40results about How to "Increase stall angle of attack" patented technology

The invention provides a high-efficiency pneumatic layout structure of synergistic jet for a high-altitude propeller and a control method. The high-efficiency pneumatic layout structure is characterized in that a plurality of synergistic jet devices are distributed along propeller blades of the propeller in a spanwise sectional manner; each synergistic jet device comprises an air blowing opening formed in a negative-pressure area of the front edge of the upper surface of the propeller, an air suctioning opening formed in a high-pressure area of the rear edge of the upper surface of the propeller, an airflow pipeline arranged in the paddle and an air pump arranged in the airflow pipeline; the air blowing opening and the air suctioning opening are communicated by the airflow pipeline to form an air-blowing and air-suctioning loop; the air pump is used for driving air suctioning and air spraying to be implemented simultaneously, and by control of the air pump, the air suctioning amount and the air spraying amount are same. The high-efficiency pneumatic layout structure provided by the invention has the advantages that the defects of the traditional propeller layout and the common flow control technology can be made up, and the working efficiency of a propelling system of the high-altitude propeller can be improved.

The invention relates to a wind machine blade airfoil profile capable of controlling flow stalling through standing vortex. An airfoil profile between a shaping starting point and an airfoil profile trailing edge point is modified, thus a concave pit is formed; the shaping starting point and the airfoil profile trailing edge point are connected through a straight line, a concave pit starting point and a concave ending point are connected by virtue of a 1/4 circular arc, and the concave ending point, a first transition point, a second transition point and the airfoil profile trailing edge point are connected through a B spline; and the airfoil profile trailing edge is provided with a Gurney wing flap. According to the invention, the amplitude of the thickness reduction of the upper surface is slowed down to delay the separation of the flow field of the upper airfoil, vortex with a fixed position is formed by the air flow at the concave pit of the upper surface, under the action of the vortex, the separation of the upper surface of the airfoil can be controlled effectively, the irregular falling of separated vortex is avoided, and vortex lifting force is formed at the upper surface of the airfoil, and the stalling of the airfoil is slowed down, so that the stalling incidence of the airfoil is improved.

The invention discloses a novel tailstock type axisymmetric multi-propeller vertical take-off and landing unmanned aerial vehicle. According to the scheme, the novel tailstock type axisymmetric multi-propeller vertical take-off and landing unmanned aerial vehicle comprises an unmanned aerial vehicle body assembly, a head cover assembly, a tail cover assembly, power propeller assemblies and a symmetric wing assembly. The novel tailstock type axisymmetric multi-propeller vertical take-off and landing unmanned aerial vehicle is characterized in that four wings are symmetrically arranged relativeto an unmanned aerial vehicle body in a crossed shape; the power propeller assemblies are correspondingly contained on the four wings; landing gears with shock absorbing devices are used at the lowerparts of the wings; in addition, the head cover assembly and the tail cover assembly are positioned at the two ends of the unmanned aerial vehicle body to reduce the air resistance in the cruise levelflight process. According to the novel tailstock type axisymmetric multi-propeller vertical take-off and landing unmanned aerial vehicle, through differential control of thrust forces of the four propellers in the vertical taking-off and landing or hovering stage, the attitude stabilization of the unmanned aerial vehicle is guaranteed; maneuvering actions, such as rolling and yawing, of the unmanned aerial vehicle are controlled by using trailing edge flaps and ailerons during horizontal flight; and the novel tailstock type axisymmetric multi-propeller vertical take-off and landing unmanned aerial vehicle is especially suitable for being applied to the fields such as carrier-based unmanned aerial vehicles and power line inspection or places with higher requirements on maneuverability, higher speeds and higher safeties.

The invention discloses a novel vortex generator for a wind turbine blade. The vortex generator comprises a fin body, wherein the fin body is of a back fin structure and is symmetrical relative to thelongitudinal cross section of the fin body; the middle longitudinal section is parallel to the flow direction from the leading edge to the trailing edge of the airfoil section of the wind turbine blade, so that the projection area of the fin body in the direction perpendicular to the flowing direction is reduced, and then the shape resistance is reduced. According to the vortex generator, the bionic design is adopted, and the back fin-shaped fin body has relatively small flow resistance. The middle longitudinal section of the back fin is parallel to the flow direction from the leading edge tothe trailing edge of the airfoil section of the wind turbine blade, compared with the prior art, the fin body has the advantages that the projection area is small in the direction perpendicular to the flow direction of the airflow, and the shape resistance is small. When the airflow flows through a groove, a high-energy flow direction vortex can be induced at the groove and at the edge of the groove, so that the energy in the boundary layer can be increased, and the flow separation is inhibited.

