Experimental Investigation of the Thermal Performance of Piezoelectric Fans

Açıkalın, Tolga; Wait, Sydney M.; Garimella, Suresh V.; Raman, Arvind

doi:10.1080/01457630490248223

Cited by 163 publications

(59 citation statements)

References 9 publications

(13 reference statements)

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“…Micro-and nano-scale applications of cantilevers include biosensors (Gupta et al 2006 andIlic et al 2001), atomic force microscope cantilevers (Binnig 1986), and rheological measurement devices (Boskovic et al 2002). At larger length scales, applications such as piezoelectric fans for electronics cooling (Açıkalın et al 2004) and Kimber et al 2007) and flapping wings for propulsion (Shyy et al 1999) involve vibrating cantilevers. Although different length scales are of interest depending on the application, the common feature is that the dynamic behavior is dependent on the interaction between the structure and the fluid.…”

Section: Introductionmentioning

confidence: 99%

Experimental study of aerodynamic damping in arrays of vibrating cantilevers

Kimber

Lonergan

Garimella

2009

Journal of Fluids and Structures

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Cantilever structures vibrating in a fluid are encountered in numerous engineering applications. The aerodynamic loading from a fluid can have a large effect on both the resonance frequency and damping, and has been the subject of numerous studies. The aerodynamic loading on a single beam is altered when multiple beams are configured in an array. In such situations, neighboring beams interact through the fluid and their dynamic behavior is modified. In this work, aerodynamic interactions between neighboring cantilever beams operating near their first resonance mode and vibrating at amplitudes comparable to their widths are experimentally explored. The degree to which two beams become coupled through the fluid is found to be sensitive to vibration amplitude and proximity of neighboring components in the array. The cantilever beams considered are slender piezoelectric fans (approximately 6 cm in length), and are caused to vibrate in-phase and out-of-phase at frequencies near their fundamental resonance values. Aerodynamic damping is expressed in terms of the quality factor for two different array configurations and estimated for both in-phase and out-of-phase conditions. The two array configurations considered are for neighboring fans placed face-to-face and edge-to-edge. It is found that the damping is greatly influenced by proximity of neighboring fans and phase difference. For the face-to-face configuration, a reduction in damping is observed for in-phase vibration, while it is greatly increased for out-of-phase vibration; the opposite effect is seen for the edge-to-edge configuration. The resonance frequencies also show a dependence on the phase difference, but these changes are small compared to those observed for damping. Correlations are developed based on the experimental data which can be used to predict the aerodynamic damping in arrays of vibrating cantilevers. The distance at which the beams no longer interact is quantified for both array configurations.Understanding the fluid interactions between neighboring vibrating beams is essential for predicting the dynamic behavior of such arrays and designing them for practical applications.

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Section: Introductionmentioning

confidence: 99%

Experimental study of aerodynamic damping in arrays of vibrating cantilevers

Kimber

Lonergan

Garimella

2009

Journal of Fluids and Structures

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“…They developed two-and threedimensional numerical models of acoustic streaming and Piezoelectric fans using higher flexural modes for electronics cooling applications Sydney M. Wait, Sudipta Basak, Suresh V. Garimella, and Arvind Raman P investigated the influence of wave amplitude and back pressure on the time-averaged velocity in the flow field. The flow generated by vibrating beams has been studied by several authors as a mechanism by which to enhance heat transfer [1,2,[9][10][11][12][13]. Significant promise has been shown for utilizing piezoelectric fans operating at their first resonance mode for cooling.…”

Section: Introductionmentioning

confidence: 99%

“…Piezoelectric fans are one innovative technology that are gaining acceptance as a viable solution [1,2]. These fans generally consist of a patch of piezoelectric material attached to one or both sides of a shim stock as illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

Piezoelectric Fans Using Higher Flexural Modes for Electronics Cooling Applications

Wait

Basak

Garimella

et al. 2007

IEEE Trans. Comp. Packag. Technol.

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Abstract-Piezoelectric fans are gaining in popularity as lowpower-consumption and low-noise devices for the removal of heat in confined spaces. The performance of piezoelectric fans has been studied by several authors, although primarily at the fundamental resonance mode. In this article the performance of piezoelectric fans operating at the higher resonance modes is studied in detail. Experiments are performed on a number of commercially available piezoelectric fans of varying length. Both finite element modeling and experimental impedance measurements are used to demonstrate that the electromechanical energy conversion (electromechanical coupling factors) in certain modes can be greater than in the first bending mode; however, losses in the piezoceramic are also shown to be higher at those modes. The overall power consumption of the fans is also found to increase with increasing mode number.Detailed flow visualizations are also performed to understand both the transient and steady-state fluid motion around these fans. The results indicate that certain advantages of piezoelectric fan operation at higher resonance modes are offset by increased power consumption and decreased fluid flow.

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“…Later work by Toda and Osaka [3] first proposed the use of piezoelectric fans for thermal management in electronic devices. Acikalin et al [4] investigated the feasibility of using piezoelectric fans to cool portable electronic devices. In this study, a heat source was placed into an enclosure of similar dimensions to a mobile phone and subsequently cooled by a piezoelectric fan operating in various orientations.…”

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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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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Experimental Investigation of the Thermal Performance of Piezoelectric Fans

Cited by 163 publications

References 9 publications

Experimental study of aerodynamic damping in arrays of vibrating cantilevers

Experimental study of aerodynamic damping in arrays of vibrating cantilevers

Piezoelectric Fans Using Higher Flexural Modes for Electronics Cooling Applications

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

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