October 20, 2016

The characterization of a low-profile channel-confined jet for targeted hot-spot cooling in microfluidic applications

  • Jeffers N.
  • Punch J.
  • Stafford J.
  • Waddell A.

Photonics Integrated Circuits are the backbone of the optical-fiber networks that enable high-speed communication on a global scale. Contemporary devices contain laser-bars which must be controlled within 0.1 K, and are capable of generating heat fluxes 1 kW/m2. This represents one of the highest heat fluxes found in nature or engineering applications, and the thermal challenge places a limitation on the density of laser-bar arrays on an individual chip. Chip-integrated fluidic cooling has been proposed for the thermal management of next-generation PICs to create more energy efficient devices, capable of greater data throughput. Jet impingements are of interest as the primary heat exchangers in this system due to the large heat transfer rates that can be achieved. The objective of this work is to generate a novel, low profile jet impingement within an individual channel suitable for targeting hot-spots in a densely packed circuit, at the low Reynolds numbers prevalent in micro- fluidic applications. To this end, two experiments were performed to non-invasively observe the velocity field and local heat transfer in a square miniature channel containing a curved orifice-plate to manipulate the fluid flow. A range of Reynolds numbers and obstruction opening area ratios were investigated through Particle Image Velocimetry and infrared thermography of a Joule-heated foil. The velocimetry data showed that the curved orifice-plate geometry successfully generated an inclined jet within the channel, and maximum improvements in the area-averaged heat transfer coefficient of 495 pc relative to a channel containing no obstruction were measured. The heat transfer data showed Nu scales with Re^0.59 scaling, similar to that of a micro-fluidic array of normally impinging jets, and this physical relationship is beneficial in the design and modeling of fluidic cooling systems. The findings illustrate the impact of a channel confined jet on spatial heat transport, and demonstrate the potential for controlled heat transfer enhancement using unconventional obstructions within laminar channel flows.

View Original Article

Recent Publications

August 09, 2017

A Cloud Native Approach to 5G Network Slicing

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 ...