• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a blade (1) of a rotor (11) for a rotary wing aircraft (10). Said blade (1) has laws of variation of the boom and ropes of the profiles (15) of the sections of said blade (1) in order to improve in particular the stiffness in torsion as well as in flexion of said blade (1). Said blade (1) then has a double taper and a triple boom and on the one hand, improves the aerodynamic performance of said blade (1) in forward flight and on the other hand to reduce the noise emitted by said blade (1), especially during an approach flight.
    公开号:FR3045565A1
    申请号:FR1502662
    申请日:2015-12-21
    公开日:2017-06-23
    发明作者:Debbie Leusink；David Alfano；Vincent Gareton
    申请人:Airbus Helicopters SAS；
    IPC主号:
    专利说明:

    Aircraft rotor blade with geometry adapted for acoustic enhancement during an approach flight and improved performance in forward flight
    The present invention is in the field of aerodynamic bearing surfaces and more particularly aerodynamic surfaces forming a rotary wing.
    The present invention relates to a blade for a rotary wing aircraft rotor and a rotor provided with at least two such blades. This blade is more particularly intended for a main rotor lift or propulsion of a rotary wing aircraft.
    Conventionally, a blade extends longitudinally along its span from a first end to be fixed to a rotating hub of a rotor to a second end called free end. With respect to the rotor, it is understood that the blade extends radially from the first end to the second end in a span direction. In addition, this blade extends transversely from a leading edge to a trailing edge of the blade, along the rope of this blade.
    This blade is rotated by a rotating hub of this rotor. The axis of rotation of this hub therefore corresponds to the axis of rotation of the blade.
    The first end is generally referred to as "blade start" while the second free end is referred to as "blade tip".
    In operation, each blade of a rotor is subjected to aerodynamic forces, in particular an aerodynamic lift force during the rotary movement of this rotor for sustaining the aircraft, or even propelling it.
    For this purpose, the blade has a profiled portion located between the blade tip and the blade tip. This profiled part consists of a succession of aerodynamic profiles, hereinafter referred to as "profiles" for convenience, depending on the direction of span. Each profile is located in a transverse plane generally perpendicular to this span direction and delimits a section of the blade. This profiled part ensures most of the lift of the blade.
    The shape of the transition zone between the blade start and the beginning of this profiled part is generally imposed by manufacturing constraints and structural constraints of the blade. This transition zone between the blade start and the beginning of this profiled part may be designated by the term "blade root" and has aerodynamic performance significantly reduced compared to that of the profiled part. This transition zone can, however, generate a lift force. In addition, this transition zone, located near the rotor hub, however, regardless of its aerodynamic shape, a small contribution to the total lift of the blade.
    For example, the profiles of the sections of the blade on the profiled portion are characterized by a thin trailing edge, ideally zero, while the trailing edge at the beginning of the blade and the transition zone between the blade start and the beginning of this profiled part is thick, even rounded.
    A rotary wing aircraft has the advantage of being able to evolve both with high forward speeds during cruising flights and with very low forward speeds, and to also perform stationary flights. A rotary wing aircraft thus has the advantage of being able to land on areas of reduced surfaces and therefore closer to inhabited areas for example or on landing platforms.
    However, flights at high speeds require aerodynamic characteristics of the blades which can be different or even unfavorable for flights with very low speeds and stationary flights.
    Likewise, the aerodynamic characteristics of the blades also affect the noise generated by the blades. This noise can be problematic during the approach and landing phases due to the proximity of populated areas. In addition, stringent acoustic certification standards dictate noise levels for rotary wing aircraft.
    For a predetermined selection of aerodynamic profiles, the geometric characteristics of a blade influencing the aerodynamic performance of the blade during forward flights at high speeds and stationary flights as well as the acoustic signature of the blade are notably the rope of the profiles. aerodynamic sections of the blade, the arrow and twisting of the blade.
    It is recalled that the rope is the distance between the leading edge and the trailing edge of the section profiles of the blade. This rope may vary along the span of the blade. "Taper" is generally used to refer to a decrease of the ropes along the span of the blade, but this term may also refer to an increase of these ropes along the span of the blade.
    The arrow can be defined as the angle formed by the leading edge of the blade with a particular axis of this blade. By convention, in a forward-sloping zone, the leading edge forms with the axis of the blade a positive deflection angle in the direction of rotation of the rotor, whereas in a rear-arrow zone this leading edge forms an angle negative arrow with said axis of the blade. Said axis of the blade is generally coincident with the pitch axis of the blade.
    The twisting of a blade consists of varying the wedging of the section profiles of the blade along the span of the blade. "Wedging" is understood to mean the angle formed between the chord of each profile of the sections of the blade with a reference plane of this blade, this angle being designated by "twisting angle". This reference plane is for example the plane perpendicular to the axis of rotation of the blade and having said axis of the blade.
    The "twisting law" is the evolution of the twisting angles according to the span of the blade. Conventionally, twisting is measured negatively when the leading edge of a profile of a section of the blade is lowered relative to said reference plane.
    Effective solutions are known to independently improve the performance of a blade for high speed forward flights and those of a blade for stationary flights as well as the acoustic performance of the blade during approach phases.
    For example, the improvement of the aerodynamic performance of a hovering blade is characterized by the reduction of the power consumed by this rotor isoportance blade. This improvement can be obtained by passive geometrical modifications of the blade, and in particular by increasing its twisting.
