CFD Simulation of Methanol Dehydration Step through an Adiabatic Fixed-bed Reactor of DME Synthesis

   Today, dimethyl ether (DME) is changing to ordinarily worn as a superb aerosol propellant and refrigerant for its eco-friendly characteristics. Lately, with the development of novel chemical energy in the coal industries, it has become a fascinating field of research as an alternative green fuel for diesel machines due to the high cetane number. The DME synthesis processes include catalytic dehydrating methanol in an adiabatic fixed-bed reactor. In this study, to investigate the chemical conditions of the methanol dehydration reaction, CFD simulations of the adiabatic reactor have been assessed. The advantage of the work is a sensitivity analysis was run to find the effect of pressure, kinetics, and velocity on the reactor performance. The results showed that using a γ-Al2O3 catalyst with selective mechanical properties and unique surface properties is a convenient choice for DME synthesis. The CFD simulation results also show that the laboratory data such as pressure, energy, and velocity in the adiabatic reactor meet the reaction requirements well, and deliberated a major vision of what happened in the reactor. Also, the graphs of the temperature profile with changes in physical properties pomp that methanol dehydration reaction strongly depends on environmental factors and gives different results under the influence of other conditions

Comparison between continuum and porous continuum models in studying natural convection in porous cavity with random distribution of solid obstacles

Purpose - The purpose of this paper is to improve the volume-averaged models for free convection flow in porous media. Design/methodology/approach - A pore scale simulation is conducted against which an independent volume-averaged solver is fine-tuned. Findings - Micro and macro scale results can merge if proper choice of local thermal non-equilibrium and thermal dispersion models are selected. This depends on the range of Ra values investigated. Originality/value - This is the first time a work like this is published in the literature

Numerical analysis of heat transfer enhancement in grooved vertical Multi-Cylinders at various groove geometries

In this study, the natural convection enhancement in grooved vertical multi-cylinders at various groove geometries is investigated. The effects of several grooves ranging from 3 to 7, groove thickness ranging from 0.25 to 1 mm, and cylinder surface temperature ranging from 350 to 500 K at different Rayleigh numbers are examined. The current study was simulated using the finite volume method using CFD with a laminar steady-state condition. The SIMPLE scheme is used for the pressure–velocity coupling discretization and the second-order upwind method is utilized to discretize the momentum and energy equations. The results obtained from the present research show that the presence of grooves on the cylinders will increase the heat transfer surface, create and intensify the secondary flow and mixing, and ultimately increase the heat transfer. Moreover, by increasing the number of grooves and its thickness, the amount of heat transfer increases dramatically. It’s also found that the groove thickness parameter's effectiveness on heat transfer is more than the groove number parameter. Ultimately, it’s demonstrated that using grooved cylinders leads to a 14 % augmentation in Nusselt number in comparison with employing plain cylinders