Transient CFD model for the combustion of sewage sludge powder

This upload is a supplement to the publication:

"Application of computationally inexpensive CFD model in steady-state and transient simulations of pulverized sewage sludge combustion" [1]

Abstract from the publication: 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.

HOW TO USE THE ANSYS FLUENT MODEL

1) Read the .cas.h5 and .dat.h5 file in FLUENT. This is a steady-state solution that will serve as initialization data for the transient simulation - but it does not include initialized particles yet.

2) Read the exemplary .inj files that have been generated in advance for the DPM initialization with realistic initial conditions. This should work automatically. 

3) Run the transient CFD simulations.

[1] B. Ortner et al.,  Application of computationally inexpensive CFD model in steady-state and transient simulations of pulverized sewage sludge combustion

Advanced Powder Technology 2023, 34(12)