Mesoscopic simulations of a molten sand droplet spreading on thermal barrier coatings under non-isothermal conditions

ORAL

Abstract

The deposition, infiltration and the ensuing solidification of molten sand on the thermal barrier coating (TBC) of gas turbine engine components alters the thermal properties of the TBC causing severe damage. The mesoscopic dynamics of a highly-viscous molten sand droplet spreading on a smooth TBC surface are investigated under non-isothermal conditions using the energy-conserving dissipative particle dynamics (eDPD) framework in conjunction with the many-body interactions to model the multiphase effects. Following the experiments conducted at the Army Research Laboratory, the droplet is subjected to a linear ramp-up of temperature from 1140 degrees Celsius to 1260 degrees Celsius where it is held constant till the end of the simulation. The contact angle obtained from the experiments is used to calibrate the contact angle in the eDPD simulations. The eDPD system is carefully parameterized to model the temperature-dependent non-linear viscosity of the molten sand droplet by setting the exponent of the weighting function as a function of temperature. The temporal evolution of the spreading radius and the corresponding scaling laws are evaluated for different drop sizes and final equilibrium contact angles and compared to previously obtained results from isothermal spreading on a smooth surface.

*The authors acknowledge the support received from the Army Research Office Mathematical Sciences Division for this research through grant number W911NF-17-S-0002. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies or positions, either expressed or implied, of the U.S. Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein.

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Presenters

  • Rahul Babu Koneru

    • University of Maryland, College Park

Authors

  • Rahul Babu Koneru

    • University of Maryland, College Park

  • Zhen Li

    • Clemson University
    • Department of Mechanical Engineering, Clemson University, Clemson, SC 29634, USA

  • Alison Flatau

    • University of Maryland, College Park

  • Luis Bravo

    • US Army Research Laboratory

  • Muthuvel Murugan

    • US Army Research Laboratory

  • Anindya Ghoshal

    • US Army Research Laboratory

  • George E Karniadakis

    • Brown University