Large‐eddy simulation of coal combustion in 15 MW pilot‐scale boiler‐simulation facility

Abstract

High‐fidelity modeling provides a useful approach to investigate the multiscale multiphysics mechanism in the pulverized coal combustion. This research focuses on understanding the pulverized coal combustion in a pilot‐up facility: General electric (GE) 15 MW pilot‐scale boiler simulation facility (BSF). The heat flux to the boiler water wall, O2 concentration, and gas temperature are the quality of interest (QoI's) for this research, as they are the most important parameters for designing a full‐scale pulverized coal boiler. Even the heat flux in boiler is largely determined by the heat transfer mechanism, and other detailed multiphysics mechanisms, including multiphase turbulent flow, radiation heat transfer, ash deposition, coal devolatilization, and oxidation, also need to be accounted. This work applies large‐eddy simulation (LES) code on high‐performance computing facility to simulate pulverized coal combustion in BSF. The physics‐based submodel that contains the significant sensitivity for QoI's has been identified using the detailed impact factor analysis on this high‐fidelity modeling. Results indicate that the most sensitive submodel on QoI's is the wall‐heat‐transfer coupling with the ash‐deposition model, which allows us to prioritize to improve this submodel in the LES simulation. Thus, ash deposition and wall‐heat‐transfer processes have been modeled and integrated into coal combustion numerical simulation. The simulation results show quantitative agreement between the simulation with experimental data regarding gas temperature, O2 concentration, and heat‐flux profile across the exposed boiler walls. Another implication of this research is to demonstrate a positive societal impact of extreme computing and accelerate the development of new combustion technology using a capable exascale computing technique.

Optimization of the Air Distribution in a Biomass Grate-Fired Furnace

“…Traditionally, the choice of the air distribution mode for chain-grate furnaces relied mainly on the experience of the operators. Due to the lack of thorough theoretical understanding, the primary research methods are field adjustments or the use of cold flow fields in the furnace and the homogeneous combustion simulation of the gas phase [10]. To address this issue, Chang studied the effect of different ratios of the air on the process of combustion [11], while Wang used cold air to simulate flue gas behavior to guide the design of furnace arches [12].…”