Despite numerous experimental investigations, the characterization of microgavity laminar jet diffusion flames remains incomplete. Measurements to date have included shapes, temperatures, soot properties, radiative emissions and compositions, but full-field quantitative mesurements of velocity are lacking (Law and Faeth 1994). Since the differences between normal-gravity and microgravity diffusion flames are fundamentally influenced by changes in velocities, it is imperative that the associated velocity fields be measured in microgavity :flames. Velocity measurements in nonbuoyant flames will be helpful both in validating numerical models and in interpreting past microgravity combustion experiments.
Pointwise velocity techniques are inadequate for full-field velocity measurements in microgravity facilities. In contrast, Particle Image Velocimetry (PIV) can capture the entire flow field in less than 1% of the time required with Laser Doppler Velocimetry (LDV). Although PIV is a mature diagnostic for normal-gravity flames (Mungal et al., 1995; Goss et al., 1991), restrictions on size, power and data storage complicate these measurements in microgravity (Kato et al., 1998).
Results from the application of PIV to gas jet flames in normal gravity are presented here. Ethane flames burning at 13, 25 and 50 kPa are considered. These results are presented in more detail in Wernet et al. (2000). The PIV system developed for these measurements recently has been adapted for on-rig use in the NASA Glenn 2.2- second drop tower.
Sunderland, P.B., Greenberg, P.S., Urban, D.L., Wernet, M.P., Yanis, W., PIV Measurements in Weakly Buoyant Gas Jet Flames, Sixth International Microgravity Combustion Workshop, NASA Glenn Research Center, Cleveland, OH, CP-2001-210826, pp. 45-48, May, 2001.