The invention discloses a vortex generator, a fan blade and a manufacturing method of the fan blade. The vortex generator comprises at least one pair of grooves formed in the blade, and when airflow flows nearby the groove, high-energy vortex is generated under the function of the groove and flows downstream to disturb airflow on the upper surface of the blade. The vortex generator has the main functions of a current vortex generator, can generate enough vortex disturbance to restrain the flowing separation of the wing section surface, improves the lift-drag ratio of a wing section, improves the pneumatic performance of the blade, reduces the flowing noise of the blade, increases the annual energy output of a wind driven generator, and has the characteristics of being low in cost, high inreliability and the like.

The invention discloses a wind turbine blade capable of improving stalling characteristics based on fractal optimization. The wind turbine blade comprises a blade body positioned at the front part corresponding to a flow incoming direction, and a blade tail edge positioned at the back part corresponding to the flow incoming direction; the blade tail edge is distributed with multiple elastic pieces and fractal holes with fractal structures; the elastic pieces are arranged on suction surface sizes of the fractal holes, and are suffered from a pressure difference effect of a blade pressure surface and a suction furnace to locate in a closing or opening state; and the fractal holes penetrate through the pressure surface and the suction furnace. When the blade incoming flow attack angle dose not reach stalling conditions, as the pressure difference between the blade pressure surface and the suction surface is smaller, and at this time, the elastic pieces are located in the closing state to stop passing of a fluid to stop small-scale turbulence so as to guarantee the blade pneumatic performances; when the blade incoming flow attack angle is increased to reach the stalling conditions, the elastic pieces are located in the opening state due to the effect of pressure difference, and the fluid can pass through the fractal holes to generate small-scale turbulence on the suction furnace to delay separation of a blade surface boundary layer, so that the formation of stalling clusters is delayed, and the purpose of improving the blade stalling characteristics is achieved.

The invention discloses a novel configuration vertical take-off and landing unmanned aerial vehicle belonging to the field of aircraft transmission system and lifting rotor, which comprises a fuselage, a rolling wing system, a vertical tail, a rudder, an aileron, a flap, a detection pod and an take-off and landing actuating cylinder. A rolling wing system is installed in the duct of the wing, andthe rolling wing system is composed of two groups of rolling wings with the same size and opposite rotating directions. The propeller shaft of each roller section is coaxial, and the full vector propulsion system of cycloidal propeller is composed of two sections of each group. The invention discloses a novel configuration vertical take-off and landing unmanned aerial vehicle, which can realize vertical take-off and landing on land-based platform and sea-based platform, and has better flying quality. The invention combines the characteristics of a rotor aircraft and a fixed-wing aircraft, andhas low dependence on take-off and landing site and strong environmental adaptability. At the same time, the whole structure of cycloidal propeller system is light and simple, which has broad militaryand civilian prospects.

Provided are a deformable aircraft leading edge slat and a method for designing the same. An outer section of the leading edge slat is divided at the 20-40% position of the leading edge slat to form a movable section and a fixed section. The movable section is located at the position of the leading edge of the slat, the fixed section is connected with a main wing section through a leading edge slat sliding rail, and the movable section is connected with the fixed section through a hinge, so that the movable section can be deflected through delta degrees around the fixed section. The air flow separation of the leading edge slat can be effectively delayed, the stall attack angle of an aircraft is increased, the flight border is expanded, and the flight safety is improved. The deformable aircraft leading edge slat improves maximum lifting power of the aircraft at a take-off and landing stage, and accordingly the loading capacity of the aircraft is improved. The aerodynamic load limitation borne by the leading edge slat is reduced too, the design difficulty of the leading edge slat is reduced, the deflection angle of the movable section of the leading edge slat is flexibly adjusted according to the specific requirements of different flight phases, and the deformable aircraft leading edge slat has high task adaptive capability.

