WO2024097669A1 - Hélice avec surface de réduction de bruit et dentelures de bord - Google Patents

Hélice avec surface de réduction de bruit et dentelures de bord Download PDF

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Publication number
WO2024097669A1
WO2024097669A1 PCT/US2023/078217 US2023078217W WO2024097669A1 WO 2024097669 A1 WO2024097669 A1 WO 2024097669A1 US 2023078217 W US2023078217 W US 2023078217W WO 2024097669 A1 WO2024097669 A1 WO 2024097669A1
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WIPO (PCT)
Prior art keywords
serrations
propeller
pattern
propeller blade
blade
Prior art date
Application number
PCT/US2023/078217
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English (en)
Inventor
Grace Xiang GU
Stanley Wang
Zixiao Wei
Sean FARRIS
Stara SHINSATO
Ningping WANG
Naga CHENNURI
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The Regents Of The University Of California
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Publication of WO2024097669A1 publication Critical patent/WO2024097669A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/321—Rotors specially for elastic fluids for axial flow pumps for axial flow compressors
    • F04D29/324—Blades
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63H—MARINE PROPULSION OR STEERING
    • B63H1/00—Propulsive elements directly acting on water
    • B63H1/02—Propulsive elements directly acting on water of rotary type
    • B63H1/12—Propulsive elements directly acting on water of rotary type with rotation axis substantially in propulsive direction
    • B63H1/14—Propellers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C11/00—Propellers, e.g. of ducted type; Features common to propellers and rotors for rotorcraft
    • B64C11/16—Blades
    • B64C11/18—Aerodynamic features
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/38—Blades
    • F04D29/384—Blades characterised by form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/20—Rotors
    • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05D2240/303—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the leading edge of a rotor blade
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/20—Rotors
    • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05D2240/304—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the trailing edge of a rotor blade
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/10—Two-dimensional
    • F05D2250/18—Two-dimensional patterned
    • F05D2250/184—Two-dimensional patterned sinusoidal

Definitions

  • the technology of this disclosure pertains generally to propellers, and more particularly to a noise-reducing and efficiency increasing propeller blade configuration.
  • leading edge serrated airfoils tend to facilitate a span-wise turbulence distortion, which keeps the far-field , high-speed airstream attached to the surface of an airfoil. This interaction reduces flow separation and the corresponding energy dissipation that would otherwise be caused by increased noise generation.
  • leading and trailing edge serration configurations inspired by wings of owls have been explored to reduce turbulence-associated broadband noise of propellers.
  • owl-inspired serration designs such designs mainly consist of two-dimensional configurations. These propellers are designed with modifications to the leading or trailing edge without altering the shape of the propeller along the rest of the chord.
  • these serrations comprise three- dimensional sinusoidal-shaped features applied to the surface topology of the propeller’s blades, which alters the airflow characteristics and ameliorates both aeroacoustic and aerodynamic performance metrics. Extensive empirical results have shown that this propeller configuration is able to improve the power efficiency and reduce the associated noise emissions when compared to conventional propeller designs.
  • FIG. 1 A is an orthographic perspective view of a serrated propeller blade.
  • FIG. 1 B is an enlarged section of the serrated propeller blade of FIG. 1A on the trailing edge, which shows that a sinusoidal pattern extends across the propeller with a sinusoidal amplitude (A) and a wavelength (X).
  • FIG. 1 C is a planform view of a cicada wing that extends from wing root to wing tip.
  • FIG. 1 D is a graph of the digitization measurements of the cicada wing of FIG. 1 C, where the upper edge of the cicada wing appears on the upper curve of the graph as a polynomial fit of the leading edge, and similarly, the trailing edge appears as the lower curve on the graph as a polynomial fit of the trailing edge.
  • FIG. 1 E is a side view of the propeller of FIG. 1 A.
  • FIG. 1 F is a top view of the propeller blade of FIG. 1 A.
  • FIG. 1 G is an enlarged portion of the leading edge of the propeller blade of FIG. 1 F.
  • FIG. 1 H is a side view of the propeller blade of FIG. 1 F.
  • FIG. 2A is a graph of a planform shape using a polynomial fit of a leading edge and a trailing edge for a wingspan length of b, which is a more detailed representation of the cicada wing digitization previously seen and described in FIG. 1 D.
