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Measurements of Turbulent Jet Mixing in a Turbulent Co-Flow Including the Influence of Periodic Forcing and Heating

Klinner, Joachim and Willert, Christian (2017) Measurements of Turbulent Jet Mixing in a Turbulent Co-Flow Including the Influence of Periodic Forcing and Heating. Flow Turbulence and Combustion, 98 (3), pp. 751-779. Springer. DOI: 10.1007/s10494-016-9789-3 ISSN 1386-6184

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Official URL: http://link.springer.com/article/10.1007/s10494-016-9789-3

Abstract

In this work, the turbulent mixing of a confined coaxial jet in air is investigated by means of simultaneous particle image velocimetry and planar laser induced fluorescence of the acetone seeded flow injection. The jet is injected into a turbulent duct flow at atmospheric pressure through a 90 ∘ pipe bend. Measurements are conducted in a small scale windtunnel at constant mass flow rates and three modes of operation: isothermal steady jet injection at a Dean number of 20000 (Red=32000), pulsed isothermal injection at a Womersley number of 65 and steady injection at elevated jet temperatures of ΔT=50 K and ΔT=100 K. The experiment is aimed at providing statistically converged quantities of velocity, mass fraction, turbulent fluctuations and turbulent mass flux at several downstream locations. Stochastic error convergence over the number of samples is assessed within the outer turbulent shear layer. From 3000 samples the statistical error of time-averaged velocity and mass fraction is below 1 % while the error of Reynolds shear stress and turbulent mass flux components is in the of range 5-6 %. Profiles of axial velocity and turbulence intensity immediately downstream of the bend exit are in good agreement with hot-wire measurements from literature. During pulsed jet injection strong asymmetric growing of shear layer vortices lead to a skewed mass fraction profile in comparison with steady injection. Phase averaging of single shot PLIF-PIV measurements allows to track the asymmetric shear layer vortex evolvement and flow breakdown during a pulsation cycle with a resolution of 10∘. Steady injection with increased jet temperature supports mixing downstream from 6 nozzle diameters onward.

Item URL in elib:https://elib.dlr.de/109909/
Document Type:Article
Title:Measurements of Turbulent Jet Mixing in a Turbulent Co-Flow Including the Influence of Periodic Forcing and Heating
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Klinner, JoachimJoachim.Klinner (at) dlr.dehttps://orcid.org/0000-0003-2709-9664
Willert, ChristianChris.Willert (at) dlr.dehttps://orcid.org/0000-0002-1668-0181
Date:18 March 2017
Journal or Publication Title:Flow Turbulence and Combustion
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:98
DOI :10.1007/s10494-016-9789-3
Page Range:pp. 751-779
Publisher:Springer
ISSN:1386-6184
Status:Published
Keywords:Turbulent mixing, Pipe bend, Acetone PLIF, Turbulent flux, Error convergence
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:propulsion systems
DLR - Research area:Aeronautics
DLR - Program:L ER - Engine Research
DLR - Research theme (Project):L - Virtual Engine and Validation methods
Location: Köln-Porz
Institutes and Institutions:Institute of Propulsion Technology
Deposited By: Klinner, Joachim
Deposited On:03 Apr 2017 10:01
Last Modified:06 Sep 2019 15:21

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