Thermodiffusion is one of the mechanisms in transport phenomena in which molecules are transported in a multicomponent mixture driven by temperature gradients. Thermodiffusion in associating mixtures presents a larger degree of complexity than non-associating mixtures, since the direction of flow in associating mixtures may change with variations in composition and temperature. In this study a new activation energy model is proposed for predicting the ratio of evaporation energy to activation energy. The new model has been implemented for prediction of thermodiffusion for acetone-water, ethanol-water and isopropanol-water mixtures. In particular, a sign change in the thermodiffusion factor for associating mixtures has been predicted, which is a major step forward in modeling of thermodiffusion for associating mixtures. In addition, a new model for the prediction of thermodiffusion coefficients for linear chain hydrocarbon binary mixtures is proposed using the theory of irreversible thermodynamics and a kinetics approach. The model predicts the net amount of heat transported based on an available volume for each molecule. This model has been found to be the most reliable and represents a significant improvement over the earlier models. Also a new approach to predicting the Soret coefficient in binary mixtures of linear chain and aromatic hydrocarbons using the thermodynamics of irreversible processes is presented. This approach is based on a free volume theory which explains the diffusivity in diffusion-limited systems. The proposed model combined with the Shukla and Firoozabadi model has been applied to predict the Soret coefficient for binary mixtures of toluene and n-hexane, and benzene and n-heptane. Comparisons of theoretical results with experimental data show a good agreement. The proposed model has also been applied to estimate thermodiffusion coefficients of binary mixtures of n-butane & carbon dioxide and n-dodecane & carbon dioxide at different temperature. The results have also been incorporated into CFD software FLUENT for 3-dimensional simulations of thermodiffusion and convection in porous media. The predictions show the thermodiffuison phenomenon is dominant at low permeabilities (0.0001 to 0.01), but as the permeability increases convection plays an important role in establishing a concentration distribution. Finally, the activation energy in Eyring’s viscosity theory is examined for associating mixtures. Several methods are used to estimate the activation energy of pure components and then extended to mixtures of linear hydrocarbon chains. The activation energy model based on alternative forms of Eyring’s viscosity theory is implemented to estimate the thermodiffusion coefficient for hydrocarbon binary mixtures. Comparisons of theoretical results with the available thermodiffusion coefficient data have shown a good performance of the activation energy model.

Le but de ce mémoire de recherche est d'étudier les convections naturelle et mixte d'écoulements fluides, et de développer et valider des méthodes numériques pour le suivi d'interfaces afin de traiter plus tard des écoulements incompressibles de fluides immiscibles. Dans une première étape, une méthode numérique originale, basée sur des discrétisations Volumes Finis, est développée pour modéliser les écoulements à faible nombre de Mach et grands écarts de température. Trois applications physiques, portant sur l'écoulement d'air à travers des plaques verticales parallèles chauffées, sont étudiées. Nous avons montré que l'espacement optimal, correspondant au pic de flux de chaleur transféré d'un réseau de plaques parallèles isothermes refroidies par convection mixte, est plus faible que ceux obtenus en convections naturelle ou forcée lorsque la chute de pression à la sortie est constante. Nous avons également prouvé que les écoulements de convection mixte à débit imposé peuvent présenter des solutions physiques inattendues ; un modèle alternatif basé sur une pression totale imposée à l'entrée et une pression fixée à la sortie donne de meilleurs résultats. Pour des canaux soumis un flux de chaleur sur une paroi seule, le rayonnement de surface tend à supprimer l'apparition des recirculations à la sortie et à