Chemical kinetic uncertainty quantification for Reynolds-Averaged Navier-Stokes simulations of turbulent premixed combustion

Motegi, Kosuke  ; Shiotsu, Hiroyuki  ; Matsumoto, Toshinori ; Hibiki, Takashi*; Shibamoto, Yasuteru 

We established a methodology to quantify chemical kinetic uncertainties, specifically the uncertainty in reaction rate constants, in Reynolds-Averaged Navier-Stokes (RANS) simulations of turbulent premixed combustion. The methodology consists of three main steps. First, an uncertainty database for the hydrogen combustion reaction was constructed. Second, these uncertainties were propagated to the laminar flame speed, which served as the input data for the subsequent RANS simulation, through a freely propagating flat flame simulation. Third, the uncertainty in the laminar flame speed was propagated to quantities of interest (QoIs) through the RANS simulation. We employed the non-intrusive polynomial chaos method to reduce the number of demanding RANS simulation runs. The established methodology was applied to the flame acceleration benchmark experiments in the ENACCEF facility, revealing that the analysis successfully quantified the uncertainty within an acceptable computational cost. The uncertainty analysis showed that the uncertainty in the propagating flame was closely related to the physical mechanisms involved in the acceleration process. Finally, we discussed the factors influencing the results and examined the validity of the proposed uncertainty analysis.