Numerical Analysis of a Turbulent Pulverized Coal Flame Using a Flamelet/Progress Variable Approach and Modeling Experimental Artifacts

Abstract

A coaxial burner with a hydrogen-supported pulverized coal flame, operated by the Central Research Institute of Electric Power Industry (CRIEPI, Japan), is investigated numerically. The flame is modeled using massively parallel large eddy simulation (LES). A flamelet/progress variable (FPV) approach is used for modeling the complex multiphase flow of the laboratory coal flame. A four-dimensional tabulation method based on non-premixed flamelets is introduced, which uses two mixture fractions for the hydrogen pilot and coal volatiles, respectively, as well as the absolute enthalpy and the reaction progress to parametrize the thermochemical space. Simulations are compared to the experiments in terms of the temperature, gas-phase velocities (with and without consideration of buoyancy), and gas compositions along the centerline and in the radial direction at different heights. The effect of the suction probe on the scalar field measurements is tested by simulating this probing, observing relative changes up to 50% in various quantities and locations. By consideration of these probe effects, the agreement between the experiment and simulation can be improved significantly; at the same time, the simulation also provides the unperturbed scalar fields, without probing effects. The new flamelet model gives a robust and cost-effective prediction of the investigated laboratory flame, provided that the probing effects are considered.

Special Issue in Memory of Professor Mário Costa

“…Finally, the reactor network approach provides a fast and reliable tool to quickly assess several aspects of complex reactors, supporting the development of more efficient reactor concepts. Meller et al 11 numerically investigate a coaxial burner with a hydrogen-supported pulverized coal flame using massively parallel large eddy simulation (LES). A flamelet/ progress variable approach was used to describe the thermochemical processes.…”

A Validation Study for RANS Based Modelling of Swirling Pulverized Fuel Flames

“…Pulverized fuel combustion has been investigated by many researchers over several decades [10][11][12][13][14][15][16][17][18][19][20][21][22]. Comprehensive overviews on simulation procedures for the combustion of pulverized coal are provided in Epple et al [23] and Hasse et al [24].…”