uniformiser les températures des parois. Dans une seconde étape, le modèle mathématique couplant les équations de Navier-Stokes incompressibles et la méthode Level-Set pour le suivi d'interfaces est développé. Des améliorations de la conservation du volume fluide par l'utilisation de schémas de discrétisation d'ordres élevés (ENO-WENO) pour l'équation de transport et des variantes de l'équation de la distance signée sont discutées / The aim of this research dissertation is at studying natural and mixed convections of fluid flows, and to develop and validate numerical schemes for interface tracking in order to treat incompressible and immiscible fluid flows, later. In a first step, an original numerical method, based on Finite Volume discretizations, is developed for modeling low Mach number flows with large temperature gaps. Three physical applications on air flowing through vertical heated parallel plates were investigated. We showed that the optimum spacing corresponding to the peak heat flux transferred from an array of isothermal parallel plates cooled by mixed convection is smaller than those for natural or forced convections when the pressure drop at the outlet keeps constant. We also proved that mixed convection flows resulting from an imposed flow rate may exhibit unexpected physical solutions; alternative model based on prescribed total pressure at inlet and fixed pressure at outlet sections gives more realistic results. For channels heated by heat flux on one wall only, surface radiation tends to suppress the onset of recirculations at the outlet and to unify the walls temperature. In a second step, the mathematical model coupling the incompressible Navier-Stokes equations and the Level-Set method for interface tracking is derived. Improvements in fluid volume conservation by using high order discretization (ENO-WENO) schemes for the transport equation and variants of the signed distance equation are discussed

Le modèle numérique que nous avons développé au cours de cette thèse présente deux caractéristiques principales : un modèle dilatable pour l'eau et la prise en compte de domaines ouverts. Les difficultés associées au premier aspect concernent l'adaptation de la loi d'état de l’eau au modèle dilatable sous l’approximation à faibles nombres de Mach, tandis que celles associées au second sont relatives à la mise en œuvre de conditions aux limites numériques de sortie compatibles avec l'algorithme de projection utilisé. Les résultats de simulations d'écoulement de convection mixte en canal horizontal chauffé par le bas ont été confrontés à celles utilisant l'approximation de Boussinesq et aux expériences. / The 3D numerical model which we developed in this thesis presents two main features: a Low-Mach-Number approximation for water along with an open boundary condition formulation. Indeed, the difficulties related to the former point stand in a computationally efficient adaptation of the water equation of state in the framework of Low Mach number approximation, whereas the difficulties related to the latter concern the introduction of Open Boundary Conditions in the projection algorithm used. We have computed a mixed convection flow in a horizontal channel uniformly heated from below and compared the results obtained with both the Boussinesq approximation and experimental results.

A two-dimensional mathematical model is adopted to investigate the development of buoyancy driven circulation patterns and temperature contours inside a rectangular enclosure filled with a compressible fluid where one of the vertical walls of the enclosure is kept at a higher temperature than the opposite one. Fluid thermodynamic and transport properties are assumed to be functions of temperature. The governing equations are discretized using second order accurate differencing for spatial and temporal derivatives and then linearized using Newton's linearization method. The resulting set of algebraic equations is solved using the Coupled Modified Strongly Implicit Procedure for the unknowns of the problem. The results of this study show that the variable property model predicts lower values for wall heat fluxes and Nu number than the constant property one for Rayleigh numbers between 104 and 105.

