface and the fuselage. More specifically, the second flow opening is arranged downstream of the first flow opening in a predetermined flow direction. The second flow opening forms an air outlet area, wherein the air inlet area is smaller than the air outlet area.

[0010] Advantageously, the air guiding device of the invention involves a dynamic scoop covering the outlet portion, which in the forward flight state has an upstream inlet and a downstream outlet. The upstream inlet has a rounded lip at the leading edge of the scoop to avoid local air flow separation when the flow stream is not properly aligned in the longitudinal direction of the scoop. More specifically, in the forward flight state, air flowing along the solid surface enters the scoop through the inlet and pushes the air flow from the internal compartment to the outlet. In the hovering state, both the inlet and the outlet of the scoop act as flow outlets, thereby having a larger outflow portion area.

[0011] The dimensions of the inlet and outlet sections of the air guiding device are arranged so that in nominal forward flight conditions, the mass flow from the internal compartment and the mass flow from the scoop inlet section add up in the outlet flow to a speed substantially equal to that of the air flow around the scoop outlet section. In addition, the flow direction will be tangential to the fuselage surface. These characteristics will avoid local and thus larger air flow separations which, when interacting with the lifting surfaces, could lead to strong vibrations which could impair comfort and / or endanger the structural integrity of the rotorcraft due to fatigue.

[0012] Thus, the present air guiding device ensures an outflow direction tangential to the surface on which the air guiding device is mounted and ensures that the flow velocity at the outlet portion is substantially equal to the flow velocity around the scoop itself, so that air flow separation at the outlet portion will be avoided. Furthermore, the present air guiding device can be retrofitted on an existing outlet portion by, for example, removing the outlet grille and installing a new outlet grille.

[0013] According to some aspects, the continuous surface may include a platform section and two curved sections. Preferably, the platform section is separated from the chamber outlet by a predetermined distance to define the opening height of each of the first flow opening and the second flow opening. The two curved sections may define the opening width of each of the first flow opening and the second flow opening.

[0014] Preferably, the opening height and the opening width of the first flow opening are respectively smaller than or equal to the opening height and the opening width of the second flow opening.

[0015] According to some aspects, the platform segment may be formed in a predetermined flow direction to have a profile including an airfoil-shaped end at a first location such that a thickness of the platform segment at the first location is greater than a thickness at a second location.

[0016] Preferably, the greater thickness at the first location reduces the air inlet area compared to the air outlet area.

[0017] According to some aspects, the platform segment may include a protrusion at a first position disposed opposite the cabin outlet, such that the platform segment forms an inclined portion on an inner side opposite the cabin outlet.

[0018] Preferably, in the inclined portion, the distance between the inner side and the compartment outlet increases from the protrusion toward the second flow opening in the predetermined flow direction.

[0019] According to some aspects, the platform segment may include a portion extending parallel to an outer surface of the fuselage from the inclined portion toward the second flow opening.

[0020] According to some aspects, the first flow opening and the second flow opening may be positioned opposite to each other along a longitudinal direction of the continuous surface.

[0021] Preferably, the two curved sections are positioned at least substantially symmetrically with respect to the longitudinal direction.

[0022] In a reference plane perpendicular to the longitudinal direction, a tangent line at any point on any curved segment forms an angle less than or equal to 90° with the outer side surface of the platform segment.

[0023] According to some aspects, the air guiding device may further include a flow splitter. The flow splitter may extend along a longitudinal reference plane, wherein the longitudinal reference plane divides the continuous surface into two symmetrical parts.

[0024] According to some aspects, the air guiding device may further include a wave-shaped structure arranged at the second flow opening.

[0025] The present invention also provides a rotorcraft having the air guiding device as described above. The rotorcraft comprises a fuselage, a cabin outlet located on the fuselage, and the air guiding device as described above installed on the fuselage at the cabin outlet.

[0026] According to some aspects, the cabin outlet may include at least one arcuate cabin outlet edge disposed within the fuselage interior for directing an air flow from the fuselage interior through the cabin outlet.

[0027] Preferably, in a forward flight direction of the rotorcraft, the at least one arcuate cabin outlet edge is formed by a front arcuate means and a rear arcuate means curved in opposite directions.

[0028] According to some aspects, the continuous surface of the air guiding device may include a portion directing the air flow towards the second flow opening of the air guiding device, and the portion is preferably arranged parallel to the outer surface of the fuselage.

