Energy Consumption in Turbulent Two-Phase Flows: Expectations and Surprises
Prof. Artur Bartosik
Kielce University of Technology, Poland
Abstract: Solid-liquid flow appears widely in the mining and food industries. The behaviour of solid particles in a carrier liquid is very complex. Generally, fine solid particles are responsible for an increased viscosity (Shook and Roco, 1991). Viscosity can be measured using different techniques; however, rheological measurements are the most common (May and Henderson, 2013). If coarse solid particles are considered, which is the objective of this study, it is not possible to measure solid-liquid viscosity, since the sedimentation process plays the primary role. In such a case, it is common for researchers to assume that the two-phase flow possesses the carrier liquid viscosity.
The presence of solid particles can cause an increase or decrease in turbulence, depending on the physical properties of both phases and flow conditions (Gai et al., 2020; Nouri and Whitelaw, 1992; Schreck and Kleis, 1993; Kuboi et al., 1974). The main objective of these studies is analysis of energy consumption during the transportation of solid-liquid flows that contain narrowly sized coarse particles. The energy consumption was determined as the minimum energy required for the transport of solid particles to the unit distance of the pipeline. Energy consumption depends on pressure gradient, solid density, and solid concentration by volume (Joshi et al., 2025; Wu et al., 2010). In this investigation, several solid-liquid flows are considered, containing solid particles with diameters of 0.125 mm, 0.240 mm, 0.470 mm, and 0.780 mm, respectively. The solid volume concentration changed from 10% to 40% in a turbulent flow in the vertical pipeline. Based on the physical model in which the physical properties of solid and liquid phases were determined, and on the basis of the flow domain, the mathematical model was developed. The mathematical model contains time-averaged continuity and momentum equations, whereas the problem of a closure of equations set was solved by including a two-equation turbulence model in which a self-developed wall damping function has been applied. Considering the cylindrical coordinates, the computational domain was discretised along the r axis, perpendicular to the pipeline symmetry axis, and most of the nodal points were situated close to the pipe wall. The set of equations was solved using the finite-volume method (Roache, 1982) and its own computer code. The mathematical model was previously validated, providing a good agreement with experiments (Jones, 2023; Bartosik, 2020; Cotas et al., 2015; Bartosik and Shook, 1991). Based on numerical simulations, it was found that the solid concentration and median diameter of the solid particles play a crucial role in the energy consumption during pipeline transport. Simulations demonstrated that in solid-liquid flow containing particles with a median diameter of 0.47 mm, the energy consumption is the lowest in the entire range of concentrations studied. The highest energy consumption was found for the lowest solid concentration, while the lowest energy consumption occurred for a solid concentration equal to 40%. The novelty and value of this study is that it provides a deeper analysis of the influence of solid particles on friction losses.
Brief Biography of the Speaker: Artur Bartosik has been appointed a researcher and academic teacher at the Kielce University of Technology (KUT) since 1983. In 1993 he established the Centre for Continuing Education at the University and in 2001 the Swietokrzyskie Centre for Innovation and Technology Transfer, which he managed as President of the Board from 2001 to 2007. In years 2012-2020, he acts as Dean of Faculty of Management and Computer Modelling at the KUT. Currently, he is the head of the Department of Production Engineering and the head of the Industrial Laboratory for Low-Emission and Renewable Energy Sources. Together with his team, he works to establish a structure for university-wide multidisciplinary collaboration in terms of energy self-sufficiency. His scientific interest is focused on experiments, modelling, and simulation of microgrid efficiency and fluid mechanics. Artur, as a researcher, spent 2 years at the University of Saskatchewan in Canada and several weeks at Ilmenau Technical University in Germany. He is the Editor-in-Chief of WSEAS Transactions on Fluid Mechanics and an Associate Editor of the Journal of Hydrology and Hydromechanics; Journal of Hydrology and Water Resources; Modern Subsea Engineering and Technology. He is a member of the professional bodies and scientific committees of several international conferences. He lectures to students on fluid mechanics and heat transfer.