Wetting and Spreading of Molten Volcanic Ash in Jet Engines

Song, Wenjia; Lavallee, Yan; Wadsworth, Fabian B.; Hess, Kai-Uwe and Dingwell, Donald B. (2017): Wetting and Spreading of Molten Volcanic Ash in Jet Engines. In: Journal of Physical Chemistry Letters, Vol. 8, No. 8: pp. 1878-1884

Abstract

A major hazard to jet engines posed by volcanic ash is linked to the wetting and spreading of molten ash droplets on engine component surfaces. Here, using the sessile drop method, we study the evolution of the wettability and spreading of volcanic ash. We employ rapid temperature changes up to 1040-1450 degrees C, to replicate the heating conditions experienced by volcanic ash entering an operating jet engine. In this scenario, samples densify as particles coalesce under surface tension until they form a large system-sized droplet (containing remnant gas bubbles and crystals), which subsequently spreads on the surface. The data exhibit a transition from a heterogeneous to a homogeneous wetting regime above 1315 degrees C as crystals in the drops are dissolved in the melt. We infer that both viscosity and microstructural evolution are key controls on the attainment of equilibrium in the wetting of molten volcanic ash droplets.

• Item Type: Journal article
• Faculties: Geosciences > Department of Earth and Environmental Sciences
• Subjects: 500 Science > 550 Earth sciences and geology
• ISSN: 1948-7185
• Language: English