Laminar flame speed measurements and laser absorption characterization of high-temperature, premixed ethane–air flames

Laminar flame speed, temperature, and pressure measurements were conducted in high-temperature, spherically expanding ethane–air flames. The experiments were conducted in a shock tube, which allows access to a high-temperature regime previously under-explored for premixed ethane–air flames. The stoichiometric ethane–air mixtures were initially shock-heated to unburned gas conditions of 461–537 K, 1 atm. An Nd:YAG laser was used to spark-ignite the heated gas mixtures and initiate laminar flame propagation. High-speed, OH* endwall imaging was used to record the propagation of the spherically expanding flames in time, and the images were analyzed to determine the unburned, unstretched laminar flame speed. The measurements show close agreement with available literature results and kinetic model simulations (AramcoMech 3.0, NUIGMech1.3, and FFCM-2). A comprehensive survey of available ethane–air flame speed data was conducted to enable a high-fidelity power-law fit to describe the temperature dependence of ethane–air flame speeds. A single line-of-sight laser absorption diagnostic was additionally used to measure burned-gas temperature and pressure. The temperature and pressure measurements confirmed that flames generated using the shock-tube laminar flame method are adiabatic and constant-pressure.