Determining the heating characteristics of non-spherical particles in combusting flows

Highlights: • Efficient Euler-Lagrange calculations of combustion and inert particle heating. • Comprehensive model validation for heat transfer to non-spherical particles. • Specially developed closure relations for drag and heat transfer were applied. • Evaluation on the applicability of two different combustion models. • Good accordance between numerical results and experimental data. -- Abstract: In order to perform efficient numerical calculations of the heating characteristics of inert, non-spherical particles, an Euler – Lagrangian approach was used for this work. The continuous phase was the combusting flow field in a lab-scale furnace. The Steady Laminar Flamelet (SLF) and the Flamelet Generated Manifold (FGM) combustion model were used for simulations of the continuous phase and the corresponding results were evaluated. It was concluded that the FGM combustion model offers superior performance and moderate computational effort in combustion modelling of air and natural gas. The second phase consisted of discrete coal slag particles which were injected into the furnace. The heating characteristics of spherical and non-spherical particles were evaluated and a model for calculating the temperature of non-spherical particles was validated. The application of the FGM in combination with the Euler-Lagrange approach and specially developed multiphase model adaptions led to very precise results. The maximum deviation between experimentally and numerically determined mean temperatures of non-spherical particles was only 6 K at a temperature level of 680 K.