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Binary collision of CMAS droplets—Part I: Equal-sized droplets
Published online by Cambridge University Press: 23 June 2020
Abstract
This study focuses on binary droplet collisions of equal calcium–magnesium–aluminosilicate (CMAS) droplets formed by the melting of dust and sand ingested by gas turbine engines. Head-on, off-center, and grazing collision of 1 mm CMAS droplets traveling toward each other at a relative velocity of 100 m/s are numerically investigated using a volume-of-fluid-based direct numerical simulation approach at operating pressure and temperature of 20 atm and 1548 K, respectively. It is found that head-on and off-center collisions lead to droplet coalescence, whereas stretching behavior is observed for the grazing configuration. To elucidate the effect of viscosity, a fictitious fluid with all properties the same as CMAS except for viscosity (1/10 of CMAS) is also studied. It is found that the lower viscosity liquid deforms significantly as compared to CMAS for the head-on and off-center cases. These differences are quantified using the budgets of kinetic, surface, and dissipation energies. This paper represents the first study of its kind on the binary collision of CMAS droplets.
Keywords
- Type
- Invited Paper
- Information
- Journal of Materials Research , Volume 35 , Issue 17: Focus Issue: Sand-phobic Thermal/Environmental Barrier Coatings for Gas Turbine Engines , 14 September 2020 , pp. 2260 - 2274
- Copyright
- Copyright © The Author(s), 2020, published on behalf of Materials Research Society by Cambridge University Press
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