    An adequate increase in the twist of the blade makes it possible to distribute the lift more uniformly over the entire surface of the blade and, as a result of the rotor, and thus to reduce the power absorbed by each rotor blade in hovering flight. It is recalled that the increase of twisting is in fact to lower the leading edge relative to said reference plane and that all the more towards the tip of the blade than towards the beginning of blade due to revolution of the circumferential speed of the flow of air depending on the span. The aerodynamic performance of the hovering blade is notably increased, thus homogenizing the speeds induced along the span of the blade.
    However, a strong twisting of the blade can cause the tip of blade to wear negatively, that is to say to generate a deportation which is in fact a lift force oriented in the direction of gravity, for a blade in a azimuthal position called "advancing blade" by the skilled person when the rotary wing aircraft is moving at high speed. The aerodynamic performance of the blade is then degraded in forward flight. In addition, the aerodynamic load levels experienced by the blade as well as the vibrations are also greatly increased in forward flight. The addition of a dihedron at the end of the blade also makes it possible to improve the aerodynamic performance of the hovering blade. A dihedron is formed by a blade surface at the end of the blade which is oriented upwards or downwards. This dihedral makes it possible to reduce the influence of the marginal vortex generated by a blade on the following blades of the hovering rotor. Nevertheless, this dihedral can be accompanied by a decrease in the aerodynamic performance of the blade in forward flight as well as an increase in vibration.
    In addition, the improvement of the aerodynamic performance of a blade in forward flight is characterized by the reduction of the power consumed by each blade of the rotor for a given lift and forward speed. This improvement can be obtained by passive geometrical modifications of the blade, and in particular by modifying its rope along the span of the blade and / or by reducing its twisting.
    For example, the chord of section profiles of the blade increases from the beginning of the blade along the span, then decreases before reaching the blade tip. This is called "double taper" of the blade. EP 0842846 discloses a double-tapered blade whose maximum chord is located at a distance between 60% and 90% of the total span of the blade of the axis of rotation of the blade.
    However, the use of a double taper on a blade often results in an increase in the noise in approach flight following the increase in the swirling intensity emitted, then impacted by each blade. The use of this double taper also results in aerodynamic performance hovering degraded compared to a blade of the same twist and the same aerodynamic strength, this term designating the ratio between the total surface of the rotor blades seen from above and the rotor disk surface which is the surface described by a blade of this rotor during a rotation of a turn.
    Moreover, and in accordance with the aforementioned, a decrease in the kinking of the blade induces an increase in aerodynamic impacts at the end of the advancing pale blade edge. The incidences for a blade tip that is twisted are therefore closer to zero advancing blade side, which on the one hand reduces the deportation of this end of the advancing pale blade blade and, on the other hand, reduces the local drag, in particular the bound drag. the appearance of shock waves.
    On the other hand, a decrease in the kinking of the end of the blade is accompanied by a reduction in the stall margin of the retreating blade blade. In addition, this decrease in the twisting of the blade is not favorable to hovering as mentioned above.
    US 722479 discloses a blade adapted for high speed forward flights combining a double taper of the blade and a twisting law.
    Finally, the improvement of the acoustic performance of a blade in approach flight can be characterized by the reduction of the noise generated by the interaction between the blade and the air vortex generated by the preceding blades of the rotor. This improvement can be obtained by passive geometrical modifications of the blade, and in particular by modifying its deflection along the span.
    For example, as described in EP 1557354, US 512/021326 and US 6116857, a blade with a first forward-arrow zone and a second back-arrow zone prevents the leading edge of the blade from being parallel to the line of vortices emitted by the preceding blades on these first and second zones. Such a blade thus makes it possible to limit the interactions between this blade and these vortices by decreasing, for example, the intensity of the impulsive noise linked to the interaction between the blade and these vortices and, consequently, of limiting the appearance of noises.
    In addition, this double-headed blade can also include a taper on the second rear-arrow zone which also reduces the level of noise generated in flight. Indeed, for a given profile, the thickness of the blade is even lower than the rope is short, which reduces the appearance of noise called "thick". Similarly, the surface of the blade being reduced as a result of its taper, the lift is also modified, which can reduce the appearance of the so-called "load" noise.
    It is also possible to intervene on the aerodynamic load at the end of the blade in order to modify the eddies emitted in the wake of the blade and, consequently, to reduce the noise level of the blade. For this purpose, it modifies the laws of variation of twisting and ropes profiles of sections of the blade. However, such variations are incompatible with the optimizations previously mentioned in the context of stationary flights or advancement.
    Moreover, it is also possible, independently of the geometry of the blade, to modify the rotation speed of the blade or to adopt aircraft-specific approach trajectories designated "approach paths with less noise" in order to reduce the noise radiated on the ground by the blades of the aircraft.
    However, a modification of the rotation speed of the blade makes the dynamic balancing work of the blade more complex. In addition, a decrease in the rotational speed of the blade can in particular generate an increase in aerodynamic stalls at the blade end and, consequently, an increase in the dynamic control forces of the blade.
    It is also possible to combine the application of a double arrow with variations of the ropes of the profiles of the sections of the blade and a twisting law adapted to either the hover or the advancing flight. Thus, the documents EP1557354 and US 512/021326 describe blades adapted for hovering while reducing the noise generated during the approach flights. Similarly, document EP084946 is known which describes a blade adapted for the flight of advancement at high speeds and makes it possible to limit the noise in approach flights.
