TY - JOUR

T1 - Dynamics of annular gas-liquid two-phase swirling jets

AU - Siamas, George A.

AU - Jiang, Xi

AU - Wrobel, Luiz C.

PY - 2009/5

Y1 - 2009/5

N2 - The dynamics of annular gas-liquid two-phase swirling jets have been examined by means of direct numerical simulation and proper orthogonal decomposition. An Eulerian approach with mixed-fluid treatment, combined with an adapted volume of fluid and a continuum surface force model, was used to describe the two-phase flow system. The unsteady, compressible, three-dimensional Navier-Stokes equations have been solved by using highly accurate numerical methods. Two computational cases have been performed to examine the effects of liquid-to-gas density ratio on the flow development. It was found that the higher density ratio case is more vortical with larger spatial distribution of the liquid, in agreement with linear theories. Proper orthogonal decomposition analysis revealed that more modes are of importance at the higher density ratio, indicating a more unstable flow field. In the lower density ratio case, both a central and a geometrical recirculation zone are captured while only one central recirculation zone is evident at the higher density ratio. The results also indicate the formation of a precessing vortex core at the high density ratio, indicating that the precessing vortex core development is dependent on the liquid-to-gas density ratio of the two-phase flow, apart from the swirl number alone. 

AB - The dynamics of annular gas-liquid two-phase swirling jets have been examined by means of direct numerical simulation and proper orthogonal decomposition. An Eulerian approach with mixed-fluid treatment, combined with an adapted volume of fluid and a continuum surface force model, was used to describe the two-phase flow system. The unsteady, compressible, three-dimensional Navier-Stokes equations have been solved by using highly accurate numerical methods. Two computational cases have been performed to examine the effects of liquid-to-gas density ratio on the flow development. It was found that the higher density ratio case is more vortical with larger spatial distribution of the liquid, in agreement with linear theories. Proper orthogonal decomposition analysis revealed that more modes are of importance at the higher density ratio, indicating a more unstable flow field. In the lower density ratio case, both a central and a geometrical recirculation zone are captured while only one central recirculation zone is evident at the higher density ratio. The results also indicate the formation of a precessing vortex core at the high density ratio, indicating that the precessing vortex core development is dependent on the liquid-to-gas density ratio of the two-phase flow, apart from the swirl number alone. 

KW - DIRECT NUMERICAL-SIMULATION

KW - COHERENT STRUCTURES

KW - INFLOW CONDITIONS

KW - SURFACE-TENSION

KW - FLOW

KW - INSTABILITY

KW - TURBULENCE

KW - INTERFACE

KW - SYSTEMS

KW - STREAMS

U2 - 10.1016/j.ijmultiphaseflow.2009.02.001

DO - 10.1016/j.ijmultiphaseflow.2009.02.001

M3 - Journal article

VL - 35

SP - 450

EP - 467

JO - International Journal of Multiphase Flow

JF - International Journal of Multiphase Flow

SN - 0301-9322

IS - 5

ER -