Effect of acoustic velocity on the primary atomization of a hollow cone spray in a swirling flow field

In advanced gas turbine technology, lean premixed combustion is an effective strategy to reduce peak temperature and thus, NO[Formula: see text] emissions. The swirler is adopted to establish recirculation flow zone, enhancing mixing and stabilizing the flame. Therefore, the swirling flow is dominant in the combustor flow field and has impact on the vane. This paper mainly investigates the swirling flow effect on the turbine first stage vane cooling system by conducting a group of numerical simulations. Firstly, the numerical methods of turbulence modeling using RANS and LES are compared. The computational model of one single swirl flow field is considered. Both the RANS and LES results give reasonable recirculation zone shape. When comparing the velocity distribution, the RANS results generally match the experimental data but fail to at some local area. The LES modeling gives better results and more detailed unsteady flow field. In the second step, the RANS modeling is incorporated to investigate the vane film cooling performance under the swirling inflow boundary condition. According to the numerical results, the leading edge film cooling is largely altered by the swirling flow, especially for the swirl core-leading edge aligned case. Compared to the pressure side, the suction side film cooling is more sensitive to the swirling flow. Locally, the film cooling jet is lifted and turned by the strong swirling flow.

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The Model Analysis of Inclusion Moving in the Swirl Flow Zone Sourcing from the Inner-Swirl-Type Turbulence Controller in Tundish

High Temperature Materials and Processes ◽

10.1515/htmp-2016-0135 ◽

2017 ◽

Vol 36 (5) ◽

pp. 541-550 ◽

Cited By ~ 4

Author(s):

Yan Jin ◽

Chen Ye ◽

Xiao Luo ◽

Hui Yuan ◽

Changgui Cheng

Keyword(s):

Flow Field ◽

Swirling Flow ◽

Mathematic Model ◽

Swirl Flow ◽

Water Model ◽

Medium Size ◽

Force Analysis ◽

Inclusion Removal ◽

Flow Band ◽

Turbulence Inhibitor

AbstractIn order to improve the inclusion removal property of the tundish, the mathematic model for simulation of the flow field sourced from inner-swirl-type turbulence controller (ISTTC) was developed, in which there were six blades arranged with an eccentric angle (θ) counterclockwise. Based on the mathematical and water model, the effect of inclusion removal in the swirling flow field formed by ISTTC was analyzed. It was found that ISTTC had got the better effect of inhibiting turbulence in tundish than traditional turbulence inhibitor (TI). As the blades eccentric angle (θ) of ISTTC increasing, the intensity of swirling flow above it increased. The maximum rotate speed of fluid in swirling flow band driven by ISTTC (θ=45°) was equal to 25 rmp. Based on the force analysis of inclusion in swirling flow sourced from ISTTC, the removal effect of medium size inclusion by ISTTC was attributed to the centripetal force (Fct) of swirling flow, but removal effect of ISTTC to small size inclusion was more depend on its better turbulence depression behavior.

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Non-premixed swirl-type tubular flames burning liquid fuels

Journal of Fluid Mechanics ◽

10.1017/jfm.2018.248 ◽

2018 ◽

Vol 846 ◽

pp. 210-239

Author(s):

Vinicius M. Sauer ◽

Fernando F. Fachini ◽

Derek Dunn-Rankin

Keyword(s):

Flow Field ◽

Swirling Flow ◽

Flame Structure ◽

Flow Analysis ◽

Liquid Fuels ◽

Reacting Flow ◽

Surface Mass ◽

Surface Mass Transfer ◽

Incompressible Viscous Flow ◽

Porous Walls

Tubular flames represent a canonical combustion configuration that can simplify reacting flow analysis and also be employed in practical power generation systems. In this paper, a theoretical model for non-premixed tubular flames, with delivery of liquid fuel through porous walls into a swirling flow field, is presented. Perturbation theory is used to analyse this new tubular flame configuration, which is the non-premixed equivalent to a premixed swirl-type tubular burner – following the original classification of premixed tubular systems into swirl and counterflow types. The incompressible viscous flow field is modelled with an axisymmetric similarity solution. Axial decay of the initial swirl velocity and surface mass transfer from the porous walls are considered through the superposition of laminar swirling flow on a Berman flow with uniform mass injection in a straight pipe. The flame structure is obtained assuming infinitely fast conversion of reactants into products and unity Lewis numbers, allowing the application of the Shvab–Zel’dovich coupling function approach.

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Spray Drop Size and Velocity Measurements in a Swirl-Stabilized Combustor

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations ◽

10.1115/91-gt-043 ◽

1991 ◽

Cited By ~ 1

Author(s):

B. Chehroudi ◽

M. Ghaffarpour

Keyword(s):

Drop Size ◽

Cone Angle ◽

Hollow Cone ◽

Flow Rates ◽

Fuel Droplets ◽

Radial Profiles ◽

Fuel Nozzle ◽

Pass Through ◽

Yellow Region ◽

Hollow Cone Spray

A pressure-swirl fuel nozzle generating a hollow-cone spray with nominal cone angle of 30 degrees is used in a swirl-stabilized combustor. The combustor is circular in cross section with swirl plate and fuel nozzle axes aligned and coinciding with the axis of the chamber. Kerosene is injected upward inside the chamber from the fuel nozzle. Separate swirl and dilution air flows are uniformly distributed into the chamber that pass through the honey comb flow straighteners and screens. Calculated swirl number of 1.5 is generated with the design swirl plate exit air velocity of 30 degrees with respect to the chamber axis. Effects of swirl and dilution air flow rates on the shape and stability of the flame are investigated. Stable and classical liquid fuel sheet disintegration zone exists close to the nozzle with no visible light followed by a luminous blue region and a mixed blue/yellow region that subsequently turns into yellow for most of the part in the flame. A Phase Doppler Particle Analyzer (PDPA) is used to measure drop size, mean and rms axial velocity for two cases of with and without combustion at six different axial locations from the nozzle. For the no-combustion case all air and fuel flow rates were kept at the same values as the combusting spray condition. Results for mean axial drop velocity profiles indicate widening of the spray due to combustion while the magnitudes of the peak velocities are slightly increased. No measurements inside the hollow-cone spray are possible due to burning of fuel droplets. Drop turbulence decreases due to combination of increase in gas kinematic viscosity and elimination of small drops at high temperatures. Sauter Mean Diameter (SMD) radial profiles at all axial locations increase with combustion due to preferential burning of small drops.

