Computational fluid dynamics simulations of pressure drop and heat transfer in fixed bed reactor with spherical particles

Abstract

Fixed bed reactors are among the most important equipment in chemical industries as these are used in chemical processes. An accurate insight into the fluid flow in these reactors is necessary for their modeling. The pressure drop and heat transfer coefficient have been studied for the fixed bed reactor with tube to particle diameter ratio (N) of 4.6 and comprising 130 spherical particles using computational fluid dynamics (CFD). The simulations were carried out in a wide range of Reynolds number: 3.85≤Re≤611.79. The RNG k-ε turbulence model was used in the turbulent regime. The CFD results were compared with empirical correlations in the literature. The predicted pressure drop values in laminar flow were overestimated compared with the Ergun's [27] correlation and underestimated in the turbulent regime due to the wall friction and the flow channeling in the bed, respectively. It was observed that the CFD results of the pressure drop are in good agreement with the correlations of Zhavoronkov et al. [28] and Reichelt [29] because the wall effects have been taken into account in these correlations. Values of the predicted dimensionless heat transfer coefficient showed better agreement with the Dixon and Labua's [32] correlation. This is explained by the fact that this correlation is a function of the particle size and shape in the bed.

Particle‐resolved turbulent flow in a packed bed: RANS, LES, and DNS simulations

“…Therefore, particle‐resolved simulations of a small section of PBR (i.e., with a few hundreds of particles) are extensively used to evaluate the effects of particle shape, to innovate new particle shapes. and also to analyze particle‐scale heat and mass transfer (see 1–7 and the references cited therein). However, despite the extensive use of particle‐resolved computational fluid dynamics (CFD) simulations, the rigorous validation of the predictions of particle‐resolved simulations lacks to a great extent.…”

“…One of the approaches, traditionally used to validate the particleresolved simulations, is to compare their predictions of bed-scale performance with the predictions of semi-empirical correlations available in the literature, for example, the pressure drop characteristics are compared with the predictions of correlations proposed by Ergun, 1,2,7 Reichelt, 3,8 Zhavoronkov et al, 3,4,8 and so forth. The predicted pressure drops, and other bed-scale characteristics are in a reasonable agreement with the correlations.…”