Veröffentlichungen und Präsentationen

Modern adiabatic calorimeters are designed to keep thermal inertia as low as possible so that temperature-dependent reaction rates and heats of reaction can be accurately extracted from the thermocouple data. Published models of this type of equipment are generally zero dimensional (0D) in that they assume spatial uniformity while following the excursion of the temperature with time. However, once thermal runaway begins, it is likely that the very rapid rise of the temperature in the vessel leads to the formation of hot-spots in the calorimeter which can lead to errors in the reaction calculations.

A 2D-axisymmetric numerical model of an adiabatic calorimeter was prepared using the CFD Module, Heat Transfer Module, and mass transfer functionalities in COMSOL Multiphysics^® simulation software, including an agitated liquid reactant phase with a vapor headspace, glass or titanium reaction vessels, a nitrogen heating blanket and guard heaters. This resulting simulation is able to predict temperature and pressure profiles throughout the calorimeter including turbulent mixing inside the reaction vessel and natural convection in the nitrogen blanket as well as radiative and conductive heating of the vessel content from the guard heaters. The results of this simulation are compared with experimental data.