Abstract
Across the metal industry the risk of explosions due to liquid water trapped in molten metal is very real. Accidents, often killing one or a few employees, or blowing out walls, are common in the metal industry. Despite awareness of such explosions it can be challenging to predict consequences and thus evaluate vulnerability and design safety measures. In a recent risk assessment an attempt was made to estimate consequences from water explosions in molten metal furnaces using a combination of spreadsheet calculations and a CFD-tool. With the spreadsheet source terms for blast waves were estimated, calculating how pockets of water within milliseconds could accelerate and throw molten metal at high velocities out of the furnace, and at the same time generate strong pressure waves. Using the CFD-tool FLACS the pressure wave propagation was calculated. The effect of a heavy metal hood above the furnace, with a limited area door opening in one direction would help protect the building and employees against projectiles. The hood would also prevent damaging shockwaves from the explosion to reach wall/roof surfaces in directions of main concern. Using this modelling methodology the amount of water entrained in molten metal required to cause critical damage to building was estimated. Based on a qualitative/quantitative assessment it was thereafter concluded that the potential for water explosions to severely damage the building with the actual furnace design and hood was very limited. The study approach and results from calculations are described in this article.