[0029] According to some aspects, the first flow-through opening of the air guiding device and the second flow-through opening of the air guiding device are preferably located opposite to each other in a longitudinal direction of the continuous surface of the air guiding device.

[0030] The continuous surface may comprise two curved sections positioned at least substantially symmetrically with respect to the longitudinal direction.

[0031] In a reference plane perpendicular to the longitudinal direction, a tangent line at any point on any one of the curved segments preferably forms an angle greater than or equal to 90° with the outer surface of the fuselage.

[0032] According to some aspects, the sum of the air inlet area of ​​the first flow opening of the air guiding device and the air outlet area of ​​the second flow opening of the air guiding device is preferably larger than the outlet area of ​​the cabin outlet.

[0033] Preferably, the dimensions of the air inlet area of ​​the first flow opening of the air guiding device, the air outlet area of ​​the second flow opening of the air guiding device and the outlet area of ​​the cabin outlet are arranged to guide air from the interior of the fuselage through the cabin outlet towards the air inlet area and the air outlet area during hovering flight of the rotorcraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Preferred embodiments of the present invention are summarized by way of example in the following description with reference to the accompanying drawings. In these drawings, identical or functionally identical components and elements are marked with the same reference numerals and characters and are therefore described only once in the following description.

[0035] Figure 1 A side view of a rotorcraft is shown with an illustrative compartment for receiving an air directing device,

[0036] Figure 2A Shows Figure 1 The cabin with the illustrative air guide installed,

[0037] Figure 2B Shown is the installation Figure 1 In the cabin Figure 2A A perspective view of an illustrative air guide device,

[0038] Figure 2C is from Figure 1 The interior of the cabin is shown Figure 2A A perspective view of an illustrative air guide device,

[0039] Figure 3 Shown is a wavy structure Figure 2A A perspective view of an illustrative air guide device,

[0040] Figure 4A Shown is the installation Figure 1 In the cabin Figure 2A A top view of an illustrative air guide device,

[0041] Figure 4B Shows Figure 4A An enlarged detail of an illustrative air guide arrangement,

[0042] Figure 5A Shown is the installation Figure 1 In the cabin Figure 4B A cross-sectional view of an illustrative air guide device, wherein the cross-sectional view is taken along Figure 4B The AA intercepted

[0043] Figure 5B In the forward flight direction, Figure 4B A forward perspective view of an illustrative air guide mounted on a cabin.

[0044] Fig. 6A A longitudinal cross-sectional view showing an illustrative air directing device mounting configuration relative to a cabin outlet,

[0045] Figure 6B An illustrative air guide device is shown in FIG. Fig. 6A Another cross-sectional view of the airflow being directed at the cabin exit.

[0046] Figure 6C An illustrative air guide device is shown during forward flight operation. Fig. 6A Another cross-sectional view of the airflow being directed at the cabin exit.

[0047] Fig. 7A an enlarged view of an illustrative platform segment of an air guide device illustrating the inclination at one point of the inner side of the platform segment, and

[0048] Figure 7B Shows Fig. 7A The inclination of another point of the platform section of the air guiding device.

[0049] Reference numerals list

[0050] 1-rotorcraft; 1a-multi-blade main rotor; 1b, 1c-rotor blades; 1d-rotor head; 1e-forward flight direction; 1f, 1g, 1h, 1i, 1j-flow direction; 2-fuselage; 2a-cockpit; 2b-cockpit; 2c-left side wall; 2d-cabin; 2e-cabin exit; 2f-outer surface; 2g-exit area; 3-tail boom; 3a-horizontal stabilizer; 4-anti-torque device; 4a-tail rotor; 5-vertical stabilizer; 6-access door; 7-cockpit door; 8-air guide device; 8a-first position; 8b-second position; 8c-air inlet area; 8d-air outlet area; 8e-platform section; 8f, 8g-bend section; 8h-distance; 8i, 8j-reference Consider plane; 8k, 11e, 11f, 12e, 12f-tangent; 8l-longitudinal direction; 9-continuous surface; 9a-first flow opening; 9b-second flow opening; 9c, 9d-opening height; 9e, 9f-opening width; 10-contour; 10a-end of airfoil shape; 10b-protrusion; 10c-front area; 10d-rear area; 10e, 10f, 10g, 10h-point; 11-inside surface; 11a-inclined part; 11b-plane part; 12-outside surface; 13-divider; 14-wavy structure; 15-bow cabin outlet edge; 15a, 15b-bow device; 16-mounting plate; 17-flow channel; α, β, γ1, γ2-angles. DETAILED DESCRIPTION

[0051] Figure 1 An aircraft is shown, which is exemplarily shown as a rotorcraft 1, more specifically, a helicopter. Therefore, for simplicity and clarity, the aircraft is referred to as "helicopter 1" hereinafter. However, the present invention is not limited to helicopters, but can also be applied to any other means of transportation.

