From Physical Modeling to CFD:-20 Years of Development in Kiln Modeling Techniques

摘要

Modeling has become an invaluable tool in the successful design of combustion systems in lime recovery kilns over the last decade.Traditionally physical modeling techniques,such as the use of water bead and acid/alkali,have been employed to replicate the aerodynamic and combustion processes taking place within the kiln.It has provided burner designers and kiln operators alike with a direct and visual representation of the kiln operation,in particular the flame profile.As a result,it has been widely accepted by the lime recovery kiln community but the physical modeling techniques have their limitations.With the dramatic increase in computer power as well as the advances in numerical techniques,computational fluid dynamics(CFD)have now matured to a point that they are now able to be applied in a practical way for the design of combustion systems within lime recovery kilns.In many ways not only can CFD be used to mimic the physical modeling but also provides more in-depth understanding of the complex combustion processes which are indispensable for the development of emissions reduction measures in the kilns.This paper describes how a systematic and practical approach has been developed to ensure smooth transitions from the traditional physical modeling to modern CFD in the study of lime recovery kilns.The process to validate the CFD is presented.It compares these two different techniques with practical case studies and highlights the increased level of information and diagnostic capabilities that CFD modeling can provide within kiln design to optimize performance.