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Analysis of a Prototype High-Pressure “Hollow Cone Spray” Diesel Injector Performance in Optical and Metal Research Engines

10.4271/2017-24-0073 ◽

2017 ◽

Cited By ~ 1

Author(s):

Carlo Beatrice ◽

Giacomo Belgiorno ◽

Gabriele Di Blasio ◽

Ezio Mancaruso ◽

Luigi Sequino ◽

...

Keyword(s):

High Pressure ◽

Hollow Cone ◽

Metal Research ◽

Hollow Cone Spray

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Decomposition of the swirling flow field downstream of Francis turbine runner

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/15/6/062008 ◽

2012 ◽

Vol 15 (6) ◽

pp. 062008 ◽

Cited By ~ 9

Author(s):

P Rudolf ◽

D Štefan

Keyword(s):

Flow Field ◽

Swirling Flow ◽

Francis Turbine ◽

Turbine Runner

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Investigation of the Dynamics of an Ultra Low NOx Injection System by POD Data Post-Processing

Volume 4A: Combustion, Fuels and Emissions ◽

10.1115/gt2015-42638 ◽

2015 ◽

Cited By ~ 2

Author(s):

M. Berrino ◽

D. Lengani ◽

F. Satta ◽

M. Ubaldi ◽

P. Zunino ◽

...

Keyword(s):

Flow Field ◽

Spatial Information ◽

Vortex Breakdown ◽

Swirling Flow ◽

Measurement Techniques ◽

Injection System ◽

Post Processing ◽

Particle Image Velocimetry Technique ◽

Annular Sector ◽

Random Fluctuations

The present paper is focused on the investigation of the dynamics of the flow downstream of an Ultra Low NOx (ULN) injection system, designed to reduce NOx emissions and combustor axial length. Two rectangular flame tubes have been experimentally investigated: one aimed at simulating an unconfined exit flow, and another with the same transverse dimensions of the combustor annular sector, to simulate the confined flow field. The effects induced by the realistic flame tube presence are investigated comparing the flow field with that generated in the unconfined case. Particular attention is paid to the vortex breakdown phenomena associated with the flow generated by the two co-rotating swirlers constituting the injection system. Two different and complementary measurement techniques have been adopted to characterize the aerodynamics of the vortex breakdown. The hot-wire investigation results reveal the frequencies associated with the precession motion due to the vortex breakdown. The Particle Image Velocimetry technique has been coupled with Proper Orthogonal Decomposition (POD) for data post-processing in order to reconstruct the swirling motion generated by the injection system. The property of POD, which consists of splitting temporal from spatial information of the flow field in analysis, allows the distinction between deterministic and random fluctuations without the need of an external trigger signal. This feature is fundamental for the better understanding of an highly-swirling flow.

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Validation of a CFD Model of a Hollow-Cone Spray with Gasoline Fuel Blends

10.4271/2011-01-0379 ◽

2011 ◽

Cited By ~ 3

Author(s):

Lars Schmidt ◽

Jason King ◽

John Stokes ◽

James Mullineux ◽

Calvin R.Ramasamy ◽

...

Keyword(s):

Cfd Model ◽

Hollow Cone ◽

Fuel Blends ◽

Hollow Cone Spray

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Feasibility Study on Application of a Self-Formed Flow Field Downstream of Elbows to Divertor Cooling

Volume 5: Fuel Cycle, Radioactive Waste Management and Decommissioning; Reactor Physics and Transport Theory; Nuclear Education, Public Acceptance and Related Issues; Instrumentation and Controls; Fusion Engineering ◽

10.1115/icone21-16105 ◽

2013 ◽

Author(s):

Shoichi Kodate ◽

Tatsuya Kubo ◽

Shinji Ebara ◽

Hidetoshi Hashizume

Keyword(s):

Heat Transfer ◽

Flow Field ◽

Reynolds Stress ◽

Swirling Flow ◽

Pipe Wall ◽

Three Dimensional ◽

High Heat ◽

Turbulent Pipe Flow ◽

High Heat Transfer ◽

Piv Measurement

In this study, the characteristic of the swirling flow was analyzed in detail in terms of flow field by means of a visualization experiment using matched refractive index PIV measurement to evaluate the applicability of the swirling flow generated downstream of a three-dimensionally connected dual elbow to the divertor cooling. The dual elbow used in the experiment comprises two 90-degree elbows with the same curvature connected directly in three-dimensional configuration. From the experiment, it was found that strong swirling velocity component appears locally near the pipe wall downstream of the second elbow. Moreover, although the strength of the swirling flow changed gradually as it flowed downstream, it attenuated little even 8D downstream of the dual elbow, where D was the diameter of the piping. Therefore, this swirling flow is expected to survive for a considerable distance downstream of the elbow, and the applicability of this flow field to divertor cooling can be promising. Furthermore turbulence quantities such as Reynolds stress were analyzed in terms of heat transfer performance. Since there were some regions where larger Reynolds stress than a developed turbulent pipe flow was observed near the pipe wall, high heat transfer is expected there.

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