[0052] Illustratively, the helicopter 1 comprises at least one main rotor 1a, preferably a multi-blade main rotor, for providing lift and forward or backward thrust during operation. Arrow 1e illustrates the forward flight direction of the helicopter 1. For example, at least one main rotor 1a comprises a plurality of rotor blades 1b, 1c, which are mounted at an associated rotor head 1d to a rotor shaft that rotates about an associated rotor axis during operation of the helicopter 1.

[0053] Furthermore, the helicopter 1 comprises a fuselage 2 which preferably forms an aircraft interior area 2a, 2b, 2d. Illustratively, the left side of the fuselage 2, thus the left side wall 2c of the fuselage 2 of the helicopter 1, is shown.

[0054] The aircraft interior regions 2a, 2b may house a cockpit 2a and may also house a cabin 2b for passengers and / or cargo. If necessary, the aircraft interior region 2d may further house a cabin 2d for avionics. Illustratively, the aircraft interior regions 2a, 2b may be accessed via a plurality of access doors 6. For example, the plurality of access doors 6 include a cockpit door 7. However, for simplicity and clarity of the drawings, only the cockpit door 7 is individually labeled, while the other doors in the plurality of access doors 6 are not individually labeled.

[0055] For example, a tail boom 3 having a horizontal stabilizer 3a is connected to the fuselage 2 of the helicopter 1. The helicopter 1 illustratively further comprises at least one preferably shrouded anti-torque device 4, which is configured to provide an anti-torque during operation, i.e., to counteract the torque generated by the rotation of at least one main rotor 1a in order to balance the helicopter 1 in yaw. The at least one anti-torque device 4 is illustratively arranged at the rear portion of the tail boom 3 and preferably comprises a tail rotor 4a. The rear portion of the tail boom 3 preferably further comprises a vertical stabilizer 5.

[0056] Figure 2A Shows Figure 1 The cabin 2d of the helicopter 1 is provided with an air guiding device 8. Illustratively, the air guiding device 8 can be installed on the top of the cabin 2d.

[0057] Illustratively, the air guiding device 8 is provided for controlling Figure 1 The air at the cabin outlet 2e of the fuselage 2 of the helicopter 1 flows in a predetermined direction (e.g., Figure 6B and Figure 6C The air guiding device 8 comprises a longitudinal direction (e.g., Figure 4A The continuous surface 9 is formed to form a flow channel (e.g., Figure 2BFlow channel 17).

[0058] The air guiding device 8 further comprises a first flow opening 9a and a second flow opening 9b. The first flow opening 9a is formed at a first position 8a of the flow passage between the continuous surface 9 and the fuselage. The first flow opening 9a forms an air inlet area (e.g. Fig. 6A or Figure 6B In addition, a second flow opening 9b is formed at a second position 8b of the flow passage between the continuous surface 9 and the fuselage, wherein the second flow opening 9b is oriented in a predetermined flow direction (e.g., Figure 6B or Figure 6C The second flow opening 9b forms an air outlet area (eg, FIG. 6A to FIG. 6C More specifically, the air inlet area is smaller than the air outlet area.

[0059] Preferably, the flow direction at the second flow opening 9b (eg Figure 6B or Figure 6C The flow direction 1i) is substantially parallel to the outer surface 2f of the fuselage. Figure 2A As shown, the air guiding device 8 may include a longitudinal reference plane (eg, Figure 2B The longitudinal reference plane 8i) extends through the flow divider 13. If necessary, the longitudinal reference plane divides the continuous surface 9 into two symmetrical parts. Illustratively, the longitudinal reference plane can divide the continuous surface 9 into two asymmetrical parts.

[0060] In some embodiments, the air guiding device 8 may not have a splitter. In other embodiments, the air guiding device 8 may include more than one splitter 13. For example, the air guiding device 8 may include two, three, four or more splitters, each of which extends along a respective longitudinal reference plane. The respective longitudinal reference planes may not be parallel to each other. If desired, at least two of the respective longitudinal reference planes may be parallel to each other.

