The purpose of this study was to develop and demonstrate a method for experimentally determining the convective heat transfer in a rigid vessel while air was being injected. The heat transfer took place between the air in the pressurized vessel and the surrounding walls which were maintained at a temperature of 32 F. with a circulating ice water bath. The study considers the effects of injection geometry and injection flow rate on the heat transfer process. The problem of heat transfer after injection has been considered by Means (1), and was responsible for establishing this study. The experimental technique used in this thesis provides a method by which Means may establish the heat transfer just after the injection period.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1979. / Microfiche copy available in Archives and Science. / Bibliography : leaves 82-83. / by Frank Parker Colby, Jr. / M.S.

京都大学 / 0048 / 新制・論文博士 / 博士(理学) / 乙第12830号 / 論理博第1541号 / 新制||理||1578(附属図書館) / 31368 / (主査)教授 余田 成男, 教授 石川 裕彦, 教授 向川 均 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM

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An experimental study of turbulent forced convection heat transfer to water flowing in a vertical annular passage is reported in this paper. The study investigates the influence of eccentricity (ranging from 0% to 80%) and diameter ratio (ranging from 1.5 to 4.0) upon the heat transfer phenomena occurring at the inner boundary of the annular passage. Dimensionless heat transfer parameters calculated from measurements made at the two locations corresponding to the maximum and minimum separation of the inner and outer boundaries of the annular passage are correlated in terms of the Reynolds number, the eccentricity and the diameter ratio. Analysis of the correlations indicates that eccentricity affects the heat transfer phenomena occurring at the two locations on the inner boundary of the annular passage in different fashions; increasing eccentricity causes the heat transfer to increase at the location corresponding to the maximum separation of the boundaries and causes the heat transfer to decrease at the location corresponding to the minimum separation of the boundaries. The magnitude of the increase or decrease in heat transfer is dependent upon the diameter ratio; at a particular level of eccentricity, the greater variations in heat transfer occur at the smaller diameter ratios. Ranges in which eccentricity does not influence heat transfer are found in connection with the larger diameter ratios. Moody friction factors calculated from measurements made with concentric annular passages are correlated as a function of Reynolds number. / Thesis / Master of Engineering (ME)

<p>The laminar natural convection in air-filled rectangular cavities with and without a partition on the wall was experimentally investigated. Temperature measurements and flow visualizations were performed for cases with heated and cooled vertical walls (corresponding to global Grashof numbers GrH of approximately 1.4 x 10^8 to 1.8 x 10^8) and non-dimensional top wall temperatures θT of 0.52 (insulated) to 2.3. In the rectangular cavities without the partition and with aspect ratios of 0.5, 1.0 and 2.0, the heated top wall caused the natural convection boundary layer flow to separate from either the top wall (for the cases with Or ;S 1.2) or the heated vertical wall (for the cases with θT >~ 1.2) due to the negative buoyancy force. For the cases with θT >~ 1.2, there is an anti-clockwise recirculating flow in the upper left corner region. The extent of the recirculating flow decreased with an increase of the aspect ratio. The temperature gradient in the core region, dθ∞ /d(y/H), increased with an increase of θT. For a given aspect ratio, dθ∞/d(y/H) changed more rapidly with the change in θT for the cases with θT <~ 1.2 compared to the cases with θT >~ 1.2. The increase in dθ∞/ d(y/H) was more significant for the smaller aspect ratio cavity. The temperature profiles predicted from the similarity solutions proposed by Kulkarni et al. [1] and from the non-similarity model developed by Chen and Eichhorn [2] for natural convection on an isothermal vertical wall in a stratified environment were compared to the measurements in the current cases. These models were not able to accurately describe the characteristics of the natural convection flow in the rectangular cavities.</p> <p>An aluminium partition with non-dimensional heights Hp/H of 0.0625 and 0.125 was attached either to the heated vertical wall or top wall at y/H = 0.65, 0.95 and x/H = 0.1, 0.2, 0.4 and 0.6 to study the effect of the partition on the laminar natural convection flow in a square cavity. The blockage and thermal effects of the partition resulted in changes in the temperature and flow fields, but were mainly limited in the vicinity of the partition. The effect of the partition changed with the height and location of the partition. When the partition was attached to the heated top wall, a recirculating flow was formed between the partition and the heated vertical wall. For a given partition height, the structure of this recirculating flow was dependent on the partition location and θT. A thermal boundary layer developed along the rear surface of the partition due to the thermal effect of the partition. The ambient temperature outside the boundary layer and Nu near the corner region were affected by the partition height due to the changes in the recirculating flow and the rear surface of the partition.</p> / Thesis / Doctor of Philosophy (PhD)

Error of labeling pages or Page 102 Not included in thesis. / <p> A semi-explicit scheme for the solution of transient multdimensional natural convection is made to study natural convection in porous media. The conservation equations are phrased in primitive form. Heat tranfer between the solid and liquid phases is modelled by representing the porous medium as an assemblage of spherical particles, and solving the conduction problem for such a system at every time step. Nusselt numbers were calculated from the temperature and velocity profiles. Numerical results for heat transfer through fluid saturated porous media heated from below are in good agreement with published experiments.</p> / Thesis / Master of Engineering (MEngr)

Note:

In northeastern Mississippi, land cover types vary from agriculture, forests, urban surfaces, pasture, to bodies of water. Substantial evidence exists supporting the contribution of land cover and land cover discontinuities, or physiographic transition zones, to cloud formation on synoptically benign days in many areas across the globe. However, research is lacking on the specific type of land cover and/or land cover discontinuities that convection favors in the warm season. The objective of this study was to develop a synoptically benign convective cloud climatology for northeastern Mississippi and compare this climatology to land cover to determine whether a relationship between land cover type and convective cloud enhancement exists. The study shows a statistically significant clustered pattern occurring in the study area. In addition, enhanced convective events appear to favor land use regions of evergreen needleleaf forest; dryland, cropland, and pasture; and savanna. The study indicates that these three land cover types occur significantly more frequently for the enhancement points than in the study area. The findings support the existence of a significant relationship between land cover and convective enhancement in northeastern Mississippi and provide opportunities for additional future research on relationships between land cover and convection to improve forecast applications and our knowledge of mesoscale circulations.