3D numerical simulation of compressible swirling flow induced by means of tangential inlets

Abstract

SUMMARYThe objective of the present work is to predict compressible swirl flow in the nozzle of air-jet spinning using the realizable k-turbulence model and discuss the effect of the nozzle pressure. The periodic change of flow patterns can be observed. The recirculation zone near the wall of the injectors upstream increases in size and moves gradually upstream, whereas the vortex breakdown in the injector downstream shifts slowly towards the nozzle outlet during the whole period. A low axial velocity in the core region moves gradually away from the centerline, and the magnitude of the center reverse flow and the area occupied by it increase with axial distance due to the vortex breakdown. From the tangential velocity profile, there is a very small free-vortex zone. With increasing nozzle pressure, the velocity increases and the location of vortex breakdown is moved slightly downward. However, the increase in the velocity tends to decline at nozzle pressure up to a high level.

A Novel Method for Dynamic Simulation of Flexible Fibers in a 3D Swirling Flow

“…When Equation (1) is solved, it is important that a constraint algorithm should be developed to Brought to you by | Carleton University OCUL Authenticated Download Date | 6/12/15 7:40 PM maintain the integrity of the discretized fiber chain during the whole period of motion, i.e., -/·;.,) = // (10) where r,.\ and r, are the position vectors of adjacent beads i-l and /', respectively. Substituting Equations (3), (5), and (7)-(9) into Equations (1), the equations of motion for the fiber in a flow field can be obtained.…”

“…For the swirling flow in the nozzle, the numerical formulation of the problem and the flow characteristics have been fully described by Guo et al [10]. Here, only the velocity vector and streamline plots at different sections are provided (Fig.4).…”

Numerical simulation of tangentially injected turbulent swirling flow in a divergent tube

“…Since high-velocity compressed air is forced into the twisting chamber through the injectors from the air reservoirs, its Mach number is large (on the range of 0.6-0.9) [6,12], compressibility effects are important. For compressible flows, the modeling of its equations is often made with two kinds of averages: velocity components (u i ), temperature (T ) and total energy (e) are Favre massweighted averaged while a Reynolds average is used for density ( ) and pressure ( p).…”

“…However, their predictions [6, 7] cannot show certain properties of the swirling flow since the flow instabilities are three-dimensional and time dependent in nature [8]. In order to investigate more deeply the flow field in the first nozzle (including the slotting-tube), three-dimensional flow characteristics have been studied by Guo et al [9][10][11][12]. The flow patterns show clearly periodic change and the velocity appears to be decaying over time.…”

Application of maximum entropy principle for estimation of droplet-size distribution using internal flow analysis of a swirl injector

“…It is evident that the classical k-" model could not provide reliable results. 20 The major problem in the numerical simulation of the flow in injectors is true tracking of liquid-air interfaces. Steinthorsson and Lee 21 utilized the volume of fluid (VOF) method to simulate the 3D flow with Reynolds stress model (RSM) for prediction of the flow turbulence characteristics.…”