[0061] Illustratively, the continuous surface 9 may include a platform segment 8e and two curved segments 8f, 8g. The platform segment 8e may be separated from the compartment outlet 2e by a predetermined distance (e.g., Figure 5B 8h) to define the opening heights of the first flow opening 9a and the second flow opening 9b (eg Fig. 6A The opening height 9c, 9d).

[0062] Illustratively, the two curved sections 8f, 8g may define the opening widths of the first flow opening 9a and the second flow opening 9b, respectively (eg, Figure 4AFor example, the opening height and opening width of the first circulation opening 9a are respectively less than or equal to the opening height and opening width of the second circulation opening 9b.

[0063] Figure 2B Shown from another angle Figure 2A Illustrative air guiding device 8 of FIG. As described above, the two curved sections 8f, 8g of the continuous surface 9 and the platform section 8e define a flow channel 17 between the continuous surface 9 and the fuselage 2.

[0064] Illustratively, the flow splitter 13 may extend along a longitudinal reference plane 8i. The longitudinal reference plane 8i divides the continuous surface 9 into two symmetrical parts. For example, a longitudinal flow splitter or longitudinal guide plate 13 may be installed inside the air guiding device 8 to stabilize the flow in the flow channel 17.

[0065] For example, the platform segment 8e can be arranged in a predetermined flow direction (e.g., Figure 6B or Figure 6C The profile 10 may include an airfoil-shaped end at a first position 8a (eg, FIG. 6A to FIG. 6C The end portion 10a of the airfoil shape is formed such that the thickness of the platform segment 8e at the first position 8a is greater than the thickness at the second position 8b. Preferably, the greater thickness at the first position 8a is consistent with the air outlet area (e.g., Fig. 6A The air outlet area 8d) is reduced compared to the air inlet area (e.g. Fig. 6A Air inlet area 8c).

[0066] For example, in the forward flight direction, the first position 8a may be located at the front region 10c of the profile 10, and the second position 8b may be located at the rear region 10d of the profile 10. If necessary, the profile 10 at the front region 10c may be formed as a smooth inlet lip to prevent airflow separation on the outer and inner sides of the continuous surface 9 at the air inlet region 8c.

[0067] Figure 2C The interior of cabin 2d shows Figure 2A Illustrative air guide device 8. Figure 2A and Figure 2B on the contrary, Figure 2C An outlet region 2g of a cabin outlet 2e and a structure around the outlet region 2g are shown.

[0068] Illustratively, the cabin outlet 2e may include at least one arcuate cabin outlet edge 15. The at least one arcuate cabin outlet edge 15 may be arranged inside the fuselage 2. If desired, the at least one arcuate cabin outlet edge 15 may guide the air flow from the inside of the fuselage 2 through the cabin outlet 2e.

[0069] In the forward flight direction (e.g. Figure 1 In the forward flight direction 1e) of the helicopter 1, at least one bow-shaped cabin outlet edge 15 may be formed by a front bow device 15a and a rear bow device 15b that are bent in opposite directions. For example, the front bow device 15a and the rear bow device 15b may be made of a metal sheet, a plastic sheet or any other sheet material installed at the outlet area 2g to prevent the airflow at the cabin outlet 2e from separating.

[0070] For example, front bow 15a may have an overall positive curvature (convexity) toward rear bow 15b, and rear bow 15 may have an overall positive curvature (convexity) toward front bow 15. If desired, front bow 15a may be smaller than rear bow 15b.

[0071] Figure 3 The second flow opening 9b has a wavy structure. Figure 2A The illustrative air guide device 8 is shown in FIG. Figure 3 As shown, the air guiding device 8 comprises a continuous surface 9 covering the cabin outlet 2e. Illustratively, two curved sections 8f, 8g and a platform section 8e of the continuous surface 9 define a first flow opening 9a and a second flow opening 9b.

[0072] Illustratively, the air guiding device 8 may include a wave-shaped structure 14. The wave-shaped structure 14 may be arranged at the second flow opening 9b.

[0073] Figure 4A and Figure 4B Shown is a device installed in a cabin (e.g. Figure 3 In the cabin 2d) Figure 2A A top view of an illustrative air guide device 8. A portion of the outer surface 2f of the cabin is Figure 4A and Figure 4B It is shown transparently in the figure to illustrate the installation structure of the air guiding device 8.