    However, the aerodynamic performance of such blades are not optimized for the flight phase to which the blades are adapted. Indeed, significantly reducing the noise emitted by the blade is in all cases preferred and the aerodynamic performance of the blade can be degraded in certain phases of flight. This degradation is due in particular to a lack of stiffness in torsion and / or flexion of the blade which can then deform under the aerodynamic and inertial forces experienced by the blade.
    On the other hand, the optimization of the profiles of the blade for the flights of advancement with high speeds is different and seems antagonistic with the optimization of these profiles for the stationary flights. Optimizing the profiles common to stationary flights and advancing at high speeds is particularly complex to define, the aerodynamic conditions encountered by the blade being different. In addition, the position of the blade which is, during the rotation of the rotor, alternately advancing and receding vis-à-vis the air flow, increases the differences between these aerodynamic conditions encountered by the blade.
    Finally, the document entitled "Multiobjective-Multipoint Rotor Blade Optimization in Forward Flight Conditions Using Surrogate-Assisted Memetic Algorithm" presented at the European Rotorcraft Forum in Gallarate (Italy) in September 2011 compares several methods of optimizing a blade in flight of advancement. This blade may comprise only a twisting law, present a combination of the laws of variation of the strings and the arrow or have a combination of the laws of variation of twist, cords and arrow.
    The present invention aims to overcome the limitations mentioned above and to provide a blade improving the aerodynamic performance of the blade while reducing the noise emitted by the blade during an approach flight. The invention also relates to a rotor intended for a rotary wing aircraft comprising at least two such blades.
    The present invention therefore relates to a blade for a rotary wing aircraft rotor intended to be rotated about an axis of rotation A, the blade extending firstly along a blade axis B between a start blade adapted to be connected to a hub of the rotor and a blade tip located at a free end of the blade and secondly along a transverse axis T substantially perpendicular to the blade axis B between a leading edge and a trailing edge, the blade having a profiled portion located between the blade tip and the blade tip, the profiled portion being constituted by a succession of aerodynamic profiles, each aerodynamic profile being located in a transverse plane substantially perpendicular to the axis of blade B, each profile delimiting a section of the blade, the blade tip being situated at a reference distance equal to a rotor radius R of the axis of rotation A, a maximum distance between the leading edge and the blade. e trailing edge in this transverse plane constituting a rope c for the aerodynamic profile of the blade, an average rope c being an average value of the rope c on the profiled part, a first direction towards the front being defined of the trailing edge towards the leading edge and a second backward direction being defined from the leading edge to the trailing edge.
    The average chord c is preferably defined by a squared weighting of the radius r of each section profile of the blade according to the formula
    L (r] being the length of the local chord of a profile of the blade located at a radius r of the axis of rotation A, Ro being the radius of the beginning of the profiled part and R the radius of the blade tip.
    However, the average chord c can be defined by an arithmetic average of the c-strings of the sections of the blade over the whole of the profiled part of the blade.
    This blade according to the invention is remarkable in that it has a combination of the laws of variation of the strings and the arrow, the rope increasing between the beginning of the profiled part and a first section SI located at a first distance from the axis of rotation A between 0.6 R and 0.9 R, the rope decreasing beyond the first section SI, the arrow of the blade being first directed towards the front of the blade between the beginning of the profiled portion and a second section S2 located at a second distance from the axis of rotation A between 0.5 R and 0.8Æ, the leading edge forming a first forward deflection angle between 0 ° and 10 ° with the blade axis B , the arrow then being directed towards the front of the blade between the second section S2 and a third section S3 situated at a third distance from the axis of rotation A between 0.6 R and 0.95 R, the leading edge forming a second forward boom angle between 1 ° and 15 ° with the blade axis B, the arrow finally being directed towards the rear of the blade between the third section S3 and the tip of blade, the leading edge forming a third angle of rear arrow included between -35 ° and -15 ° with the blade axis B.
    This blade according to the invention is preferably intended for the main rotor lift or propulsion of a rotary wing aircraft. The axis of rotation A of the blade corresponds to the axis of rotation of the hub of the rotor.
    The profiled portion of the blade provides the bulk of the lift of the blade during the rotation of the blade about the axis A. The beginning of this profiled portion is characterized in particular by a thin trailing edge, while between the beginning of the blade and the beginning of this profiled part, the trailing edge is thick, even rounded. The beginning of this profiled part is therefore generally distinct from the beginning of the blade and situated between the beginning of the blade and the tip of the blade, close to the beginning of the blade.
    The blade tip is located at a reference distance equal to the rotor radius R of the axis of rotation A, and this rotor radius R is used to locate a profile or a section of the blade along the blade axis B. For example, the blade start is located at a fourth distance between 0.05R and 0.3R of the axis of rotation A and the beginning of the profiled part of the blade is located at a fifth distance between 0.1 R and 0.4R the axis of rotation A. The fifth distance is greater than or equal to the fourth distance.
    Likewise, the medium rope c of the blade is used on the profiled part to define the rope of each profile of the blade along its span.
    The law of variation of the arrow thus defines a blade with a triple arrow which advantageously makes it possible to improve the acoustic signature of the blade. Preferably, the first forward deflection angle is strictly greater than 0 °.
    This triple arrow advantageously prevents the leading edge of the blade from being parallel to the vortices emitted by the preceding blades during the rotation of a blade. This triple arrow thus makes it possible to reduce the intensity of the acoustic energy generated by the interaction between the blade and the air vortices emitted by the preceding rotor blades over a portion of the blade span, particularly during an approach flight.