  • FIG. 2B is a graph that shows the planform shape curves of FIG. 2A with additional sinusoidal serrated edges incorporated, which can be used to model a drone propeller that utilizes both three-dimensional surface serrations and a planform with sinusoidal serrated edges.
  • FIG. 3A is a planform view of a prior art propeller most analogous to the 3D-SC propeller disclosed herein.
  • FIG. 3B is a planform view of the 3D-SC serrated propeller prototype that was manufactured using a Polyjet 3D printing on a Stratasys Objet 260 platform.
  • FIG. 4A is a graph of the observed Overall Sound Pressure Level (OASPL) in dB compared between a conventional propeller curve and the 3D- SC curve at a rotational rate of 2000 rotations per minute (RPM), showing the 3D-SC to be significantly quieter.
  • OASPL Overall Sound Pressure Level
  • FIG. 4B is a graph comparing the sound power level (SPL) in dB for the conventional propeller and the 3D-SC propeller, showing that that the 3D- SC propeller is quieter over a broad frequency range of 0-20 kHz at a 2000 RPM test speed.
  • SPL sound power level
  • FIG. 4C is a graph comparing the sound power level (SPL) in dB for the conventional propeller and the 3D-SC propeller, showing that that the 3D- SC propeller is quieter over a broad frequency range of 0-20 kHz at a 5000 RPM test speed.
  • SPL sound power level
  • FIG. 5A is a graph of the 3D-SC surface serration propeller sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leadingedge serration propeller with an amplitude of 2.5 mm and a wavelength of 5 mm.
  • SPL surface serration propeller sound power level
  • FIG. 5B is a graph of the 3D-SC surface serration propeller sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leading- edge serration propeller with an amplitude of 8.0 mm and a wavelength of 5 mm.
  • SPL surface serration propeller sound power level
  • FIG. 5C is a graph of the 3D-SC surface serration propeller sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leadingedge serration propeller with an amplitude of 2.5 mm and a wavelength of 10 mm.
  • SPL surface serration propeller sound power level
  • FIG. 5D is a graph of the 3D-SC surface serration propeller sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leadingedge serration propeller with an amplitude of 6.5 mm and a wavelength of 10 mm.
  • SPL surface serration propeller sound power level
  • FIG. 5E is a graph of the 3D-SC surface serration propeller sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leadingedge serration propeller with an amplitude of 2.0 mm and a wavelength of 15 mm.
  • SPL surface serration propeller sound power level
  • FIG. 5F is a graph of the 3D-SC surface serration propeller sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leadingedge serration propeller with an amplitude of 2.5 mm and a wavelength of 15 mm.
  • SPL surface serration propeller sound power level
  • FIG. 6A is a graph displaying the very similar aerodynamic thrust performance of a conventionally designed propeller and the 3D-SC propeller.
  • FIG. 6B is a graph of propulsive efficiency versus rotational speed in RPM of the conventional propeller and the 3D-SC propeller.
  • FIG. 7A and 7B are streamline plot visualizations of the 3D-SC design in FIG. 7A, and the smooth cicada design in FIG. 7B, both of which are modeled as operating at 2000 RPM.
  • FIG. 7C and FIG. 7D are visualizations that show helicity isosurface contours of the propellers of FIG. 7A and 7B, respectively.
  • FIG. 7E and FIG. 7F are visualizations that show the dipole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 7A and 7B, respectively.
  • FIG. 7G and FIG. 7H are visualizations that show the quadrupole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 7A and 7B, respectively.
  • FIG. 8A and 8B are streamline plot visualizations of the 3D-SC design in FIG. 8A, and the smooth cicada design in FIG. 8B, both of which are modeled as operating at 5000 RPM.
  • FIG. 8C and FIG. 8D are visualizations that show helicity isosurface contours of the propellers of FIG. 8A and 8B, respectively.
  • FIG. 8E and FIG. 8F are visualizations that show the dipole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 8A and 8B, respectively.
  • FIG. 8G and FIG. 8H are visualizations that show the quadrupole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 8A and 8B, respectively.
  • a three-dimensional (3D) surface serration design has been created by lofting two-dimensional airfoils with spatial splines. These splines are created by adding a sinusoidal wave function to the propeller’s leading and trailing edge.
  • FIG. 1 A is an orthographic perspective view 100 of a propeller blade 102.
  • the propeller blade 102 rotates about an axis of rotation 104 in the counter-clockwise rotational direction indicated 106, with a leading edge 108 and a trailing edge 110.