[0074] Illustratively, the air guiding device 8 completely covers the cabin outlet of the cabin (e.g. Figure 3 Therefore, the cabin exit and its exit area are Figure 4A and Figure 4B The top view of the air guide device 8 is not shown. Figure 4B As shown, the mounting plate 16 may be provided at the fastening position of the air guiding device 8 and the outer surface 2f.

[0075] Illustratively, Figure 4AAs shown, the opening width 9e of the first flow opening 9a is smaller than the opening width 9f of the second flow opening 9b. If necessary, the opening width 9e of the first flow opening 9a may be equal to the opening width 9f of the second flow opening 9b.

[0076] Figure 5A Shows Figure 4B 2a is a cross-sectional view of an illustrative air guiding device 8. As described above, the mounting plate 16 is disposed between the air guiding device 8 and the outer surface 2f, while the bow devices 15a, 15b are disposed inside the compartment 2d.

[0077] Illustratively, the arcuate devices 15a, 15b may direct the air flow from the interior of the compartment 2d in the flow direction 1g towards the inner side 11 of the continuous surface 9. If necessary, the flow splitter 13 may divide the air flow in the flow channel 17 into two parts.

[0078] Figure 5B Shows Figure 4B illustrative front perspective view of the air guide device 8. Figure 5A In contrast, in order to illustrate the shape of the continuous surface 9, the diverter (i.e. Figure 5A The shunt 13 in the embodiment.

[0079] Reference Figure 4B and Figure 5B , the first flow opening 9a and the second flow opening 9b can be positioned opposite to each other along the longitudinal direction 81. More specifically, the first flow opening 9a and the second flow opening 9b can be positioned opposite to each other at different positions along the longitudinal direction 81 of the continuous surface 9 to be substantially perpendicular to the longitudinal direction 81.

[0080] The two curved segments 8f, 8g may be at least substantially symmetrical with respect to the longitudinal direction 81. Illustratively, in a reference plane 8j perpendicular to the longitudinal direction 81, a tangent line 8k at any point on any curved segment 8f, 8g may form an angle α less than or equal to 90° with the outer side surface 12 of the platform segment 8e.

[0081] like Figure 5B As shown, the angle between the tangent line 8k on the curved segment 8f and the outer side surface 12 of the platform segment 8e is equal to the angle between the tangent line 8k on the curved segment 8g and the outer side surface 12 of the platform segment 8e. If necessary, the angle between the tangent line 8k on the curved segment 8f and the outer side surface 12 of the platform segment 8e can be different from the angle between the tangent line 8k on the curved segment 8g and the outer side surface 12 of the platform segment 8e, and both are still less than or equal to 90°.

[0082] When described with reference to the outer surface 2f of the fuselage, in a reference plane 8j perpendicular to the longitudinal direction 81, a tangent line 8k at any point on any curved segment 8f, 8g may form an angle β greater than or equal to 90° with the outer surface 2f of the fuselage.

[0083] It should be understood that when the outer surface 2f is schematically shown as having a certain degree of curvature, the above-mentioned angle β can be formed between a tangent line tangent to the outer surface 2f through a given point of the outer surface 2f and a tangent line 8k of the curved segments 8f, 8g passing through the given point.

[0084] Fig. 6A is along the longitudinal direction (e.g. Figure 4B 81 ) through an illustrative air guiding device 81 , which shows the dimensions of the first flow opening 9a , the second flow opening 9b and the outlet region 2g of the cabin outlet.

[0085] like Fig. 6A As shown, the platform segment (e.g., Figure 4A The platform section 8e) is formed in a predetermined flow direction to have a profile having an end 10a including an airfoil shape at a first position 8a, so that the thickness of the platform section at the first position 8a is greater than the thickness at the second position 8b. The greater thickness at the first position 8a reduces the air inlet area 8c compared to the air outlet area 8d, so that the air inlet area 8c is smaller than the air outlet area 8d.

[0086] Illustratively, the sum of the air inlet area 8c of the first flow opening 9a of the air guiding device 8 and the air outlet area 8d of the second flow opening 9b of the air guiding device 8 may be greater than the outlet area 2g of the cabin outlet 2e.

[0087] Figure 6B and Figure 6C Shows the different flight conditions Fig. 6A Illustrative air guide device 8.

[0088] For example, Figure 6B Shown during hover flight Fig. 6A illustrative air guiding device 8. Illustratively, the air inlet area 8c of the first flow opening 9a of the air guiding device 8, the air outlet area 8d of the second flow opening 9b of the air guiding device 8, and the outlet area 2g of the cabin outlet 2e are sized to guide air from the interior of the fuselage 2 through the cabin outlet 2e toward the air inlet area 8c and the air outlet area 8d during hovering flight.

