FUNDAMENTALS OF TURBULENT MOTION, MIXING AND KINETICS

Abstract

Abstract The principles of mixing on a macroscopic level have been known and used for a number of years for the scale-up of mixing processes. However, these scale-up methods have been empirical in nature due to the lack of information about mixing theory on a microscopic level. The complexity of problems involving turbulence, such as mixing, has made a quantitative description difficult. However, the modern turbulence approach has led to a much deeper understanding of the field of mixing and of related turbulent scalar transport processes. The analysis allows us to define measurable mixing criteria. A knowledge of the parameters of the turbulence provides the information necessary to estimate the degree of mixing. The parameters can often be estimated from the geometry of the flow system and from simple empirical relationships. With a knowledge of the mixing, the problem of chemical kinetics, when mixing cannot be ignored, can be studied. A theoretical approach is possible that with limited assumptions allows one to predict the course of second-order chemical reactions. Recent advances in this area arc reviewed, as well as the results and predictions for a specific flow reactor.