The objective of this thesis is to predict numerically the optimal spacing between parallel heat generating boards. The isothermal boards are stacked in a fixed volume of electronic package enclosed by insulated lateral walls, and they are cooled by laminar forced convection of air with prescribed pressure drop. Fixed pressure drop assumption is an acceptable model for installations in which several parallel boards in electronic equipment receive the coolant from the same source such as a fan. In the numerical algorithm, the equations that govern the process of forced convection for constant property incompressible flow through one rectangular channel are solved. Numerical results of the flow and temperature field in each rectangular channel yield the optimal board-to-board spacing by which maximum heat dissipation rate from the package to the air is achieved. After the results of the optimization procedure are given, the correlations for the determination of the maximum heat transfer rate from the package and optimal spacing between boards are, respectively, derived in terms of prescribed pressure difference, board length, and density and kinematic viscosity of air. In conclusion, the obtained correlations are compared and assessed with the available two-dimensional studies in literature for infinite parallel plates. Furthermore, existing two-dimensional results are extended to a more generalized three-dimensional case at the end of the thesis.

This thesis tries to display the practice of forced migration experienced in East and Southeast Anatolia after 1980s in Turkey and its consequences through the lived experiences of internally displaced women and children. In the first phase, the historical background of the practice of forced migration, which continues ever since the Ottoman period and the Republican period as well, has been analyzed within the framework of implementations and laws on settlement. In the second phase, in-depth interviews were made with internally displaced women and children living in Diyarbakir and Istanbul and embarking upon the lived experience of internally displaced women and children before, during and after the flight, the issue of social integration with the &lsquo / host&rsquo / population was analyzed comparatively. What was claimed with this comparative analysis was the fact that there would be a significant difference on experiencing the consequences of forced migration and social integration among the internally displaced women and youngsters living in Diyarbakir, which is a metropolis Kurdish citizens are intense, and those living in Istanbul, where Kurdish citizens are relatively low in numbers. Consequently, through the information gathered with this study, the extent that internally displaced persons are socially integrated with the &lsquo / host&rsquo / populations was depicted and that whether the spatial difference had a significant effect on the issue of social integration was analyzed.

A nanofluid is the suspension of nanoparticles in a base fluid. Nanofluids are promising for heat transfer enhancement due to their high thermal conductivity. Presently, discrepancy exists in nanofluid thermal conductivity data in the literature, and enhancement mechanisms have not been fully understood yet. In the first part of this study, a literature review of nanofluid thermal conductivity is performed. Experimental studies are discussed through the effects of some parameters such as particle volume fraction, particle size, and temperature on conductivity. Enhancement mechanisms of conductivity are summarized, theoretical models are explained, model predictions are compared with experimental data, and discrepancies are indicated. Nanofluid forced convection research is important for practical application of nanofluids. Recent experiments showed that nanofluid heat transfer enhancement exceeds the associated thermal conductivity enhancement, which might be explained by thermal dispersion, which occurs due to random motion of nanoparticles. In the second part of the study, to examine the validity of a thermal dispersion model, hydrodynamically developed, thermally developing laminar Al2O3/water nanofluid flow inside a circular tube under constant wall temperature and heat flux boundary conditions is analyzed by using finite difference method with Alternating Direction Implicit Scheme. Numerical results are compared with experimental and numerical data in the literature and good agreement is observed especially with experimental data, which indicates the validity of the thermal dispersion model for explaining nanofluid heat transfer. Additionally, a theoretical analysis is performed, which shows that usage of classical correlations for heat transfer analysis of nanofluids is not valid.

Turkey experienced conflict-induced internal displacement due to the political and social unrest, in the late 1980s and during the 1990s, in East and South East Anatolia regions. The unplanned and involuntary nature of migration led internally displaced persons (IDPs), and in particular forced many Kurdish migrants&rsquo / children to poverty. Within this framework, this study aims to explore how internally displaced families&rsquo / high school attending children experience poverty in two cities, Izmir and Diyarbakir. In this thesis, it is argued that the motive behind child poverty among internally displaced children is an overlapping process of forced migration and consequences of neo-liberal economic policies in Turkey. Although high school education is not compulsory in Turkey, these displaced students prefer to attend high schools instead of working (or besides working) to contribute household budget despite the fact that they are from poor families. In particular, the research aims to understand internally displaced children&rsquo / s expectations from high school and the barriers to their education. Based on the assumption that education, in today&rsquo / s economic structure, is the only way for displaced children to achieve upward social mobility, the main research question of this study is that whether high school education would enable these children once caught in poverty in Diyarbakir and Izmir to achieve social upward mobility. All in all, but, it is claimed that although these children seem far from improving their lives through attending high school, social and economic inequalities from the beginning of their lives are barrier to their futher educational achievement and developing their human capital, and hence hinders their social upward mobility.

This thesis investigates the refrigerant (R-134a) flow in a minitube experimentally. The small scale heat transfer is a relatively new research area and has been in favor since the end of 1970&rsquo / s. Refrigerant flow in mini- and microscale media is a potential enhancement factor for refrigeration technology in the future. For the forthcoming developments and progresses, experimental studies are invaluable in terms of having an insight and contributing to the establishment of infrastructure in the field in addition to leading the numerical and theoretical approaches. The studies in the literature show that low mass flow rate and constant wall temperature approach in minitubes and minichannels were not among the main areas of interest. Therefore, an experimental set-up was prepared in order to perform experiments of two-phase refrigerant flow in a 1.65 mm diameter copper minitube with the constant wall temperature approach. The design, preparation, and modifications of the experimental set-up are explained in this thesis. Two-phase flow and quality arrangements were done by pre-heating the refrigerant at saturation pressure and the constant wall temperature was achieved by a secondary cycle with water and ethylene glycol mixture as the working fluid. The heat transfer coefficient and the pressure drop for the two-phase flow with varying quality values and saturation temperatures of the refrigerant were calculated and compared with the results available in literature.

