Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Numerical Determination of Permeability and Interfacial Convective Heat Transfer Coefficient for Non-Isotropic and Periodic Dual Scale Porous Medium(Izmir Institute of Technology, 2015) Sabet, Safa; Barışık, Murat; Mobedi, MoghtadaIn this study, the fluid flow and heat transfer in a periodic, non-isotropic dual scale porous media consisting of permeable square rods in inline arrangement is analyzed to determine permeability and interfacial convective heat transfer coefficient, numerically. A periodical representative elementary volume (REV) with the dimensions of H×H is chosen as the computational domain. The flow in the REV is assumed fully developed and periodical. The permeable square particles are placed with in-line arrangement. There are two symmetrical intraparticle pores considered here which are in longitudinal flow direction. The continuity, Navier-Stokes and energy equations are solved to obtain the velocity, pressure and temperature distributions in the unit structures of the dual scale porous media. The obtained fields are upscaled by using volume average method to obtain the intrinsic inter and intraparticle permeabilities, bulk permeability tensor, interfacial convective heat transfer coefficients and the corresponding Nusselt numbers of the dual scale porous media for different values of inter and intraparticle porosities. The study is performed for interparticle porosities between 0.4 and 0.75 and for intraparticle porosities range of 0.2 to 0.8. A correlation based on Kozeny-Carman theory in terms of interparticle and intraparticle porosities and permeabilities is proposed to determine the bulk permeability tensor of the dual scale porous media. The intraparticle porosity value increase the flow rate passes through the porous media and the particle becomes more permeable. However; for high interparticle porosity values, the intraparticle porosity does not have importance effect on bulk permeability. Additionally, the results predicts that the interfacial convective heat transfer coefficient increases with increase of Reynolds number and the ratio of intra to interparticle porosity, while the increase rate shows variation with the porosity ratio and Reynolds number values.Master Thesis Heat and Fluid Flow Analysis in a Channel Partially Filled With Permeable Isotropic Porous Layer(Izmir Institute of Technology, 2012) Uçar, Eren; Mobedi, MoghtadaA theoretical study is performed on heat and fluid flow in a parallel plate channel completely and partially filled with porous medium. An asymmetric heat flux is imposed onto the boundary conditions of the channel fully filled with porous media. However, a symmetrical heat flux is applied to the channel partially filled with porous medium. Dimensional analysis is performed on three parallel plates having different permeability and effective thermal conductivity values. The dimensionless analysis is performed for parallel plates with different values of Da and thermal conductivity ratio. Darcy-Brinkman model is used to investigate the velocity distribution in porous media. The dimensional and dimensionless energy equation and appropriate boundary conditions are written for the analyzed channels. The dimensional equations of motion and heat are solved by numerical methods, while the dimensionless form of those equations are analytically solved to obtain analytical expressions for the velocity and temperature fields in the channel. The dimensional temperature and velocity profiles, obtained by numerical methods, are compared with the analytical expressions of dimensionless temperature and velocity profiles and good agreement between the results were observed. For both fully filled asymmetric heated channel and partially filled symmetrical heated channel, it is observed that the traditional temperature difference (difference between surface and mean temperatures) is not proper to be used in the individual heat transfer coefficient since heat transfer coefficient approaches to infinity and changes sign without changing of heat transfer direction. Hence, a proper temperature difference is required to be defined.