Concentric Multi-Rotor Assembly for Low-Noise Thrust Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotor systems suffer from inefficiencies in thrust production, noise generation, and aerodynamic performance due to mechanical friction, fluidic turbulences, and non-laminar flow, which are not adequately addressed by existing technologies.
Innovation Solution
The implementation of concentric multi-rotor systems with controlled angular speeds and minimal gaps between rotors, combined with stator structures and air guiding fins, to enhance laminar flow and reduce noise, while optimizing the utilization of rotor area for improved thrust and maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotor blade tip speed is increased to improve thrust, then thrust is improved, but noise increases and aerodynamic efficiency decreases
Solution Approach 1:
The invention divides the rotor system into multiple concentric rotors (first rotor, second rotor, third rotor) with different blade configurations. Each rotor operates at optimized speeds and diameters to collectively produce thrust while maintaining lower individual blade tip speeds, thereby reducing noise generation from air shear while preserving total thrust output.
Solution Approach 2:
The invention transitions from a single rotor to a multi-dimensional concentric rotor arrangement, utilizing radial spacing and axial stacking to create multiple airflow paths. This dimensional expansion allows thrust to be generated across multiple radii and planes simultaneously, reducing the need for high-speed single-rotor operation and associated noise.
2Productivity
If rotor blade tip speed is increased to improve thrust, then thrust is improved, but aerodynamic efficiency decreases
Solution Approach 1:
The rotor system is segmented into multiple concentric rotors with different blade counts and diameters. The first rotor has 3 blades, the second has 4 blades, and the third has 5 blades, creating a distributed thrust generation system that operates at lower tip speeds and maintains better aerodynamic efficiency across the entire rotor area.
Solution Approach 2:
Each rotor in the concentric arrangement has locally optimized blade characteristics tailored to its specific radius and speed range. The inner rotors operate at higher speeds with fewer blades while outer rotors operate at lower speeds with more blades, creating optimal local aerodynamic conditions across the entire rotor assembly.
3Productivity
If single rotor area is increased to improve thrust, then thrust is improved, but device complexity increases
Solution Approach 1:
Rather than using one large complex rotor, the invention segments the thrust generation function across multiple simpler concentric rotors. Each rotor can be independently designed and manufactured with standard blade configurations, reducing overall system complexity while achieving the required total thrust through distributed contribution.
Solution Approach 2:
The rotors are arranged in a nested concentric configuration where the first rotor is positioned within the second rotor, which is positioned within the third rotor. This nested arrangement compactly packs multiple thrust-generating elements into a unified structure, achieving high thrust output without proportionally increasing the overall device footprint or complexity.
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 multi-rotor system achieves higher rotor area efficiency, reduced noise, and enhanced maneuverability by minimizing turbulence and optimizing airflow, resulting in improved thrust production and operational performance.
Implementation Method 1
The aerodynamic efficiency of rotating blades decreases as their linear (= tangential) speed decreases or as their linear speed approaches the speed of sound due to the abrupt change in the density of the air
Implementation Method 2
the thrust obtainable from a rotating rotor is proportional to the square of the linear speed of a given part of the rotor's blade
Implementation Method 3
combined with stator structures and air guiding fins, to enhance laminar flow and reduce noise
Implementation Method 4
noise caused by the rotation of a rotor or a propeller is mainly due to air shear caused by neighboring/adjacent air flows having different air flow speeds
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3~4
AI summary
A multi-rotor system comprising: at least two concentric rotors rotatable about a common axis and disposed radially with respect to each other; wherein the at least two concentric rotors are rotatable at different angular speeds with respect to each other to rotate rotors blade tips of the at least two concentric rotors at substantially the same tangential speed.