## Applications of Computational Transport Analysis: Micro to Macro - In memory of Edward P. Furlani

A. Verma, P. Vishnoi, I.H. Karampelas, E.P. Furlani
University at Buffalo,
United States

Keywords: oil spill, drift-flux, dynamics of oil spill, fused deposition modeling, additive manufacturing process

Summary:

We demonstrate the use of Computational Fluid Dynamics (CFD) for the analysis of two distinct applications that span six orders of magnitude in scale, microns to meters. The first application involves the use of CFD to analyze complex and large scale transport phenomena that govern the dynamics of an off-shore oil spill. Specifically, we study the spill of oil from a drilling platform that is tethered to the sea floor off-shore from a land mass. In this paper, we study the spread of oil taking into account key phenomena and factors including water-oil two-phase flow, spill rate, properties of different oil grades and fluid-structure interactions as the platform is rocked under the influence of varying wave conditions. We use parametric CFD analysis to determine the impact of these factors on the spill dynamics [1]. The model used for studying these effects is the Drift Flux Model which analyses the relative flow of two intermixed fluid components, one continuous and the other dispersed, based on a difference in densities. The computational model extends 3937ft (1200m) in x- direction, 3280ft (1000m) in y- direction; 328ft (100m) in depth in z- direction and the distance between the platform and landmass is 1640ft (500m). The second application that we discuss involves heat exchange at the microscale, demonstrating a 3D simulation of the Fused Deposition Modeling process. In this process, as the nozzle moves over the build platform to fabricate a pre-specified geometry, it deposits a thin thread of heated flowing material, which is extruded from a nozzle. The material solidifies quickly once it is deposited. Solid layers are created by following a horizontal movement where the extruded threads are deposited side-by-side inside an obtrusive boundary [2]. 3D solid structures can be formed by either drop wise solidification or continuous solidification. In this paper, we present a fully coupled thermo-fluidic computational model of the FDM printing process. The key tunable parameters taken into account in this coupled heat and fluid flow simulation include the feed mechanism of the material, extruder nozzle dimensions, extruder angle with respect to substrate, extruder velocity with respect to the substrate, substrate temperature, extrusion velocity, and formed structure residual stresses. We use a state-of-the-art multiphysics CFD program, FLOW3D, (wwwflow3d.com) for parametric analysis of the underlying physics for the oil spill as well as the FDM process.