Nonuniform Temperature Distribution in Electronic Devices Cooled by Flow in Parallel Microchannels

By Gad Hetsroni, A. Mosyak, Z. Segal. Packaging of Electronic and Photonic Devices, 2000

204 citations recorded by the source corpus.

We fabricated a novel thermal microsystems (simulating a computer chip) consisting of a heater, microchannels, inlet and outlet plena and we studied the effect of the geometry on the flow and heat transfer. The vapor - water two-phase flow patterns were observed in the parallel microchannels through a microscope and high-speed video camera. It was observed that hydraulic instabilities occur. Existence of a periodic annular flow was also observed, which consist of a symmetrically distributed liquid ring surrounding the vapor core. Along the microchannel axis, the periodic dry zone appears and develops. The thermal visualization and temperature measurements of the heated device were carried out using infrared thermography. As long as the flow was single phase liquid, the forced convection heat transfer resulted in a moderate irregularity on the heated chip. These temperature differences do not cause damage to the device. The steady-state heat transfer for different types of microchannels has been studied also at the range of heat flux where phase change of the working fluid from liquid to vapor took place. Under conditions of flow boiling in microchannels, a significant enhancement of heat transfer was established. In the case of uniform heat flux the hydraulic instabilities lead to irregularity of temperature distribution on the heated chip. In the case of nonuniform heat flux the irregularity increased drastically.

Subfields: Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/27e2f631585672046d38ce5bb0c7d81ee572b3f3

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In Mechanical Engineering

Citations in the corpus

Two-Phase Flow Patterns, Pressure Drop, and Heat Transfer during Boiling in Minichannel Flow Passages of Compact Evaporators (2002, background): “Hestroni et al. [ 29 ] studied the evaporation of water in multichannel evaporators.”
Effect of axial conduction on the heat transfer in micro-channels (2004, background): “The experimental facility and flow loop, are described in detail in [21,22].”
History, Advances, and Challenges in Liquid Flow and Flow Boiling Heat Transfer in Microchannels: A Critical Review (2012, methodology): “During 1992–2001, the major developments included a systematic study in minichannels and silicon microchannels, local heat transfer coefficient data, and identifying major obstacles [113–117].”
Measurements and High-Speed Visualizations of Flow Boiling of a Dielectric Fluid in a Silicon Microchannel Heat Sink † (2006, background): “Hetsroni et al. (2001) observed periodic annular flow represented by a symmetrically distributed liquid ring surrounding the vapor core interspersed with periodic dry zones characterized by the occurrence of dry spots on the channel walls.”
Fundamental issues related to flow boiling in minichannels and microchannels (2002, background): “[18] studied the evaporation of water in multichannel evaporators.”
Effects of inlet/outlet configurations on flow boiling instability in parallel microchannels (2008, methodology): “The method was similar to those used by Hetsroni et al [7,8] and Xu et al.”
A uniform temperature heat sink for cooling of electronic devices (2002, background): “The measurements performed in the same experimental set-up [15] show that the pressure drop, DP , is proportional, under these conditions, to the mean velocity, u.”
Unstable and stable flow boiling in parallel microchannels and in a single microchannel (2007, background): “Recently, a great deal of attention has been given to the study of dynamic flow boiling instability in microchannels [8–17].”
Nucleation characteristics and stability considerations during flow boiling in microchannels (2006, background): “[10] observed periodic annular flow in microchannels of 103–129 lm hydraulic diameters with water flow; Kennedy et al.”