A numerical simulation of burning of pulverized peat fuel in a bidirectional vortex combustor

Abstract

Bidirectional (or countercurrent) vortex combustors are some of the most promising vortex-flow devices in terms of the fuel and oxidizer mixing efficiency, the combustion efficiency, the emission characteristics, and the combustion stability. This paper suggests a new arrangement principle for combustion of solid pulverized peat in conditions of vortex countercurrent flow which has never been studied earlier; we developed a combustion unit implementing this principle and carried out a numerical analysis of the combustion process with various operating parameters. The calculation results confirmed the possibility of combustion within a wide range of parameters and showed that varying the air-fuel equivalence ratio from λ = 0.5 to λ = 5.05 results in significant change in both the structure of the limited vortex flow and the distribution of total pressure and temperature, as well as the averaged volume concentration of fuel particles. We calculated the boundaries of lean and rich flame blowouts where the gas-dynamic flow loses its stability and the toroidal vortex is disrupted. At the same time, secondary vortex structures are formed throughout the combustor volume.