Non-isothermal generalized coalescence/redispersion model for micromixing

Abstract

The non-isothermal coalescence/redispersion micromixing model is presented and analysed using the population balance approach. Development of the model is based on the concept of diffusive mass and heat exchange interactions of the fluid elements identified as the Kolmogorov-scale eddies. The model is formulated as a non-linear, multidimensional population balance equation describing deterministic chemical reactions and temperature variations inside the fluid elements and stochastic mass and heat exchange processes between the fluid elements by their impacts. The population balance equation is solved by applying a hybrid continuous time/Monte Carlo method. The behaviour and properties of the model is analysed by numerical experimentation using an adiabatic continuous stirred tank coalescence/redispersion reactor model. Simulation results are presented for second order uni-molecular and quasi-linear consecutive–competitive chemical reactions. It is shown that non-isothermal micromixing in a reactor can be evaluated and characterized by applying appropriately chosen concentration and temperature configurations of partially premixed or segregated feeds measuring the mean concentrations and temperature of the reaction mixture both in dynamic and steady state processes. In well-designed conditions measurement of the mean temperature in itself provides satisfactory information on the mixing state of reactors at microscale.