[0089] Therefore, during hovering flight, both the first flow opening 9a and the second flow opening 9b work as outlets, so that the flow of the air mass from the cabin is only the cabin overpressure ΔP COMPAs a result, the air mass enters the air guiding device 8 from the interior of the cabin along the flow direction 1g and then leaves the first flow opening 9a and the second flow opening 9b along the flow directions 1h and 1i, respectively.

[0090] The law of conservation of mass can be applied to determine the relationship between the size of the outlet area 2g of the cabin outlet 2e and the size of the air inlet area 8c of the first flow opening 9a and the air outlet area 8d of the second flow opening 9b during hovering flight:

[0091]

[0092] Which gives at constant air density:

[0093] A COMP * v COMP = A INLET * v INLET + A OUTLET * v OUTLET , (2)

[0094] in, is the mass flow rate from the inner chamber 2d, is the mass flow rate at the air inlet area 8c, is the mass flow rate at the air outlet area 8d, and the unit of mass flow rate is kilogram per second (kg / s). COMP is the cross-sectional area of ​​the chamber outlet 2e, A INLET is the cross-sectional area of ​​the first flow opening 9a (i.e., the air inlet area 8c), A OUTLET is the cross-sectional area of ​​the second flow opening 9b (ie, the air outlet area 8d), the unit of the cross-sectional area is square meters (m 2 ). Therefore, v COMP is the average flow velocity from the inner chamber 2d, v INLET is the average flow velocity at the first flow opening 9a, v OUTLET is the average flow velocity at the second flow opening 9b, and the unit of the average flow velocity is meter per second (m / s).

[0095] In order to keep the pressure loss as low as possible, it is necessary to INLET and A OUTLET Therefore, the following rules should be applied when determining the size of the air inlet area 8c of the first flow opening 9a and the air outlet area 8d of the second flow opening 9b during hovering flight:

[0096] A COMP < A INLET + A OUTLET (3).

[0097] exist Figure 6C During the illustrative forward flight, air flows outside the fuselage in a flow direction 1f to the air guiding device 8 and enters the air guiding device 8 in a flow direction 1j at the first flow opening 9a. Air from inside the cabin flows in a flow direction 1g and enters the air guiding device 8 via the cabin outlet 2e. The air then leaves the air guiding device 8 in a flow direction 1i at the second flow opening 9b.

[0098] The law of conservation of mass can be applied to determine the relationship between the dimensions of the outlet area 2g of the cabin outlet 2e and the dimensions of the air inlet area 8c of the first flow opening 9a and the air outlet area 8d of the second flow opening 9b during forward flight:

[0099]

[0100] Which gives at constant air density:

[0101]

[0102] The air flow velocity at the first flow opening 9a and the air flow velocity at the second flow opening 9b may be approximately equal to the air flow velocity around the portion of the fuselage where the air guiding device 8 is installed, which is the forward speed v of the rotorcraft. RC Therefore, the exit area can be approximated as:

[0103]

[0104] Where ρ refers to the air density, which is expressed in kilograms per cubic meter (kg / m 3 ), Kv is composed of v / v RC The ratio obtained is, where v is the local flow velocity on the fuselage, v RC is the forward speed of the rotorcraft in meters per second (m / s).

[0105] It will be appreciated that it is necessary to determine the mass flow from the internal compartment and the Kv parameter, which depends on the local flow velocity on the fuselage.

[0106] By solving equations (3) and (6), an estimate of the size of the air guiding device 8 can be determined. This estimate can be refined by more detailed aerodynamic simulations.

[0107] At this point, it should be noted that methods for further calculation and simulation based on the flight state of the helicopter are well known to those skilled in the art. Therefore, for the sake of brevity, a more detailed description of these methods is omitted.

[0108] Return to reference Fig. 6A , the platform segment 8e of the continuous surface 9 is shown as having an inner side 11 and an outer side 12. Fig. 6A The platform segment 8e in the Figure 4B A cross-sectional view of the platform segment 8e along the longitudinal direction 81.

