Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Direct Numerical Simulation of Turbulent Flow of Power-Law Fluids in Annular Pipe
Submission Author:
Lucas L. Palladino , PR
Co-Authors:
Lucas L. Palladino, Diogo B. Pitz
Presenter: Lucas L. Palladino
doi://10.26678/ABCM.COBEM2023.COB2023-0497
Abstract
Non-Newtonian fluids are present in a wide range of applications within industrial processes, such as polymer processing and many biological flows. The understanding of turbulent flows of non-Newtonian fluids remains substantially unsolved, since their behavior gets increasingly complex compared to Newtonian fluids, which already have their own complexity when it comes to turbulence. Flows encountered both in nature and in engineering are usually turbulent due to the high velocities and resulting shear stresses involved. For this reason, canonical problems are used to investigate fundamental aspects of a certain problem and to verify the accuracy of the solutions found, such as flows in channels and pipes. Fully developed turbulent concentric annular pipe flow is an interesting subject with important applications in engineering. One motivation for studying annular flows of GNFs (Generalized Newtonian Fluids) comes from the Oil & Gas sector, particularly in the application of perforation mud during oil well drilling. The physics of a bypass air over a combustion chamber in a jet engine and material removal on an oil drilling shaft are also examples of turbulent flow through a pipe with an annular cross section. The flow physics in a concentric annular pipe flow is more complex than in a circular pipe flow since it has two walls with different curvatures instead of one. In this work, a spectral element-Fourier method (SEM) for direct numerical simulation (DNS) of the Navier–Stokes equations is used to evaluate turbulent statistics of flow of a non-Newtonian fluid through a pipe with an annular cross section. A power-law rheology model is used for a GNF. Average velocity profiles and Reynolds stresses obtained from the DNS are compared to an annular concentric Newtonian fluid turbulent flow. This investigation sheds light on how the flow index n of the power-law model influences the flow statistics.
Keywords
DNS, GNF, Turbulent flow, Annular pipe, Power-law fluids
