Flettner Rotor Flap Segmentation for Lift and Weight

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Solution Overview

Problem

Flettner rotors are large, heavy, and inefficient at low wind speeds and undesirable wind directions due to their size and material requirements, limiting their propulsive force and fuel efficiency.

Innovation Solution

A flap is integrated with the rotor to increase lift, allowing for a smaller, lighter design with improved performance at low wind speeds and adjustable angles to optimize the Magnus-effect, using materials with high strength-to-weight ratios and cambered cross-sections for enhanced aerodynamics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If Flettner rotors are made large to provide sufficient propulsive force, then the propulsive force increases, but the weight and material usage increase

Engineering Contradiction:
Improvepropulsive forceVSAvoidweight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The rotor system is segmented into two functional parts: the rotating Flettner rotor and the stationary flap. This segmentation allows the rotor to be smaller and lighter while the flap provides additional aerodynamic surface area to generate propulsive force, resolving the contradiction between force generation and weight reduction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stationary flap acts as an intermediary element that enhances the aerodynamic performance of the rotor system without adding rotational mass. The flap mediates between the wind flow and the rotor, creating additional lift and drag forces that contribute to propulsive force while keeping the rotating component lightweight

Inventive Principle:
Principle #24Intermediary (Mediator)

2Force

If Flettner rotors are made large to provide sufficient propulsive force, then the propulsive force increases, but the material usage increases

Engineering Contradiction:
Improvepropulsive forceVSAvoidmaterial usage
Core Design Contradiction:
ForceVSQuantity of substance

Solution Approach 1:

By dividing the force-generating system into a rotating rotor and a stationary flap, the design reduces the material required in the rotor structure itself. The flap provides additional aerodynamic surface area without requiring rotational structural integrity, thus reducing overall material usage while maintaining propulsive force

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the operational parameters by introducing a stationary flap with specific geometric characteristics (area, orientation, position relative to rotor). This parameter change allows the system to generate sufficient propulsive force with reduced rotor size and material consumption

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If the rotor size is reduced to decrease weight, then the weight decreases, but the propulsive force decreases

Engineering Contradiction:
ImproveweightVSAvoidpropulsive force
Core Design Contradiction:
Weight of moving objectVSForce

Solution Approach 1:

The invention merges the functions of a smaller rotor with a stationary flap into a hybrid aerodynamic system. The combination of the rotating rotor and stationary flap creates a unified force-generating system that maintains propulsive force output despite the reduced rotor size and weight

Inventive Principle:
Principle #5Merging (Combining)

4Quantity of substance

If the rotor size is reduced to decrease material usage, then the material usage decreases, but the propulsive force decreases

Engineering Contradiction:
Improvematerial usageVSAvoidpropulsive force
Core Design Contradiction:
Quantity of substanceVSForce

Solution Approach 1:

Segmenting the aerodynamic surface into a smaller rotating rotor and a stationary flap allows the system to use less total material while maintaining force generation. The flap provides additional surface area for force generation without requiring the same structural investment as a larger rotating rotor would

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By changing the system configuration to include a stationary flap with optimized geometric parameters, the invention achieves sufficient propulsive force with reduced material consumption in the rotor structure

Inventive Principle:
Principle #35Parameter changes

5Force

If the rotor performance is improved at low wind speeds, then the propulsive force increases, but the device complexity increases

Engineering Contradiction:
Improvepropulsive force at low wind speedsVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The stationary flap can be designed with adjustable or movable characteristics that allow it to adapt dynamically to different wind conditions. This dynamic capability enables the system to maintain optimal performance at low wind speeds without requiring complex active control systems

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention optimizes geometric parameters of the flap (area, shape, position relative to rotor) to enhance performance at low wind speeds. By carefully selecting these parameters, the system achieves improved low-speed performance without introducing complex mechanical or control systems

Inventive Principle:
Principle #35Parameter changes

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 flap design reduces material usage, increases lift force, and improves rotor performance at low wind speeds and undesirable wind directions, enabling more efficient propulsion and energy savings.

Implementation Method 1

A rotor ship, or Flettner ship, is a ship designed to use the Magnus-effect for propulsion. The Magnus-effect is a force acting on a spinning body in a moving airstream, which acts perpendicularly to the direction of the airstream.

Methodology Applied
Scientific EffectMagnus effect: Magnus Effect

Implementation Method 2

the flap substantially increases lift of the rotor, therefore allowing it to be smaller while generating the same propulsive force

Methodology Applied
Scientific EffectAerodynamic lift: Aerofoil

Data Source

PatentEP2917100B1Vessel comprising a rotor having a flap arranged near the rotor
Publication Date: 2020.06.17 WINKLER
  • EP2917100B1 patent drawingFigure 1~2
  • EP2917100B1 patent drawingFigure 3
  • EP2917100B1 patent drawingFigure 4~4b

AI summary

The invention relates to vessel (1) comprising a hull (3) and a deck (2), a substantially cylindrical rotor (6) having a peripheral wall (8) rotatable with respect to the deck (2) around a longitudinal center line (20), the rotor (6) being mounted on the deck (2) in such a manner that in an operational state the rotor (6) is substantially vertically oriented, characterized in that a flap (18) is arranged near the rotor (6) extending substantially in a plane which is parallel to the rotational axis of the rotor (6), and the length of the flap chord (Rfc) is between 20%-90% of the rotor (6) diameter (Dr), wherein the position of the flap (18) can be adjusted with reference to the longitudinal center line (20).