Dynamics of laminar ethylene lifted flame with ozone addition.

Autor: Wu, Bin, Hastings, Mitchell, Sun, Wenting, Ombrello, Timothy, Carter, Campbell
Zdroj: Proceedings of the Combustion Institute; 2020, Vol. 38 Issue 4, p6773-6780, 8p
Abstrakt: The effect of ozone (O 3) addition on ethylene (C 2 H 4) non-premixed jet flames is investigated. Stable C 2 H 4 lifted flames are established with oxygen/nitrogen co-flow at reduced oxygen content conditions. It is observed in the experiments that after O 3 addition, the flame liftoff height could either increase or decrease, depending on the initial value of the flame liftoff height before O 3 is added. Formaldehyde (CH 2 O) planar laser-induced fluorescence (PLIF) measurement shows that prompt ozonolysis reaction between C 2 H 4 and O 3 produces large amounts of CH 2 O upstream of the flame. In contrast to previous studies of O 3 addition on lifted flames—with saturated hydrocarbon fuels in which O 3 decomposition dominates—the ozonolysis reaction between C 2 H 4 and O 3 changes the chemical composition of flow even at room temperature. Such chemical reaction causes the simultaneous increase of both the triple flame propagation speed of lifted flame and the axial jet velocity along the stoichiometric contour, which also therefore changes the dynamic balance between these two values to stabilize the flame. While the increase of triple flame propagation speed tends to decrease the flame liftoff height, the increase of axial jet velocity along the stoichiometric contour tends to have the opposite effect. A competing kinetic-dynamic process forms, and the final location of the flame depends on the degree of ozonolysis reaction, which is determined by the initial flame liftoff height before O 3 is added. [ABSTRACT FROM AUTHOR]
Databáze: Supplemental Index
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