The ice melting and lateral cavity formation caused by in situ burning (ISB) of liquid fuels in ice-infested waters was studied in order to improve predictions on the removal efficiency of this oil spill mitigation method. For this purpose, several experimental studies were conducted to increase the fundamental understanding of the mechanisms that lead to ice melting and lateral cavity formation. The findings of the experimental studies provided the required knowledge to mathematically formulate the ice melting problem. Mathematical scaling analysis of ice melting during burning of oils in the vicinity of ice was performed to create a tool to estimate the extent of melting that occurs during ISB in ice-infested waters. A series of lab-scale experiments were designed to systematically investigate the ice melting problem. The first set of experiments were conducted in cylindrical shaped ice cavities with a 5.7 cm diameter. Burning of n-octane from ignition to natural extinction and the subsequent geometry change of the ice, fuel thickness, and fuel temperature were measured. The preliminary experimental observations showed that the melting of the ice walls was higher in areas where the fuel layer was in contact with ice compared with places of flame exposure. Based on these observations, a hypothesis that suggested the convective flows in the liquid fuel (driven mainly by surface tension and buoyancy) were contributing in melting of the ice was proposed to explain the origins of the lateral cavity. To evaluate this hypothesis, two dimensionless numbers (Marangoni and Rayleigh) were calculated as the indicators of the mechanisms of convection in the fuel layer. The comparison between the melting speed and these dimensionless numbers indicated surface tension driven flow was dominant while the role of buoyancy was negligible. In another set of experiments, Particle Image Velocimetry (PIV) was used to study the flow structure within the liquid-phase of n-octane pool fire bound on one side by an ice wall. Experiments were conducted in a square glass tray (9.6 cm × 9.6 cm × 5 cm) with a 3 cm thick ice wall placed on one side of the tray. Burning rate, flame height, and melting front velocity were measured to analyze the effect of heat feedback on melting of the ice. The melting rate of the ice increased from 0.6 cm/min for the first 50 seconds after ignition to 1 cm/min for the rest of burning period. Meanwhile, the measurement of the burning rates and flame heights showed two distinctive behaviors; a growth period from self-sustained ignition to the peak mass loss rate (first 50 seconds after ignition) followed by a steady phase from the peak of mass loss rate until the manual extinguishment. Similarly, the flow field measurements by a 2-dimensional PIV system indicated the existence of two different flow regimes. In the moments before ignition of the fuel, coupling of surface tension and buoyancy forces led to a combined one roll structure in the fuel. This was when a single large vortex was observed in the flow field. After ignition the flow field began transitioning toward an unstable flow regime (separated) with an increase in number of vortices around the ice wall. As the burning rate/flame height increased the velocity and evolving flow patterns enhanced the melting rate of the ice wall. Experimentally determined temperature contours showed that a hot zone with thickness of approximately 3 mm was present below the free surface, corresponding to the multi-roll location. The change in the flow field behavior was found to relate to the melting front velocity of ice. To further study the lateral cavity phenomena, a parametric experimental study on melting of ice adjacent to liquids exposed from above to various heat fluxes was conducted in order to understand the role of liquid properties in formation of cavities in ice. Multiple liquids with wide variety and range of thermophysical properties were used in order to identify the key influential properties on melting. The melting rate of the ice and penetration speed of the liquid in a transparent glass tray (70 mm × 70 mm × 45 mm) with a 20 mm thick ice wall (70 mm × 50 mm × 20 mm) was measured. The melting front velocities obtained from experiments were then compared to surface flow velocities of liquids obtained through a scaling analysis of the surface flow to elucidate the influence of the various thermophysical properties of the liquids on ice melting. The surface velocity of the liquids correlated well to the melting front velocities of the ice which showed a clear relationship between the flow velocity and melting front velocity. As the final step of this work, to extend the findings of the experimental studies conducted herein to larger sizes comparable to realistic situations in the Arctic, an order of magnitude scaling analysis was performed to obtain the extent of ice melting. The scaling considered the heat feedback from the flame to fuel surface, the convective heat transfers toward the ice, and the melting energy continuity of ice. The existing experimental data on the size of lateral cavity were also collected and were correlated to the results of the scaling analysis using a nonlinear regression fitting technique. The mathematical correlation that was obtained by the scaling analysis can be used to predict the size of the lateral cavity for a given fuel, pool fire diameter, and burning time. This correlation will provide a predictive tool to estimate the size of a potential lateral cavity formed during ISB of a given spill scenario. In general, the ability to predict the ice melting caused by burning of spilled oil in ice-infested waters is of great practical importance for assessment of the response outcome. This would assist with quantifying the geometry change of the burning medium which in turn will define oil burning rate and extinction condition. Knowledge of burning behavior and extinction condition indicate the burned volume which can directly be used to define the removal effectiveness of ISB. Nevertheless, this analysis was conducted on a generic interaction of oil and ice and the specific details that are observed in actual application of ISB in ice-infested waters were neglected for simplicity. Extending the outcome of this study to more specific (scenario-based) oil-in-ice situation and improving the predictability of the melting correlation with large-scale experiments are the next steps to develop this work.

