Bifurcated Molecular Pump for Flywheel Vacuum Drag Reduction
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Solution Overview
Problem
Existing flywheel energy storage systems face increased aerodynamic drag due to high-pressure exhaust gas being directed near moving parts, which negates the benefits of reduced pressure in the vacuum housing, leading to inefficiencies and higher system costs when integrating molecular pumps with flywheel components.
Innovation Solution
A novel molecular pump configuration that evacuates gas from the vacuum chamber into a separate, higher-pressure exhaust chamber, utilizing a stationary element with a scroll pattern that conveys molecules from both the outer and inner diameters of the pump, minimizing interaction with moving parts and reducing drag losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a molecular pump is integrated with existing flywheel components, then system cost is reduced by minimizing redundant components, but aerodynamic drag increases due to high-pressure exhaust gas being conveyed near moving parts
Solution Approach 1:
The pump is divided into distinct functional zones: a vacuum chamber portion and an exhaust chamber portion, separated by a partition wall. This segmentation isolates the high-pressure exhaust gas from the vacuum chamber containing moving parts, eliminating aerodynamic drag while maintaining component integration benefits
Solution Approach 2:
Different regions of the pump are assigned different pressure characteristics - the vacuum chamber portion maintains low pressure while the exhaust chamber portion operates at high pressure. This local quality differentiation allows the pump to simultaneously achieve vacuum functionality and exhaust gas management without compromising system efficiency
2Ease of manufacture
If high-pressure exhaust gas is conveyed to a volume adjacent to flywheel rotor, motor or bearing, then pump integration is simplified, but aerodynamic drag increases and vacuum efficiency is reduced
Solution Approach 1:
An exhaust chamber acts as an intermediary space between the pump's gas intake and the external environment. High-pressure exhaust gas is conveyed to this intermediate chamber rather than directly adjacent to moving parts, serving as a buffer that protects the vacuum environment while maintaining pump integration
Solution Approach 2:
The exhaust chamber is nested within or adjacent to the vacuum chamber, with the partition wall creating a nested structure. This allows the pump to be integrated with flywheel components while the nested exhaust chamber contains and isolates high-pressure gas, preventing it from affecting vacuum efficiency
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 configuration effectively reduces aerodynamic drag and system costs by isolating high-pressure exhaust gas from the flywheel rotor and motor, enhancing the efficiency of energy storage by maintaining a vacuum environment while integrating with existing flywheel components.
Implementation Method 1
A molecular pump works on the principle that gas molecules can be given momentum in a desired direction by repeated collision with a moving solid surface. In a turbomolecular pump, a rapidly spinning rotor 'hits' gas molecules and directs them towards the inlet of a pump and through pump channels into an exhaust region or volume
Implementation Method 2
A flywheel is a type of energy storage system that stores energy as rotational kinetic energy. A flywheel rotor is a mass that spins while physically coupled, directly or indirectly, to a motor that itself is electrically coupled to a converter
Data Source
AI summary
A flywheel device that includes a housing that surrounds a vacuum chamber, a flywheel rotor within the vacuum chamber, which rotates during normal operation of the flywheel, thus agitating residual gasses, an exhaust chamber that receives the exhaust gases from the vacuum chamber, and an annular shaped stationary element, within the vacuum chamber that includes scroll channels where some of the scroll channels have an intake port on an inner diameter of the stationary element and some of the scroll channels have an intake port on an outer diameter of the stationary element, and the scroll channels enable gasses to flow from the vacuum chamber, through the scroll channels, into the exhaust chamber.