• Donnelly B.
  • Jeffers N.
  • Stafford J.

Piezoelectric fans are receiving increased interest for thermal management applications because of their reliability, minimal power consumption, and noise-free operation. These features are of particular interest to companies who have strict reliability constraints and have reached the thermal limit of conventionally used natural convection heat sinks. For a classical piezoelectric fan operated at its primary resonance frequency mode, the majority of airflow propagates from the fan tip. This type of airflow is advantageous if the heat source is positioned perpendicular to the long side of the fan, however if the heat source is parallel to the fan these advantages are not observed. This paper investigates the fluid mechanics and heat transfer from a fan operating at its secondary resonant frequency mode. The objective was to generate superior airflow and cooling when the fan is positioned parallel to a heated surface. The piezoelectric fan used in this study is a 12.7mm x 110mm fan with the second resonant mode at 77Hz. A custom built experimental facility was developed to capture both the fluid flow fields from the fan using Particle Image Velocimetry (PIV) and the subsequent thermal patterns that occur on a heated surface with infrared imaging. A constant heat flux foil was employed to capture the full field infrared measurements. The results show two jets are formed in opposing directions emanating from the midsection of an unconfined fan in free space. Enhanced heat transfer is observed on the heated foil caused by the impingement of the lower jet. The results found in this paper show that there are advantages to operating the fan at its second resonant frequency mode.

Recent Publications

August 09, 2017

A Cloud Native Approach to 5G Network Slicing

  • Francini A.
  • Miller R.
  • Sharma S.

5G networks will have to support a set of very diverse and often extreme requirements. Network slicing offers an effective way to unlock the full potential of 5G networks and meet those requirements on a shared network infrastructure. This paper presents a cloud native approach to network slicing. The cloud ...

August 01, 2017

Modeling and simulation of RSOA with a dual-electrode configuration

  • De Valicourt G.
  • Liu Z.
  • Violas M.
  • Wang H.
  • Wu Q.

Based on the physical model of a bulk reflective semiconductor optical amplifier (RSOA) used as a modulator in radio over fiber (RoF) links, the distributions of carrier density, signal photon density, and amplified spontaneous emission photon density are demonstrated. One of limits in the use of RSOA is the lower ...

July 12, 2017

PrivApprox: Privacy-Preserving Stream Analytics

  • Chen R.
  • Christof Fetzer
  • Le D.
  • Martin Beck
  • Pramod Bhatotia
  • Thorsten Strufe

How to preserve users' privacy while supporting high-utility analytics for low-latency stream processing? To answer this question: we describe the design, implementation and evaluation of PRIVAPPROX, a data analytics system for privacy-preserving stream processing. PRIVAPPROX provides three properties: (i) Privacy: zero-knowledge privacy (ezk) guarantees for users, a privacy bound tighter ...