Dielectrophoretic Cooling for Vapor Backflow Control
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Solution Overview
Problem
Current cooling technologies for high power density electronics face limitations in managing heat flux, with passive cooling becoming insufficient and mechanical pumps introducing reliability issues, noise, and vibration, while two-phase cooling in microchannels is challenged by bubble expansion causing pressure oscillations and vapor backflow.
Innovation Solution
A dielectrophoretic cooling system with electrodes positioned in cooling tubes creates a non-uniform electric field that repulses vapor bubbles away from the inlet, preventing upstream expansion and directing them downstream, thereby reducing pressure oscillations and vapor backflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical pumps are used for fluid pumping, then heat flux management is improved, but reliability deteriorates due to mechanical failures, noise, and vibration
Solution Approach 1:
The patent replaces mechanical pumps with a dielectrophoretic pumping system that uses non-uniform electric fields to move dielectric liquid through microchannels. This eliminates mechanical moving parts, thereby improving reliability while maintaining effective heat flux management through controlled fluid circulation.
2Object-generated harmful factors
If physical restrictions are used to inhibit bubble growth, then vapor backflow is reduced, but pressure drop increases
Solution Approach 1:
The patent replaces physical restrictions with a dielectrophoretic force field generated by electrodes. The non-uniform electric field exerts forces on vapor bubbles to control their motion and prevent upstream migration, eliminating the need for physical constrictions that would cause pressure drops while still effectively reducing vapor backflow.
3Productivity
If microchannels are used for two-phase cooling, then cooling efficiency is improved, but bubble expansion causes pressure oscillations and flow mal-distribution
Solution Approach 1:
The patent uses dielectrophoretic forces from non-uniform electric fields to control bubble behavior in microchannels. The electric field selectively acts on vapor bubbles (not the dielectric liquid) to prevent upstream expansion and stabilize flow, maintaining high cooling efficiency while eliminating pressure oscillations and flow mal-distribution caused by uncontrolled bubble expansion.
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 dielectrophoretic cooling system effectively manages heat flux by supplementing or replacing mechanical pumps, reducing pressure oscillations and vapor backflow, enhancing cooling efficiency in microchannels.
Implementation Method 1
A dielectrophoretic force is generally provided by varying an electrical response relative to a bubble which is formed in a dielectric fluid. In general, the dielectric liquid behaves in one way relative to a dielectrophoretic force, but a bubble of vapor will react in a distinct manner.
Data Source
Figure 1~2
Figure 3~4
AI summary
A cooling system has an inlet plenum (28) and at least one cooling channel (30) which communicates with the inlet plenum (28). The cooling channel (30) passes adjacent to a component (22) to be cooled from an upstream inlet to a downstream outlet (36). A pair of electrodes (42) are positioned adjacent the inlet to create an electric field tending to resist a bubble (43) formed in an included dielectric liquid from moving in an upstream direction due to a dielectrophoretic force. Instead, a dielectrophoretic force urges the bubble (43) in a downstream direction.