Propeller Blade Leading-Edge Conduits for Cavitation Suppression

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Solution Overview

Problem

Existing methods for manufacturing propeller blades to prevent cavitation, such as using conduits for pressurized air distribution, are complex and costly, with risks of cracks and increased noise, and do not effectively address cavitation erosion and noise reduction.

Innovation Solution

The use of wire-based additive manufacturing (WAAM) to form conduits within the edge part of propeller blades, which are completely enclosed and designed to reduce stress and crack risks, allowing for a strong and cost-effective air distribution system that suppresses cavitation and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional groove and cover welding technique is used to create air distribution conduits, then cavitation protection is achieved, but manufacturing complexity and crack risk increase

Engineering Contradiction:

Improvecavitation protectionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the conduit formation process with the blade manufacturing process itself. The air distribution conduits are formed as integral parts of the blade structure during additive manufacturing, eliminating the need for separate groove machining and cover welding operations. This integration reduces manufacturing complexity while maintaining cavitation protection functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention replaces the mechanical welding process with an additive manufacturing process. Instead of joining a cover to a grooved surface through welding (which creates crack risks), the conduits are directly built into the blade structure layer by layer using wire-based additive manufacturing, eliminating the welding step entirely.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional groove and cover welding technique is used to create air distribution conduits, then cavitation protection is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvecavitation protectionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention merges multiple manufacturing operations into a single additive manufacturing process. The conduits, blade structure, and surface finishing are all created in one integrated process, eliminating the need for separate machining, welding, and surface treatment operations, thereby reducing manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention replaces costly and time-consuming welding operations with additive manufacturing. The wire-based additive process eliminates welding-related costs including labor, equipment, and post-weld machining, while directly producing the required conduit structure with smooth surfaces.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If pressurized air is blown to suppress cavitation, then cavitation erosion is reduced, but noise spectrum increases

Engineering Contradiction:

Improvecavitation erosion resistanceVSAvoidnoise spectrum

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention applies local quality by providing cavitation protection only where needed - at the leading edge and suction side regions most susceptible to cavitation. The air is distributed through strategically positioned holes in these specific areas rather than uniformly across the entire blade, reducing overall noise while maintaining erosion resistance where critical.

Inventive Principle:

Principle #3Local quality

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

This method provides a reliable and cost-effective solution for propeller blades by forming conduits using WAAM, reducing the risk of cracks and effectively managing cavitation and noise, while maintaining structural integrity and efficiency.

Implementation Method 1

The use of wire-based additive manufacturing (WAAM) to form conduits within the edge part of propeller blades

Methodology Applied

Scientific EffectWire-based additive manufacturing (WAAM): 3D Printing

Implementation Method 2

By blowing air, via the supply duct, the conduit, and the holes, the cavitation collapse process is supressed such that cavitation erosion is eliminated or at least reduced

Methodology Applied

Scientific EffectCavitation suppression: Cavitation

Data Source

PatentEP3765229B1A method for manufacturing a propeller blade and a propeller blade

Publication Date: 2022.11.02 KONGSBERG MARITIME SWEDEN AB

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AI summary

The present invention involves a method for manufacturing a blade (1) for a propeller, which blade (1) has a leading edge (2) and a trailing edge, the method comprising the steps of : forming a conduit in the blade (1), making a plurality of holes (7) through which the conduit (6) communicates with the exterior of the blade (1), and providing a blade blank having an edge part receiving surface (4) extending along at least a major part of the leading edge (2) of the blade (1) to be manufactured, wherein forming a conduit (6) comprises building up an edge part (3) onto the edge part receiving surface (4) by a wire-based additive manufacturing process, wherein the additive manufacturing process is adapted to form the conduit (6) at least partly delimited by the edge part (3) and extending along the leading edge (2) of the blade (1) to be manufactured.