ISR research accomplishments
EHD MEMS for Micro-Channel Cooling
Research team
D. DeVoe (ME/ISR), S. Vohra, M. Ohadi, J. Darabi (UMd), Robin Hamilton (Northrop Grumman)
Accomplishment
Prototype EHD
mirochannels have been designed and fabricated. Device will implement a silicon
heat fin design with incorporated electrodes. Observe boiling characteristics
and flow regimes in micro-channels (~50µm). Determine increase in heat transfer
when electric field applied to dielectric fluid.
Electrohydrodynamic (EHD) Technique Heat transfer techniques can be classified into two categories. Passive--does not require any application of external power (e.g. the use of treated, rough, or extended surfaces and swirl flow devices. Active--require external power. Examples include surface vibration, injection, suction and the electrohydrodynamic effect.
Definition of EHD Effect. EHD technique utilizes the effect
of an applied voltage and low current electric field. This technique creates and utilizes
the effects of secondary motions generated by the coupling of
high-voltage, low current electric field with the flow field
in a dielectric fluid medium. The enhancement generated by
the electric field is electronically controllable and responds
spontaneously to operating condition and load demand.
Benefits of EHD Effect. Elimination of Boiling Hysteresis (which results in instantaneous ebullition at nucleation sites). Enhancement of film boiling regime-consequent increase in critical heat flux. Leads to modified bubble dynamics and enhanced fluid convection on both phases, which promotes increase in heat transfer. First demonstration of a silicon-based EHD Micro-Channel Cooling Device
Funded by Northrop Grumman, device to be incorporated into microwave transmit/receive modules with wide applications in electronnic cooling.
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