Acoustic Suppression of Alkane Fueled Line-Flames

摘要

Acoustic perturbations were successfully used to suppress laminar diffusion line-flames. The flames were produced from the alkanes pentane, hexane, heptane, and octane using fuel-laden wicks. The acoustics ranged in frequency between 30 - 50 Hz, and the pressures between 5 - 50 Pa. As a basis for comparison, suppression of the flames was also achieved using a fan-driven flow. To determine if the results were unique the alkanes, flames fueled by JP-8 were subjected to the same testing regime. Analysis of high speed video showed that during acoustically driven extinctions, the flames were periodically displaced from the fuel bed. It was assumed that the fuel bed experienced convective cooling during this displacement period. Using the data collected, the magnitude of this cooling was modeled using a modified Nusselt number. It was found that at the minimum speaker power required to cause extinction for each fuel, the ratio of the modified Nusselt number to the fuel's Spalding B number was a constant for all fuels at all acoustic frequencies and pressures tested.