Hull Bubble Generators for Ship Drag Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for reducing ship hull drag, such as Air Lubrication and fluidic oscillators, are limited in integration with the shipbuilding process, ease of installation, maintenance, and drag reduction effectiveness, particularly in new builds and in avoiding damage during operations.
Innovation Solution
Incorporating elongated slots in the hull with arrays of bubble generator units, each with inlet and outlet openings, mounted in a side-by-side manner to fill the slot, allowing for controlled air bubble generation and easy maintenance, and using fluidic oscillators to produce pulsating air flows for drag reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Air Lubrication concepts rely on a series of orifices or air injection chests placed at the bow of the ship, then air can be injected to produce bubbles and reduce friction, but the system complexity and difficulty of integration with shipbuilding process increase
Solution Approach 1:
The invention divides the hull surface into multiple zones with different bubble generation requirements. Multiple independent bubble generator units are distributed across the hull, each可控 independently. This segmentation allows the system to achieve comprehensive drag reduction while maintaining modularity and ease of integration with the shipbuilding process.
Solution Approach 2:
The bubble generator units are designed with universal mounting structures that can be integrated into various hull designs and configurations. The standardized units serve multiple functions: drag reduction, fuel efficiency improvement, and adaptability to different ship types, thereby reducing overall system complexity despite the distributed architecture.
2Ease of operation
If bands with fluidic oscillators are retrofitted to the outside of the ship's hull, then bubble distribution can be controlled, but the protrusion increases drag and components are vulnerable to damage
Solution Approach 1:
The bubble generator units are nested within recesses or slots in the hull surface, allowing the oscillators to be housed inside the hull structure rather than protruding outward. This nesting approach maintains the bubble distribution control functionality while eliminating the drag-increasing protrusion and protecting the components from external damage.
Solution Approach 2:
The hull surface itself acts as an intermediary structure that houses the bubble generators. By integrating the oscillators into the hull's skin or surface features, the system achieves protected housing and streamlined外形, while the hull structure mediates between the internal oscillator and the external water flow.
3Ease of manufacture
If bubble generator units are mounted in slots filled and closed off by the units, then easy installation and maintenance are achieved, but manufacturing precision requirements increase
Solution Approach 1:
The bubble generator system is segmented into standardized modular units that can be manufactured independently with tolerances suitable for mass production. The slots in the hull are designed to accommodate these standard units, allowing for easy installation and removal during maintenance while the segmentation distributes the precision requirements across multiple identical components rather than requiring high precision for the entire system.
Solution Approach 2:
The mounting design incorporates adjustable parameters such as slot dimensions, mounting tolerances, and unit positioning features that can be optimized to balance manufacturing precision requirements with ease of installation. By carefully selecting and adjusting these parameters, the system achieves both easy maintenance access and acceptable alignment precision.
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
This method enhances drag reduction by optimizing bubble generation and distribution, allowing for easier maintenance and integration into new ship construction, while minimizing damage risks during operations, thereby improving the overall efficiency of air lubrication systems.
Implementation Method 1
Air Lubrication (AL) is a known and proven way to reduce the friction experienced by ships moving through water, by injecting air under the bottom of the ship
Implementation Method 2
The physical principle that leads to lower friction is assumed to be either a reduction of water dynamic viscosity caused by the two-phase mixture of bubbles and water
Implementation Method 3
These bands are fitted with so-called fluidic oscillators, that generate and distribute streams of bubbles in a controlled way. The oscillation frequency may be used to control the bubble size produced by these devices
Implementation Method 4
interacting with the flowing water, produces a sheet of bubbles or a homogeneous air layer
Data Source
AI summary
A method for providing a hull of a vessel with bubble generators for reducing the drag of the hull includes providing at least one elongated slot in the hull, the slot having a length extending in a lateral direction of the vessel and a width extending perpendicular thereto; providing a multitude of bubble generator units, each having an inlet opening for supplying air and a bottom surface with at least one outlet opening for discharging air bubbles; and mounting the multitude of bubble generator units in the slot in a side by side manner along the length of the slot such that the slot is filled and substantially closed off by the bubble generator units, and such that the inlet openings of the bubble generator units face the interior of the hull and the bottom surfaces with the outlet openings of the bubble generator units face the exterior of the hull.