In this paper the characteristics of primary breakup a liquid jet is analyzed numerically. We applied Volumes Fluids (VOF) approach utilizing Direction Averaged Curvature (DAC) model, to estimate interface curvature, and Normal (DAN) propagate interface. While being used for first time predict atomization, methodology showed high accuracy. The influence varying fluid properties, namely liquid-gas density viscosity ratio, injection conditions discussed related required grid resolution....

SUMMARY The breakup of a liquid jet into irregular structures and droplets leading to the formation dilute spray has been simulated numerically. To overcome shortcomings certain numerical methods in specific flow regimes, combined approach chosen. intact core, its primary dense regime are using volumes fluid (VOF) method combination with LES, whereas Lagrangian particle tracking (LPT) LES context is applied secondary droplets. A developed couple both simulation types on statistical basis....

An experimental investigation of both confined and unconfined flames on a Triple Annular Research Swirler (TARS) is presented. The paper focuses post-processing techniques aiming at extracting information the dynamics that are lost through classical statistics approach. POD together with derived a-posteriori phase averaging procedure successfully reconstructed under thermo-acoustic instabilities in case. For flames, an analysis azimuthal modes performed.

In the recent years, large progresses in laser imaging techniques have allowed to extract spatially resolved 2D and 3D quantitative spray information even optically dense situations. The main breakthrough of these is possibility suppressing unwanted effects from multiple light scattering using Structured Illumination. Thanks this new feature, due extinction can also be corrected allowing measurement local coefficient. These which available challenging conditions, where Phase Doppler does not...

This paper considers the effects of intermittent injection a liquid jet or spray on initial break-up and mixing one fluid with surrounding ambient fluid. The aim analysis is to describe physical process indicate mechanisms that control under different flow conditions (time-dependent its frequency relative time scales flow) properties (density ratio), Schmidt number for single phase case which studied comparison, Weber two-phase cases. computations use Large Eddy Simulation (LES) account...

The impacts of swells on the atmospheric boundary layer (ABL) flows and by this standalone offshore wind turbine (WT) performance are investigated using large eddy simulations (LES) actuator-line techniques. At high swell to speed ratio, swell-induced stress reduces total resulting in higher velocity, less shear, lower turbulence intensity level. These effects increase increasing ratio (C/U) and/or steepness. Moreover, for same hub-height (Uhub), presence increases power extraction rate...

Modern gas turbine spray combustors feature multiple swirlers with distributed fuel injection system for rapid fuel/air mixing and flame stabilization ensuring low NOx operations. In the present paper, we investigate effects of different swirler designs on characteristics, stabilization, behavior at lean blow out using a Triple Annular Research Swirler (TARS) burner. Simultaneous planar measurements laser diagnostics, namely, Planar Laser Induced Fluorescence (LIF) OH radicals indicating...

In this paper, the influence of swirl number on mixing two confined coaxial jets is analysed.The generator a set fixed vanes located in annular nozzle.Different trailing edge angles result numbers ranging from 0.14 to 0.95.Numerical model validated using non reactive benchmarks.Low, intermediate and large swirling injectors are simulated contrast flow pattern.The presence Inner Recirculation Zone associated high plays an important role heat mass transfer since promote gradients with minimum...

The acoustic field generated by two coaxial jets is studied numerically. turbulent non-isothermal flow handled Large Eddy Simulations (LES) and the acoustical perturbations are treated solving an inhomogeneous wave equation. source obtained from instantaneous LES field. computed fields compared to measured data. Good agreement between results has been found.

We investigate the ability of fluidic injection to control noise a model gas-turbine nozzle exhaust. The work is conducted using hybrid method LES for flow field and Lighthill's acoustic analogy field. impact on development in terms coherent structures characteristic frequencies evaluated. main results show that low momentum ratio can trigger vortex pairing mechanism, resulting energy transfer sub-harmonic jet preferred shedding frequency. This changes structure flow. corresponding sources...

An experimental investigation of both confined and unconfined flames on a Triple Annular Research Swirler (TARS) is presented. The paper focuses post-processing techniques aiming at extracting information the dynamics that are lost through classical statistics approach. POD together with derived a-posteriori phase averaging procedure successfully reconstructed under thermo-acoustic instabilities in case. For flames, an analysis azimuthal modes performed.

The dependency of the atmospheric boundary layer (ABL) characteristics on ABL’s height is investigated by using large eddy simulations (LES). impacts wind turbine (WT) power production are also simulating two subsequent turbines actuator line method (ALM). results show that, for same driving pressure forces and aerodynamic roughness height, velocity higher at deeper ABL, while shear veer not affected depth. Moreover, turbulence intensity, kinetic energy, kinematic stress increase with...

Swirl flame stabilization is widespread among burners’ manufacturers, but the complex flow patterns are not yet fully understood. The interaction of two confined swirling jets leads to formation recirculation zones being located on shear layer between both zones. In such conditions, lean mixtures can be burned producing low emissions. present study, structure and turbulent mixing isothermal coaxial investigated using Large Eddy Simulation (LES). This a challenging tool achieve accuracy it...

The surface temperature of a burner nozzle using three different pilot hardware configurations was measured lifetime phosphor thermometry with the ZnS:Ag in gas turbine model combustor designed to mimic Siemens DLE (Dry Low Emission) burner. included non-premixed injection setup and two partially premixed injections where one had relatively higher degree premixing. For each configuration, operated either methane or hydrogen-enriched (H2/CH4: 50/50 volume %). local heating from flames much...

The factors that affect the compatibility of engine generators with switchmode rectifiers are identified. performance input sections active power factor corrected (PFC) rectifiers, compatibility, examined including turn on characteristics, impedance and control loop stability. Recommendations given for characteristics to assure An overview experiments conducted three different 3-phase rectifier systems operated both AC mains generator sources is given. Typical system designs address harmonic...

In the current study, effects of nonlocally generated long sea surface waves (swells) on power production a 2 × wind farm are investigated by using large-eddy simulations (LES) and actuator-line method (ALM). The short modeled as roughness height, while wave-induced stress accounting for swell is added an external source term to momentum equations. results show that marine atmospheric boundary layers (MABLs) obtained in this study have similar characteristics MABLs observed during conditions...

Purpose – One current trend in burner technology is to obtain high efficiency while keeping low levels of NOx emissions. A swirling flow combustion ensures a fixed position compact flame. Therefore, it necessary design efficient swirlers. Flow patterns are simulated for the different swirl devices proposed this work. Two axial-swirlers studied: one based on curve-vanes consisting straight line with an arc circle as trailing edge and other common flat-vanes. The purpose paper assess accuracy...

The flow and acoustic fields that are generated by two coaxial jets considered. problem is handled solving the field using Large Eddy Simulation (LES) acoustics a wave equation with source terms provided instantaneous LES. paper focused on influence of grid resolution solution accuracy.

Computational Fluid Dynamics has been used to study the mixing and combustion of two confined jets whose setup operating conditions are those benchmark Roback Johnson. Numerical model solves 3D transient Navier Stokes for turbulent reactive flows. Averaged velocity profiles using RNG swirl dominated k-epsilon have validated with experimental measurements from other sources non case. The is Probability Density Function. Bearing in mind annular jet number over 0.5, a vortex breakdown appears...