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Experimental and numerical investigation of turbulent flow and heat (mass) transfer in a two-pass trapezoidal channel with turbulence promotersOh, Sung Hyuk 15 May 2009 (has links)
Experiments and numerical predictions were conducted to study heat (mass) transfer characteristics in a two-pass trapezoidal channel simulating the cooling passage of a gas turbine blade. Three different rib configurations were tested for the air entering the smaller cross section of the trapezoidal channel as well as the larger cross section of the trapezoidal channel at four different Reynolds numbers of 9,400, 16,800, 31,800, and 57,200. (+) 60º ribs, (–) 60º ribs and 60º V-shaped ribs were attached on both the top and bottom walls in parallel sequence. A naphthalene sublimation technique was used, and the heat and mass transfer analogy was applied to convert the mass transfer coefficients to heat transfer coefficients. Numerical predictions of three-dimensional flow and heat transfer also were performed for the trapezoidal channel with and without 90º ribs tested by Lee et al. (2007). Reynolds stress turbulence model (RSM) in the FLUENT CFD code was used to calculate the heat transfer coefficients and flow fields at Re = 31,800. The results showed that the combined effects of the rib angle, rib orientation, and the sharp 180° turn significantly affected the heat (mass) transfer distributions. The secondary flows induced by the sharp 180° turn and the angled or V-shaped ribs played a very prominent role in heat (mass) transfer enhancements. The heat (mass) transfer enhancements and the pressure drops across the turn for 60° V-shaped ribs had the highest values, then came the case of (+) 60° ribs, and the heat (mass) transfer enhancements and the friction factor ratios for (–) 60º ribs was the lowest. However, comparing (–) 60º ribs with the 90º ribs, (–) 60º ribs produced higher heat (mass) transfer enhancements than the 90º ribs, as results of the secondary flow induced by the (–) 60º ribs. The overall average heat (mass) transfer for the larger inlet cases was always higher than that for the smaller inlet cases in the ribbed trapezoidal channel. Considering the thermal performance comparisons of the (+) 60° ribs, the (–) 60º ribs, and 60° V-shaped ribs for the smaller inlet cases, the highest thermal performance was produced by the (–) 60º ribs, and the 60° V-shaped ribs and the (+) 60° ribs had almost the same levels of the thermal performance since the 60° V-shaped ribs produced the highest heat (mass) transfer enhancement but also produced highest pressure drops. For the larger inlet cases, the (+) 60° ribs produced the highest values, then came the case of the 60° V-shaped ribs, and the thermal performance for the (–) 60º ribs was the lowest. The Reynolds stress model (RSM) showed well flow fields and heat transfer distributions but underpredicted average Nusselt number ratios.
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Experimental and numerical investigation of turbulent flow and heat (mass) transfer in a two-pass trapezoidal channel with turbulence promotersOh, Sung Hyuk 15 May 2009 (has links)
Experiments and numerical predictions were conducted to study heat (mass) transfer characteristics in a two-pass trapezoidal channel simulating the cooling passage of a gas turbine blade. Three different rib configurations were tested for the air entering the smaller cross section of the trapezoidal channel as well as the larger cross section of the trapezoidal channel at four different Reynolds numbers of 9,400, 16,800, 31,800, and 57,200. (+) 60º ribs, (–) 60º ribs and 60º V-shaped ribs were attached on both the top and bottom walls in parallel sequence. A naphthalene sublimation technique was used, and the heat and mass transfer analogy was applied to convert the mass transfer coefficients to heat transfer coefficients. Numerical predictions of three-dimensional flow and heat transfer also were performed for the trapezoidal channel with and without 90º ribs tested by Lee et al. (2007). Reynolds stress turbulence model (RSM) in the FLUENT CFD code was used to calculate the heat transfer coefficients and flow fields at Re = 31,800. The results showed that the combined effects of the rib angle, rib orientation, and the sharp 180° turn significantly affected the heat (mass) transfer distributions. The secondary flows induced by the sharp 180° turn and the angled or V-shaped ribs played a very prominent role in heat (mass) transfer enhancements. The heat (mass) transfer enhancements and the pressure drops across the turn for 60° V-shaped ribs had the highest values, then came the case of (+) 60° ribs, and the heat (mass) transfer enhancements and the friction factor ratios for (–) 60º ribs was the lowest. However, comparing (–) 60º ribs with the 90º ribs, (–) 60º ribs produced higher heat (mass) transfer enhancements than the 90º ribs, as results of the secondary flow induced by the (–) 60º ribs. The overall average heat (mass) transfer for the larger inlet cases was always higher than that for the smaller inlet cases in the ribbed trapezoidal channel. Considering the thermal performance comparisons of the (+) 60° ribs, the (–) 60º ribs, and 60° V-shaped ribs for the smaller inlet cases, the highest thermal performance was produced by the (–) 60º ribs, and the 60° V-shaped ribs and the (+) 60° ribs had almost the same levels of the thermal performance since the 60° V-shaped ribs produced the highest heat (mass) transfer enhancement but also produced highest pressure drops. For the larger inlet cases, the (+) 60° ribs produced the highest values, then came the case of the 60° V-shaped ribs, and the thermal performance for the (–) 60º ribs was the lowest. The Reynolds stress model (RSM) showed well flow fields and heat transfer distributions but underpredicted average Nusselt number ratios.
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Development of techniques for in-situ measurement of heat and mass transfer in ammonia-water absorption systemsLee, Sangsoo. January 2007 (has links)
Thesis (Ph. D.)--Mechanical Engineering, Georgia Institute of Technology, 2008. / Ghiaasiaan, S. Mostafa, Committee Member ; Sheldon, M. Jeter, Committee Member ; Fuller, Tom, Committee Member ; Teja, Amyn, Committee Member ; Garimella, Srinivas, Committee Chair.
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Heat and mass transfer characteristics of a wiped film evaporatorLopez-Toledo, Jacinto, January 1900 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.
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Flow through a model fin and tube heat exchanger and its influence on mass and heat transfer /Gilbert, Gregory P. January 1987 (has links) (PDF)
Thesis (M. Eng. Sc.)--University of Adelaide, 1988. / Includes bibliographical references (leaves 114-119).
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Numerical modelling of heat and mass transfer and optimisation of a natural draft wet cooling towerWilliamson, N. J. January 2008 (has links)
Thesis (Ph. D.)--University of Sydney, 2007. / Title from title screen (viewed February 12, 2009). Includes graphs and tables. Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Aerospace, Mechanical and Mechatronic Engineering. Includes bibliographical references. Also available in print form.
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Transport phenomena in variable-property boundary layersLiu, Ke-Tien. January 1972 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1972. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 214-217).
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Heat and mass transfer in molten core/croncrete interactionsPaik, In Kul. January 1982 (has links)
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 498-507).
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Analysis of heat and mass regenerators with time varying or spatially nonuniform inlet conditionasBrandemuehl, Michael John. January 1900 (has links)
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 352-356).
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Heat transfer in a sound-assisted fluidized bed /Huang, Deshau, January 2002 (has links)
Thesis (Ph. D.)--Lehigh University, 2003. / Includes vita. Includes bibliographical references (leaves 104-107).
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