School of Mechanical Engineering Elad Weinberg

School of Mechanical Engineering Seminar
Monday, May 14, 2018 at 14:00
Wolfson Building of Mechanical Engineering, Room 206

Developed Flow and Heat Transfer from a Micro Jet Array with Inter-Jet Liquid Extraction

Elad Weinberg

 M.Sc. student of Dr. Herman D. Haustein

Small high-power electronic components produce high heat fluxes and therefore need sufficient cooling to maintain high performance and prevent them from failing. Current cooling systems are not be able to provide future needs and new methods of cooling are required. The present study studies the flow structure and heat transfer of a submerged jet array, with inter-jet spent-fluid extraction, as a promising solution for cooling high power chips (VLSI) obtained from this configuration. The jets are 600 microns in diameter and extraction employs 1.2mm pipes in a 3x3 and 4x4 array, accordingly. This array cools a simulated microchip - a square 25x25mm transparent heater (from ITO). The apparatus emulates a micro cooling system where the flow rates are low, the flow in the jets is kept fully developed and in the laminar regime. The system developed is highly modular, symmetrical and transparent for detailed study and comparison to flow field simulations and results from the literature. High speed visualization of the flow and the wall temperature was obtained through real time micro-PIV and dynamic IR thermography/microscopy. The flow and heat transfer under these developed laminar conditions was found to be quasi-steady, allowing in situ calibration and image subtraction to give high velocity and thermal resolution (0.04m/s & 0.045K).  The effect of flow rate and distance between incoming jet and heated surface on heat transfer, under inter-jet liquid extraction are examined. The velocity profiles at various locations under the jet agreed well with those obtained by simulation, and showed that at the microscale under controlled condition the jet-edge vortices do not arise even up to Re≤2,000.