N2 CARS thermometry and O2 LIF concentration measurements in a flame under electrically induced microbuoyancy

Microgravity combustion is fundamentally characterized by the absence of buoyancy driven flows. To facilitate a large range of diagnostics on microgravity flames, it is useful to create an equivalent microbuoyant condition in an earth-based laboratory. This experiment simulates microbuoyancy using electric fields to balance local convection in a region of the flame. Previous studies used N2 coherent anti-Stokes Raman spectroscopy (CARS) temperature measurements to show that a region exists in which the temperature profile corresponds to that of a spherically symmetric diffusion profile, as would be expected in a true microgravity environment. The current study utilizes CARS thermometry and laser induced fluorescence (LIF) to examine the temperature and O2 concentration profiles in a region below the flame. The results show that the electrically balanced flame apparatus produces a spherically symmetric wedge of microbuoyant flame extending 10° from the vertical axis of the capillary flame arrangement; thereby quantifying the extent of the microbuoyant region. © 2003 The Combustion Institute. All rights reserved.