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Mixing dynamics and scalar dissipation rate in split-injection gaseous jets

Mixing dynamics and scalar dissipation rate in split-injection gaseous jets
Mixing dynamics and scalar dissipation rate in split-injection gaseous jets
Split fuel injection is studied by Direct Numerical Simulations (DNS) to characterize the entrainment and scalar dissipation in turbulent gaseous jets. The mixing physics identified in this study are important for the understanding of split-injection compression-ignition engine operation, in which mixing rates and fuel residence time control the rate of heat release and pollutant formation. Three injection scenarios are compared: a starting jet, a stopping jet, and a restarting the fuel jet. It is observed that the entrainment is suppressed or enhanced when the jet accelerates or decelerates respectively, in agreement with previous studies. The results show that the one-dimensional entrainment model by Musculus (Journal of Fluid Mechanics 638 (2009) 117-140) provides a good qualitative description for the entrainment in the stopping jet. It is found that the suppression and enhancement due respectively to a starting and a stopping jet can be superimposed to give an estimate for the entrainment in the restarted jet simulation. Scalar dissipation rate is found to increase or decrease by one order of magnitude as the jet accelerates or decelerates respectively. The wake of the stopping jet reduces the scalar dissipation rate in the following restarting jet, implying that the dissipation rate from the stopping jet and the starting jet are not additive, and highlighting the different dynamics of the large and small scale mixing processes described by entrainment and scalar dissipation respectively
Shin, D.-H.
aefc1292-87fd-48ab-94bc-a857692ccabe
Richardson, E.S.
a8357516-e871-40d8-8a53-de7847aa2d08
Shin, D.-H.
aefc1292-87fd-48ab-94bc-a857692ccabe
Richardson, E.S.
a8357516-e871-40d8-8a53-de7847aa2d08

Shin, D.-H. and Richardson, E.S. (2015) Mixing dynamics and scalar dissipation rate in split-injection gaseous jets. 7th European Combustion Meeting, Budapest, Hungary. 30 Mar - 02 Apr 2015. 6 pp .

Record type: Conference or Workshop Item (Paper)

Abstract

Split fuel injection is studied by Direct Numerical Simulations (DNS) to characterize the entrainment and scalar dissipation in turbulent gaseous jets. The mixing physics identified in this study are important for the understanding of split-injection compression-ignition engine operation, in which mixing rates and fuel residence time control the rate of heat release and pollutant formation. Three injection scenarios are compared: a starting jet, a stopping jet, and a restarting the fuel jet. It is observed that the entrainment is suppressed or enhanced when the jet accelerates or decelerates respectively, in agreement with previous studies. The results show that the one-dimensional entrainment model by Musculus (Journal of Fluid Mechanics 638 (2009) 117-140) provides a good qualitative description for the entrainment in the stopping jet. It is found that the suppression and enhancement due respectively to a starting and a stopping jet can be superimposed to give an estimate for the entrainment in the restarted jet simulation. Scalar dissipation rate is found to increase or decrease by one order of magnitude as the jet accelerates or decelerates respectively. The wake of the stopping jet reduces the scalar dissipation rate in the following restarting jet, implying that the dissipation rate from the stopping jet and the starting jet are not additive, and highlighting the different dynamics of the large and small scale mixing processes described by entrainment and scalar dissipation respectively

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ECM2015_Shin_Richardson_final.pdf - Accepted Manuscript
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More information

Published date: 30 March 2015
Venue - Dates: 7th European Combustion Meeting, Budapest, Hungary, 2015-03-30 - 2015-04-02
Organisations: Aerodynamics & Flight Mechanics Group

Identifiers

Local EPrints ID: 381691
URI: http://eprints.soton.ac.uk/id/eprint/381691
PURE UUID: fae74076-2844-47e1-9a20-46076ada44b5
ORCID for E.S. Richardson: ORCID iD orcid.org/0000-0002-7631-0377

Catalogue record

Date deposited: 09 Oct 2015 14:16
Last modified: 15 Mar 2024 03:37

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Contributors

Author: D.-H. Shin
Author: E.S. Richardson ORCID iD

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