Ring Propeller Forward Skew Cavitation Control
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Solution Overview
Problem
Existing permanent magnet-driven ring propellers lack efficiency and effective cavitation control, with known designs not incorporating sufficient skew in their propeller blades, leading to suboptimal performance in water interaction and increased cavitation issues.
Innovation Solution
The ring propeller features propeller blades with a forward skew and S-shaped leading and trailing edge profiles, along with a concave shape at the point of attachment to the ring, which reduces cavitation and enhances hydrodynamic conditions by ensuring the outermost part of the blade meets altered water zones earlier, thereby improving thrust efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If propeller blades are designed without skew or with minimal skew, then the blade structure is simpler and easier to manufacture, but the hydrodynamic efficiency is reduced and cavitation control is poor
Solution Approach 1:
The patent applies parameter changes by introducing forward skew as a geometric parameter modification to the propeller blades. The skew angle is optimized to balance manufacturing complexity with hydrodynamic performance, achieving improved thrust efficiency and cavitation control without excessive manufacturing difficulty
Solution Approach 2:
The patent employs curvature principles through the S-shaped leading and trailing edge profiles. These curved geometries optimize water flow interaction along the blade, improving hydrodynamic efficiency and thrust generation while maintaining reasonable manufacturing feasibility
2Device complexity
If propeller blades have no forward skew, then the blade design is simpler, but the outermost part of the blade does not meet altered water zones earlier, reducing thrust efficiency
Solution Approach 1:
The forward skew introduces a parameter change in the blade geometry, creating an angular offset between the blade root and tip. This parameter modification enables the outermost part of the blade to encounter altered water zones earlier in the rotation cycle, improving thrust efficiency while keeping the design within manageable complexity limits
3Device complexity
If propeller blades lack S-shaped leading and trailing edge profiles, then the blade geometry is simpler, but cavitation conditions are poor and cavitation control is reduced
Solution Approach 1:
The S-shaped leading and trailing edge profiles apply curvature principles to optimize the blade geometry. These curved transitions smooth water flow along the blade surface, preventing abrupt flow separation and reducing pressure differentials that cause cavitation, thereby improving cavitation control
Solution Approach 2:
The patent applies local quality by differentiating the edge profiles at specific locations. The S-shaped curves are concentrated at the leading and trailing edges where flow separation is most critical, providing localized cavitation control without requiring complex modifications throughout the entire blade structure
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 solution results in reduced cavitation and improved hydrodynamic performance, allowing for better control over cavitation onset and extent, leading to enhanced efficiency and control of the thruster's operation.
Implementation Method 1
The combination of the S-shape on the at least one propeller blade's leading edge profile and possibly trailing edge profile and the forward skew of the at least one propeller blade provide better cavitation conditions, i.e. reduced cavitation
Data Source
AI summary
A ring propeller (12) for a thruster (10) is described. The ring propeller (12) comprises a ring (15), a centre element (16) and at least one propeller blade (18) extending between and attached to the centre element (16) and the ring (18) respectively. The at least one propeller blade (18) is provided with forward skew and the leading edge profile (19) of the at least one propeller blade (18) has an S- shape in a cross section perpendicular to the ring propeller's (12) axis of rotation A.