Atmospheric moist convection is one of the main topics discussed on weather and climate. This study purpose is to understand why different and similar cloud microphysics parameterizations produce different patterns of precipitation at the ground through several numerical sensitivity tests with the WRF model in the simulation of a squall line case observed on the Amazon region. Four different bulk microphysics parameterizations (Lin, WSM6, Morrison, and Milbrandt) were tested, and the main results show that statistical errors do not change significantly among each other for the four numerical domains (from 27 km up to 1 km grids). The correlations between radar rainfall data and the simulated precipitation fields show the double-moment parameterization Morrison scheme was the one that displayed better results in the overall: While Morrison scheme show 0.6 correlation in the western box of the 1 km domain, WSM6 and Lin schemes show 0.39 and 0.05, respectively. Nevertheless, because this scheme presents good correlations with the radar rain rates, it also shows a fairly better system lifecycle, evolution, and propagation when compared to the satellite data. Although, the complexity that the way microphysics variables are treated in both one-moment and double-moment schemes in this case study do not highly affect the simulatios results, the tridimensional vertical cross-sections show that the Purdue Lin and Morrison schemes display more intense systems compared to WSM6 and Milbrandt schemes, which may be associated with the different treatments of the ice-phase microphysics. In the specific comparison between double-moment schemes, the ice quantities generated by both Morrison and Milbrandt schemes highly affected thesystem displacement and rainfall intensity. This also affects the vertical velocities intensity which, in its, turn, changes the size of the cold pools. Differences in ice quantities were responsible for distinct quantities of total precipitable water content, which is related with the verticallly integrated ice mixing ratio generated by Morrison. The system moves faster in Milbrandt scheme compared to Morrison because the scheme generated more graupel quantities, which is smaller in size than hail, and it evaporates easier in the processes inside the cloud due to its size. This fact also changed the more intense cold pools intensity for Milbrandt scheme compared to Morrison. / A convecção atmosférica é um dos principais tópicos discutidos no tempo e clima. O objetivo deste estudo é entender por que diferentes e semelhantes parametrizações de microfísica de nuvens produzem diferentes padrões de precipitação no solo através de vários testes numéricos de sensibilidade com o modelo WRF na simulação de um caso de linha de instabilidade observado na região amazônica. Quatro diferentes parametrizações microfísicas de tipo bulk (Lin, WSM6, Morrison e Milbrandt) foram testadas, e os principais resultados mostram que os erros estatísticos não se alteram significativamente entre si para os quatro domínios numéricos (da grade de 27 km até a de 1 km). As correlações entre dados pluviométricos de radar e os campos de precipitação simulados mostram que o esquema Morrison de parametrização de duplo momento foi o que apresentou melhores resultados, no geral: enquanto o esquema de Morrison mostra correlação 0,6 na caixa oeste do domínio de 1 km, os esquemas WSM6 e Lin mostram 0,39 e 0,05, respectivamente. No entanto, como esse esquema apresenta boas correlações com as taxas de chuva do radar, ele também mostra um ciclo de vida, evolução e propagação do sistema relativamente melhores quando comparado aos dados de satélite. Embora a complexidade com que as variáveis microfísicas são tratadas nos esquemas de um momento e de duplo momento neste estudo de caso não afetam muito os resultados simulados, as seções transversais verticais tridimensionais mostram que os esquemas de Purdue Lin e Morrison exibem mais intensos em comparação com os esquemas WSM6 e Milbrandt, que podem estar associados aos diferentes tratamentos da microfísica da fase de gelo. Na comparação específica entre esquemas de momento duplo, as quantidades de gelo geradas pelos esquemas de Morrison e Milbrandt afetaram muito o deslocamento do sistema e a intensidade da chuva. Isso também afeta a intensidade das velocidades verticais que, por sua vez, altera o tamanho das piscinas frias. As diferençaas nas quantidades de gelo foram responsáveis por quantidades distintas de conteúdo total de água, que está relacionado com a razão de mistura de gelo verticalmente integrada gerada por Morrison. O sistema se move mais rápido no esquema de Milbrandt comparado a Morrison porque o esquema gerou mais quantidades de graupel, que é menor em tamanho do que o granizo, e evapora mais facilmente nos processos dentro da nuvem devido ao seu tamanho. Este fato também mudou a intensidade das piscinas frias mais intensas, porém menores em extensão horizontal, para o esquema Milbrandt em comparação com Morrison.

