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Local Heat Transfer Rate and Bubble Dynamics during Jet Impingement Boiling

Characterization of local boiling trends, in addition to the typically reported area-averaged trends, is essential for the robust design and implementation of phase change technologies to sensitive heat transfer applications such as electronics cooling. Obtaining the values of heat fluxes corresponding to locally varying surface temperatures has been a challenge limiting most investigations to areaaveraged results. This thesis illustrates the importance of a spatially local heat transfer analysis during boiling. Pool and submerged jet impingement boiling scenarios on a silicon surface are considered at the macroscale (27.5 mm heater with multiple nucleation sites) and microscale (1000 μm heater for isolated bubble generation), by the use two thin film serpentine heater geometries. Unique to this study is the documentation of local boiling curves for different radial locations on the macroscale heater surface and their comparison with the corresponding area-averaged representations. The effect of jet inertia on bubble departure characteristics and latent heat transfer during jet impingement boiling at the microscale hot-spot are compared with pool boiling using quantitative microscale high-speed visualization. Overall, the results from this study will aid the local characterization of boiling heat transfer for applications in electronics cooling. Monday, October 29, 2012 1:00 PM, Valley LibraryWillamette West Room School of Mechanical, Industrial and Manufacturing Engineering