The invention provides a notch airfoil shape of a stamping parafoil and an optimum design method thereof. The optimum design method comprises the following steps of selecting a high aerodynamic efficiency base airfoil shape, designing a front edge notch and designing front edge notch parameter optimization. Compared with a conventional traditional CLARK-Y notch airfoil shape, the notch airfoil shape has the advantages that the max thickness of the notch airfoil shape is large, the thickness distribution is uniform, the space of a parafoil air chamber is large, and the notch airfoil shape is beneficial to improving of the charge efficiency and the charge rigidity of the parafoil; as the distribution of surface pressure along a thread direction is uniform, the notch airfoil shape is beneficial to arrangement of a parafoil parachute cord, and the pitching driving efficiency is improved; the stalling angle is large, the usable aerodynamic efficiency is high, and the notch airfoil shape has the large stalling angle range for smooth and stable control.

The invention belongs to the technical field of aviation aircrafts, and discloses a high-aspect-ratio high-strength double-layer wing solar unmanned aerial vehicle which comprises a fuselage, wings and an empennage. The wings are transverse through wings, the number of the wings is two, the wings are an upper layer wing and a lower layer wing respectively, the fuselage is arranged between the upper layer wing and the lower layer wing, and the upper layer wing and the lower layer wing are connected through a wingtip supporting wall; solar panels are arranged on the upper surfaces of the upper-layer wing and the lower-layer wing; the empennage is arranged at tail of the fuselage. According to the double-layer united wing layout, on the premise that structural strength limitation is met, the aspect-ratio of the wings is increased to 30 or above, and the double-layer united wing layout has great significance in designing aerodynamic drag reduction of airplanes with large lift coefficients; the wingspan is reduced by 29%, the structural weight is reduced by 22%, and the mission load and the continuous flight time of the aircraft can be remarkably improved; the wings are high in bending resistance and torsion resistance; and satisfactory three-axis stability and control capability can be provided.

The invention discloses an ejection type glider model comprising a glider body, a wing and an empennage mounted on the glider body. The wing is formed by a wing middle section and two wing tips; the two wing tips are respectively fixed on two ends of the wing middle section; an anhedral of each wing tip is 15 to 25 degrees; the back edge of the wing tip on the left end of the wing middle section is 0.8 to 1mm upwardly staggered in a vertical direction; the back edge of the wing tip on the right end of the wing middle section is 0.8 to 1mm downwardly staggered in the vertical direction; the upper surface of the wing forms a step bench along a length direction of the wing; the empennage is formed by a first empennage and a vertical second empennage; the first empennage is installed on the glider body in a way of forming a rotation angle of 2-3 DEG by taking the glider body as a center shaft and the horizontal plane as a starting point; the lower end of the second empennage is fixed on the upper surface of the first empennage; and the side surface of the second empennage is fixed on the glider body. The wing tip staggered installation provides a stable rising path when the ejection glider model vertically rises; and the climbing height can surpass 30 meters.

The invention discloses a step wing used for an ejection type glider model. The step wing comprises a wing body, a stair is formed on the upper surface of the wing body in the length direction and located at the position of 45-55% wing chord length, and the step height of the stair is 4-6% of the wing chord length. The step wing has the advantages that the stair makes the wing into the step wing, the step wing is easy to manufacture, time and labor are saved, airfoil processing and control are precise, and the weight of the wing is reduced. If the step wing is installed on the ejection type glider model, the lift-drag ratio of the wing can be improved, and the stalling attack angle of the wing is increased.

The invention discloses an ejection type glider model, which comprises a glider body, and a wing and an empennage which are installed on the glider body. The wing comprises a middle section and two wing ends that are installed on two ends of the middle section, respectively. A reverse angle on the wing ends is 15-25 degrees, wherein a stepped edge is formed on the upper surface of the wing in the length direction of the wing and located at a point of 45-55% of the length of a wing chord, and the height of the stepped edge is 4-6% of the length of the wing chord. The empennage comprises a first empennage and a second vertical empennage. The first empennage is installed on the glider body at an angel of 2-3 degrees that is formed by rotating the first empennage with the glider body as a central axis and with a horizontal level as a starting point. The lower end of the second empennage is fixed on the upper surface of the first empennage. Both sides of the second empennage are fixed on the glider body. The stepped edge makes the wing become a stepped wing, increasing lift-drag ratios and stalling angles of the wing.