  • FIG. 1 B is an enlarged section 112 of the propeller 102 on the trailing edge 110, which shows that a sinusoidal pattern that extends across the propeller 102 with an amplitude of A (giving rise to a peak to valley depth of 2A) and a wavelength of X.
  • FIG. 1 C is a planform view 114 of a cicada wing 116 that extends from a wing root 118 to wing tip 120.
  • a horizontal reference line 122 connects the wing root 118 to the wing tip 120.
  • FIG. 1 D is a graph 124 of the y versus x measurements of the cicada wing of FIG. 1 C, where the upper edge of the cicada wing 116 appears as a polynomial fit of the leading edge 126. Similarly, the lower, trailing edge 128 appears below.
  • the measured cicada wing 116 points are indicated by small circles on the FIG. 1 D graph 124.
  • the serration feature detailed in FIG. 1 B may be made to extend across the entire surface of the propeller blade 102.
  • the serrations are substantially perpendicular to the horizontal reference line 122.
  • FIG. 1A and FIG. 1 C Refer now to FIG. 1A and FIG. 1 C.
  • the horizontal reference line 122 of FIG. 1 C would be observed to be parallel to a radial line extending from the propeller blade 102 axis 104 of rotation.
  • the three-dimensional surface serration design may be created by lofting two-dimensional airfoils with spatial splines. These splines are created by adding a sinusoidal wave function to the propeller blade 102 on the leading edge 108 and the trailing edge 110. As previously shown in FIG. 1A, these splines may be used as reference lines for lofting, thereby causing the serration feature to extend across to the entire surface of the propeller blade 102.
  • spline is used loosely here, meaning that the spline may be a Gaussian spline fit, or a fit to the 5 th degree polynomial described herein.
  • the geometry of the serrations is driven by a fundamental sinusoidal function.
  • This sinusoid is applied to the guide curves used to generate the propeller in a lofting process, which results in a regular pattern of depressed grooves and raised features along the span of the propeller blade 102.
  • the wavelength (X) of the sinusoid dictates the distance between two adjacent sinusoidal grooves on the propeller, while the amplitude (A) dictates the depth and height of each individual waveform (giving rise to an overall top to bottom depth of 2A).
  • the sharpness of the tips of the projections on the edge of the propeller are quantified by the ratio of amplitude to wavelength (A/X).
  • A/X amplitude to wavelength
  • the edge serration features are more “sharp” and “thin”.
  • the edge serration features are more “blunted” and “rounded.”
  • the aim is to mitigate the aerodynamic performance reduction typically coupled with noise reduction by using an innovative propeller profile.
  • the overall propeller profile is modeled with an emphasis on placement of the maximum chord length at an outward location relative to the span of the propeller blade.
  • Three-dimensional (3D) serrations are added across the entire surface of the propeller with the geometry as described above. These serrations are applied along the spanwise dimension of the propeller and follow a fundamental sinusoidal pattern with a consistent waveform throughout.
  • the resultant geometry comprises a uniform pattern of parallel raised features and grooves along the primary surface of the propeller. At the leading and trailing edges of the propeller, these features terminate to create three-dimensional pointed protrusions-effectively adding an advanced edge serration.
  • These projections represent the local extrema points of the fundamental sinusoidal used, and are of uniform sharpness and angle throughout as dictated by the ratio A/X.
  • the planform is defined by first obtaining discretized points for the leading and trailing edge obtained from point-tracking of a reference cicada wing image as previously described in FIG. 1 C and FIG. 1 D. These points are subsequently interpolated into two fifth-order polynomial functions, yielding an analytical description of the bio-inspired geometry.
  • FIG. 1 E is a side view of the propeller blade 102 of FIG. 1A.
  • the rake angle of the propeller blade 102 is 20°.
  • FIG. 1 F is a top view 130 of the propeller blade 102 of FIG. 1A, with a length 132 of 76.2 mm, and a width 134 of 22.4 mm.
  • FIG. 1G is an enlarged portion of the propeller blade 102 of FIG. 1 F.
  • the actual serrations used here have a wavelength X of 2 mm, and an amplitude A of 1 mm.
  • FIG. 1 H is a corresponding side view of the propeller blade 102 of FIG. 1 F.
  • the rotor 136 is seen to have a thickness 138 of 5 mm.
