Axial Fan Blade Tip Appendage for Higher Airflow With Less Drag

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Solution Overview

Problem

Large-dimension industrial axial fans face challenges in increasing airflow rate without significantly increasing aerodynamic drag, which is exacerbated by manufacturing limitations and the complexity and cost of modifying pitch angles, especially in plants with multiple fans.

Innovation Solution

The introduction of a tip lift appendage on the blade, which extends beyond the trailing edge, allows for adjustable pitch angles to enhance lift without substantial drag, using an adjustment device to optimize efficiency and airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the blade surface is increased to improve efficiency, then the lift increases, but the aerodynamic drag also increases significantly

Engineering Contradiction:

ImproveefficiencyVSAvoidaerodynamic drag

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The blade is segmented into a main airfoil body and a separate tip lift appendage. The appendage is attached only to the tip portion of the airfoil, extending beyond the trailing edge. This segmentation allows the lift-enhancing function to be localized to the blade tip, where it can increase overall blade surface area and lift without significantly increasing the drag of the main blade structure.

Inventive Principle:

Principle #1Segmentation

2Productivity

If the pitch angle is increased to improve airflow rate, then the lift increases, but the aerodynamic drag increases and power absorption increases

Engineering Contradiction:

Improveairflow rateVSAvoidaerodynamic drag

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

Instead of increasing the pitch angle of the entire blade, the invention adds a third-dimensional element at the blade tip - the appendage extending beyond the trailing edge. This dimensional addition effectively increases the blade's aerodynamic surface area and lift-generating capacity without requiring a change in the pitch angle of the main blade, thereby avoiding the associated drag penalty.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If molding techniques are used to optimize blade shape for large-dimension fans, then the lift-to-drag ratio improves, but the manufacturing cost becomes excessively high

Engineering Contradiction:

Improvelift-to-drag ratioVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

4Productivity

If the fan is redesigned to increase airflow rate, then the flow rate requirement is met, but the costs of redesign and replacement are substantial

Engineering Contradiction:

Improveflow rateVSAvoidredesign cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The tip lift appendage is designed as a pre-fabricated component that can be attached to existing blades. This preliminary preparation of the appendage component allows for easy installation on existing fan blades without requiring a complete redesign or replacement of the fan, thereby significantly reducing the costs associated with increasing airflow rate.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The tip lift appendage increases airflow efficiency by balancing lift and drag, enabling easy configuration adjustments and reducing operational costs through adaptable pitch angles.

Implementation Method 1

The blades are provided with an airfoil, so that, on account of the rotation impressed by the motor, a pressure difference is generated between extrados and intrados of the blades. In turn, the pressure difference produces an air flow in a direction substantially parallel to the axis of the hub.

Methodology Applied

Scientific EffectLift: Aerofoil

Implementation Method 2

a pressure difference is generated between extrados and intrados of the blades. In turn, the pressure difference produces an air flow

Methodology Applied

Scientific EffectPressure difference: Pressure Gradient

Implementation Method 3

Practically, the tip lift appendage is configured to extend, limitedly to the tip portion, the lift surface of the airfoil and provide an additional flow rate contribution.

Methodology Applied

Scientific EffectSurface area effect on lift: Aerofoil

Data Source

PatentUS12577958B2Blade for an industrial axial fan with tip lift appendage

Publication Date: 2026.03.17 COFIMCO

AI summary

A blade for an industrial axial fan includes an extruded or pultruded airfoil, having a leading edge, a trailing edge, a tip portion, an intrados and an extrados. A tip lift appendage is applied to the tip portion of the airfoil and projects beyond the trailing edge so as to form an extension of the airfoil in a downstream direction.