Asymmetric Vortex Generator for Propeller Cavitation Control
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Solution Overview
Problem
Existing propeller noise and vibration reduction technologies require large blade-shaped appendages or flow control fins with predetermined angles of attack, leading to increased cavitation and inefficiencies, particularly in the first quadrant where cavitation is most pronounced.
Innovation Solution
A vortex generator with asymmetrically attached metal plates on the hull, reducing the angle of attack and increasing flow speed in the first quadrant by generating an asymmetric wake, thereby minimizing cavitation and improving flow rectification performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If blade-shaped appendages or flow control fins with predetermined angles of attack are used to control flow moving to the propeller, then flow speed and flow direction can be controlled, but the devices become large in size and generate excessive cavitation
Solution Approach 1:
The patent applies asymmetry by attaching vortex generators only on one side of the hull (port or starboard) rather than symmetrically on both sides. This asymmetric configuration generates a targeted wake pattern that specifically addresses cavitation in the first quadrant of the propeller without creating excessive cavitation elsewhere, thus controlling flow speed while minimizing harmful cavitation effects
Solution Approach 2:
The patent changes the flow parameters by generating vortices that modify the wake structure upstream of the propeller. The vortex generators create rotational flow components that alter the velocity distribution and pressure field, thereby changing the flow speed and direction parameters to reduce cavitation without requiring large blade-shaped structures
2Object-affected harmful factors
If blade-shaped appendages are used to control flow moving to the propeller, then cavitation noise can be reduced, but the devices become large and increase device complexity
Solution Approach 1:
The asymmetric placement of vortex generators on one side of the hull simplifies the device configuration compared to symmetric bilateral structures. This single-sided arrangement achieves cavitation noise reduction through targeted wake modification while minimizing the number of components and overall structural complexity
Solution Approach 2:
The patent extracts only the essential vortex-generating function from complex blade-shaped appendages. By using simple vortex generators that produce the necessary rotational flow components, the design eliminates unnecessary structural elements while maintaining the core functionality of cavitation control and noise reduction
3Productivity
If pre-swirl effect is generated by changing tangential speed of flow, then propeller efficiency can be improved, but the angle of attack increases and excessive cavitation is generated
Solution Approach 1:
The patent applies local quality by generating vortices with specific characteristics tailored to the local flow conditions in the first quadrant of the propeller. The asymmetric vortex configuration creates localized flow modifications that improve efficiency in critical areas without increasing the angle of attack excessively or generating widespread cavitation
Solution Approach 2:
The patent changes the flow parameters by generating vortices that modify both the tangential and axial velocity components. This dual-parameter modification approach allows for efficient propeller operation while controlling the angle of attack and preventing excessive cavitation through balanced flow field adjustment
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 effectively reduces propeller noise and vibration by minimizing cavitation through asymmetric wake distribution, enhancing flow speed and reducing angles of attack, thus addressing the inefficiencies and increased noise caused by existing technologies.
Implementation Method 1
a vortex generator that generates an asymmetric wake for reducing propeller noise and vibration
Implementation Method 2
minimizing cavitation that is generated on the blades of the propeller by controlling a flow moving to the propeller
Data Source
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AI summary
The present invention relates to a vortex generator that generates an asymmetric wake for reducing propeller noise and vibration, the vortex generator being capable of reducing propeller noise and vibration by reducing cavitation on blade surfaces of the propeller in a vessel by controlling a flow moving to the propeller in the vessel. The present invention provides a vortex generator that generates asymmetric wakes for reducing propeller noise and vibration, the vortex generator being cable of minimizing cavitation noise by generating asymmetric wake distribution for increasing the speed of a flow in the first quadrant of a propeller where cavitation is generated most by reducing an angle of attack of a blade by changing an axial speed using asymmetric wakes.