  • FIG. 2A shows a graph 200 of the planform shape using a polynomial fit of a leading edge 202 and a trailing edge 204 for a wingspan length of b, which is a more detailed representation of the previously seen and described in FIG. 1 D.
  • Equation 1 may suitably be increased or decreased in size based on the desired span of the propeller.
  • the sinusoidal serrations are then added by superimposing a sinusoidal function onto the polynomial function for the leading edge 202 and trailing edge 204, as seen in the equations below.
  • FIG. 2B shows the results in the curves of FIG. 2A with sinusoidal serrated edges superimposed, which can be used to model a drone propeller that utilizes both three-dimensional surface serrations and a planform with sinusoidal serrated edges.
  • A is the amplitude of the sinusoidal serrations
  • FIG. 3A a planform view of a propeller 300 (Prior Art), is shown.
  • This propeller 300 utilizes a cambered airfoil, the NACA8412, and a constant attack angle of 20 degrees.
  • the chosen propeller span length (b) i.e. , rotor radius
  • FIG. 3B is a planform view of the 3D-SC serrated propeller prototype 302 that was manufactured using a Polyjet 3D printing on a Stratasys Objet 260 platform. Experimental testing results were collected to further validate the design.
  • This 3D-SC propeller prototype 302 was compared to the prior art propeller 300 with a more conventional design previously seen in FIG. 3A.
  • FIG. 4A where comparisons between the experimental outcomes of a 3D-SC propeller and a conventional propeller are depicted.
  • FIG. 4A where a graph 400 of the observed Overall Sound Pressure Level (OASPL) (in dB) compares a conventional propeller 402 curve to the 3D-SC 404 curve at a rotational rate of 2000 rotations per minute (RPM).
  • OASPL Overall Sound Pressure Level
  • FIG. 4B a graph 406 is presented comparing the sound power level (SPL) in dB for the conventional propeller 408 and the 3D-SC 410 propeller. From this graph, it is clear that the 3D-SC propeller is quieter over a broad frequency range of 0-20 kHz at the 2000 RPM test speed.
  • SPL sound power level
  • FIG. 4C a graph 412 is presented comparing the sound power level (SPL) in dB for the conventional propeller 414 and the 3D-SC 416 propeller. From this graph, it is clear that the 3D-SC is again quieter over a broad frequency range of 0-20 kHz at the increased 5000 RPM speed.
  • SPL sound power level
  • FIG. 5A Refer now to FIG. 5A, FIG. 5B, FIG. 5C, FIG. 5D, FIG. 5E, and FIG. 5F.
  • FIG. 5A is a graph 500 of the 3D-SC surface serration propeller 502 sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leading-edge serration propeller 504 with an amplitude of 2.5 mm and a wavelength of 5 mm.
  • SPL sound power level
  • FIG. 5B is a graph 506 of the 3D-SC surface serration propeller 502 sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leading-edge serration propeller 508 with an amplitude of 8.0 mm and a wavelength of 5 mm.
  • SPL sound power level
  • FIG. 5C is a graph 510 of the 3D-SC surface serration propeller 502 sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leading-edge serration propeller 504 with an amplitude of 2.5 mm and a wavelength of 10 mm.
  • SPL sound power level
  • FIG. 5D is a graph 514 of the 3D-SC surface serration propeller 502 sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leading-edge serration propeller 516 with an amplitude of 6.5 mm and a wavelength of 10 mm.
  • SPL sound power level
  • FIG. 5E is a graph 518 of the 3D-SC surface serration propeller 502 sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leading-edge serration propeller 520 with an amplitude of 2.0 mm and a wavelength of 15 mm.
  • SPL sound power level
  • FIG. 5F is a graph 522 of the 3D-SC surface serration propeller 502 sound power level (SPL) in dB over a range of 0-20 kHz, compared to a leading edge serration propeller 524 with an amplitude of 2.5 mm and a wavelength of 15 mm.
  • SPL sound power level
  • FIG. 5A, FIG. 5B, FIG. 50, FIG. 5D, FIG. 5E, and FIG. 5F study set described above of leading-edge serrated prototypes were developed with varied amplitudes and wavelengths, encompassing the baseline prototype of 2.5mmx10mm (found in FIG. 50), to facilitate a comprehensive comparison between the leading-edge serration and the overall lofted 3D-SC serrations (in all plots, depicted as curve 502).
