An experimental framework for investigation of the effects of Micro Pin Fin Arrays (MPFA) on the fuel oxidation efficiency of catalytic combustion is presented in this thesis. Complete combustion of the fuel is essential for operation at maximum efficiency and high standards of environmental cleanliness desired in existing microscale combustion...
A combined experimental and computational fluid dynamics (CFD) study of single-phase liquid nitrogen flow through a microscale pin-fin heat sink is presented. Such cryogenic heat sinks could find use in applications such as high performance computing, spacecraft thermal management, and hydrogen storage thermal management. A circular pin fin heat sink...
Modern electronics have created increased demand for innovative cooling solutions. Typical forced convective cooling systems consist of pumps that circulate cooling fluid. However pumps can be unwieldy for many applications. This research is a continuation of work done at Oregon State University and Auburn University on the passive pumping of...
A novel microscale combustor-heat exchanger (μCHX) for hydrogen storage applications is presented in this dissertation. The design of the μCHX is motivated by its application to two particular systems for automotive use- those that utilize metal hydrides (MH) and cryo-adsorbents (CA) to store hydrogen. Thermal energy needs to be supplied...
The research presented in this thesis is a continuation of collaboration between Oregon State University and Auburn University studying the feasibility of passively pumping liquid during boiling in a preferential direction using meso-scaled asymmetric surface patterns. Such a passive phase-change mechanism has great potential for thermal management in spacecraft and...
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...
Technologies such as avionics and power electronics are driving the demand for thermal management schemes towards high heat fluxes and low surface temperatures. Typically, these applications require the dissipation of heat fluxes in the rage of 100-1000 W/cm² while maintaining surface temperatures lower than about 85 °C. Phase-change heat transfer...
Recent studies of flow boiling within microchannels have shown high heat fluxes, leading to successful design and testing of compact heat exchangers, cooling systems for electronics and other high efficiency, miniature components. An experimental study of flow boiling of a concentrated salt solution in microchannels is presented. Experiments examined flow...
Infrared (IR) thermography is applied to estimate heat transfer rates in external and internal microscale convective flows. The technique and analysis are developed in the context of external jet impingement flow and internal single-phase liquid flows. A heated-thin-foil thermography technique is applied to perform surface temperature visualization on a submerged...
Experiments on a novel, microscale hydrogen combustor heat exchanger (µCHX) are presented in this thesis. The µCHX has been designed to efficiently transfer thermal energy to a heat transfer fluid for use in desorption of hydrogen from a metal hydride storage system of a hydrogen-powered fuel cell vehicle. The experimental...