Consideration on Accuracy of Numerical Analysis of Solid–Gas Two-Phase Flow with Reaction Using Energy Conservation Equation with Temperature as a Variable

Abstract

Heterogeneous reactions such as solid–gas reactions are found in various processes that are indispensable to our daily lives, and numerical simulations are becoming more and more widely used to study these processes. In the analysis of processes involving heat transfer, since the conservation equation of energy is solved numerically to obtain temperatures at arbitrary coordinates, the appropriate governing equations should be solved for an accurate understanding of the phenomenon. In this study, the source term of the conservation equation of energy with temperature as a variable is reconsidered for a system with heterogeneous reactions. As a result, it was confirmed that when the source term is inappropriate, temperatures cannot be calculated correctly when chemical species are generated, while temperatures can be calculated correctly when the equation derived in this study is applied. In addition, as an application of the equation derived in this study to solid–gas two-phase flow, a numerical analysis simulating a biomass gasification experiment in a fluidized bed was conducted, and it was confirmed that the equation can represent the experimental result well. The equation derived in this study is expected to ensure the accuracy of analysis of processes related to heat and mass transfer involving heterogeneous reactions.

Keywords

• Numerical analysis
• Heat and mass transfer
• Conservation of energy
• Heterogeneous reaction
• Source term