TY - JOUR
T1 - Application of computationally inexpensive CFD model in steady-state and transient simulations of pulverized sewage sludge combustion
AU - Ortner, Benjamin
AU - Schmidberger, Christian
AU - Gerhardter, Hannes
AU - Prieler, René
AU - Schröttner, Hartmuth
AU - Hochenauer, Christoph
N1 - Publisher Copyright:
© 2023 The Society of Powder Technology Japan
PY - 2023/12
Y1 - 2023/12
N2 - The combustion process of pulverized fuels with high ash contents, such as sewage sludge, is significantly impacted by the amount of slag deposition in a furnace. A CFD model based on the Steady Diffusion Flamelet (SFM) approach was applied to numerically simulate the combustion of pulverized sewage sludge in a drop tube furnace. Steady-state solutions of the Reynolds-Averaged Navier–Stokes (RANS) equations already displayed good agreement with species and temperature measurements. Still, they failed to accurately predict the significant amount of ash trapped on the internal furnace surfaces (minimum deposition of 28% of the generated ash versus 5% predicted by the RANS simulations). The SFM-based CFD model's computational efficiency enabled the conduction of large eddy simulations (LES), significantly improving the model's predictive capabilities (27% of the generated ash deposited). Additionally, the transient simulations further improved the agreement with temperature measurement data. A novel initialization procedure was developed, which allowed the transient LES simulations to be conducted in a computationally efficient manner. The SFM-based model can effectively support research and development efforts, even for large-scale systems which require high cell counts. It provides valuable insights during the early design phases of industrial furnaces for pulverized sewage sludge combustion.
AB - The combustion process of pulverized fuels with high ash contents, such as sewage sludge, is significantly impacted by the amount of slag deposition in a furnace. A CFD model based on the Steady Diffusion Flamelet (SFM) approach was applied to numerically simulate the combustion of pulverized sewage sludge in a drop tube furnace. Steady-state solutions of the Reynolds-Averaged Navier–Stokes (RANS) equations already displayed good agreement with species and temperature measurements. Still, they failed to accurately predict the significant amount of ash trapped on the internal furnace surfaces (minimum deposition of 28% of the generated ash versus 5% predicted by the RANS simulations). The SFM-based CFD model's computational efficiency enabled the conduction of large eddy simulations (LES), significantly improving the model's predictive capabilities (27% of the generated ash deposited). Additionally, the transient simulations further improved the agreement with temperature measurement data. A novel initialization procedure was developed, which allowed the transient LES simulations to be conducted in a computationally efficient manner. The SFM-based model can effectively support research and development efforts, even for large-scale systems which require high cell counts. It provides valuable insights during the early design phases of industrial furnaces for pulverized sewage sludge combustion.
KW - Entrained flow furnace
KW - Flamelet modelling
KW - Sewage sludge combustion
KW - Slag deposition
UR - http://www.scopus.com/inward/record.url?scp=85175804016&partnerID=8YFLogxK
U2 - 10.1016/j.apt.2023.104260
DO - 10.1016/j.apt.2023.104260
M3 - Article
AN - SCOPUS:85175804016
SN - 0921-8831
VL - 34
JO - Advanced Powder Technology
JF - Advanced Powder Technology
IS - 12
M1 - 104260
ER -