The effects of nanoparticles (NPs) on heat transfer in extended surface channels have been analyzed using a two-component (TC) model. The results show that unlike the single-component model, the TC model leads to more accurate predictions of the system’s heat transfer performance as a result of the direct influence of the NPs’ distribution on the hydrodynamics. It is found that the average Nusselt number varies non-monotonically with the block’s heights, and the trend is explained by the interplay between heat transfer mechanisms and the hydrodynamics. A similar non-monotonic trend observed in the case of the friction factor has been explained by the variations of the concentration- and temperature-dependent viscosity of the nanofluids. A guideline for an optimum design based on the combination of the variation of average Nusselt number and friction factor with respect to the geometrical parameters has also been presented.
In a gas condensate reservoir, a drastic pressure drop in the vicinity of the wellbore makes it subject to gas condensate drop‐out. This phenomenon can adversely affect the productivity of the well and reduce gas recovery. The objective of this paper is to conduct a two‐phase fluid flow simulation on two‐dimensional porous media to understand the effect of the gas condensate drop‐out on the gas relative permeability values. In order to do so, lattice Boltzmann (LB) modelling was applied as a computational fluid dynamics (CFD) approach to perform the simulations in homogeneous and heterogeneous porous structures. The developed model was constrained by periodic boundary conditions at inlet and outlet and bounce‐back boundary condition at fluid‐solid interfaces. It was shown that the model can appropriately monitor formation and movement of the condensate droplets as a result of the pressure drop as well as blockages due to the entrance of the droplets into the throats. A consistent decrease in gas relative permeability values with condensate saturation was observed. It was also indicated that the condensate droplets become mobile at higher critical saturations in the heterogeneous system due to the dominance of capillary forces over viscous forces in the less permeable areas. Such dominance results in more severe blockages in the heterogeneous systems, as the simulation results confirmed.
Drilling mud plays an important role in drilling operations. Forming a thin layer called mudcake is one of these roles which prevents the aquatic phase of drilling mud called mud filtrate from penetrating through the reservoir rock and therefore reduces the damage caused by that work. So knowing about the mudcake characteristics such as thickness, solid contents and also filtration rate of mud filtrate will help the drilling engineer. Factors affecting filtration process are time, temperature and pressure. In this paper, a mathematical model will be presented which estimates mudcake thickness and filtration radius in both static and dynamic conditions with consideration a radial system at constant temperature conditions. The mudcake thickness and permeability variation with time are also considered in the dynamic model.
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