Miniaturization of Electrostatic Fluid Accelerators

Hsu, Cheng-Wei; Jewell-Larsen, N.E.; Rollins, Allison; Krichtafovitch, Igor; Montgomery, S.W.; DiBene, J.T.; Mamishev, A.V.

doi:10.1115/imece2006-13990

Cited by 10 publications

(7 citation statements)

References 14 publications

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“…Recently, ionic wind devices reduced to microscale dimensions have been proposed for on-chip thermal management of electronic devices [19] [20]. As the electrode gap is decreased to 10-20 μm, the ionization phenomenon is no longer due to the acceleration of free electrons (i.e., corona discharge) but rather the injection of electrons into air from the cathode by field emission.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of external forced convection by ionic wind

Maturana

Fisher

et al. 2008

International Journal of Heat and Mass Transfer

129

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An ionic wind is formed when air ions are accelerated by an electric field and exchange momentum with neutral air molecules, causing air flow. Because ionic winds can generate flow with no moving parts and have low power consumption, they offer an attractive method for enhancing convection heat transfer from a surface. In the present work, corona discharges are generated between a steel wire and copper-tape electrode pair on a flat plate, perpendicular to the bulk flow direction such that the ensuing ionic wind is in the direction of the bulk flow. The corona discharge current is characterized, and experimental measurements of heat transfer from a flat plate are reported. Infrared images demonstrate that the cooling occurs along the entire length of the wire, and local heat transfer coefficients are shown to increase by more than 200% above those obtained from bulk flow alone. The magnitude of the corona current and the heat flux on the flat plate are varied. The heat transfer coefficient is shown to be related to the fourth root of the corona current both analytically and experimentally, and heat transfer enhancement is seen to be a solely hydrodynamic effect.Variation of the spacing between electrodes demonstrates that while the local peak enhancement is largely unaffected, the area of heat transfer enhancement is dependent on this spacing.

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Section: Introductionmentioning

confidence: 99%

Enhancement of external forced convection by ionic wind

Maturana

Fisher

et al. 2008

International Journal of Heat and Mass Transfer

129

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show abstract

“…The heat-transfer coefficient and temperature drop are higher for the smaller emitter radius (i.e., an average temperature drop of 2.7 °C versus 2.2 °C and a heat-transfer coefficient of 510 W/m^ K versus 500 W/m^ K) when all other conditions are the same. The main reason for this is that the inception or onset voltage is reduced with a smaller emitter radius (i.e., a higher curvature co- rona electrode) [21,26]. Reducing the size of the sharp electrode will produce higher electric field strength, which generates a stronger electric force resulting in more pronounced air jet impingement.…”

Section: Varying Emitter Radiusmentioning

confidence: 99%

“…A prior generation of a microfabricated ionic wind pump similar to that described herein was previously used as for air monitoring sensors [20][21][22]. Others have specifically investigated the use of ionic wind pumps for thermal management applications [23][24][25][26][27][28][29][30]. For example, a device consisting of a microfabricated silicon cantilever corona electrode and a copper-based flat collecting electrode [29] demonstrated an impressive power consumption of only 165 mW, which is only one-eighth of the total heating power removed with a constant surface-to-ambient-temperature difference of approximately 38.3 °C.…”

Section: Introductionmentioning

confidence: 99%

Electrohydrodynamic Microfabricated Ionic Wind Pumps for Thermal Management Applications

Ong

Abramson

Tien

2014

Journal of Heat Transfer

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This work demonstrates an innovative microfabricated air-cooling technology that employs an electrohydrodynamic (EHD) corona discharge (i.e., ionic wind pump) for electronics cooling applications. A single, microfabricated ionic wind pump element consists of two parallel collecting electrodes between which a single emitting tip is positioned. A grid structure on the collector electrodes can enhance the overall heat-transfer coefficient and facilitate an IC compatible batch process. The optimized devices studied exhibit an overall device area of 5.4 mm x 3.6 mm, an emitter-to-collector gap of 0.5 mm. and an emitter curvature radius of'-^12.5 p.m. The manufacturing process developed for the device uses glass wafers, a single mask-based photolithography process, and a low-cost copper-based electroplating process. Various design configurations were explored and modeled computationally to investigate their influence on the cooling phenomenon. The single devices provide a high heat-transfer coefficient of up to ^3200 Wlrrf K and a coefficient of performance (COP) of up to ~47. The COP was obtained by dividing the heat removal enhancement, Ag by the power consumed by the ionic wind pump device. A maximum applied voltage of 1.9kV, which is equivalent to approximately 38 mW of power input, is required for operation, which is significantly lower than the power required for the previously reported devices. Furthermore, the microfabricated single device exhibits a flexible and small form factor, no noise generation, high efficiency, large heat removal over a small dimension and at low power, and high reliability (no moving parts); these are characteristics required by the semiconductor industry for next generation thermal management solutions.

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“…EHD gas pumps are usually driven by a corona discharge. Although a needle electrode [10], [11] and a razor electrode [12], [13] are used as a corona electrode, such electrodes with sharp edges seem to be undesirable because a transition to a spark discharge can easily occur. On the other hand, a wire electrode has been proven to achieve a stable corona discharge, for example, in many commercial ESPs [14] and copy machines [15].…”

Section: Introductionmentioning

confidence: 99%

Efficiency of a Wire-Rod Type Electrohydrodynamic Gas Pump Under Negative Corona Operation

Takeuchi

Yasuda

2009

IEEE Trans. Plasma Sci.

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A wire-rod type electrohydrodynamic (EHD) gas pump was driven by a negative applied voltage with pipes of different inner diameters. An EHD gas flow was generated from a wire electrode to a rod electrode under a negative corona discharge. The flow velocity was proportional to the applied voltage and the square root of the discharge current. Before spark onset, the maximum volumetric flow rate of 43 L/min was achieved with a pipe having an inner diameter 20 mm, and the pump efficiency was higher than that of a conventional dc motor fan. In a narrow channel, the corona discharge became unstable. In addition, the EHD gas flow velocity was smaller because a pressure loss due to the rod electrode became significant, resulting in a lower electromechanical efficiency.

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Miniaturization of Electrostatic Fluid Accelerators

Cited by 10 publications

References 14 publications

Enhancement of external forced convection by ionic wind

Enhancement of external forced convection by ionic wind

Electrohydrodynamic Microfabricated Ionic Wind Pumps for Thermal Management Applications

Efficiency of a Wire-Rod Type Electrohydrodynamic Gas Pump Under Negative Corona Operation

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