Numerical analysis of combustion around a strut in supersonic airflow

Numerical simulation of combustion around a strut in supersonic airflow at Mach 1.5 was conducted. In previous papers, experimental results on flame-h olding characteristics have been shown for the strut divided into two parts , indicating the effectiveness of the flame-holding characteristics of this strut. Stable flame-holding is due to a comparatively long residence time in the subsonic flow region between the two parts of the strut. The present study is analytical evidence of the stable flame-holding of this strut. Th e Stahl and Warnatz's detailed chemistry of hydrogen/oxygen reactions and t he Baldwin Lomax turbulence algebraic model were employed to simulate the c hemical reaction and turbulent flow, respectively. Flame structures such as distributions of chemical species and temperature were obtained. For examp le, the predicted density distributions explicitly showed an attached shock wave, expansion fans and shear layers, and had good agreement with the sha dowgraph of the experiment. The overall equivalence ratio in the space betw een two strut parts was calculated to evaluate the reaction time in the spa ce between the struts and a particle trace analysis was performed to evalua te the residence time in the space. By obtaining the Damkohler number from two characteristic times, two flame-holding limits, namely the chemical kin etic limit at small interval between two struts and the dynamic limit at la rge interval, were discussed. The numerical results were qualitatively cons istent with the previous experimental results.