Measurement and prediction of the cooling characteristics of a generalized vibrating piezoelectric fan

Kimber, Mark; Garimella, Suresh V.

doi:10.1016/j.ijheatmasstransfer.2009.03.055

Cited by 113 publications

(27 citation statements)

References 23 publications

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“…This is in contrast to much of the literature on oscillating piezoelectric fans where airflow emanates in a forward direction from the fan tip. The cooling capabilities of these airflows as they impinge on a heated surface have been studied extensively ( [5], [11], [12], [13]). The lateral wake regions in the current work Fig.…”

Section: X-y Plane Measurementsmentioning

confidence: 99%

“…A heat transfer enhancement of over 100% was recorded when operating in the horizontal orientation relative to e-mail: ciaran.conway@ul.ie passive cooling. Kimber and Garimella [5] investigated the influence of variables such as amplitude, frequency and fan height on the thermal performance of piezoelectric fans oscillating normal to a heated surface. It was found that the performance of a given fan can be described in terms of oscillation frequency and amplitude only, with frequency being more influential on maximum heat transfer rates.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of Surface Roughness on the Flow Fields Generated by an Oscillating Cantilever

Conway

Punch

2018

EPJ Web Conf.

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Abstract. With the current trend of miniaturisation of electronic devices, piezoelectric fans have attracted increasing interest as a means of inducing forced convection cooling, instead of traditional rotary solutions. Although there exists an abundance of research on various piezo-actuated flapping fans in the literature, the geometries of these fans all consist of a smooth rectangular cross section with thicknesses typically of the order of 100 µm. The focus of these studies has primarily been on variables such as frequency, amplitude and, in some cases, resonance mode. It is generally noted that the induced flow dynamics are a direct consequence of the pressure differential at the fan tip as well as the pressure driven 'over the top' vortices generated at the upper and lower edges of the fan. Rough surfaces such as golf ball dimples or vortex generators on an aircraft wing have proven to be beneficial by tripping the boundary layer and energising the adjacent airflow. This paper aims to examine the influence of surface roughness on the airflow generation of a flapping fan, and to determine if the induced wake can be manipulated or enhanced by energising the airflow around the fan tip. Particle-Image Velocimetry (PIV) is carried out on mechanically oscillated rigid fans with surfaces consisting of protruding pillars and dimples. A smooth rigid fan surface is also investigated as a control. No significant difference was noted between the smooth and roughened fans through observation of the induced flow fields. Both fans produced results that were largely consistent with the existing literature on oscillating cantilevers. The results of this paper may be used to inform the design of piezoelectric fans and to aid in understanding the complex aerodynamics inherent in flapping wing flight.

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Section: X-y Plane Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Influence of Surface Roughness on the Flow Fields Generated by an Oscillating Cantilever

Conway

Punch

2018

EPJ Web Conf.

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“…Liu et al [6] tested the thermal performance of fans with various fan geometries and horizontal/vertical arrangements. Kimber and Garimella [7] measured various piezoelectric fans mounted perpendicular to a constant heat flux surface and studied the thermal performance across specific range of fan dimensions, vibration frequency, and amplitude. The experimental results show that vibration frequency has more significant effect on the heat transfer rate than vibration amplitude.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on the Flow Field Produced by Oscillating Foils

et al. 2017

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Abstract. In present manuscript, the flow field produced by oscillating foils in a duct were under investigation numerically. The flow field was considered as an incompressible laminar transient flow. In this paper, the oscillating frequencies were 2, 4 and 6 Hz; the span angles of the foil were 30˚, 60˚, 90˚, 120˚, and 150˚, respectively. The flow field produced by a particular oscillating pattern (fast forward slow backward, FFSB) has been made in comparison with that by the sinusoidal oscillating pattern. The flow field produced by dual oscillating foils was also analysed. Two foils oscillated in the same direction (in-phase) and in the opposite direction (counter-phase) were studied as well. Commercial software ANSYS-FLUENT was employed for the 2D numerical simulation. A moving grid technique was utilized in the analysis. Results present the flow average velocity increases as the oscillating frequency increases. It is also shown that the flow average velocity with span angle of 120˚ is the largest among these cases. In addition, the flow average velocity with dual foils is better than that with a single foil.

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“…Since then, many studies experimentally examined the performance of heat transfer enhancement under the actuation of a piezofan [3][4][5][6][7]. Some numerical studies were performed to investigate the flow fields and heat transfer performance of piezofans [8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

A Study of an Effective Heat-Dissipating Piezoelectric Fan for High Heat Density Devices

Lin

Jang

Leu³

2016

Energies

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Abstract:Heat dissipation per unit volume has grown rapidly, as the size of modern electronic devices has continued to decrease. The air flow induced by an oscillating cantilever blade enhances the heat transfer performance of high heat density devices. The heat transfer improvement mainly depends on the velocity magnitude and distribution of air streams induced by the vibrating blade. Accordingly, this study numerically and experimentally examines the time-varying flow characteristics of a vibrating cantilever for five blade types. The blades are rectangular or trapezoidal with various widths and actuated at various frequencies. The fluid domain is numerically discretized using a dynamic meshing scheme to model the three-dimensional time-varying vibrating blade. The experiment utilizes nine hot-wire velocity meters to measure the average velocities. The flow structure with streamlines and velocity contours of the induced air flow are determined at various section planes. The results show that a major maximum-velocity region appears around the blade tip and that four minor local-maximum-velocity regions appear at the four corners. In addition, the width and width ratio of the blade significantly affects the velocity distribution of the flow induced by the vibrating cantilever blade.

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Measurement and prediction of the cooling characteristics of a generalized vibrating piezoelectric fan

Cited by 113 publications

References 23 publications

The Influence of Surface Roughness on the Flow Fields Generated by an Oscillating Cantilever

The Influence of Surface Roughness on the Flow Fields Generated by an Oscillating Cantilever

Numerical Investigation on the Flow Field Produced by Oscillating Foils

A Study of an Effective Heat-Dissipating Piezoelectric Fan for High Heat Density Devices

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