Rotatable Cylinder Blade Assembly for Stable Wind Ship Propulsion
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Solution Overview
Problem
Existing wind-assisted ship propulsion systems face challenges in efficiently adapting to varying wind directions from both starboard and port sides, leading to unstable flow patterns, vibrations, and resonance, which reduce propulsion efficiency.
Innovation Solution
A blade assembly with asymmetrical aerofoil assemblies and a rotatable cylinder between them, designed to stabilize airflow by reducing boundary layer separation and incorporating a flow blocking arrangement to optimize airflow direction based on wind direction, using cylinder rotation and a movable wing element to enhance stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a blade assembly is designed with symmetrical aerofoil assemblies for both starboard and port side wind, then the adaptability to different wind directions is improved, but the flow stability deteriorates due to boundary layer separation and unstable flow patterns
Solution Approach 1:
The patent applies asymmetry by configuring the aerofoil assemblies with different camber directions relative to the central plane. The first aerofoil assembly has camber curving away from the central plane toward the starboard side, while the second aerofoil assembly has camber curving away from the central plane toward the port side. This asymmetric configuration allows each aerofoil assembly to be optimized for its respective wind direction while maintaining overall system adaptability.
Solution Approach 2:
The patent applies local quality by giving different geometric properties to different parts of the blade assembly. Each aerofoil assembly has its camber line specifically configured to curve in a particular direction, creating locally optimized flow characteristics for starboard or port side winds. This local differentiation allows the system to handle various wind directions effectively while maintaining stable flow patterns through carefully designed boundary layer characteristics.
2Stability of the object's composition
If the boundary layer thickness on the inner side of the aerofoil assembly is reduced, then the flow stability is improved by reducing separation risk, but additional complex structures are required
Solution Approach 1:
The patent introduces a flow control element as an intermediary component positioned between the first and second aerofoil assemblies. This element acts as a mediator to manipulate the boundary layer characteristics on the inner side of the aerofoil assemblies, reducing boundary layer thickness and preventing flow separation. The flow control element achieves this through its specific geometric configuration and positioning, providing flow stabilization without requiring complex active control systems.
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 provides stable airflow and reduced losses, minimizing vibrations and resonance, thereby enhancing propulsion efficiency and adaptability to different wind directions.
Implementation Method 1
The effect on the thickness of the boundary layer of a cylinder that is rotated about its own axis and situated in a cross flow is known from the Magnus effect, which is utilised in the Flettner rotor for propulsion of a ship.
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
Herein is disclosed a blade assembly (1) for providing wind propulsion for a ship (2) as well as a ship (2) provided with one or more of such blade assemblies (1), the blade assembly (1) comprising a top end part and a lower end part for being coupled to a part of the ship (2), and a first and a second aerofoil assembly (3, 4), each of the first and the second aerofoil assembly (3, 4) comprising at least two aerofoils (5a, 5a', 5b, 5b', 5c, 5c', 105a, 105a', 105b, 105b', 105c, 105c'), wherein the first aerofoil assembly (3) is arranged at one side of a central plane (CP) of the blade assembly (1) and the second aerofoil assembly (4) is arranged at the opposite side of the central plane (CP) than the first aerofoil assembly (3), wherein the at least two aerofoils (5a, 5a', 5b, 5b', 5c, 5c', 105a, 105a', 105b, 105b', 105c, 105c') of each of the first and the second aerofoil assembly (3, 4) are oriented with a leading edge (LE) of the aerofoil (5a, 5a', 5b, 5b', 5c, 5c', 105a, 105a', 105b, 105b', 105c, 105c') towards an inlet gap (IG) of the blade assembly (1) between the first aerofoil assembly (3) and the second aerofoil assembly (4), wherein the at least two aerofoils (5a, 5a', 5b, 5b', 5c, 5c', 105a, 105a', 105b, 105b', 105c, 105c') of each of the first and the second aerofoil assembly (3, 4) are arranged in an overlapping sequence so that one or more flow channels (FC) are formed between neighbouring aerofoils (5a, 5a', 5b, 5b', 5c, 5c', 105a, 105a', 105b, 105b', 105c, 105c'), and wherein for each of the first and the second aerofoil assembly (3, 4) an assembly camber line (ACAL) connecting the leading edge (LE) of the front aerofoil (5a, 5a', 105a, 105a') nearest the inlet gap (IG) with the trailing edges (TE) of each of the aerofoils (5a, 5a', 5b, 5b', 5c, 5c', 105a, 105a', 105b, 105b', 105c, 105c') in the aerofoil assembly (3, 4) from the front aerofoil (5a, 5a', 105a, 105a') towards the back aerofoil (5b, 5b', 105b, 105b') nearest an outlet gap (OG) of the blade assembly (1) deviates from an assembly chord line (ACHL) connecting the leading edge (LE) of the front aerofoil (5a, 5a', 105a, 105a') with the trailing edge (TE) of the back aerofoil (5b, 5b', 105b, 105b') in a direction with a component away from the central plane (CP), the blade assembly (1) further comprising a cylinder (14) extending parallel to the central longitudinal axis (7) and being rotatable around a cylinder longitudinal axis (16), the cylinder (14) being arranged between the first aerofoil assembly (3) and the second aerofoil assembly (4) adjacent to a leading aerofoil (5a, 105a,) of the first aerofoil assembly (3), wherein the leading aerofoil (5a, 105a) is bordering the inlet gap (IG).