Sharif Digital Repository

Understanding the chemistry of sandstone acidizing is important in designing an effective treatment for subsurface rock formations. The complex chemistry of sandstone systems leads to the precipitation of minerals that contribute to formation damage. Thus, monitoring the concentration and location of precipitates is necessary. In this work, a continuum-scale sequential implicit LEA/PLEA reactive transport model is developed and programmed through coupling OpenFOAM and Reaktoro to improve the model prediction. The proposed LEA/PLEA models are compared for core acidizing simulations at relatively high and low Damköhler numbers. We found that the common assumption of kinetically-controlled flow... 

The Eddy Dissipation Concept (EDC) combustion model, in comparison with some other combustion models, has drawn attention, especially for the Moderate or Intense low oxygen Dilution (MILD) combustion. The original formulation of the EDC combustion model is not developed for the MILD combustion regime, and a revision of the model could be considered. In this study, the effect of the characteristic frequency on the EDC combustion model has been investigated, and some parametric studies on the ratios of length and time scales of the fine structures to the Kolmogorov scales have been performed. Results revealed that finding optimum model constants for all combustion field with a wide range of... 

The reaction progress variable is a crucial concept in the advanced flamelet combustion models. As a controlling variable, a well-defined progress variable must consider the essential features of the combustion process. It is usually a heuristically defined linear combination of some major chemical species mass fractions. However, such a simple definition could lead to inaccurate results for the fuel-rich reactive mixtures or complicated fuels, due to the vast number of chemical species in the combustion process. In this paper, a new method for generating a reaction progress variable is proposed through solving a constrained optimisation problem. The proposed method uses a genetic algorithm... 

We outline a comprehensive numerical procedure for modeling of species transport and surface reaction kinetics in electrokinetically actuated microfluidic devices of rectangular cross section. Our results confirm the findings of previous simplified approaches that a concentration wave is created for sufficiently long microreactors. An analytical solution, developed for the wave propagation speed, shows that, when normalizing with the fluid mean velocity, it becomes a function of three parameters comprising the channel aspect ratio, the relative adsorption capacity, and the kinetic equilibrium constant. Our studies also reveal that the reactor geometry idealized as a slit, instead of a...