Hydrodynamic instability in flame-vortex interaction

Conference · Thu Jul 01 04:00:00 EDT 1999

OSTI ID:20002661

Qian, J; Law, C K; Tryggvason, G

A front tracking method is adopted to study multi-fluid flows in which a sharp interface separates two incompressible fluids of different density and viscosity to simulate unsteady premixed flame motion. Results for flame propagation through a two-dimensional vortical flow formed by a vortex array are presented. It is shown that during the flame and vortex interaction, the initial vorticity field can be significantly distorted or even mostly eliminated by the flame, being substituted by flame generated vorticity (FGV) corresponding to the tilted flame element, and that the magnitude of the FGV can also be higher than that of the incident vortex. Furthermore, it is mainly the transverse pressure on the wrinkled flame surface, as a consequence of flame front instability, that results in the baroclinic torque which in turn generates the vorticity through thermal expansion. Furthermore, linear hydrodynamic stability analysis shows that the periodic flame wrinkling results in the periodic generation of vorticity of opposite signs. The presence of gravity can qualitatively change the vorticity development, with the influence depending on the Froude number associated with the flame speed as well as the characteristic length scale of the phenomenon.

• Research Organization: Princeton Univ., NJ (US)
• OSTI ID: 20002661
• Report Number(s): CONF-990805--
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
40 CHEMISTRY
COMBUSTION INSTABILITY
FLAME PROPAGATION
FLAMES
GAS FUELS
HYDRODYNAMICS
VORTEX FLOW