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Journal articles
Turbulent spectrum model for drop-breakup mechanisms in an inhomogeneous turbulent flow
Abstract : Drop-breakup models for liquid/liquid dispersion in turbulent flow mostly derive from Kolmogorov and Hinze analysis. They are of a semi-empirical type, since they are based on power laws involving at least Weber and Reynolds numbers. The pre-factors are determined by fitting the experimental data on droplet diameters in the various configurations. The main cause for the discrepancies in the fitting constant between different flow types is the intrinsic spatial heterogeneity of the turbulent field, especially the turbulent kinetic energy (TKE) dissipation rate epsilon. This feature explains why there is no universal physical model suitable for breakup prediction throughout the range of flow geometries. In the present work, we investigate the drop size distribution by reference to Hinze's actual theory in a local approach, attempting a direct interpretation thanks to the turbulence spectra measured (by LDA) in the most dissipative locations of a flow which is basically inhomogeneous. This method allows estimation of droplet size with no constant fitting and with acceptable accuracy; however the knowledge of the turbulence field is required. The present study is carried out with low dispersed-phase fraction, so that the coalescence is negligible. Experiments show that the "typical value" for the TKE dissipation rate to fit the raw model of Hinze and Kolmogorov lies between the maximum and the mean value in the flow field. The issue of "typical e value" hence avoided is discussed by physical arguments for the flow structure.
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01438957
Contributor : Laurent Jonchère Connect in order to contact the contributor
Submitted on : Wednesday, July 12, 2017 - 1:10:40 PM
Last modification on : Wednesday, October 20, 2021 - 3:19:30 AM
Long-term archiving on: : Friday, January 26, 2018 - 4:26:08 PM
Contributor : Laurent Jonchère Connect in order to contact the contributor
Submitted on : Wednesday, July 12, 2017 - 1:10:40 PM
Last modification on : Wednesday, October 20, 2021 - 3:19:30 AM
Long-term archiving on: : Friday, January 26, 2018 - 4:26:08 PM
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Lemenand et al. - Turbulent sp...
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