    In addition, the ends of the preceding blades emit swirls forming helical shaped vortex lines. It is then interesting to limit the portions in span of the leading edge of the blade which are simultaneously interacting with these lines of vortices to limit the effect of the noise generated on the human ear.
    Indeed, with a leading edge of the blade with a continuously evolving deflection angle on one or more of the zones delimited by the second and third sections S2, S3 and by the tip of the blade, the interaction between this leading edge and vortices emitted by the blades preceding a subsequent blade occurs simultaneously on several points of this leading edge and causes the appearance of acoustic energy. The result is a remission of an impulsive and annoying sound for the human ear, this phenomenon being penalizing for the acoustic certification.
    Advantageously, with a leading edge of the rectilinear blade and inclined vis-à-vis the blade axis on each zone delimited by the second and third sections S2, S3 as well as by the blade tip, the interaction between the leading edge and these vortices occur simultaneously on a reduced number of points of the leading edge. This results in a decrease in the impulsivity of the emitted signal which is then less troublesome for the human ear.
    Consequently, the leading edge of the blade is preferably rectilinear and inclined on each zone delimited by the second and third sections S2, S3 as well as by the blade tip in order to reduce the acoustic energy perceived by an observer.
    The boom is therefore preferably formed by a first forward deflection angle, a second forward deflection angle and a third trailing deflection angle which are respectively constant between the beginning of the profiled portion and the second section S2, and then between the second section S2 and the third section S3 and finally between the third section S3 and the blade tip.
    For example, the first forward deflection angle is 4 °, the second forward deflection angle is 8 °, and the third forward deflection angle is -23 °.
    According to the law of variation of the ropes of the profiles of the sections of the blade, this rope varies around the average rope c of +/- 40% between the beginning of the profiled part and the first section SI. The rope varies from 0.6c to 1.4c respectively from the beginning of the profiled part to the first section SI. The variation of the ropes can also be smaller between the beginning of the profiled part and the first section SI, in particular to lessen the aerodynamic performance of the blade during a hover. The rope varies for example by +/- 20% around the average rope c between the beginning of the profiled part and the first section SI.
    In addition, the chord of the profiles of the sections of the blade is preferably smaller than the average chord c on a first part of the blade, for example between the beginning of the profiled part of the blade and a fourth section S4 located at a sixth distance from the axis of rotation A between 0.5R and 0.8R. The chord of the profiles of the sections of the blade is then greater than this average chord c between this fourth section S4 and a fifth section 55 located at a seventh distance from the axis of rotation A between 0.85R and 0.95R, then lower than this average rope c beyond this fifth section 55 and to the tip of the blade. For example, the chord of the profile of the section of the blade at the beginning of blade is between 0.4c and 0.9c while the chord of the profile of the section of the blade at the end of blade can be between 0.2c and 0.8c.
    Furthermore, the rope may decrease non-linearly beyond a sixth section 56 to the blade tip, this sixth section 56 being located at an eighth distance from the axis of rotation A between 0.9R and 0.95R . Preferably, the chord of the section profiles of the blade decreases along a parabolic curve beyond the sixth section 56. This is generally referred to as "parabolic salmon" present at the end of the blade. Other non-linear shapes are also possible for this blade tip according to polynomial curves such as a Bezier curve.
    In this case, the chord of the profile of the blade end section is between 0.2ci and 0.8a, a being the value of the chord of the section profile of the blade at the sixth section 56, it is at the beginning of this zone of non-linear decrease of the chord of the profiles of the sections of the blade. Preferably, the rope at the end of the blade is equal to 0.3a.
    The combination of these laws of variation of the boom and the ropes of the profiles of the sections of the blade thus makes it possible to improve the aerodynamic performance in forward flight while reducing the noise emitted by the blade, especially during approach flights. .
    In addition, the blade can combine with the laws of variation of the strings and the arrow a twisting law. According to this twisting law, the twisting of the profiles of the sections of the blade is decreasing between a seventh section 57 located at a ninth distance from the axis of rotation A between 0.3R and 0.4i and the blade tip, a first twisting gradient being between -25 ° / R and -4 ° / R between the seventh section 57 and an eighth section S8 located at a tenth distance from the axis of rotation A between 0.4 R and 0.6R, a second twisting gradient being between -25 ° / R and -4 ° / R between the eighth section S8 and a ninth section 59 located at an eleventh distance from the axis of rotation A between 0.65R and 0.85Æ, a third twisting gradient being between -16 ° / R and -4 ° / R between the ninth section 59 and a tenth section S10 located at a twelfth distance from the axis of rotation A between 0.85R and 0.95R, a fourth twist gradient being between -16 ° / R and 0 ° / R between the tenth section S10 and the blade tip.
    Advantageously, the combination of the laws of variation of the ropes and the deflection of the profiles of the sections of the blade with this twisting law makes it possible to improve the aerodynamic performance of the blade mainly in hover without degrading on the one hand the aerodynamic performances of the blade in flight of advancement and on the other hand the noise generated by the blade during approach flights.
    Indeed, twisting is important in a first zone of the blade, for example between 0.3R and 0.7Æ, and thus makes it possible to compensate for the weak rope which is essentially less than the average rope c. In addition, the unscrewing in a second zone of the blade, for example between 0.7 R and 0.9 R, is favorable to the advancing flight for an advancing blade, but generates an increase in forces on a retreating blade.
