Contra-Rotating Propeller Layout for Cavitation Loss Recovery
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Solution Overview
Problem
Conventional electric motors and generators with a single propeller suffer from efficiency losses due to cavitation, leading to reduced performance and increased heat generation, which affects durability and marketability.
Innovation Solution
A rotating machine design featuring contra-rotating propellers, where two propellers rotate in opposite directions on the same axis, recovering rotational energy lost by the front propeller and enhancing heat dissipation through a fluid duct system and cooling holes, while minimizing volume and optimizing the placement of permanent magnets and windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single propeller is used in the rotating machine, then the device complexity is reduced, but cavitation occurs behind the propeller causing efficiency to deteriorate
Solution Approach 1:
The single propeller is segmented into two separate propellers (first propeller and second propeller) that rotate in opposite directions. This segmentation allows the second propeller to recover rotational energy from the fluid flow behind the first propeller, preventing energy loss due to cavitation while maintaining manageable device complexity through modular construction
2Loss of energy
If contra-rotating propellers are used to improve efficiency, then energy loss is reduced, but the volume of the rotating machine increases
Solution Approach 1:
The second rotation module is positioned within the space occupied by the first rotation module, with the second propeller located behind the first propeller along the same rotational axis. This nested arrangement allows both propellers to occupy overlapping spatial volumes, recovering energy without significantly increasing the overall machine volume
3Power
If high output is pursued in fluid-based electric propulsion, then power is increased, but heat generation increases affecting durability
Solution Approach 1:
The harmful heat generated during high-power operation is converted into a beneficial cooling mechanism. The fluid flow that would normally cause cavitation and energy loss is redirected through cooling passages to dissipate heat from the motor and generator components, transforming a harmful effect into a useful cooling function that enhances durability
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 contra-rotating propeller design improves maximum output, efficiency, and durability, while minimizing the machine's volume and facilitating effective heat dissipation, thereby enhancing marketability and performance.
Implementation Method 1
the electric motor may be a rotating machine including a permanent magnet by allowing a current to flow through a winding wound around a fixation part
Implementation Method 2
cavitation may occur behind the propeller, thus significantly lowering efficiency of the motor or the generator
Data Source
AI summary
Provided is a rotating machine which may include a fixed shaft; a fixation module having at least one fixation part coupled to an outer peripheral surface of the fixed shaft; and a rotation module rotatably supported by the fixed shaft, wherein the rotation module includes a first rotation module and a second rotation module, the first rotation module including a first rotation module support, a first rotation module-permanent magnet installed on an inner peripheral surface of the first rotation module support, and a first rotation module propeller installed on an outer peripheral surface of the first rotation module support, and the second rotation module including a second rotation module support, a second rotation module-permanent magnet installed on an inner peripheral surface of the second rotation module support, and a second rotation module propeller installed on an outer peripheral surface of the second rotation module support.