Modelling electric field driven convection in small combustion plasmas and surrounding gases
Titel:
Modelling electric field driven convection in small combustion plasmas and surrounding gases
Auteur:
Papac, M. J. Dunn-Rankin, D.
Verschenen in:
Combustion theory and modelling
Paginering:
Jaargang 12 (2008) nr. 1 pagina's 23-44
Jaar:
2008-02
Inhoud:
Electric fields applied to flames can be used to impart force directly on the reaction zone and local surroundings due to the presence of flame ions. The resultant electric body force modifies the flow field surrounding the combustion environment. This paper describes a numerical simulation of the flow field of entrained gases and exhaust surrounding a gaseous fuel flame when it is exposed to electric fields by formulating the problem as a unipolar two fluid system (neutrals and positive ions). An analysis, performed at steady state, is verified by comparison to published experimental results (total current, current density profiles, and qualitative flow measurements). The results indicate a complex interaction between the combustion and current discharge environments where the flow field is dominated by the presence of a toroidal vortex structure and the discharge is dominated by space charge effects. In addition, a transient analysis of the flow field is performed, and four fundamental timescales in the system are identified. These timescales are (1) steady state discharge establishment, (2) plume establishment, (3) vortex establishment, and (4) heating of the feed tube. Timescales (1)-(3), being the fastest timescales of the system, are evaluated and compared. The results show good agreement between computational and analytical timescale values.
Tijdschrift beschrijving