Abstract
The dripping of molten thermoplastics is a widely observed phenomenon in cable and façade fire, where the large drips can often carry a blue chain flame during the free fall to ignite other flammable materials and escalate the fire hazard. This work simulated the flame evolution behind a falling thermoplastic drip with the DNS model and finite-rate flame chemistry. The accelerated free-fall of drip was modeled by fixing the position of drip, increasing the upward airflow, and setting a fuel jet on the top of the drip. Modeling reproduces the dripping flame and reveals the flame shedding to be a combination of a lifted flame and a vortex street, where the lifted flame caused by the gravity acceleration of drip is identified as the critical factor that governs the shedding formation. As the diameter of drip decreases, the falling drip becomes difficult in forming a stable shedding structure in the wake region, so that the dripping extinction occurs due to the dilution and cooling of airflow, agreeing well with the experimental observation. This work reveals the underlying mechanism of stabilizing the dripping flame and helps evaluate the fire risk and hazard of dripping phenomena.
Original language | English |
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Pages (from-to) | 745-758 |
Number of pages | 14 |
Journal | Flow, Turbulence and Combustion |
Volume | 107 |
Issue number | 3 |
DOIs | |
Publication status | Published - 27 Feb 2021 |
Keywords
- DNS
- Dripping flame
- Extinction
- Flame shedding
- Moving fuel
ASJC Scopus subject areas
- General Chemical Engineering
- General Physics and Astronomy
- Physical and Theoretical Chemistry