Submitted by Cátia Araújo (catia.araujo@unipampa.edu.br) on 2017-09-29T13:05:00Z No. of bitstreams: 1 Mariovane Sabino Donini - 2017.pdf: 4347435 bytes, checksum: b83edb6c2d0b7868757722dc435be9fa (MD5) / Approved for entry into archive by Marlucy Farias Medeiros (marlucy.farias@unipampa.edu.br) on 2017-09-29T16:25:43Z (GMT) No. of bitstreams: 1 Mariovane Sabino Donini - 2017.pdf: 4347435 bytes, checksum: b83edb6c2d0b7868757722dc435be9fa (MD5) / Made available in DSpace on 2017-09-29T16:25:43Z (GMT). No. of bitstreams: 1 Mariovane Sabino Donini - 2017.pdf: 4347435 bytes, checksum: b83edb6c2d0b7868757722dc435be9fa (MD5) Previous issue date: 2017 / In the present work, vaporization and combustion of an isolated fuel droplet at diferente ambient temperatures are examined numerically in order to analyze the effect of buoyancy force on the flame. Generally, fuel droplets in combustion devices are so small that the influence of buoyancy force on vaporization and combustion of droplets is negligible. On the other hand, fuel droplets in experimental devices are affected by the buoyancy force due to their diameters being around or more than 1 mm. To reduce the buoyancy effects, expensive experimental studies are performed in microgravity ambient (drop-tower or out of space). In normal-gravity conditions, the buoyancy force is induced by temperature gradient on ambient atmosphere. The buoyancy is positive in regions of hot gases and negative in regions of cold gases compared with the ambient atmosphere gas. Hot gases move upward and cold gases downward. Playing with the positive buoyancy force of hot gases around the flame and with the negative (cold) buoyancy force of cold gases around the droplet via ambient atmosphere temperature, it is possible to modify the flame shape. In the numerical simulations, incompressible Navier–Stokes equations along with mixture fraction and excess enthalpy conservation equations are solved using a finite volume technique with a uniform structured grid. An artificial compressibility method was applied to reach steady state solutions. The numerical predictions have been compared with analytical results for a zero gravity condition, showing good agreement. For normal gravity condition the numerical results showed that when the ambient temperature increases, the velocity gradient and buoyancy source term decreases. Despite that, the flame increased in all directions. The results have also shown that increasing the ambient temperature, decreases the temperature gradient in the flame, which ends up affecting the flame position. / No presente trabalho, a vaporização e a combustão de uma gota de combustível isolada a diferentes temperaturas ambiente são examinadas numericamente para analisar o efeito da força de flutuação na chama. Geralmente, as gotículas de combustível em dispositivos de combustão são tão pequenas que a influência da força de flutuação na vaporização e na combustão de gotículas é insignificante. Por outro lado, as gotículas de combustível em dispositivos experimentais são afetadas pela força de flutuabilidade devido ao seu diâmetro em torno de ou mais de 1 mm. Para reduzir os efeitos de flutuabilidade, estudos experimentais caros são realizados em ambiente de microgravidade (drop-tower ou fora do espaço). Em condições de gravidade normal, a força de flutuação é induzida por gradiente de temperatura na atmosfera ambiente. A flutuabilidade é positiva em regiões de gases quentes e negativas em regiões de gases frios em comparação com o gás atmosférico ambiente. Os gases quentes movem-se para cima e os gases frios para baixo. Jogando com a força de flutuação positiva dos gases quentes ao redor da chama e com a força de flutuação negativa (fria) dos gases frios ao redor da gota através da temperatura da atmosfera ambiente, é possível modificar a forma da chama. Nas simulações numéricas, as equações de Navier-Stokes incompressíveis juntamente com a fração de mistura e as equações de conservação de entalpia em excesso são resolvidas usando uma técnica de volume finito com uma grade estruturada uniforme. Foi aplicado um método de compressibilidade artificial para alcançar soluções de estado estacionário. As previsões numéricas foram comparadas com resultados analíticos para uma condição de gravidade zero, mostrando boa concordância. Para a condição de gravidade normal, os resultados numéricos mostraram que, quando a temperatura ambiente aumenta, o gradiente de velocidade e o termo da fonte de flutuação diminuem. Apesar disso, a chama aumentou em todas as direções. Os resultados também mostraram que aumentar a temperatura ambiente, diminui o gradiente de temperatura na chama, o que acaba afetando a posição da chama.