    Advantageously, on this second zone, the chord of the section profiles of the blade is substantially greater than the average rope c and thus makes it possible to withstand these increased forces without degrading the aerodynamic behavior of the retreating blade.
    This variation law of the twisting of the blade can be piecewise linear, that is to say between two adjacent sections among the sections S7, S8, S9, S10 and between the tenth section S10 and the tip of the blade or not linear on the whole of the profiled part of the blade.
    In the case where the twisting law is piecewise linear, this twisting law is constituted by straight line segments, a segment characterizing the twisting variation between two adjacent sections among the sections S7, S8, S9, S10 and between the tenth section S10 and the blade tip. The twist gradient, which is the local derivative of the twist along the span of the blade, then corresponds to the directing coefficient of the lines supporting these segments. This twisting gradient is then formed by discontinuous horizontal lines, a straight line being located between the adjacent sections and between the tenth section S10 and the tip of the blade.
    In addition, in order to allow a variation of the twisting compatible with both a hovering flight and a forward flight and with the law of variation of the strings, the first twisting gradient located between the seventh section 57 and the eighth section S8 is preferably less than the second twisting gradient between the eighth section S8 and the ninth section 59, the second twisting gradient is preferably greater than the third twisting gradient located between the ninth section 59 and the tenth section S10 and the third gradient twisting is preferably lower than the fourth twisting gradient located between the tenth section S10 and blade tip.
    In the case where this twist law is non-linear, on the profiled part, the twisting gradient is preferably a continuous curve over the entire profiled portion of the blade. The first twist gradient then reaches a first level between -25 ° / R and -15 ° / R at the eighth section S8, the second twist gradient reaches a second level between -14 ° / R and -4 ° / R at the ninth section 59, the third twisting gradient reaches a third level between -16 ° / R and -6 ° / R at the tenth section S10 and the fourth twisting gradient is between - 10 ° IR and 0 ° / R at the blade tip.
    This twisting law can correspond to a polynomial curve, for example a Bézier curve of order 6 or higher.
    Preferably, the first step is equal to -18 ° / Æ, the second step to -6 ° / R, the third step to -13 ° / R and the fourth step of the twist is equal to -8 ° / R at the tip of the blade.
    Whatever the law of variation of twisting, the ninth distance is for example equal to 0.35R, the tenth distance to 0.48R, the eleventh distance to 0.78R and the twelfth distance to 0.92 R.
    The twisting law only defines the variation of the twisting of the blade between the beginning of the profiled part and the tip of the blade, but it does not define the wedging of the profiles of the sections of the blade. The wedging of the section profiles of the blade at the beginning of the profiled part has no direct influence on the aerodynamic behavior of the blade. In fact, the wedging of the profiles of the sections of the blade at the beginning of the profiled part and of all the profiles of the blade along the profiled part depends during the flight of the adjustment of the collective pitch and that of the not cyclic of the blade. It is therefore the variation of twisting that characterizes the aerodynamic behavior of the blade, the value of the wedging of the profiles of the sections of the blade being taken into account in the adjustment of the collective pitch and that of the cyclic pitch of the blade.
    In addition, the areas of the blade located near this axis of rotation A and in particular the area between the axis of rotation A and the eighth section S8 are not stressed by the aerodynamic forces during the rotation of the blade. The twisting near this axis of rotation A therefore has little influence on the aerodynamic behavior of the blade. In this way, the twisting may be substantially constant or vary slightly between the beginning of the profiled portion and the eighth section S8 without significantly modifying the behavior and aerodynamic performance of the blade. The twist variation is for example less than or equal to 2 ° between the beginning of the profiled part and the eighth section S8.
    In addition, the blade may comprise a dihedron starting at the sixth section S6 and ending at the end of blade. This dihedron is preferably oriented downwards and improves the aerodynamic performance of the hovering blade.
    The present invention also relates to a rotor for a rotary wing aircraft. This rotor comprises at least two blades as previously described. This rotor is more particularly intended to be a main rotor lift or propulsion of a rotary wing aircraft. The invention and its advantages will appear in more detail in the context of the description which follows with exemplary embodiments given by way of illustration with reference to the appended figures which represent: FIGS. 1 and 2, a blade according to the invention, FIG. 3, an aircraft provided with a rotor formed by such blades, FIG. 4, a variation curve of the ropes of the section profiles of the blade, FIG. 5, a curve of variation of the deflection arrow. the blade, - Figure 6, a variation curve of the twist of the blade, and - Figure 7, a curve of variation of the twisting gradient of the blade.
    The elements present in several separate figures are assigned a single reference.
    FIGS. 1 and 2 show a blade 1 extending on the one hand in span along a blade axis B between a blade start 2 and a blade tip 9 and, on the other hand, along a transverse axis T perpendicular to the blade blade axis B between a leading edge 6 and a trailing edge 7. The blade 1 comprises a profiled portion 4 situated between the blade tip 2 and the blade tip 9. The profiled part 4 is constituted by a succession of aerodynamic profiles 15 located in a transverse plane substantially perpendicular to the blade axis B, each profile delimiting a section of the blade 1. The blade 1 also comprises a dihedron 5 at the free end of the blade 1, that is, ie at the tip of the blade 9.
    The blade 1 is intended to form a rotary wing aircraft rotor 11 as shown in FIG. 3. This rotor 11 comprises a hub 12 and five blades 1 intended to be rotatable about an axis of rotation A of the hub. 12. Each blade 1 is connected to the hub 12 at the beginning of blade 2.
