Laminar Flame Speed Measurements

Laminar flame speed is a fundamental combustion property that characterizes both the global combustion kinetics and important transport properties (thermal and diffusion) of a flammable mixture.

Several techniques are commonly used to experimentally measure laminar flame speeds, but they all struggle to reach the high unburned-gas temperatures (800+ K) frequently encountered in current and next-generation engines.

In the Hanson Group, we have overcome this limitation through our development of the shock-tube flame speed method [1]. Through the combined use of an optically accessible shock-tube as an impulse heater, a nanosecond laser to ignite a spherically expanding flame (SEF), and high-speed imaging to record the flame’s growth, we have demonstrated laminar flame speed measurements at the highest temperatures ever reported (1,100+ K) [2].

Using this novel technique, our group is able to study and provide new insights into the flame behavior of conventional and alternative fuels at previously unexplored, high-temperature conditions and in unison with advanced laser diagnostics [3,4].

results from a laminar flame speed measurement — Results of the highest-ever-temperature flame speed measurements, performed in our lab. Experimental results (black circles) diverge from the simulated flame speeds (lines) at high temperatures, suggesting the models do not accurately capture the real behavior at these engine-relevant conditions. [2]

To learn more, check out some of our publications:

[1] A. M. Ferris, A. J. Susa, D. F. Davidson, and R. K. Hanson, “High-temperature laminar flame speed measurements in a shock tube,” Combustion and Flame, Vol. 205 (2019) pp. 241–252. DOI: 10.1016/j.combustflame.2019.04.007

[2] A. J. Susa, L. Zheng, and R. K. Hanson, “Schlieren-based measurements of propane flame speeds at extreme temperatures,” in 12th US National Combustion Meeting (2021) pp. 1G05

[3] A.J. Susa, A. M. Ferris, D. F. Davidson, and R. K. Hanson, “Experimental observation of negative temperature dependence in iso-octane burning velocities,” AIAA Journal, Vol. 57:10 (2019) pp. 4476–4481. DOI: 10.2514/1.J058530

[4] A. M. Ferris, J. J. Girard, A. J. Susa, D. F. Davidson, and R. K. Hanson, “Temperature, species, and laminar flame speed measurements in high-temperature, premixed ethane-air flames,” In 11th US National Combustion Meeting (2019)