[0109] Illustratively, the continuous surface 9 of the air guiding device 8 may include a portion 11b that guides the air flow toward the second flow opening 9b of the air guiding device 8. In some embodiments, the portion 11b is parallel to the outer surface 2f of the fuselage. For example, Fig. 6A A dashed line is shown for illustrating the extension of the outer side 12 of the platform segment 8e, which extension is substantially parallel to the outer surface 2f of the fuselage.

[0110] For example, the platform segment 8e may include a protrusion 10b at the first position 8a. The protrusion 10b may be arranged opposite to the compartment outlet 2e so that the platform segment 8e forms an inclined portion 11a on the inner side 11 opposite to the compartment outlet 2e.

[0111] Illustratively, in the inclined portion 11 a , the distance between the inner side surface 11 and the chamber outlet 2 e may increase from the protrusion 10 b toward the second flow opening 9 b in the predetermined flow direction 1 i .

[0112] Fig. 7A and Figure 7B An enlarged view of a platform segment 8e of the continuous surface 9 of the air guide device is shown. Illustratively, the inclined portion of the platform segment 8e (e.g. Fig. 6A The inclined portion 11a) may form an angle γ1 that inclines from the protrusion 10b at the first position 8a to the second flow opening 9b at the second position 8b.

[0113] like Fig. 7A As shown, the angle γ1 may be the angle at the intersection between the first tangent line 11e and the second tangent line 12e. The first tangent line 11e may be tangent to the inner side surface 11 at a point 10e close to the protrusion 10b. The second tangent line 12e may be tangent to the outer side surface 12 at a point 10g close to the protrusion 10b. The angle γ1 may describe the inclination of the inclined portion 11a at the point 10e. Figure 7B As shown, the angle γ2 may be the angle at the intersection between the third tangent line 11f and the fourth tangent line 12f. The third tangent line 11f may be a tangent line to the inner side surface 11 at point 10f, and the fourth tangent line 12f may be a tangent line to the outer side surface 12 at point 10h. The angle γ2 may describe the inclination of the inclined portion 11a at point 10f. Illustratively, the angle γ1 is slightly greater than the angle γ2. Therefore, the inclination of the profile 10 may gradually flatten from the first position 8a to the second position 8b.

[0114] It should be noted that modifications to the above-described embodiments are within the common knowledge of those skilled in the art and are therefore considered part of the present invention. It should also be noted that the drawings are only used to schematically represent embodiments of the present invention and are not used to illustrate their detailed construction. For example, Figure 3 The air guiding device 8 shown and described has a wave-shaped structure 14 with three wave peaks. However, the number of wave peaks can also be less than or more than three. In addition, instead of having wave peaks divided by the flow divider 13, the wave-shaped structure 14 can also be formed with two wave peaks on each side of the flow divider 13. In addition, the air guiding device 8 can also be used without the flow divider 13.

Claims

1. An air guiding device (8) for controlling the flow of air at a cabin outlet (2e) of a fuselage (2) of a rotorcraft (1) in a predetermined flow direction (1i, 1j, 1h), the air guiding device (8) comprising: a continuous surface (9) having a longitudinal direction (81), the continuous surface (9) covering the cabin outlet (2e) outside the fuselage (2) and forming a flow channel (17) for guiding the air flow at the cabin outlet (2e); a first flow opening (9a) formed at a first position (8a) of the flow channel (17) between the continuous surface (9) and the fuselage (2), wherein the first flow opening (9b) forms an air inlet area (8c); as well as a second flow opening (9b) formed at a second position (8b) of the flow channel (17) between the continuous surface (9) and the fuselage (2), wherein the second flow opening (9b) is arranged downstream of the first flow opening (9a) in the predetermined flow direction (1i, 1j, 1h), and wherein the second flow opening (9b) forms an air outlet area (8d); The air inlet area (8c) is smaller than the air outlet area (8d).

2. The air guiding device (8) according to claim 1, wherein the continuous surface (9) comprises a platform section (8e) and two curved sections (8f, 8g), wherein the platform section (8e) is separated from the chamber outlet (2e) by a predetermined distance (8h) to define the opening heights (9c, 9d) of the first flow opening (9a) and the second flow opening (9b), respectively, and wherein the two curved sections (8f, 8g) define the opening widths (9e, 9f) of the first flow opening (9a) and the second flow opening (9b), respectively, and The opening height (9c) and opening width (9e) of the first circulation opening (9a) are respectively smaller than or equal to the opening height (9d) and opening width (9f) of the second circulation opening (9b).