    The rotor 11 is characterized by the rotor radius R, that is to say the distance between the axis of rotation A and the blade tip 9 along the blade axis B. The rope c profiles 15 sections of the blade 1 corresponds to the maximum distance between the leading edge 6 and the trailing edge 7 of this blade 1 in a transverse plane substantially perpendicular to the blade axis B. An average rope c is defined as an average value of the rope c on the profiled portion 4. The beginning of the blade 2 is located at a fourth distance equal to 0.17 of the axis of rotation A and the beginning 3 of the profiled portion 4 of the blade 1 is located at a fifth distance equal to 0.2Æ of the axis of rotation A.
    The blade 1 according to the invention has a combination of the laws of variation of its arrow and the ropes of the profiles 15 of the blade 1 in order to reduce the noise emitted by each blade 1 of the rotor 11 during a flight of approach and secondly to improve the aerodynamic performance of each blade 1 in flight of the aircraft 10.
    Furthermore, the blade 1 can also present a combination of the laws of variation of the boom and the ropes of the profiles 15 of the sections of the blade 1 with a twist variation law in order to reduce the noise emitted by each blade 1 of the rotor 11 during an approach flight and secondly to improve the aerodynamic performance of each blade 1 both during a hovering flight and a forward flight of the aircraft 10.
    The laws of variation of the strings, the deflection and the twisting of the profiles of the sections of the blade 1 are represented respectively in FIGS. 4 to 6. FIG. 7 represents the twisting gradient of the blade 1 which is the local derivative of the twisting along the span of the blade 1 of rotor 11 of rotor R.
    The law of variation of the ropes of the profiles 15 of the sections of the blade 1 represented in FIG. 4 comprises on the abscissa the ratio of the position of the profiles 15 of the sections of the blade 1 according to the span of this blade 1 by the rotor radius R. and ordinate the ratio of the rope c profiles 15 sections of the blade 1 by the average rope c.
    The average chord c is defined by a squared weighting of the radius r in each section 15 of the sections of the blade 1 according to the formula
    L (r] being the length of the local chord of a profile of the blade 1 located at a radius r of the axis of rotation A, Ro being the radius of the beginning 3 of the profiled part 4 and Λ the radius of the end of blade 9.
    According to this law of variation of the strings, the rope c of the profiles 15 of the sections of the blade 1 increases between the beginning 3 of the profiled part 4 and a first section S1 situated at a first distance from the axis of rotation A equal to 0.85 R. Beyond the first section S1, the rope decreases to the end of the blade 9. It can be seen that the rope c is less than the average rope c between the beginning of the profiled part of the blade 1 and a fourth section S4 located at a sixth distance from the axis of rotation A equal to 0.6R. In addition, the chord c varies between the beginning 3 of the profiled part 4 and the first section SI of 0.8c to 1.2c which represents a variation of +/- 20% around the average chord c. The rope at the end of the blade is equal to 0.3c.
    Then, the chord of the profiles 15 of the sections of the blade 1 is greater than this average chord c between this fourth section S4 and a fifth section 55 located at a seventh distance from the axis of rotation A between 0.85R and 0.95R. Finally, the chord of the profiles 15 of the sections of the blade 1 is smaller than this average chord c beyond this fifth section 55 and up to the blade tip 9.
    In addition, the chord c decreases along a parabolic curve beyond a sixth section 56 situated at an eighth distance equal to 0.95 R. The end of the blade 1 thus forms a parabolic salmon 8.
    The law of variation of the arrow of the blade 1 according to FIG. 5 defines a triple arrow. The ratio of the position of the profiles of the sections of the blade 1 along the blade axis B by the rotor radius R is on the abscissa and the deflection angle α of these profiles is on the ordinate.
    Thus, the arrow is first directed towards the front of the blade 1 between the beginning 3 of the profiled portion 4 and a second section S2 located at a second distance from the axis of rotation A equal to 0.67 / the leading edge 6 forming a first forward deflection angle ch equal to 4 ° with the blade axis B. Then, the arrow is directed towards the front of the blade 1 between the second section 52 and a third section S3 located at a third distance from the axis of rotation A equal to 0.85R, the leading edge 6 forming a second forward deflection angle a2 equal to 8 ° with the blade axis B. Finally, the arrow is directed towards the rear of the blade 1 between the third section S3 and the blade tip 9, the leading edge 6 forming a third rear deflection angle a3 equal to -23 ° with the blade axis B.
    The connections between the first, second and third boom angles are preferably made by a connecting radius to avoid having sharp angles at each of these connections. These connecting radii are for example of the order of 500mm.
    Moreover, the blade 1 comprises the dihedron 5 at its free end oriented downwards. This dihedron 5 begins at the sixth section 56 and ends at the end of blade 9. This dihedron 5 mainly improves the aerodynamic performance of the blade 1 hovering by reducing the influence of the vortex generated by the previous blade .
    In addition, a twisting law of the profiles 15 can be added to this blade 1 to improve the aerodynamic performance of the blade 1 both during a hovering flight in advance flight. This twisting law of the blade 1 shown in FIG. 6 is a nonlinear law corresponding to a polynomial curve. The ratio of the position of the profiles of the sections of the blade 1 according to the span by the rotor radius R is on the abscissa and the twist angle Θ of these profiles 15 of the sections of the blade 1 is on the ordinate.
