Session: 10.5 - Non-Newtonian fluid flows

Paper Number: 156271

156271 - Inflow Inertia and the Evolution Characteristics of Submerged Annular Viscoplastic Jets 

Abstract: 

Detailed understanding of jet flows is important to the design of chemical reactors, jet mixers, polymer mixing and injection molding devices. The flow behavior of jets can be impacted by inlet conditions, swirl, co-flow, confinement, composition and rheology. Previous work mostly focused on round Newtonian jets. However, numerous materials display yield-pseudoplastic non-Newtonian characteristics such as slurries, pastes, plastics, electro-rheological fluids, suspensions of solids in liquids, and emulsions. A viscoplastic material behaves like a solid under the application of small stresses and flows once the applied stress exceeds a critical value called the yield stress. Familiar viscoplastic materials include mayonnaise, ketchup, toothpaste, gelled products, and paint.

The current study focuses on the influence of inflow inertia and viscoplastic non-Newtonian rheology on the flow behavior of submerged annular jet. Non-Newtonian jet flows are found in important industries such as food processing, biotechnology, plastics and polymers, pulp and paper, and petrochemicals. Environmental applications of non-Newtonian jet flows include the mobilization of the settled sludge and mixing of the radioactive nuclear waste stored in numerous underground tanks at various U.S. Department of Energy, DOE, sites. The governing fully-elliptic partial differential equations of motion will be used here to model annular non-Newtonian jets and provide accurate and valid flow field information. The Bingham constitutive equation accounts for the presence of a yield stress and will be used here to model the viscoplastic rheology. The presence of yield stress was found to have a strong influence on the global flow field characteristics of submerged jets.

The evolution of the jet and the flow patterns in the initial flow region depend on the inflow conditions of the jet, i.e., velocity profile and jet inertia, and the fluid rheology. The primary objective here is to investigate the impact of incoming flow inertia on the evolution characteristics of a laminar submerged Bingham viscoplastic annular jet. Non-Newtonian fluids are highly viscous and most of their flows are typically laminar.

Presenting Author: Khaled J. Hammad Central Connecticut State University

Presenting Author Biography: Prof. Khaled J. Hammad received his Ph.D. degree in Mechanical Engineering from New York University Polytechnic School of Engineering and did his postdoctoral work at the Pacific Northwest National Laboratory. He joined the Department of Engineering at Central Connecticut State University (CCSU) in August 2011 after working more than 12 years for Dantec Dynamics. He chaired the ASME Fluids Engineering Division Executive Committee (2018-2019). His technical expertise and research interests include Laser Diagnostics, Fluid Flow, Heat, and Mass Transfer in Single and Multiphase Systems, Non-Newtonian Fluids, and Energy Conversion Systems. Prof. Hammad is a contributing author to over 95 peer reviewed publications.