Speaker Name: Prof. Himanshu Goyal, Associate Professor, Department of Chemical Engineering, IIT Madras

Date: 07-10-2026 (Wednesday)

Time: 14:30

Venue: LC001

Abstract: Complexity of the real-world reactors necessitates the use of engineering models. However, these models are often based on strong simplifying assumptions and fitted to limited experimental data. This talk emphasizes that developing fast yet physically grounded reactor models is essential to advancing reaction engineering, and illustrates this through our recent work on slender packed bed reactors. Packed beds with low tube-to-particle diameter ratios (<10) are widely used as catalytic reactors. In such beds the confining wall strongly influences the local packing structure, causing radial porosity oscillations, flow channelling near the wall, and non-uniform heat transfer. Industrial design relies largely on continuum models with lumped parameters calculated using empirical correlations. These models often fail to capture the bed heterogeneity. Particle-Resolved CFD (PRCFD) offer a high-fidelity option but is too computationally expensive at reactor-scale. This talk presents a multiscale framework that combines the fidelity of PRCFD with the efficiency of (continuum) porous medium modelling for fluid flow and heat transfer in slender beds of randomly packed particles. Representative unit cells of a few particles are extracted from numerically generated packed beds. PRCFD simulations of these unit cells provide the radially varying effective properties of the porous medium, such as permeability and effective thermal conductivity. The resulting porous medium model accounts for the spatial variation of bed structure. The model is verified against several full-bed PRCFD simulations for pressure drop and radial temperature profiles. The developed approach demonstrates how multiscale modeling can connect first-principles models with practical design tools.

Bio: Dr Himanshu Goyal is an Associate Professor in the Department of Chemical Engineering and the Radha and PK Narayanan Early Career Chair at Indian Institute of Technology (IIT) Madras. He received his BTech in Chemical Engineering from IIT Guwahati and PhD from Cornell University, followed by postdoctoral research at the University of Delaware. His research develops fast, first-principles models of chemical reactors for conventional and emerging chemical processes and energy systems. Examples include fixed and fluidized beds, bubble columns, electrochemical cells, and electric reactors. His group combines computational fluid dynamics (CFD), multiscale and multiphysics simulations, and ML/AI to build models that are both physically rigorous and practical for real-world reactor design.