NOISE REDUCING IMPELLER VANE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 63/500,914, filed on May 9, 2023, which is hereby incorporated by reference in its entirety for all purposes.

BACKGROUND OF THE INVENTION

Field of the Invention

The field of the invention relates to fluid movement devices, specifically impellers used in pumps, blowers, propulsion systems, fans, turbines, vents, wind turbines, or other fluid handling equipment.

• • The invention is directed towards an improvement in the surface geometry of impeller vanes that reduces the noise generated during operation.
  • In particular, this novel folded surface geometry of impeller vanes aims to address the issue of excessive noise production in higher RPM applications, which can be a concern in various industrial, commercial, and residential applications where quiet operation is desirable.
  • Furthermore, the folded surface geometry suppresses pressure oscillations over a large spectrum of RPMs, making the configuration ideal for variable RPM applications such as impeller-based propulsion systems in multirotor aerial vehicles.

Description of the Related Art

Summary of the Problem being Solved: As the RPM of an impeller increases, pressure increases on the leadings surface of a vane and decreases on the trailing surface of the impeller vane. Once the pressure imbalance reaches a threshold, it will trigger a pressure oscillation that presents itself as noise shockwaves or cavitation. These oscillations ricochet across vane surfaces and in addition to unpleasant noise, they affect performance. The oscillations tend to be more prominent at certain RPMs zones, which can be a challenge for variable RPM applications such as for multirotor drone propulsion systems.

Increasing Vane Number Approach: Existing impeller designs primarily address this oscillation issue by increasing the number of vanes to decrease the pressure imbalance between vane surfaces. This approach both increases the rotating mass and the additional vane surfaces increase the friction in the flow path.

Asymmetric Vane Distribution Approach: Other impellers seek to minimize the overall noise by addressing resonance. This is accomplished by varying the distance between each vane and the geometry of each vane. The objective of this method is to prevent the individual oscillation frequencies from overlapping to produce resonance. Addressing resonance though does not address the underlying oscillation shockwave issues.

Airfoil Vane Profile Approach: Many vanes utilize a three-dimensional profile in an airfoil configuration. The issue with this design is that it adds weight, rotating mass, and reduces the flow path volume. In contrast, the folded surface configuration enables the use of thin vane walls.

Distinguishing Existing Designs

JP4400686B2 (Publication Date: 2010 Jan. 6) “Propeller fan” discloses a propeller fan with a corrugated trailing edge. This is distinguished from the present invention because 1) it is only limited to the trailing edge, 2) the trailing edge is rounded, not folded to an edge, and 3) the propeller fan is configured for axial flow and doesn't involve the pressure relationship between a leading and trailing surface of an impeller vane.

• • JP4973249B2 (Publication Date: 2012 Jul. 11) “Multi-wing fan” discloses a crossflow fan with notched trailing edges. This is distinguished from the present invention because 1) it is only limited to the trailing edge, 2) the trailing edge is notched, not folded to an edge, and 3) the fan is configured for a cross flow fan which doesn't involve the pressure relationship between a leading and trailing surface of an impeller vane.
  • KR101483340B1 (Publication Date: 2015 Jan. 15) “Fan” discloses a fan design that aims to minimize airflow noise by preventing air flow separation on the blade's negative pressure surface. The negative pressure surface features multiple projections, including one for guiding air flow and another with a different size. These projections create turbulence to increase kinetic energy and reduce flow separation. This is distinguished from the present invention because 1) the projections are rounded, not folded to an edge, 2) they are limited to the negative pressure surface, and 3) the propeller fan is configured for axial flow and doesn't involve the pressure relationship between a leading and trailing surface of an impeller vane.

SUMMARY OF THE INVENTION

Objects and Advantages

The objective and advantage of the invention is to reduce noise, especially high pitch frequencies, due to pressure oscillations between the leading and trailing surfaces of an impeller vane during higher RPM operation. The sharp edges of the vane surfaces act as a shock absorbing surface by deflecting and absorbing shock waves from internal oscillations produced at higher RPMs.

• • Extending the fold from the leading edge to the trailing edge of the vane provides an advantage in variable RPM applications, such as with impeller based multi-rotor aerial vehicle propulsion systems. This is because the optimal impeller geometry changes depending on the RPM, air pressure, temperature, humidity, and composition of the flow medium. As a result, the internal oscillation zones change locations depending on the RPM. Fully extending the fold profile accommodates these shifts.

Where the normal operational range is defined, the fold can be tapered from leading edge to trailing edge to reduce weight and increase efficiency by decreasing the boundary layer surface area.

Brief Description of the Invention

The noise suppressing Impeller Vane Comprises either one Fold or a plurality of Folds extruded along a Fold Path. Where there is a plurality of Folds, they are either interconnected at a Hinge or by a separator.

