Ship Propeller Contra-Rotation Energy Recovery
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Solution Overview
Problem
Conventional ship propulsion systems with single spiral propellers suffer from energy loss due to unutilized rotational energy from the propeller, and contra-rotating propellers, while offering improved performance, are complex to manufacture and maintain due to their contra-rotating units and hollow shafts.
Innovation Solution
A propulsion system with a rear propeller fixed to a rotary shaft, a front propeller rotatably supported, and a contra-rotating device installed at the hull's rear end to reverse rotation, using a gearbox and planetary gear unit for efficient energy transfer, along with a corrosion-resistant unit and thrust supporting device to simplify assembly, disassembly, and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If contra-rotating propellers are used to recover rotational energy, then propulsion performance is improved, but device complexity increases due to contra-rotating units and hollow shafts
Solution Approach 1:
The propulsion system is divided into independent modular components: a drive source housed in a drive source housing, a propeller assembly with front and rear propellers, and a contra-rotating mechanism. This segmentation allows each module to be manufactured, assembled, and maintained separately, reducing overall system complexity while maintaining the energy recovery function of contra-rotation.
Solution Approach 2:
The contra-rotating mechanism is nested within the propeller assembly structure, where the front propeller and rear propeller are arranged coaxially with the rear propeller positioned behind the front propeller. The drive source housing contains the drive source and transmits power to the propeller assembly. This nested arrangement consolidates multiple functions into a compact structure, improving energy recovery without proportionally increasing complexity.
2Loss of energy
If contra-rotating propellers with hollow shafts are installed, then propulsion performance improves, but ease of manufacture deteriorates
Solution Approach 1:
The propulsion system separates the drive source housing from the propeller assembly, allowing each to be manufactured using standard processes. The front and rear propellers are manufactured as separate components that can be assembled onto the drive shaft in sequence, avoiding the need for complex hollow shaft manufacturing while achieving contra-rotation functionality.
Solution Approach 2:
The invention uses conventional, easily manufactured components such as standard propellers and a simple drive source housing rather than expensive specialized hollow shafts. These components can be produced using common manufacturing techniques and replaced if needed, significantly improving ease of manufacture while maintaining the energy recovery function.
3Loss of energy
If contra-rotating propellers are installed, then propulsion performance improves, but ease of operation deteriorates due to high-tech maintenance requirements
Solution Approach 1:
The modular design with separate drive source housing and propeller assembly allows maintenance personnel to access and service individual components independently. The front propeller, rear propeller, and drive source can be inspected, removed, and replaced separately, greatly simplifying maintenance operations compared to integrated contra-rotating systems.
Solution Approach 2:
The simple modular structure enables routine maintenance such as propeller inspection and replacement to be performed with basic tools and skills. The system does not require specialized high-tech maintenance equipment or procedures, allowing operators with standard training to perform maintenance tasks, thereby improving ease of operation.
4Loss of energy
If a complex contra-rotating unit is used, then propulsion performance improves, but ease of repair deteriorates
Solution Approach 1:
The system is divided into repairable modules: drive source housing, front propeller, rear propeller, and drive shaft. If a component fails, only that specific module needs to be removed and replaced, not the entire contra-rotating mechanism. This segmentation dramatically simplifies repair operations compared to complex integrated systems.
Solution Approach 2:
The invention uses simple, conventional components that can be easily replaced rather than repaired. The propellers and drive shaft are designed as replaceable components that can be swapped out quickly, eliminating the need for complex repair procedures. This approach improves ease of repair while maintaining the rotational energy recovery function.
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 enables stable contra-rotation, facilitates easy mounting and demounting from the hull, reduces energy loss by utilizing rotational energy, and provides corrosion protection, simplifying maintenance and reducing the complexity of the power transmission system.
Implementation Method 1
providing a corrosion-resistant unit using an anode between a hub of a front propeller and a rear end of a hull and/or between the hub of the front propeller and a hub of a rear propeller, and protecting a sealing unit from corrosion caused by sea water
Data Source
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AI summary
Disclosed are a propulsion system for a ship, a method of assembling the same, and a method of disassembling the same. The propulsion system for the ship includes: a rear propeller fixed to a rotary shaft; a front propeller that is rotatably supported on the rotary shaft in front of the rear propeller; a contra-rotating device that is mounted in an installation space at a rear end of a hull so as to reverse the rotation of the rotary shaft and transmit the reversed rotation to the front propeller; a propeller connecting member that connects the contra-rotating device and the front propeller to transmit a rotational force; and a thrust supporting device that is provided between the contra-rotating device and the propeller connection member to support thrust of the front propeller.