  • FIG. 6A a graph 600 is presented regarding the aerodynamic thrust performance of a conventionally designed (prior art) propeller 602 and the 3D-SC propeller 604.
  • RPM revolutions per minute
  • FIG. 6B shows a graphical comparison of thrust and propulsive efficiency of the same propellers previously shown in FIG. 6A.
  • Propulsive efficiency is defined as a ratio between a rotor system’s net power output and input:
  • Equation 3 Propulsive Efficiency of a Rotor System where: q is the efficiency;
  • T is the thrust
  • u 0 is the freestream airspeed
  • P is the electrical power input.
  • This q efficiency is indicative of the energy consumption rate under a fixed thrust.
  • the 3D-SC model 604 may generate a very slightly lower thrust compared to the conventional design 602 under the same rotational speed, as indicated by the thrust curve shown in FIG. 6A.
  • FIG. 6B which is a graph 606 of propulsive efficiency versus rotational speed in RPM, it is readily apparent that the propulsive efficiency of the conventional propeller 608 is significantly lower than the propulsive efficiency 3D-SC propeller 610. This increased efficiency is apparent across a variety of thrust conditions.
  • the 3D-SC design when subjected to a thrust equivalent of 50 grams (0.49 N) 612, the 3D-SC design demonstrates an efficiency enhancement of approximately 48.14% in comparison to traditional configurations.
  • Such a marked increase in propulsive efficiency implies that the 3D-SC configuration requires a significantly reduced energy input to achieve a thrust output commensurate with that of conventional designs.
  • FIG. 7 and FIG. 8 figure sets below depict a range of salient flow characteristics associated with the 3D-SC topology.
  • FIG. 7A and 7B are streamline plot visualizations of the 3D-SC design in FIG. 7A, and the smooth cicada design in FIG. 7B, both of which are operating at 2000 RPM.
  • FIG. 7C and FIG. 7D are visualizations that show helicity isosurface contours of the propellers of FIG. 7A and 7B, respectively.
  • the vorticity of the smooth cicada design in FIG. 7D is greatly improved as viewed in the 3D-SC design of FIG. 7C.
  • FIG. 7E and FIG. 7F are visualizations that show the dipole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 7A and 7B, respectively.
  • Such coherent vortex structures emerging from the transition from smooth propeller to serrated propeller are instrumental in diminishing harmonic sound pressure fluctuations and curtailing the magnitude of dipole pressure sources, as shown by the comparison of FIG. 7E and FIG. 7F.
  • the accentuated streamwise vorticity (shown in FIG. 7C and FIG. 7D) preserves the flow's momentum, thereby postponing its fragmentation into diminutive eddies, a process governed by the energy cascade principle.
  • FIG. 7G and FIG. 7H are visualizations that show the quadrupole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 7A and 7B, respectively.
  • Pascals Pascals
  • FIG. 8A and 8B are streamline plot visualizations of the 3D-SC design in FIG. 8A, and the smooth cicada design in FIG. 8B, both of which are operating at 5000 RPM.
  • FIG. 8C and FIG. 8D are visualizations that show helicity isosurface contours of the propellers of FIG. 8A and 8B, respectively.
  • the vorticity of the smooth cicada design in FIG. 8D is greatly improved as viewed in the 3D-SC design of FIG. 8C.
  • Such visual comparisons underscore that the three-dimensional surface serrations play a pivotal role in boosting surface vorticity and stimulating spanwise flow motion.
  • FIG. 8E and FIG. 8F are visualizations that show the dipole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 8A and 8B, respectively.
  • Such coherent vortex structures emerging from the transition from smooth propeller to serrated propeller are instrumental in diminishing harmonic sound pressure fluctuations and curtailing the magnitude of dipole pressure sources, as shown by the comparison of FIG. 8E and FIG. 8F.
  • the accentuated streamwise vorticity (shown in FIG. 8C and FIG. 8D) preserves the flow's momentum, thereby postponing its fragmentation into diminutive eddies, a process governed by the energy cascade principle.
  • FIG. 8G and FIG. 8H are visualizations that show the quadrupole pressures in Pascals (Pa) arising from the operation of the propellers of FIG. 8A and 8B, respectively.
