Counter-Rotating Rollers Aerosol Generation
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Solution Overview
Problem
Conventional methods for creating aerosols from fluids, especially those with non-Newtonian properties, face challenges due to extensional thickening which prevents the formation of small droplets as the viscous drag overwhelms inertial and surface tension forces, leading to the formation of long filaments that do not break up into a mist.
Innovation Solution
A process involving counter-rotating rollers that stretch fluid filaments until they break into droplets, creating an aerosol, with the rollers' nip allowing fluid to be drawn in, stretched, and broken into droplets on the downstream side, and the use of air flow and baffles to collect and direct the aerosol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high velocity coaxial flows are used to atomize Newtonian fluids, then fine mist droplets can be formed, but the method becomes ineffective for non-Newtonian fluids with extensional thickening
Solution Approach 1:
The invention changes the fundamental parameters of the atomization process by transitioning from high velocity inertial flows to low velocity extensional flows. This parameter change allows the system to effectively atomize non-Newtonian fluids with extensional thickening that would otherwise resist conventional atomization methods.
Solution Approach 2:
The invention replaces the conventional mechanical atomization system (high velocity coaxial flows relying on inertial forces) with an alternative mechanical system based on extensional straining. This substitution enables effective atomization of non-Newtonian fluids by using a different mechanical approach that overcomes extensional thickening.
2Reliability
If extensional straining is applied to non-Newtonian fluids, then viscous drag increases and prevents droplet formation, but the invention overcomes this by using diverging surfaces
Solution Approach 1:
The invention introduces a new dimension to the atomization process by using diverging surfaces that create extensional straining in a direction perpendicular to the substrate. This dimensional change allows the system to overcome viscous drag by applying strain in a configuration that promotes droplet formation despite the presence of extensional thickening.
Solution Approach 2:
The invention uses curved or diverging surfaces instead of flat surfaces to create the necessary extensional straining. The curvature of the diverging surfaces generates the radial outward flow pattern that produces effective extensional strain, enabling droplet formation from non-Newtonian fluids.
3Quantity of substance
If conventional atomization methods are used, then Newtonian fluids can be effectively atomized, but non-Newtonian fluids form long filaments that do not break up
Solution Approach 1:
The invention creates a dynamic flow pattern using diverging surfaces that continuously generate extensional straining. This dynamic approach prevents the formation of stable long filaments by constantly applying strain that promotes breakup into droplets, thereby increasing aerosol production from non-Newtonian fluids.
Solution Approach 2:
The rotating substrate creates a periodic motion that repeatedly applies extensional straining to the fluid. This periodic action prevents filament formation by continuously disrupting the fluid structure and promoting droplet breakup, thereby increasing the quantity of aerosol produced.
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 method effectively breaks up fluid filaments into small droplets, forming a consistent aerosol or mist, even with non-Newtonian fluids, by controlling the strain and using air flow to collect and direct the droplets efficiently.
Implementation Method 1
its extensional viscosity can increase by several orders of magnitude in the straining direction when the fluid is stretched
Implementation Method 2
the extensional thickening of component solutions having non-Newtonian properties causes the viscous drag to overwhelm the inertial and surface tension forces
Implementation Method 3
the fluid filaments stretching between respective surfaces of the pair of counter-rotating rollers and breaking into droplets on the downstream side of the nip
Implementation Method 4
results in a fine mist of drops suspended in the air
Data Source
AI summary
A process of creating an aerosol includes coating at least one of a pair of counter-rotating, adjacent rollers with a fluid, the pair of counter-rotating rollers defining a nip therebetween, rotating the counter-rotating rollers to cause the fluid to be drawn into an upstream side of the nip, causing fluid filaments of the fluid to form on a downstream side of the nip, the fluid filaments stretching between respective surfaces of the pair of counter-rotating rollers and breaking into droplets on the downstream side of the nip, and harvesting the droplets at the downstream side of the nip.