Document Type
Dissertation
Date of Award
5-31-2024
Degree Name
Doctor of Philosophy in Mechanical Engineering - (Ph.D.)
Department
Mechanical and Industrial Engineering
First Advisor
Angelantonio Tafuni
Second Advisor
Samaneh Farokhirad
Third Advisor
Simone Marras
Fourth Advisor
Samuel Lieber
Fifth Advisor
Jason W. Hartwig
Abstract
This dissertation focuses on the application of numerical models to study Fluid Structure Interaction (FSI) in the industrial context. The emphasis is on a series of case studies belonging to practical applications in design and manufacturing and that are solved by a synergistic use of theoretical and computational models. The first study looks into the hydrodynamic actions experienced by vibrating slender structures immersed in viscous fluids near the free surface. This study case is relevant to applications such as, for example, marine propulsion, micro-electro-mechanical systems, and atomic force microscopy. The hydrodynamic problem is governed by three parameters, namely the frequency, and amplitude of the oscillation, and the distance of the structure from the fluid's free surface. Smoothed Particle Hydrodynamics (SPH) models are implemented via the open-source code DualSPHysics, allowing the extraction of hydrodynamic forces and subsequent elaboration of added mass and damping coefficients for numerous values of the governing parameters. The dependence of these coefficients on the three governing parameters is elucidated and supported by flow contours, which shed light on the intricate fluid-structure interactions that arise at the different regimes considered. The second case study is an application of Computational Fluid Dynamics (CFD) for a technical assessment of the manufacturing efficacy and performance of profile plastic extrusion dies produced via subtractive and additive methods. The aim of this study is to offer insights on the advantages and challenges of each manufacturing approach. Additive Manufacturing (AM) has become commonplace to iterate concepts and realize products in different industries. The maturation of AM has made it a viable alternative to Subtractive Manufacturing (SM) processes, nevertheless, there remain several unexplored opportunities. One of these is profile plastic extrusion tooling, which is typically produced at low volumes, can be complex in geometry, and could benefit from AM's bottom-up process. Such manufacturing options raise the question of how one can evaluate whether AM should be considered as opposed to SM. The objective of this work is to establish a technology assessment method to evaluate which extrusion profile cases warrant consideration for AM. Results obtained from simulations using ANSYS Polyflow help relating polymer flow through the flow channel to several applied parameters used by the extrusion industry. This provides a means to evaluate a tool's design virtually before implementing it in production. The last study is a detailed CFD investigation of cryogenic multiphase flow of tanked liquid nitrogen (LN2) under microgravity conditions. NASA and the United States are designing multiple reduced-gravity cryogenic payloads to study various two-phase flow phenomena that will be ground-tested and subsequently flight-tested onboard parabolic flights. The minimum gravity level during a parabolic maneuver is 0 ± 0.05 g, which can last around 20 seconds, and the maximum expected gravity is 2 g, which lasts for 40-50 seconds. The study involves designing a Propellant Management Device (PMD) for a LN2-filled Dewar tank that is capable of delivering a single-phase LN2 outflow during all flight phases, based on isothermal VOF simulations. CFD and structural simulations are carried out using ANSYS FLUENT and ANSYS Static Structural solver, respectively. Additionally, a phase change model for cryogenic flow is implemented in ANSYS Fluent to capture phase change phenomena between the liquid and vapor interface.
Recommended Citation
Prasad Varghese, Allen, "Reproducible fluid structure interaction for complex flows in engineered systems" (2024). Dissertations. 1823.
https://digitalcommons.njit.edu/dissertations/1823
