Micro-fluidic Bubble Generator for Ship Hull Drag Reduction
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Solution Overview
Problem
Existing methods for reducing drag on a ship's hull are ineffective across varying operational conditions such as different speeds and water temperatures, as they fail to efficiently generate micro-bubbles that can adapt to these conditions.
Innovation Solution
A micro-fluidic device is attached to the hull to generate bubbles of controlled size and frequency, using a bubble-forming fluid like air, which can be adjusted to optimize drag reduction by varying the flow through multiple nozzles and control channels, ensuring efficient drag reduction across different operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional bubble generators with porous plates are used, then drag reduction is achieved, but the system cannot adapt to different operational conditions such as varying speeds and water temperatures
Solution Approach 1:
The patent applies dynamics by making the bubble generation system adjustable and adaptable to varying operational conditions. The micro-fluidic device allows dynamic control of bubble size and generation rate through adjustable flow rates, enabling the system to respond to different ship speeds, water temperatures, and draught conditions, thereby resolving the contradiction between adaptability and reliable drag reduction performance.
Solution Approach 2:
The patent changes physical parameters of bubble generation by controlling flow rates through the micro-fluidic device to produce bubbles of different sizes. By adjusting the flow rate parameter, the system can optimize bubble characteristics for various operational conditions, achieving both adaptability and reliable drag reduction across different scenarios.
2Manufacturing precision
If micro-fluidic devices are used to control bubble size, then precise control over bubble size and frequency is achieved, but device complexity increases
Solution Approach 1:
The patent replaces conventional mechanical bubble generation systems with micro-fluidic devices that use controlled fluid flow to generate and size bubbles. This substitution enables precise control of bubble dimensions through flow rate management rather than mechanical adjustment, achieving high manufacturing precision while managing system complexity through fluid-based control mechanisms.
3Force
If bubbles are generated to reduce drag, then frictional resistance decreases, but bubble coalescence and loss of buoyancy may occur
Solution Approach 1:
The patent employs periodic action by generating bubbles in controlled bursts or sequences through the micro-fluidic device rather than continuous generation. This periodic bubble release pattern prevents excessive bubble accumulation and coalescence, maintaining individual bubble integrity and buoyancy while still achieving effective drag reduction through sustained bubble presence in the boundary layer.
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 system provides precise control over bubble size and frequency, reducing drag effectively while maintaining sufficient buoyancy, and can be retrofitted onto existing ships, minimizing additional drag and coalescence of bubbles.
Implementation Method 1
a micro-fluidic device for generating bubbles of a well-defined bubble size of the generated bubbles. The bubbles are formed in a boundary layer of the water surrounding the hull
Implementation Method 2
The bubbles are formed in a boundary layer of the water surrounding the hull, i.e. at the interface between the hull and the surrounding water
Implementation Method 3
At small scales, where channel diameters are around 100 nanometers to several hundred micrometers, the Reynolds number, which compares the effect of momentum of a fluid to the effect of viscosity, can become very low. This results in that fluids may not mix in the traditional sense; and molecular transport between the fluids may be through diffusion.
Implementation Method 4
the Reynolds number, which compares the effect of momentum of a fluid to the effect of viscosity, can become very low
Data Source
AI summary
Disclosed is an apparatus for generating bubbles for reducing drag on a hull of a ship, wherein the bubble generating device is attachable to an outer surface of the hull, and wherein the apparatus comprises one or more microfluidic device for controlling a bubble size of the generated bubbles.