Abstract
A number of manufacturing and energy conversion processes, such as metal 3D printing and wave energy extraction, involve multiphase phenomena that vary widely in thermo-physical properties among phases. These multiphysics processes involve complex fluid-structure interactions, and some may also involve solidification, melting, and evaporation. Due to several length and time scales, numerical simulations of these multiphase problems can be challenging. In the first part of the talk, we present a robust approach to modeling isothermal/non-isothermal multiphase flows with solids, liquids, and gases that can change phases. A discrete conservation of mass, momentum, and energy fluxes is employed to enable robust numerical modeling of multiphase flows with high-contrasting thermo-physical properties (density, viscosity, thermal conductivity). We present several isothermal/non-isothermal benchmark examples to demonstrate the robustness of the technique.
The second part of the talk focuses on two contemporary problems in multiphase flow engineering: (1) wave energy conversion (WEC) and (2) metal additive manufacturing/3D printing. In particular, for WEC we present results for model predictive control (MPC) integrated wave-structure interactions, where the MPC controller finds the optimal energy-maximizing force "on the fly" by dynamically interacting with the multiphase numerical wave tank (NWT). Our results demonstrate that MPC is an adaptive controller that can adapt optimally to changing sea conditions, and is therefore quite appropriate for controlling wave energy converters. As an application of 3D metal printing, we present simulations of air bubbles getting trapped in solidifying liquid metal, a phenomenon known as the porosity defect in AM literature. Such high-fidelity simulations provide vital insights into how heat and flow cause defects in printed parts that tend to reduce their life expectancy.
About the Speaker
Dr. Amneet Bhalla obtained his Ph.D. in Mechanical Engineering from Northwestern University in 2013 and his Bachelors (2004-2008) and Masters (2009) in Mechanical Engineering from Indian Institute of Technology at Kharagpur. He has postdoctoral trainings from the University of North Carolina at Chapel Hill and Lawerence Berkeley National Laboratory. He also has an industrial experience at ExxonMobil Upstream Research Company where he worked as a computational research engineer. In his research, Dr. Bhalla develops numerical methods and high performance computing techniques for computational fluid dynamics and computational fluid-structure interaction problems. The broad goals of his research include developing mathematical models for flow phenomena in engineering devices and processes, and to use novel simulations to interrogate the underlying physics of the problem, with the aim of improving and optimizing the engineering design.
Host: Professor Andres Goza
