From the Summer of 2005 until my graduation in August 2009, I worked in Dr. Kenneth Kihm's Micro-Nano Scale Fluidics and Energy Transport (MINSFET) lab in the University of Tennessee Science and Engineering Research Facility (SERF) building. In my initial research, I collaborated with two other lab members to study the evaporation and dryout of nanofluid droplets. We used a microheater array fabricated by Dr. Sokwon Paik to spatially and temporally resolve heat transfer in an evaporating droplet of nanofluid. Our work has applications in electronic cooling and nano-lithography and resulted in two published works. You can click on the graphics below to access the publications.
The research in this dissertation addresses the steady evaporation of a capillary pore with a liquid metalworking fluid. First, the interline region of an extended meniscus thin film is considered for the uniquephysical case of a liquid metal. A new thin film evaporation model is presented that captures the unsimplifieddispersion force along with an electronic disjoining pressure component that is unique to liquid metals. Theresulting nonlinear 4th-order ODE is solved using an implicit orthogonal collocation technique along withthe Levenberg-Marquardt method. Results show that the electronic component of the disjoining pressureshould be considered when modeling liquid metal extended meniscus evaporation for a wide range of workfunction boundary values, which represent physical properties of dierent liquid metals. For liquid sodium,as an example test material, variation in the work function produces order-of-magnitude dierences in thefilm thickness and evaporation profile.
Second, the extended meniscus thin film model is spliced with a CFD model of the evaporating bulkmeniscus. The result is a multiscale model of the total evaporating capillary meniscus with a nonisothermalinterface and non-equilibrium evaporation. Integration of the evaporative mass flux across the total meniscussurface area produces total capillary evaporative mass flow rates and enables comparisons between electronicdisjoining pressure states. The clear trend from these comparisons is that a larger electronic component ofthe disjoining pressure leads towards larger extended meniscus thin film surface area, larger total capillarymeniscus surface area, and larger net evaporative mass flow rate (which corresponds with larger heat flowrate, as well).
Finally, an outline is presented of the scope of the general problem in the application of nonlinearstability theory to a liquid metal evaporating thin film.