A Turbulence Dissipation Correction to the k-epsilon Model and Its Effect on Turbulence Length Scales in Engine Flows
نویسندگان
چکیده
Non-equilibrium turbulence considerations from rapid distortion theory have been utilized to derive a correction to the turbulence dissipation rate, which then has been implemented in combination with the RNG k-epsilon model in a KIVA-based code. This correction reflects the time delay between changes in the turbulent kinetic energy due to changes in the mean flow and its turbulence dissipation rate, and it is shown that this time delay is controlled by the turbulence Reynolds number. This dissipation rate correction has been validated with experimental turbulence measurements of a small diesel engine operated in motored mode. Improvements in the turbulence length scales have then been obtained by means of this model correction for the compression and the combustion phase of two heavy-duty DI diesel engines.
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