Understanding the dynamics of gas-liquid two-phase flows (G/L), is crucial to predict the transport efficiency of the mixture and the energy needed for pumping. In addition, many industrial processes are governed by momentum, heat, and mass transfer phenomena between the phases. Many examples can be found in the different stages of refinement up to the production of petroleum products, biomass transport, chemical reactors, nuclear waste decommissioning, pulp, and paper production, among many others.In this study, an experimental facility designed to analyze G/L mixture is presented and discussed. The experimental results are presented for gas-liquid flows in horizontal 30 mm ID pipelines. The mixture involved is composed of air and water. The superficial velocity of the liquid phase is in the range of 0-2 m/s and the gas phase from 0 to 2 m/s. The experimental data accounts for pressure loss, hold-up, superficial velocities, and flow regimes. A flow map is presented covering the specified ranges, and two-phase correlations for hold-up and frictional pressure loss are reported and compared with the available experimental data.
The dynamics of three-phase flows involves phenomena of high complexity whose characterization is of great interest for different sectors of the worldwide industry. In order to move forward in the fundamental knowledge of the behavior of three-phase flows, new experimental data has been obtained in a facility specially designed for flow visualization and for measuring key parameters. These are (1) the flow regime, (2) the superficial velocities or rates of the individual phases; and (3) the frictional pressure loss. Flow visualization and pressure measurements are performed for two and three-phase flows in horizontal 30 mm inner diameter and 4.5 m long transparent acrylic pipes. A total of 134 flow conditions are analyzed and presented, including plug and slug flows in air-water two-phase flows and air-water-polypropylene (pellets) three-phase flows. For two-phase flows the transition from plug to slug flow agrees with the flow regime maps available in the literature. However, for three phase flows, a progressive displacement towards higher gas superficial velocities is found as the solid concentration is increased. The performance of a modified Lockhart-Martinelli correlation is tested for predicting frictional pressure gradient of three-phase flows with solid particles less dense than the liquid. Keywords Three-phase flows • Horizontal pipelines • Plug-to-slug flow transition • Frictional pressure drop • Flow visualization List of Symbols Variables D Internal diameter of pipeline (m) f Darcy-Weisbach friction factor g Acceleration of gravity (9.81 m/s 2) j Superficial velocity (m/s) Re Reynolds number (Re = v D/ν) X Lockhart-Martinelli parameter
There are a wide variety of devices behaving essentially as flexible and elastic systems while interacting dynamically with fluids, usually water or air, under normal operating conditions. Interactions of this kind involve a double complexity of the dynamics, as the systems go through large deformation due to the flow actions, and simultaneously, the flow dynamics is strongly influenced by the shape adopted by the systems. The present research adapts mathematical methods, still new to the field, to represent ways of dealing with flows of fluid in bidirectional interactions with those new technologies, and particularly applies them to the exploration of vorticity wind turbines (VWT), a new kind of vertical blade-less turbine that gathers energy from the vortex induced vibrations (VIV) of a relatively short and scalable mast. This research presents a framework for such modeling by coupling the discrete element method (DEM) with the Immersed Boundary Method (IBM), for the representation of VWT; and with the finite volume method (FVM), for solving the Navier-Stokes equations. Simulations show that the VWT achieves the lock-in effect for wind velocities between 9 and 15 m/s, with efficiency values between 20 and 30%. The preliminary results together with logistic and cost-related reasons, make these devices very promising, especially when considering the difficulties of implementing new approaches in developing countries.
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