  • Pascals Pascals
  • the 3D-SC propeller design presents a novel three-dimensional serration topology with geometric characteristics dominating the entire propeller surface. Distinctive from leading-edge or trailing-edge serration, the new design incorporates high design flexibility that facilitates both spanwise and chordwise optimization without diminishing the integrity of the cross-sectional airfoil. Owing to the extra design freedom, the new design is not only quieter than traditional serrations but also more advanced in aerodynamic performance in the sense that it consumes less power to produce equivalent thrust when compared to conventional designs.
  • the innovative 3D-SC propeller configuration is conducive to producing a structured vortex field over the blade surface. Reiterating, this unique vortex architecture serves to suppress the dipole and quadrupole sound pressure sources while mitigating the high energy dissipation rate caused by energy cascade, ultimately serving to improve the propulsive efficiency of a propeller.
  • the three-dimensional serration embraces a high potential for parametric improvement. Thanks to the additional degree of freedom for design, parametric optimization is promising for extra enhancement.
  • machine-learning-based modification successfully improved the performance of an optimized propeller compared to its baseline counterparts in terms of propulsive efficiency and Overall Sound Pressure Level (OASPL).
  • the propeller design disclosed herein is both aeroacousticly and aerodynamically advanced, the potential application scenario is comprehensive.
  • UAM Urban Air Mobility
  • FAA Federal Aviation Administration
  • reductions in noise emission can enable drones to become more successful in markets such as urban delivery, where current efforts have been substantially encumbered by noise-related problems.
  • drones are widely used in daily life for entertainment, such as in aerial cinematography. This trend has been dramatically increasing in recent years. Therefore, the quiet propeller design helps reduce noise pollution and keeps a healthy residential environment.
  • the applications of this aeroacoustic innovation extend even beyond the drone industry. Reductions in noise emission and fluid dynamic improvements can potentially be found in the fields of green energy and hydrodynamics, with applications in wind turbine design and quiet Unmanned Underwater Vehicle (UUV) operation.
  • UUV Unmanned Underwater Vehicle
  • Additional 3D-SC applications could include: an airplane propeller, a drone propeller, a gaseous pump component, a liquid pump component, a helicopter, a propeller designed for water operation, a wind turbine, and a tidal water turbine.
  • the propeller could be based upon curve fitting of owl wings to form an owl-equivalent 3D-SC propeller blade, otherwise termed a three-dimensional serrated owl (3D-SO) propeller.
  • a noise-reducing propeller blade apparatus comprising: a propeller blade having a surface, a leading edge, and a trailing edge; a sinusoidal pattern of depressed grooves and raised ribs spanning the surface of the propeller blade; and edge serration features along the leading edge and the trailing edge.
  • a noise-reducing propeller blade apparatus comprising: a propeller blade having a surface, a leading edge, and a trailing edge; a sinusoidal pattern of depressed grooves and raised ribs spanning the surface of the propeller blade; and edge serration features along the leading edge and the trailing edge.
  • a noise-reducing propeller blade apparatus comprising: a propeller blade having a surface, a leading edge, and a trailing edge; wherein the blade comprises a horizontal reference line that rotates about an axis of rotation of the blade; a pattern of serrations spanning at least a portion of the surface of the propeller blade; and a pattern of edge serration features disposed along at least a portion of the leading edge and at least a portion of the trailing edge of the propeller blade.
  • the pattern of serrations on the blade surface are within an angle a of perpendicular to the horizontal reference line when viewed along the axis of rotation of the blade; wherein the angle a is selected from a group ranges of of angles consisting of: 0-0.5°, 0.5-1.0°, 1.0-3.0°, 3.0-5.0 0 , 5-10°, 10-15°, 15- 20°, and 20-30°.
  • sinusoidal pattern of serrations comprises: depressed grooves and raised ribs spanning at least a portion of the surface of the propeller blade.
  • propeller blade is used in an application selected from a group of applications consisting of: an airplane propeller, a drone propeller, a helicopter, a propeller designed for water operation, a wind turbine, and a tidal water turbine.