3. The air guiding device (8) according to claim 2, wherein the platform segment (8e) is formed in the predetermined flow direction (1i, 1j, 1h) to have a profile (10), the profile (10) comprising an airfoil-shaped end (10a) at the first position (8a), so that the thickness of the platform segment (8e) at the first position (8a) is greater than the thickness at the second position (8b); and The greater thickness at the first location (8a) reduces the air inlet area (8c) compared to the air outlet area (8d).

4. The air guiding device (8) according to claim 2, wherein the platform segment (8e) comprises a protrusion (10b) arranged opposite to the chamber outlet (2e) at the first position (8a), so that the platform segment (8e) forms an inclined portion (11a) on the inner side (11) opposite to the chamber outlet (2e); and in, In the inclined portion (11a), the distance between the inner side surface (11) and the chamber outlet (2e) increases from the protrusion (10b) toward the second flow opening (9b) in the predetermined flow direction (1i, 1j, 1h).

5. The air guiding device (8) according to claim 4, The platform section (8e) includes a portion (11b) extending from the inclined portion (11a) toward the second flow opening (9b) parallel to the outer surface (2f) of the fuselage (2).

6. The air guiding device (8) according to claim 2, wherein the first flow opening (9a) and the second flow opening (9b) are positioned opposite each other along the longitudinal direction (81) of the continuous surface (9), wherein the two curved sections (8f, 8g) are positioned at least substantially symmetrically with respect to the longitudinal direction (8l), and in, In a reference plane (8j) perpendicular to the longitudinal direction (8l), a tangent line (8k) at any point on any curved segment (8f, 8g) forms an angle (α) less than or equal to 90° with the outer side surface (12) of the platform segment (8e).

7. The air guiding device (8) according to claim 1, further comprising a splitter (13) extending along a longitudinal reference plane (8i), wherein the longitudinal reference plane (8i) divides the continuous surface (9) into two symmetrical parts.

8. The air guiding device (8) according to claim 1, further comprising a wave-shaped structure (14) arranged at the second flow opening (9b).

9. A rotorcraft (1) comprising a fuselage (2), a cabin outlet (2e) located on the fuselage (2) and an air guiding device (8) according to claim 1, wherein the air guiding device (8) is mounted on the fuselage (2) at the cabin outlet (2e).

10. The rotorcraft (1) according to claim 9, The cabin outlet (2e) comprises at least one arcuate cabin outlet edge (15), and the at least one arcuate cabin outlet edge (15) is arranged inside the fuselage (2) and is used to guide the air flow from the inside of the fuselage (2) through the cabin outlet (2e).

11. The rotorcraft (1) according to claim 10, in, In the forward flight direction (1e) of the rotorcraft (1), the at least one arcuate cabin outlet edge (15) is formed by a front arcuate device (15a) and a rear arcuate device (15b) curved in opposite directions.

12. The rotorcraft (1) according to claim 9, The continuous surface (9) of the air guiding device (8) comprises a portion (11b) for guiding the air flow towards the second flow opening (9b) of the air guiding device (8), and the portion (11b) is arranged parallel to the outer surface (2f) of the fuselage (2).

13. The rotorcraft (1) according to claim 12, wherein the first flow opening (9a) of the air guiding device (8) and the second flow opening (9b) of the air guiding device (8) are positioned opposite to each other along the longitudinal direction (81) of the continuous surface (9) of the air guiding device (8), wherein the continuous surface (9) comprises two curved sections (8f, 8g) positioned at least substantially symmetrically with respect to the longitudinal direction (8l), and in, In a reference plane (8j) perpendicular to the longitudinal direction (8l), a tangent line (8k) at any point on any curved segment (8f, 8g) forms an angle (β) greater than or equal to 90° with the outer surface (2f) of the fuselage (2).

14. The rotorcraft (1) according to claim 9, The sum of the air inlet area (8c) of the first circulation opening (9a) of the air guiding device (8) and the air outlet area (8d) of the second circulation opening (9b) of the air guiding device (8) is greater than the outlet area (2g) of the cabin outlet (2e).

15. Rotorcraft (1) according to claim 14, The dimensions of the air inlet region (8c) of the first circulation opening (9a) of the air guiding device (8), the air outlet region (8d) of the second circulation opening (9b) of the air guiding device (8) and the outlet region (2g) of the cabin outlet (2e) are arranged to guide air from the interior of the fuselage (2) through the cabin outlet (2e) toward the air inlet region (8c) and the air outlet region (8d) during hovering flight of the rotorcraft (1).

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