首页|Modeling of the gravitational deposition of firebrands subject to a turbulent jet flow
Modeling of the gravitational deposition of firebrands subject to a turbulent jet flow
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NETL
NSTL
Elsevier
The deposition of firebrands carried by horizontal round jet flow was investigated using Lagrangian tracking and large-eddy simulation with a version of FDS modified by our group to include new features for additional Lagrangian models (e.g., Mankame & Shotorban, 2021). The simulations were configured to replicate previous VUFP firebrand generator experiments (Wadhwani et al., 2017), where firebrands were carried by airflow through a pipe and the resulting jet flow, before deposited on the ground. Validation of jet flow simulation was performed by comparing jet spread rate and velocity decay constant against previous experimental and theoretical values for free jet flows. Firebrands were released from the jet exit. Both drag and gravitational forces were found to play significant roles in firebrand motion, with drag reversal observed when firebrands exited the jet flow-initially accelerating and later impeding forward motion. Quantitative analysis using particle time constants and terminal velocities indicated that small-scale turbulence had a negligible effect on the firebrand trajectories, explaining the observed smoothness of the trajectories. The firebrand simulations were assessed for the considered Lagrangian models by comparing the probability density functions of the deposited firebrands' coordinates against those reported in previous experimental and simulation studies (Wadhwani et al., 2017).
NETL
NSTL
Elsevier