  • a noise-reducing and efficiency increasing propeller blade apparatus comprising: a propeller blade having a surface, a leading edge, and a trailing edge; wherein the blade comprises a horizontal reference line that rotates about an axis of rotation of the blade; a pattern of serrations spanning the surface of the propeller blade; and a pattern of edge serration features disposed the leading edge and the trailing edge of the propeller blade; wherein the pattern of serrations on the blade surface are within an angle a of perpendicular to the horizontal reference line when viewed along the axis of rotation of the blade; wherein the angle a is within a range of: 0-5.0°; wherein the pattern of serrations that span the surface of the propeller blade are substantially spatially continuous with the pattern of edge serration features disposed along the leading edge and the trailing edge of the propeller blade; wherein a depth of each individual serration in the pattern of serrations is defined by sinusoidal amplitude (A); and wherein a distance between adjacent serrations in the
  • Phrasing constructs such as “A, B and/or C”, within the present disclosure describe where either A, B, or C can be present, or any combination of items A, B and C.
  • references in this disclosure referring to “an embodiment”, “at least one embodiment” or similar embodiment wording indicates that a particular feature, structure, or characteristic described in connection with a described embodiment is included in at least one embodiment of the present disclosure. Thus, these various embodiment phrases are not necessarily all referring to the same embodiment, or to a specific embodiment which differs from all the other embodiments being described.
  • the embodiment phrasing should be construed to mean that the particular features, structures, or characteristics of a given embodiment may be combined in any suitable manner in one or more embodiments of the disclosed apparatus, system, or method.
  • set refers to a collection of one or more objects.
  • a set of objects can include a single object or multiple objects.
  • Relational terms such as first and second, top and bottom, upper and lower, left and right, and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
  • the terms can refer to a range of variation of less than or equal to ⁇ 10% of that numerical value, such as less than or equal to ⁇ 5%, less than or equal to ⁇ 4%, less than or equal to ⁇ 3%, less than or equal to ⁇ 2%, less than or equal to ⁇ 1 %, less than or equal to ⁇ 0.5%, less than or equal to ⁇ 0.1 %, or less than or equal to ⁇ 0.05%.
  • substantially aligned can refer to a range of angular variation of less than or equal to ⁇ 10°, such as less than or equal to ⁇ 5°, less than or equal to ⁇ 4°, less than or equal to ⁇ 3°, less than or equal to ⁇ 2°, less than or equal to ⁇ 1 °, less than or equal to ⁇ 0.5°, less than or equal to ⁇ 0.1 °, or less than or equal to ⁇ 0.05°.
  • Coupled as used herein is defined as connected, although not necessarily directly and not necessarily mechanically.
  • a device or structure that is “configured” in a certain way is configured in at least that way, but may also be configured in ways that are not listed.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Ocean & Marine Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

Une hélice de réduction de bruit avec des dentelures tridimensionnelles (3D) et une forme plane d'aile de cigale modifie les caractéristiques d'écoulement d'air d'hélice et améliore à la fois les performances aéro-acoustiques et aérodynamiques. La configuration d'hélice augmente l'efficacité de puissance, et réduit les émissions de bruit associées par rapport aux conceptions d'hélice classiques. Dans un mode de réalisation, l'efficacité de l'hélice s'avère augmenter de 48,14 %. Une telle hélice peut être utilisée dans des drones pour des performances de furtivité et une durée de vie de vol améliorées.
PCT/US2023/078217 2022-11-01 2023-10-30 Hélice avec surface de réduction de bruit et dentelures de bord WO2024097669A1 (fr)

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US202263421210P 2022-11-01 2022-11-01
US63/421,210 2022-11-01

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WO2024097669A1 true WO2024097669A1 (fr) 2024-05-10

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB189513789A (en) * 1895-07-19 1896-05-23 John Rochford Improvements in Screw Propellers.
US20130164488A1 (en) * 2011-12-22 2013-06-27 General Electric Company Airfoils for wake desensitization and method for fabricating same
US20160177968A1 (en) * 2014-12-17 2016-06-23 Ebm-Papst Mulfingen Gmbh & Co. Kg Blade
US20200173458A1 (en) * 2018-10-29 2020-06-04 Dri-Eaz Products, Inc. Contoured fan blades and associated systems and methods

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB189513789A (en) * 1895-07-19 1896-05-23 John Rochford Improvements in Screw Propellers.
US20130164488A1 (en) * 2011-12-22 2013-06-27 General Electric Company Airfoils for wake desensitization and method for fabricating same
US20160177968A1 (en) * 2014-12-17 2016-06-23 Ebm-Papst Mulfingen Gmbh & Co. Kg Blade
US20200173458A1 (en) * 2018-10-29 2020-06-04 Dri-Eaz Products, Inc. Contoured fan blades and associated systems and methods

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