Aerodynamic characteristics of the sawdust combustion process in a vortex furnace

Abstract

The article presents the results of a numerical study of the behavioral characteristics of the process of burning sawdust with a diameter from dmin = 25 μm to dmax = 750 μm in a vortex furnace with counter swirling air flows. The fields of static pressure and absolute velocity in the furnace volume are given. The change in flow density, volume concentration of particles along the height of the furnace is shown. Consumption concentration of particles is 0.094 kg / kg of air. Currently, one of the main directions of Ukraine's strategic development is to achieve energy independence. To achieve this, it is necessary to implement systems for the use of energy resources available in our country. Since a significant part of the country's economic activity is occupied by agricultural activities, the use of low-grade fuels, most of which are waste in this area, is relevant and profitable for economic and environmental reasons. Reconstruction of boilers, improvement of methods and ways of combustion in vortex furnaces of low-grade fuels will significantly reduce the consumption of imported natural gas and bring the country closer to the status of energy-independent state. coke burnout is 100%. The value of the volume concentration of particles β <3 · 10-2 characterizes the aerodynamic mode of motion of particles in the furnace as the mode of gas suspension. In the course of research, the main characteristics of the process of burning sawdust in a vortex furnace with counter-swirling air flows, namely: higher gas velocity is observed in the near-wall area in the lower part of the furnace; when the diameter of the fuel particles increases, the zone with the maximum coke content in them moves from the lower zone of the furnace to the upper; the gas pressure varies slightly both in height and in the cross section of the furnace.