Lo Ka Fai / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves [67]-68). / Text in English; abstracts in English and Chinese. / Lo Ka Fai / Abstract --- p.ii / Acknowledgements --- p.iii / List of Figures --- p.v / List of Tables --- p.ix / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- The First Problem: Heat Transfer and Large-scale Flow --- p.7 / Chapter 2.1 --- Circulating flow --- p.8 / Chapter 2.2 --- Shear flow --- p.10 / Chapter 3 --- Results and Discussions --- p.13 / Chapter 3.1 --- Circulating flow --- p.13 / Chapter 3.2 --- Shear flow --- p.17 / Chapter 4 --- The second problem: Intermittency --- p.22 / Chapter 5 --- Method of Analysis --- p.25 / Chapter 6 --- Results and discussions --- p.29 / Chapter 6.1 --- C=0.01 --- p.29 / Chapter 6.2 --- "C=0.05, 0.1 and 0.5" --- p.41 / Chapter 7 --- Conclusions --- p.60 / Chapter A --- Linear Scaling Exponents --- p.62 / Chapter B --- The Formula of and the Hierarchy --- p.64 / Bibliography --- p.66

The velocity and temperature fields of several air cavities have been surveyed. The cavities operated in the transitional boundary layer regime with vertical, opposing, isothermal heated and cooled walls. The cavity height, width, temperature difference and wall insulation were all changed during the study, with the aspect ratio varying from 4 to 10, and RaH varying from 2,263x10 to 4.486x101e. The local velocity and temperature were measured simultaneously using a laser Doppler anemometer and a 25jim chromel-alumel thermocouple. This allowed the turbulence quantity tT to be measured directly, as well as the mean and root mean square of the fluctuations of velocity and temperature. Several other quantities, which have not previously been available, were derived from the measured data, these were the wall shear stress, the mean lateral velocity, u'v', and v'T'. The effect of a decrease of the level of insulation on the vertical walls was to decrease the non-dimensional temperature of the fluid at the vertical centre-line. Different thermal boundary conditions on the horizontal walls resulted in significant differences between the heated and cooled wall, thermal and velocity, boundary layers. A decrease in the cavity width was seen to alter the characteristics of the mean velocity and temperature profiles when the width was less than twice the lateral extent of either boundary layer in a cavity with a larger width. Near wall distributions of u'v' have shown that the viscous sub-layer was approximately 4mm thick. Calculations of power spectral density, together with inspection of time histories, have confirmed that a laminar flow was present at the bottom of the heated wall. P.S.D. calculations showed that the dominant frequencies of transition were multiples of a base frequency and dependent on the local temperature drop between the wall and the "environment". The power relationship between frequency and power spectral density has been shown to depend on the local vertical temperature gradient. Three sub-ranges were identified in the velocity spectra, whereas four were identified in the temperature spectra. The equivalent ranges in the velocity and temperature spectra exhibited different powers on the frequency, with those of the temperature field being larger.