• • A Fold comprises a Hinge and two Limbs. The Hinge is the point where both limbs intersect. The Limbs intersect at the Hinge. The angle distance between each Limb is the Interlimb Angle. The Interlimb Angle closest to the Hinge should be less than 45 degrees.
  • The length of the limbs define the amplitude of a Fold. The limbs can be symmetrical or asymmetrical. Each Limb can come in different curvatures such as Angular, which is a Limb Angle with no curvature; or Cuspate, which is a Limb Angle with a slope toward the hinge axis; or Rounded, which is a Limb Angle that slopes away from the hinge axis.
  • The Fold Path is the extrusion path of the Fold geometry along the curvature from the leading edge to the trailing edge of the impeller vane. The optimal Fold Path is in conformity with the flow path. The amplitude of the Fold Path can be tapered in either direction from the leading edge to the trailing edge of the vane.
  • The Fold geometry can be on both the leading and trailing surfaces of the vane. The Fold can be on either the leading or trailing surface of the vane. The Impeller Vane can comprise one fold or a plurality of folds. Where a plurality of Folds define a vane surface, each Fold can interconnect at a hinge or be connected by a separator.
  • A plurality of Noise suppressing Impeller Vanes as described above and in the accompanying drawings can be integrated into an impeller assembly as shown in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows fold types of the limbs

FIG. 2 shows fold types of the limbs

FIG. 3 shows a 2D view of an Angular Symmetrical fold.

FIG. 4 shows an extruded 3D view of an Angular Symmetrical fold.

FIG. 5 shows a 2D view of stacked Angular Symmetrical folds.

FIG. 6 shows an extruded 3D view of stacked Angular Symmetrical folds.

FIG. 7 shows an extruded 3D view of stacked Rounded Symmetrical folds.

FIG. 8 shows an extruded 3D view of stacked Angular Symmetrical folds along a curved path of the fold line.

FIG. 9 shows LARGE IMPELLER—TOP ANGLED VIEW WITHOUT TOP

FIG. 10 shows LARGE IMPELLER—TOP ANGLED VIEW WITH TOP

FIG. 11 shows LARGE IMPELLER—SIDE VIEW

FIG. 12 shows LARGE IMPELLER—SIDE CROSS-SECTIONAL VIEW

FIG. 13 shows Impeller Non-Tapered Top View

FIG. 14 shows Impeller Tapered Top View

FIG. 15 shows Impeller Non-Tapered Top View

FIG. 16 shows Impeller Non-Tapered Side View

FIG. 17 shows Impeller Tapered from Leading Edge to Trailing Edge

FIG. 18 shows Impeller Tapered from Leading Edge to Trailing Edge

FIG. 19 shows Impeller Tapered from Leading Edge to Trailing Edge Top Angle View

DETAILED DESCRIPTION

Impeller Vane Design

The impeller vane, a fundamental component of the present invention, includes two limbs (101, 102) that intersect at a hinge (103). This hinge maintains a interlimb angle of less than 45 degrees, optimizing the vane's aerodynamic properties and noise reduction capabilities. The limbs and hinge are extruded along a fold path (104), forming a unique three-dimensional vane. This vane features a leading edge (105) and a trailing edge (106), where one limb forms the top edge and the other limb forms the bottom edge of the impeller vane.

Multi-layered Impeller Structure

Multiple impeller vanes (100), as described in claim 1, can be stacked one atop another (claim 2) to create a multi-layered structure. This configuration enhances the impeller's capacity to handle varying fluid volumes and pressures, making it suitable for diverse applications ranging from residential fans to industrial turbines.

Tapered Vane Design

In some embodiments (claim 3), the limbs (101, 102) of the vane are tapered in height from the leading edge (105) to the trailing edge (106). This tapering reduces the weight of the vane and optimizes fluid dynamics, contributing to improved flow volume and efficiency.

Geometric Variations of the Vanes

Each Limb can come in different curvatures such as:

• • Angular, which is a Limb Angle with no curvature; or
  • Cuspate, which is a Limb Angle with a slope toward the hinge axis; or
  • Rounded, which is a Limb Angle that slopes away from the hinge axis.

The impeller vanes may also feature various geometric configurations (claim 4), including Angular Symmetrical, Angular Asymmetrical, Cuspate Symmetrical, Cuspate/Angular Asymmetrical, Rounded Symmetrical, Rounded/Angular Asymmetrical, and Cuspate/Rounded Asymmetrical.

• • These configurations allow for customized performance characteristics to meet specific application needs, enhancing the versatility of the impeller design.

Impeller Assembly

The impeller assembly (claim 5) comprises multiple vanes arranged around a central hub (107). Each vane is affixed to this hub at its bottom edge, ensuring robust assembly and reliable operation. The impeller is configured to rotate about an axis passing through the central hub (107), facilitating effective fluid movement.

Inlet Integration

In further embodiments (claim 6), the impeller includes a top (109) with an inlet (108) that connects to the top edge of the impeller vanes. This inlet not only provides structural support to the vanes but also facilitates the directed flow of fluid into the impeller. This feature is crucial for high RPM applications requiring structural reinforcement of the vanes.

Summary of Elements

• • 100—Impeller Vane
  • 101, 102—Limbs of the Impeller Vane
  • 103—Hinge
  • 104—Fold Path
  • 105—Leading Edge
  • 106—Trailing Edge
  • 107—Central Hub
  • 108—Inlet
  • 109—Top