Passive Polymer Drag Reduction for Underwater Vehicles
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Solution Overview
Problem
Existing methods for reducing drag on underwater vehicles consume excessive energy and increase weight due to the use of active pumping systems, limiting the range, endurance, and operational envelope of these vehicles.
Innovation Solution
A polymer solution is introduced into the boundary layer of underwater vehicles using passive mixing and ejection methods, where a liquid polymer is stored in flexible bladders or a water-soluble solid polymer is used, dissolving in water to create a drag-reducing solution, which is then passively ejected into the boundary layer without the need for electrical energy, utilizing pressure differentials for distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active pumping systems are used to distribute polymer solution, then drag reduction is achieved, but energy consumption and vehicle weight increase
Solution Approach 1:
The system uses the vehicle's own motion through water to drive the polymer solution distribution. The forward movement creates pressure differentials that automatically pump the polymer solution from storage bladders through mixing chambers and ejectors into the boundary layer, eliminating the need for separate active pumping systems and their associated energy consumption
Solution Approach 2:
The system utilizes hydraulic principles by leveraging the pressure differential created by the vehicle's motion through water. This pressure differential drives the polymer solution through the distribution system passively, converting the vehicle's kinetic energy into the driving force for polymer injection without requiring additional mechanical pumps
2Object-affected harmful factors
If active pumping systems are used to distribute polymer solution, then drag reduction is achieved, but vehicle weight increases
Solution Approach 1:
The vehicle's forward motion itself performs the work of distributing the polymer solution. The system eliminates heavy active pumping components by using the vehicle's motion to create the necessary pressure differentials, thereby reducing overall system weight while maintaining drag reduction functionality
Solution Approach 2:
The invention extracts and removes the active pumping system components from the vehicle. By relying on passive pressure-driven distribution, the system eliminates motors, pumps, and associated control mechanisms that would add weight, keeping only the essential polymer storage bladders and ejector components
3Use of energy by moving object
If polymer solution is passively ejected without active pumping, then energy consumption is minimized, but polymer distribution control may be reduced
Solution Approach 1:
The system controls polymer distribution by adjusting parameters such as the concentration of polymer in storage, the size and positioning of ejector openings, and the vehicle's speed. These parameter changes allow modulation of polymer injection rates and distribution patterns without requiring active control systems, maintaining ease of operation through passive mechanisms
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 approach minimizes energy consumption, maximizing energy efficiency and reducing drag on vehicle surfaces, thereby enhancing the operational capabilities of underwater vehicles without the drawbacks of active pumping systems.
Implementation Method 1
The bladders can be exposed to ambient pressure which acts on the bladder(s) to force the liquid polymer from the bladder(s)
Implementation Method 2
The polymer solution that is then passively ejected into the boundary layer due to a pressure differential existing between one or more water inlets and the outlet(s) for the polymer solution
Implementation Method 3
The water contacting the solid polymer body dissolves some of the polymer which mixes with the water to form the polymer solution
Implementation Method 4
The solid polymer body can be disposed within the vehicle at a location so that the solid polymer body is exposed to water in which the vehicle is disposed that is passively circulated, under forced convection, around, over, and/or through channels in the solid polymer body
Data Source
AI summary
Systems and methods of reducing drag on outer surfaces of vehicles that are in contact with water using a polymer solution that reduces the drag on the outer surfaces of the vehicles as the vehicles travel through water. A polymer solution is passively ejected into the boundary layer of the water flowing past the outer surface of the vehicle. The polymer solution is mixed and introduced into the boundary layer passively with minimal or no usage of electrical energy. The passive mixing and ejection of the polymer solution minimizes energy consumption, thereby maximizing electrical energy consumption efficiency during operation of the vehicle.