SELECTION OF A GEOMETRIC MODEL OF A FIXED SOLID FUEL BED IN ANSYS FLUENT COMBUSTION MODELLING

The aim of the study is to develop a CFD-based three-dimensional model for numerical simulation of solid waste combustion. The selection of the most adequate computational domain(s) specifying different fuel-to-air ratios along the bed length to ensure oxidant distribution between individual current lines is considered. Four variants of geometry with different sized regions specifying different fuel-to-air ratios along the length of the bed were evaluated. The calculation results were evaluated in terms of flow distribution in the gas region, parameter variation along the current lines, velocity, composition and temperature of gases at the exit of the calculation region. It was found that adequate simulation results are obtained with uniformly distributed areas of fuel and air, changing the ratios of both the size of solid fuel blocks and the ratio of fuel and air flow rates in different parts of the fuel layer led to a significant deterioration of the adequacy of the results - the appearance of a large number of current lines, in which there was no oxidant and combustion ended much later than in the neighbouring current lines.