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- Genre: Doctoral Dissertation
Description
The heat transfer enhancements available from expanding the cross-section of a boiling microchannel are explored analytically and experimentally. Evaluation of the literature on critical heat flux in flow boiling and associated pressure drop behavior is presented with predictive critical heat flux (CHF) and pressure drop correlations. An optimum channel configuration allowing maximum CHF while reducing pressure drop is sought. A perturbation of the channel diameter is employed to examine CHF and pressure drop relationships from the literature with the aim of identifying those adequately general and suitable for use in a scenario with an expanding channel. Several CHF criteria are identified which predict an optimizable channel expansion, though many do not. Pressure drop relationships admit improvement with expansion, and no optimum presents itself. The relevant physical phenomena surrounding flow boiling pressure drop are considered, and a balance of dimensionless numbers is presented that may be of qualitative use. The design, fabrication, inspection, and experimental evaluation of four copper microchannel arrays of different channel expansion rates with R-134a refrigerant is presented. Optimum rates of expansion which maximize the critical heat flux are considered at multiple flow rates, and experimental results are presented demonstrating optima. The effect of expansion on the boiling number is considered, and experiments demonstrate that expansion produces a notable increase in the boiling number in the region explored, though no optima are observed. Significant decrease in the pressure drop across the evaporator is observed with the expanding channels, and no optima appear. Discussion of the significance of this finding is presented, along with possible avenues for future work.
ContributorsMiner, Mark (Author) / Phelan, Patrick E (Thesis advisor) / Baer, Steven (Committee member) / Chamberlin, Ralph (Committee member) / Chen, Kangping (Committee member) / Herrmann, Marcus (Committee member) / Arizona State University (Publisher)
Created2013
DescriptionThe purpose of this project is to explore the influence of folk music in guitar compositions by Manuel Ponce from 1923 to 1932. It focuses on his Tres canciones populares mexicanas and Tropico and Rumba.
ContributorsGarcia Santos, Arnoldo (Author) / Koonce, Frank (Thesis advisor) / Rogers, Rodney (Committee member) / Rotaru, Catalin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Whenever a text is transmitted, or communicated by any means, variations may occur because editors, copyists, and performers are often not careful enough with the source itself. As a result, a flawed text may come to be accepted in good faith through repetition, and may often be preferred over the authentic version because familiarity with the flawed copy has been established. This is certainly the case with regard to Manuel M. Ponce's guitar editions. An inexact edition of a musical work is detrimental to several key components of its performance: musical interpretation, aesthetics, and the original musical concept of the composer. These phenomena may be seen in the case of Manuel Ponce's Suite in D Major for guitar. The single published edition by Peer International Corporation in 1967 with the revision and fingering of Manuel López Ramos contains many copying mistakes and intentional, but unauthorized, changes to the original composition. For the present project, the present writer was able to obtain a little-known copy of the original manuscript of this work, and to document these discrepancies in order to produce a new performance edition that is more closely based on Ponce's original work.
ContributorsReyes Paz, Ricardo (Author) / Koonce, Frank (Thesis advisor) / Solis, Theodore (Committee member) / Rotaru, Catalin (Committee member) / Arizona State University (Publisher)
Created2013