Interactions between fluid flow, heat transfer, and particle transport in the presence of jet-axis switching and realistic fluid movers

摘要

The overarching goal of this thesis is to identify and quantify new processes and phenomena related to fluid flow, heat transfer, and particle transport interacting in unique modes. The research can be categorized into three modes of interaction: (a) heat transfer processes governed by the complex patterns of fluid flow provided by real-world fluid-moving devices, (b) heat transfer processes which are governed by a naturally occurring, extraordinary fluid-flow phenomenon, and (c) interacting fluid flow, particle transport, and heat transfer all of which are governed by the aforementioned extraordinary fluid-flow phenomenon. These categories are respectively treated in individual chapters of the thesis.;The traditional approach to convective heat transfer is virtually devoid of realistic fluid flow models. As a consequence, traditional convective heat transfer analysis is oversimplified to the point of being out of step with reality. This assertion is proven here, and a new fundamentals-based model of high fidelity involving realistic fluid movers of is created.;Next, the extraordinary fluid flow phenomenon designated as jet-axis switching is introduced and illustrated quantitatively. This phenomenon occurs whenever a non-circular jet passes into and through an unrestricted space. When the jet is involved in a process called jet-impingement heat transfer, the zone of jet incidence is highly altered due to the axis-switching process. The ignoring of the switching process, which has been standard in all previous work on non-circular-jet impingement heat transfer, has been shown here to be highly error prone.;The major part of the thesis encompasses jet-axis-switching fluid mechanics, convective heat transfer, and particle transport. An all-encompassing simulation model was created which took account of fluid-particle, particle-particle, fluid--impingement plate, and particle--impingement plate interactions, all with heat transfer. It was found that jet-axis switching exerted a major effect on the trajectories of the particles, with a corresponding impact on the particle collection efficiency of the impactor plate. The transfer of heat between the fluid and the impingement plate was little affected by any alterations in the pattern of fluid flow caused by the presence of particles. On the hand, direct particle-to-plate heat transfer is substantial.