    The twisting gradient is shown in FIG. 7 and comprises, on the abscissa, the ratio of the position of the profiles of the sections of the blade 1 according to the span of the blade 1 by the rotor radius R, and to the ordinate the local derivative of the twist of the profile 15.
    First, the twist angle Θ varies slightly between the beginning 3 of the profiled portion 4 and a seventh section 57 located at a ninth distance from the axis of rotation A equal to 0.35 R. The variation of the twisting angle Θ is less than 2 ° between the beginning 3 of the profiled part 4 and the seventh section 57. The twisting angle Θ increases slightly and then decreases according to the span, the twisting gradient being positive at the beginning 3 of the profiled portion 4 and decreasing to be negative at the seventh section 57. The twisting angle Θ then decreases between the seventh section 57 and an eighth section S8 located at a tenth distance from the axis rotation A equal to 0.48 R, the gradient of the kinking descending to a first step equal to -18 ° / R at the eighth section S8. The twisting angle Θ then decreases less between the eighth section S8 and a ninth section S9 situated at an eleventh distance from the axis of rotation A equal to 0.78R, the twisting gradient increasing to a second level equal to 6 ° / R at the ninth section 59. The kinking angle Θ is in particular equal to 0 ° for a profile 15 of the blade 1 located at a distance from the axis of rotation A equal to 0.65R. The twist angle Θ again decreases further between the ninth section 59 and a tenth section S10 situated at a twelfth distance from the axis of rotation A equal to 0.92R, the gradient of the kinking decreasing to a third level equal to -13 ° / Æ at the level of the tenth section S10.
    Finally, the twist angle Θ decreases less between the tenth section S10 and the blade tip 9, the twist gradient increasing to a twisting gradient of -8 ° / R at the blade tip 9.
    Naturally, the present invention is subject to many variations as to its implementation. Although several embodiments have been described, it is well understood that it is not conceivable to exhaustively identify all the possible modes. It is of course conceivable to replace a means described by equivalent means without departing from the scope of the present invention.
    权利要求:
    Claims (11)
    [1" id="c-fr-0001]
    1. blade (1) for rotor (11) aircraft (10) rotating wing intended to be rotated about an axis of rotation (A), said blade (1) extending firstly according to a blade axis (B) between a blade start (2) adapted to be connected to a hub (12) of said rotor (11) and a blade tip (9) located at a free end of said blade (1) and on the other hand along a transverse axis (T) perpendicular to said blade axis (B) between a leading edge (6) and a trailing edge (7), said blade (1) having a profiled part (4) situated between said blade tip (2) and said blade tip (9), said profiled portion (4) being constituted by a succession of aerodynamic profiles (15), each aerodynamic profile (15) being located in a transverse plane substantially perpendicular to said axis blade (B) and delimiting a section of said blade (1), said blade tip (9) being located at a distance equal to a rotor radius R of said axis of rotation (A), a dista a maximum cord between said leading edge (6) and said trailing edge (7) in said transverse plane constituting a rope c for said airfoil (15) of said sections of said blade (1), an average rope c being a value mean of said rope c on said profiled portion (4), a first forward direction being defined from said trailing edge (7) to said leading edge (6) and a second backward direction being defined from said edge driving device (6) towards said trailing edge (7), v characterized in that said blade (1) has a combination of the laws of variation of the ropes and the boom, said boom being the angle between said edge of said etching and said blade axis (B), said rope increasing between the beginning (3) of said profiled portion (4) and a first section SI located at a first distance from said axis of rotation (A) between 0.6R and 0.9Æ , said rope decreasing beyond said first SI section, and said boom being directed forwardly of said blade (1) between said beginning (3) of said profiled portion (4) and a second section S2 located at a second distance from said axis of rotation (A) between 0.5R and O.BR, said leading edge forming a first forward deflection angle ch between 0 ° and 10 ° with said blade axis (B), said boom being directed towards the front of said blade (1) between said second section S2 and a third section S3 located at a third distance from said axis of rotation (A) between 0.6R and 0.95R, said leading edge forming a second forward deflection angle a2 between 1 ° and 15 ° with said blade axis (B) said boom being directed rearwardly of said blade (1) between said third section S3 and said blade tip (9), said leading edge forming a third rear deflection angle 03 between -35 ° and -15 With said blade axis (B).
    [2" id="c-fr-0002]
    2. blade (1) according to claim 1, characterized in that said first forward deflection angle ch is strictly greater than 0 °.
    [3" id="c-fr-0003]
    3. Blade (1) according to any one of claims 1 to 2, characterized in that said first forward deflection angle gm, said second forward deflection angle a2 and said rear rearward angle 03 are constant respectively between said beginning (3) of said profiled portion (4) and said second section S2, between said second section S2 and said third section S3 and between said third section S3 and said blade tip (9).
    [4" id="c-fr-0004]
    4. blade (1) according to any one of claims 1 to 3, characterized in that said first forward deflection angle ch is equal to 4 °, said second forward deflection angle a2 is equal to 8 ° and said third angle back arrow a3 is equal to -23 °.
    [5" id="c-fr-0005]
    5. blade (1) according to any one of claims 1 to 4, characterized in that said blade start (2) is located at a fourth distance between 0.05 R and 0.3fi said axis of rotation (A) and said beginning (3) of the profiled portion (4) is located at a fifth distance between 0.1Æ and 0.4R of said axis of rotation (A), said fifth distance being greater than or equal to said fourth distance, said rope at said beginning of blade (2) being between 0.4c and 0.9c.
