Radiative Properties of Coal Ash Deposits with Sintering Effects

Parra-Alvarez, John; Isaac, Benjamin; Zhou, Manshui; Smith, Sean Stein; Ring, Terry A.; Harding, Stan; Smith, Philip

doi:10.1021/acs.energyfuels.8b04206

Cited by 6 publications

(2 citation statements)

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“…A shift emittance occurs if the slag appears at high temperature. The above emissivity model is validated by comparing the model results with the experimental data, 67 as shown in the author's previous publication 10,57 …”

Section: Mathematical Modelsmentioning

confidence: 99%

“…Direct representation of unsteady‐wall‐heat‐transfer model of Equation () is computationally unfeasible under LES framework; therefore, this unsteady state is approximated as the steady state using the time‐scale analysis of this system 57 . With a linear temperature profile inside the deposits' layer, a one‐dimensional wall heat transfer model is proposed Reference 56, as follows:

q_{net} = \frac{T_{s} - T_{in}}{\frac{d_{normalw}}{k_{normalw}} + \frac{d_{dep}}{k_{dep}}} = ɛ_{d} ((), q_{in} - q_{rad_normalw}) + q_{conv},

where q in , q rad , and q net are the incidental radiation heat flux from the gas phase to the wall, the heat flux of black‐body wall emission, and the net local heat flux absorbed by the wall, respectively.…”

Section: Mathematical Modelsmentioning

confidence: 99%

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

Zhou

Parra-Alvarez

et al. 2021

AIChE Journal

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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.

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Section: Mathematical Modelsmentioning

confidence: 99%