A Calibrated Computational Fluid Dynamics Model for Simulating the Rotating Disk Apparatus

Abstract

Reaction kinetics between different rock and acid systems have been studied using the rotating disk apparatus (RDA). However, simplifying assumptions have been made to develop the current equations used to interpret RDA experiments to enable solving them analytically in contrast to using numerical methods. No work has been done to investigate the validity of these assumptions and their impact on the calculation of the reaction kinetics using the RDA. This work is divided into three main parts: 1) investigating the validity of the assumptions in the equation currently used to interpret RDA results, 2) quantifying the impact of the assumptions on the calculation of the reaction kinetics, and 3) developing a calibrated computational fluid dynamics model to simulate the chemical reaction in the RDA. Chapter II provides insights on some assumptions in the mass transfer of different fluid types in the RDA. Chapter III dives deeper into these assumptions and studies the impact of disk radius on acid turbulence in the reactor. Finally, Chapter IV uses a Gaussian based proxy model to develop the first calibrated computational fluid dynamics model to calculate the diffusion coefficient and reaction rate constant between hydrochloric acid and calcite rock. The main findings are: 1) Current RDA reactor dimensions are not large enough to prevent the impact of the boundaries on the mass transfer of H+ to the disk, which can increase H+ mass transfer to the disk of up to 28%, 2) the critical Reynolds number for the flow at the surface of the disk is in the range 1–2×104 and not in the 105 as previously reported in the literature, and 3) the developed calibrated surrogate model can predict the diffusion coefficient with an improvement in prediction accuracy obtained through experimental validation of 63% over Newman’s conventional method.