In this thesis, a Thermal Model Tool (TMT) is developed for standard Avionic Transport Rack (ATR) chassis and thermal design of a standard ATR chassis is done using developed TMT. This ATR chassis is a Digital Moving Map (DMAP) of a helicopter and the tool is used to determine the cooling channel details of DMAP. TMT decreases design process steps and eliminates the complexity of the design. Experimental studies are conducted on one of the existing chassis produced in Aselsan Inc. for different operating conditions. There are two different operating conditions for the chassis as 25 &ordm / C and 55 &ordm / C, which are given, in military standard MIL-STD-810F. Critical temperature values are measured, which are used in analytical calculations, and results are represented. At the first step, outputs of the experimental studies are used in analytical calculation in order to develop TMT. Secondly, heat dissipation rate of two different chassis are v calculated easily by using the TMT, and without making effort for CFD analysis, the necessary number of plate fins of the chassis are assessed considering given geometrical constraints and heat loads. Finally, cooling channels are generated using the results of TMT. In the next step the chassis, which are designed using the results of TMT, are analyzed numerically by using Icepak Computational Fluid Dynamics (CFD) tool and results of TMT are verified. The cooling capacities of the decided plate fins, which are obtained by TMT, are checked whether or not the required heat dissipation rates are ensured. Consequently, TMT is tested under for two different operating conditions on two different chassis. Analytical and numerical studies for both conditions are compared and discussed in detail. Comparisons show that, developed TMT results are meaningful and close to numerical results, therefore TMT can be used in forthcoming ATR chassis designs.

This study attempts to better understand gender relations in the process of resettlement among families of Afghan forced migrants in Turkey. In addition it tries to gain an insight into whether those gender relations have been changed by this migration. In order to ascertain these possible changes a field study including participant observation, in depth interviews and interviews with experts was conducted in a city in Central Anatolia to which Afghan migrants are assigned. Since 2007 Afghan asylum-seekers represent a new event in Turkey. They have admitted the right to seek asylum in Turkey very recently. Furthermore, as their population has risen to become the third largest of the non-European asylum seekers in Turkey / there is a need for more research about them and the associated issues. The research findings demonstrate patterns of changes concerning gender relations. Changes can be explained by using the concepts of liminality. Those changes sometimes accommodated emancipation for women / alongside this the opposite occurred too. Liminality produced different patterns of gender relations.

No description available.

This thesis focuses on experimentally measuring the response of varying dilatation ratio bluff body flames under harmonic excitation. Such flames are often encountered in jet engine afterburners and are susceptible to combustion instabilities. Previous work has been done modeling such flames, however, only limited experimental data has been obtained at these conditions and is the motivation for this thesis. The focus of this work is to measure the transfer function of longitudinally forced, varying dilatation ratio bluff body flames. The transfer function is obtained by measuring flame position and flame luminosity fluctuations at the forcing frequency. Specifically, the amplitude and phase of the fluctuations are characterized as a function of flow velocity, axial location, and perturbation amplitude. These measurements are also compared to available theoretical predictions, showing that qualitative measured trends are consistent with theory. In addition, a detailed quantitative comparison is performed at one condition, showing good agreement between predictions and measurements in the near and mid-field of the flame response. However, agreement is not obtained in the far-field, indicating that continued theoretical work is needed to understand the flame response characteristics in this region.

<p>Finite-volume methods have been used for modeling of fluidflows involved in forced convection electrochemical coating androtating spray painting systems. Electrodeposition on a singlecircular cylinder under forced convection for Reynolds numbers10 and 200 was simulated. Comparisons with earlier numericaland theoretical results are presented and it is shown that theunsteady wake that appears for Reynolds numbers greater than 50affects the mass transfer from the surface of the cylinder onlyin an average sense. This result is compared with a heattransfer case, where unsteadiness is much more manifest. Theeffect of application of circulation movement around thecylinder surface was considered, showing that the use ofoptimal values for circulation can create a recirculation zonearound the cylinder and result in a remarkable improvement ofthe deposit uniformity. The magnetoelectrolysis researchdiscipline is presented with focus on magnetic fields uses onmass transfer processes. A classification of the governingdimensionless parameters that control the phenomena isproposed. Application of magnetoelectrolysis on electroplatingprocesses is done for the first time. It is found that the useof an alternating magnetically induced force around thecylinder can result in interesting improvement of quality andproductivity. Application of numerical methods is also studiedin another field of the surface finishing industry, thepainting atomizers. A critical situation of "reverse flow" isanalyzed. Different parameters of this phenomenon are studiedand suggestions for atomizers design are given and tested.</p><p><b>Keywords:</b>mass transfer, electrochemical coating, iontransport, forced convection, diffusion, magnetoelectrolysis,electrolyte, limiting current, numerical simulation,finite-volume methods, paint atomization, Coanda effect.</p>