Papers by Keyword: Porous Media

Abstract: Using numerical experiment the gas flow in the gravity field through a plane porous object with heat sources inside and partial closure of the object's outlet has been investigated and compared with axisymmetric case. The influence of partial closure of the object's outlet on the cooling process of the plane porous objects with a non-uniform distribution of heat sources has been analyzed by means of computational experiment. It has been revealed that effect of the top cover on a cooling process of the plane porous objects is qualitatively the same as in the axisymmetric objects, but quantitative differences are significant.

Abstract: Parallel algorithm for modeling the unsteady 2D gas flows through a porous media with energy sources is presented. A mathematical model of dynamic processes in porous heat-evolutional object is mentioned briefly. The structure of sequential algorithm and its parallel version is described in details. The performance and efficiency of parallel algorithm and its realization using OpenMP technology is evaluated.

Abstract: The following study involves the investigation of hydrodynamics inside the packed column both at laboratory scale which is HPVA high pressure adsorption analyzer chamber and pilot scale. The simulations are performed in ANSYS FLUENT14. Velocity variation due to porous media along with the pressure gradient for different adsorbent particle sizes and varying flow rates are obtained and compared for both the scales. Simulation is based on the criterion which identifies the emergence of non-Darcy flow.

Abstract: As nanotechnologies become more widely used, titania nanoparticles are being released to the subsurface environment via wastewater sludge applications. Titania nanoparticles are not only toxic to organisms in the environment, but recent studies revealed that they may also serve as carriers of hydrophobic organic contaminants and affect their fate and distribution in the subsurface environment. The mobility of titania nanoparticles varies depending on nanoparticle morphology characteristics, pH and the ionic strength of solutions, flow velocity, nanoparticle concentration, and the presence of surfactant or natural organic matter. Analogous to findings for natural and engineered carbonaceous nanoparticles, titania nanoparticles may enhance the transport of hydrophobic organic contaminants in porous media. However, to prove this hypothesis, further research is necessary. Thus experiments examining the impacts of titania nanoparticle on the hydrophobic organic matter transport in porous media were designed, which consist of three different sets of column experiments. These experimental sets will investigate the effects of the presence of titania nanoparticles, the size of nanoparticles and the organic carbon content in soil, respectively. Due to the estimation of the potential for the titania nanoparticles to facilitate organic contaminant transport, the experiment results are expected as: (a) the presence of titania nanoparticles will enhance the organic contaminant transport in porous media; (b) smaller nanoparticles will adsorb more organic contaminants and enhance their transport as the result of the increasing specific surface area; (c) soil containing higher organic matter content will compete for the adsorption of organic contaminants and retard their facilitated transport by titania nanoparticles.

Abstract: The porous ceramic holds good potential as acoustic resistance and vibration reduction material during ultra-precision machining. Porous materials absorb acoustic energy by friction with the air that moves inside the pores, and in this paper, the motion is simplified as the incompressible fluid in a single cylindrical pore. The analysis and calculation results show that the acoustic coefficient of porous ceramic is a complicated wave function and the acoustic absorption coefficient calculation model is feasible based on fluid thermal viscous theory. The acoustic absorption coefficient of porous ceramic increases with the increase of thickness, and its period and amplitude decreases with the increase of porosity of ceramic.

Abstract: In-Situ Combustion (ISC) thermal Enhanced Oil Recovery (EOR) methods are aimed at increasing the oil recoveries of heavy oil reserves that are expected to play an instrumental role in near future in meeting the world’s energy demand. The complex multiphase heat and reactive mass transport necessitate a clear understanding of thermal and kinetic models used in modeling of ISC process. A finite difference based numerical analysis is carried out on heat loss and selective productions of light oil components during ISC, which showed a significant effect on peak temperature, thermal front propagation and the corresponding production rates dictating the performance of ISC process.

Abstract: The deamplification model developed by Zendagui et al. has been adapted in this study for the case of P₁ wave propagation in porous media in order to investigate the effect of saturation degree on motion coherency at depth. The input wave amplitude distribution function is generated compatibly with the suitable free field coherency model and the top wave amplitudes are evaluated using the transfer matrix method following the Biot’s theory. The results show that even if the saturation degree decreases slightly below the complete saturation, it influences the coherencies of horizontal and vertical motion due to P₁ wave incidences. Elsewhere, the generation process shows that in this case, the wave front content, necessary to produce a coherency identical to the Luco and Wong model at the free field, is more focus with less intensity than required in the case of a complete saturation.

Abstract: The correlation of an effective thermal conductivity (k_eff) on spherical packed bed porous media with stagnant fluid was proposed. Alumina-Cordierite ceramic ball (Al-Co) having average diameter (d) of 2.1 cm and porosity (Φ) of 0.468 was examined. The experimental procedure was operated based on ASTM E1225. The tested porous sample was sandwiched by references materials (Solid Brass, 70%Cu, 30%Zn). A higher temperature (T_H) on the top of test set was obtained from wire heater with a constant electrical power of 350 W. The water cooling set was installed at the bottom of to generate a lower temperature (T_L). Four previous models established from geometrical structure were compared to validate the present correlation. From experiment, it was found that k_eff decreased with increasing T_H. Thus, the relation between k_eff and T_H was appropriately proposed by a correlating linear-equation (k_eff/k_f = 329.2(1-0.1028(T_H/100)). Agreement between the present correlation and literature models was satisfied particular.

Abstract: This article presents a thermo-mechanical approach to investigate heat transfer between solid and fluid phases in a model gasifier. A two-temperature equation approach is applied in addition to a macroscopic model for laminar flow through a porous moving bed. Transport equations are discretized using the control-volume method and the system of algebraic equations is relaxed via the SIMPLE algorithm. The effects on inter-phase heat transfer due to variation of medium permeability, thermal conductivity and thermal capacity are analyzed. Results indicate that for smaller medium permeabilities, as well as for higher solid-to-fluid thermal capacity and thermal conductivity ratios, enhancement of heat transfer between phases is observed.

Abstract: We discuss the numerical modelling of unsaturated-saturated flow in porous media and contaminant transport with adsorption in 1D. We developed an efficient numerical approximation which is a good candidate for solving inverse problems involving the determination of model parameters (hydraulic and geochemical). Also an adsorption/desorption model for mass transfer through the boundary of porous media (contact solid-liquid) is discussed, too. Our numerical solution is based on the MOL method where space discretization leads to the corresponding system of ODE. To collect the measurement data for inverse problems we consider both the gravitational and centrifugal infiltration driven forces. In series of numerical experiments we demonstrate the effectiveness of our method.