    [6" id="c-fr-0006]
    6. blade (1) according to any one of claims 1 to 5, characterized in that said rope varies around the said average rope c of +/- 40% between said beginning (3) of the profiled portion (4) and said first section SI.
    [7" id="c-fr-0007]
    7. blade (1) according to any one of claims 1 to 6, characterized in that said rope decreases non-linearly beyond a sixth section 56 located at an eighth distance from said axis of rotation (A) between 0.9Æ and 0.95R until said blade tip (9).
    [8" id="c-fr-0008]
    8. blade (1) according to claim 7, characterized in that said rope decreases parabolically beyond said sixth section 56.
    [9" id="c-fr-0009]
    9. blade (1) according to any one of claims 1 to 8, characterized in that said blade (1) comprises a dihedron at said blade tip (9).
    [10" id="c-fr-0010]
    10. blade (1) according to any one of claims 1 to 9, characterized in that said average rope c is defined by a square weighting of the radius r of each profile (15) of said sections of said blade (1) according to the formula

    L (r) being the length of said local chord of a profile (15) of said blade 1, said local profile (15) being located at a radius r of the axis of rotation A, Ro being the radius of said beginning ( 3) of said profiled portion (4) and R the radius of said blade tip (9).
    [11" id="c-fr-0011]
    11. Rotor (11) for a rotary wing aircraft (10) having at least two blades (1) according to any one of claims 1 to 10.
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    同族专利:
    公开号 | 公开日
    KR20170074174A|2017-06-29|
    JP6377709B2|2018-08-22|
    CA2951069C|2019-10-29|
    FR3045565B1|2018-07-27|
    EP3184426B1|2019-08-28|
    JP2017141014A|2017-08-17|
    US10414490B2|2019-09-17|
    US20170174339A1|2017-06-22|
    EP3184426A1|2017-06-28|
    CN106892104A|2017-06-27|
    KR101898552B1|2018-09-13|
    CA2951069A1|2017-02-07|
    CN106892104B|2020-02-11|
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    US8128376B2|2005-08-15|2012-03-06|Abe Karem|High performance outboard section for rotor blades|
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    FR2969120B1|2010-12-15|2013-08-30|Eurocopter France|IMPROVED BLADE FOR ANTI-TORQUE HELICOPTER DEVICE|
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    CN104149967B|2014-08-07|2015-05-06|西北工业大学|Low-Reynolds-number airfoil profile with cooperative fluidic control, and control method thereof|
    FR3045565B1|2015-12-21|2018-07-27|Airbus Helicopters|AIRCRAFT ROTOR BLADE WITH GEOMETRY ADAPTED FOR ACOUSTIC IMPROVEMENT DURING AN APPROACH FLIGHT AND PERFORMANCE IMPROVEMENT IN FLYING|FR3045565B1|2015-12-21|2018-07-27|Airbus Helicopters|AIRCRAFT ROTOR BLADE WITH GEOMETRY ADAPTED FOR ACOUSTIC IMPROVEMENT DURING AN APPROACH FLIGHT AND PERFORMANCE IMPROVEMENT IN FLYING|
    US11014661B2|2016-10-24|2021-05-25|Sikorsky Aircraft Corporation|Tip jet orifice for aircraft brown out mitigation|
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    法律状态:
    2016-12-22| PLFP| Fee payment|Year of fee payment: 2 |
    2017-06-23| PLSC| Publication of the preliminary search report|Effective date: 20170623 |
    2017-12-21| PLFP| Fee payment|Year of fee payment: 3 |
    2019-12-19| PLFP| Fee payment|Year of fee payment: 5 |
    2020-12-23| PLFP| Fee payment|Year of fee payment: 6 |
    2021-12-24| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1502662A|FR3045565B1|2015-12-21|2015-12-21|AIRCRAFT ROTOR BLADE WITH GEOMETRY ADAPTED FOR ACOUSTIC IMPROVEMENT DURING AN APPROACH FLIGHT AND PERFORMANCE IMPROVEMENT IN FLYING|
    FR1502662|2015-12-21|FR1502662A| FR3045565B1|2015-12-21|2015-12-21|AIRCRAFT ROTOR BLADE WITH GEOMETRY ADAPTED FOR ACOUSTIC IMPROVEMENT DURING AN APPROACH FLIGHT AND PERFORMANCE IMPROVEMENT IN FLYING|
    EP16202350.1A| EP3184426B1|2015-12-21|2016-12-06|An aircraft rotor blade of shape adapted for acoustic improvement during an approach flight and for improving performance in forward flight|
    US15/370,403| US10414490B2|2015-12-21|2016-12-06|Aircraft rotor blade of shape adapted for acoustic improvement during an approach flight and for improving performance in forward flight|
    CA2951069A| CA2951069C|2015-12-21|2016-12-07|Aircraft rotor blade with adapted geometry to improve acoustics during approach flight and the improvements in performance in forward flight|
    JP2016238637A| JP6377709B2|2015-12-21|2016-12-08|Shaped aircraft rotor blades adapted for acoustic improvement during close flight and to improve performance during forward flight|
    KR1020160168852A| KR101898552B1|2015-12-21|2016-12-12|An aircraft rotor blade of shape adapted for acoustic improvement during an approach flight and for improving performance in forward flight|
    CN201611178763.0A| CN106892104B|2015-12-21|2016-12-19|Aircraft rotor blade with a configuration suitable for acoustic improvement during approach flight and performance improvement in forward flight|
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