Thesis (Ph. D.)--University of Wisconsin--Madison, 1982. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 301-306).

Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 127-131).

Orientador: Kamal Abdel Radi Ismail / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-14T07:13:39Z (GMT). No. of bitstreams: 1 SousaFilho_LourivalMatosde_M.pdf: 2554893 bytes, checksum: 7939c6dc3737b42a91be61a78bbae721 (MD5) Previous issue date: 2009 / Resumo: No presente trabalho foi estudado numérico-experimental o processo de solidificação de água ao redor de tubos curvos com diferentes raios de curvaturas, diferentes temperaturas de entrada do fluido refrigerante e número de Dean, que quantificam o grau de curvatura do tubo. O principal objetivo fundamenta-se em analisar a influência desses parâmetros na espessura da camada de gelo. A espessura da camada solidificada foi determinada sobre fotos obtidas de câmera que captura as imagens em intervalos de tempo pré-estabelecido e eram posteriormente digitalizadas. O método numérico utilizado para a interface móvel foi a imobilização de fronteira móvel, e as equações diferenciais do modelo foram discretizadas pelo método de volumes finitos. Correlações para Nusselt nas curvaturas, externa e interna do tubo, foram empregadas no modelo. / Abstract: An experimental and theoretical investigation of water solidification around curves pipes with different brine inlet temperatures and Dean numbers, that quantify the curvature ratio of the pipe was preformed. The main objective of this work with the influence of these parameters upon the thickness of the frozen layer once one of the main application of this work consists on to obtain parameters that can be applied in the design of latent heat storage. The thickness of the frozen layer was assayed by photography, namely, a video camera was used in order to obtain images of the frozen layer at chosen time intervals and further digitized. A conductive numerical program has been developed using the moving boundary immobilization technique with the differential equations of the model discretized by the finite volume method. Nusselt correlations for the outer and inner tube curvature were used in this model. / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

Mémoire (M.Eng.)--Université du Québec à Chicoutimi, 1999. / Document électronique également accessible en format PDF. CaQCU

Yeung Man Hau. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 52-53). / Text in English; abstract also in Chinese. / Yeung Man Hau. / Chapter Chapter 1 --- Introduction / Chapter 1. --- Background of solidification --- p.1 / Chapter 1.1 --- The driving force for solidification / Chapter 1.2 --- Capillarity effect (or Gibbs-Thomson effect) / Chapter 2. --- Nucleation --- p.3 / Chapter 3. --- Growth --- p.4 / Chapter 3.1 --- Constrained growth and unconstrained growth / Chapter 3.2 --- Directional solidification / Chapter 4. --- Growth of pure substances --- p.6 / Chapter 4.1 --- Metals / Chapter 4.2 --- Stability of planar S/L interface / Chapter 4.3 --- Non-metals / Chapter 5. --- Solidification of single-phase binary alloys --- p.7 / Chapter 5.1 --- Equilibrium solidification / Chapter 5.2 --- Constitutional undercooling / Chapter 5.3 --- Stability of planar S/L morphology / Chapter 5.4 --- Minimum scale of perturbation in directional growth / Chapter 5.5 --- Development of growth morphology / Chapter 5.6 --- Growth rate of cell/dendrite tip / Chapter 5.7 --- Arm spacing and coarsening / Chapter 6. --- Solidification of binary eutectic alloys --- p.11 / Chapter 6.1 --- Classification / Chapter 6.2 --- Growth of lamellar eutectics / Chapter 6.3 --- Stability of planar morphology / Chapter 6.4 --- Coupled zone (Competitive growth of eutectic and dendrites) / Chapter 6.5 --- Off-eutectic solidification / Chapter 7. --- Solidification of ternary eutectic alloys --- p.14 / References --- p.16 / Figures --- p.17 / Chapter Chapter 2 --- Experimental Methods / Chapter 1. --- Fused silica tube cleaning --- p.37 / Chapter 2. --- Alloy preparation --- p.37 / Chapter 3. --- Undercooled specimen preparation --- p.38 / Chapter 4. --- Specimen examination --- p.38 / Chapter 5. --- TEM sample preparation --- p.39 / References --- p.40 / Figures --- p.41 / Chapter Chapter 3 --- Solidification of Undercooled Molten Pd60 .5Cu25Si14.5 Alloy / Chapter 1. --- Introduction --- p.44 / Chapter 2. --- Experimental --- p.46 / Chapter 3. --- Results --- p.46 / Chapter 3.1 --- Thermal profiles / Chapter 3.1.1 --- Temperature-time chart plotter (plotter) / Chapter 3.1.2 --- Differential thermal analysis (D TA) / Chapter 3.2 --- Microstructures / Chapter 3.2.1 --- Effect of undercooling on the microstructure / Chapter 3.2.2 --- Effect of quenching after 1st exothermic peak on the microstructure / Chapter 3.2.3 --- Effect of annealing at the onset temperature of 1st exothermic peak on the microstructure / Chapter 3.2.4 --- Effect of using slower cooling rate on the microstructure / Chapter 4. --- Discussions --- p.50 / Chapter 5. --- Conclusion --- p.51 / References --- p.52 / Figures --- p.54

Rapid solidification processing is widely used in industry, but the underlying mechanisms are not completely understood. In the present work, an effort is made to understand the effects of rapid heat extraction and large undercooling on the solidification sequence, in particular: (1) the transition from diffusion-limited growth to impingement-limited growth; and (2) crystal nucleation in deeply undercooled liquids. Rapid solidification can be achieved either by (1) rapid quenching, or (2) large undercooling. Accordingly, two different methods are used in the present work. They are, (a) nanosecond pulsed laser quenching, and (b) bulk undercooling in a liquid flux. Thin films prepared by d.c. magnetron getter sputtering have been used in pulsed laser quenching. Both pure metals (Fe, Zr, Ti, Co, Ge) and binary alloys (Nb-Ni, Ti-Co) prepared by this method are investigated. Alloys Fe<SUB>40</SUB>Ni<SUB>40</SUB>B<SUB>20</SUB>, Ni<SUB>75</SUB>Si<SUB>8</SUB>B<SUB>17</SUB> and elemental Ge have been used in bulk undercooling. The metastable structures obtained are analysed by optical microscopy, scanning electron microscopy, electron probe microanalysis, transmission electron microscopy and X-ray diffraction. The results obtained are discussed in terms of non-equilibrium crystal nucleation and growth processes.

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