Qiu, Can = / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 82-87). / Abstracts in English and Chinese. / Qiu, Can = / Abstract --- p.i / 摘要 --- p.ii / Acknowledge --- p.iii / Table of Contents --- p.iv / List of Figures --- p.v i i / List of Tables --- p.xi / Chapter Chapters I --- Introduction --- p.1 / Chapter 1.1 --- Turbulence --- p.1 / Chapter 1.2 --- Rayleigh-Benard convection --- p.3 / Chapter 1.2.1 --- Physics picture-Motion in the convection cell --- p.4 / Chapter 1.2.2 --- The governing equations and parameters --- p.6 / Chapter 1.2.3 --- Multilayer convection --- p.9 / Chapter 1.2.4 --- The Nu scaling --- p.9 / Chapter 1.2.5 --- Boundary layers --- p.11 / Chapter 1.3 --- Present work and the organization of the thesis --- p.14 / Chapter II --- Experimental Setup --- p.16 / Chapter 2.1 --- The convection cell --- p.16 / Chapter 2.2 --- The thermistors --- p.20 / Chapter 2.2.1 --- Calibration --- p.20 / Chapter 2.3 --- The multimeter --- p.21 / Chapter 2.4 --- Thermostat box --- p.22 / Chapter 2.5 --- Visualization --- p.23 / Chapter 2.6 --- Motorized translation stage --- p.24 / Chapter 2.7 --- AC Wheatstone Bridge and Lock in amplifier --- p.24 / Chapter 2.8 --- Test different heaters --- p.26 / Chapter III --- "Heat flux, boundary layer and Reynolds number measurement of one-layer FC77 thermal convection" --- p.30 / Chapter 3.1 --- Heat flux measurement with correction --- p.30 / Chapter 3.1.1 --- Sidewall correction --- p.31 / Chapter 3.1.2 --- Bottom plate correction --- p.31 / Chapter 3.1.3 --- Post correction --- p.31 / Chapter 3.2 --- The Nu result --- p.32 / Chapter 3.3 --- Boundary layer measurement --- p.34 / Chapter 3.4 --- The Pr dependence of the Reynolds number Re --- p.37 / Chapter 3.5 --- Summary --- p.40 / Chapter IV --- "Heat transfer, thermal boundary layer and flow property measurement of multilayer immiscible fluid turbulent thermal convection" --- p.41 / Chapter 4.1 --- Introduction --- p.41 / Chapter 4.2 --- Experiment --- p.44 / Chapter 4.3 --- The temperature and temperature fluctuation across the interface --- p.46 / Chapter 4.3.1 --- The temperature near the interface --- p.46 / Chapter 4.3.2 --- Position and temperature of the interface --- p.47 / Chapter (a) --- Using the profile to get the temperature of the interface --- p.47 / Chapter (b) --- Using the traveling microscope to get the absolute position of the interface --- p.50 / Chapter 4.4 --- The Nu result --- p.50 / Chapter 4.5 --- Boundary layer thickness and scaling --- p.54 / Chapter 4.6 --- Statistical properties of the temperature field across the interface --- p.58 / Chapter 4.6.1 --- Temperature time series and the corresponding histogram of the interface --- p.58 / Chapter 4.6.2 --- "The mean, root mean square, skewness, time derivative skewness and flatness of the temperature profiles across the interface" --- p.64 / Chapter 4.6.3 --- Scaling of the temperature fluctuation in two-layer system --- p.71 / Chapter 4.7 --- The temperature oscillation --- p.74 / Chapter 4.8 --- Passive scalar and active scalar --- p.77 / Chapter 4.9 --- Summary --- p.79 / Chapter V --- Conclusion --- p.80 / Chapter 5.1 --- One-layer thermal convection --- p.80 / Chapter 5.2 --- Two-layer thermal convection --- p.80 / Chapter 5.3 --- Future works --- p.81 / References --- p.82