Effect of phase changes on parameters of turbulent

Yu. V. Zuev

Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mehanika, no. 83 (2023), pp. 86-101

Résumé

A mathematical model of a gas-drop non-isothermal polydisperse turbulent jet is developed with account for phase changes (the evaporation of drops and the condensation of vapor on them). The model is used in calculations of a two-phase jet outflowing into a gaseous medium with the temperature significantly exceeding the temperatures of phases in the initial section of the jet. It is shown that the occurrence of phase changes leads to a quantitative change in the dependences of phase velocities and volume concentrations of drops along the jet axis, while the type of the dependences remains constant. When phase changes are neglected in calculations of temperatures of phases, not only quantitative but also qualitative errors may arise. The obtained results show that under certain conditions some areas may appear near the jet axis where, along with evaporation of small drops, the vapor condensation occurs on larger drops, and these areas extend with the gas temperature rise in the environment. The behavior of the intensity of phase changes along the jet axis is identical for drops of all sizes. Namely, near the initial section of the jet, the intensity of phase changes of low value decreases to the minimum, then it increases significantly, and when the maximum is attained, it starts to decrease tending to zero (while the drops evaporate completely). The research results show that phase changes must be considered when calculating gas-drop non-isothermal jets to avoid quantitative and qualitative errors.

Détail

Keywords: two-phase jet, fluid vapor, drops, evaporation, mathematical modeling, calculation results.
Mots-clés : condensation