Host: The Japan Society of Mechanical Engineers
Name : The 30th International Conference on Nuclear Engineering (ICONE30)
Date : May 21, 2023 - May 26, 2023
In RANS simulations, two of the standard simplified models that model combustion progress variable source are TFC model, which accurately models progress variable source for purely turbulent combustion, and its extended variant ETFC, which should provide increased accuracy in slow combustion regime. Recently, we have implemented ETFC combustion model into our open-source CFD solver flameFoam. The aim of this paper is to present preliminary validation of the implemented model against the experiment UFPE.
RANS simulations of UFPE hydrogen-air-steam diluent premixed combustion in Hyka-A2 experimental facility were performed using ETFC and previously implemented TFC model, using Malet correlation for laminar flame velocity. Adiabatic boundary conditions were applied. The simulations provide promising results.
Overall, TFC significantly underestimates flame velocity in slow combustion regimes, whereas upward flame velocity strongly resembles the experiment in simulations using ETFC. A significantly slower laminar flame in TFC allowed for buoyancy to tear it apart and induce turbulence, therefore accelerating the flame. Peak pressure rise is mildly (~30%) overestimated in both cases with gravity. Without gravity, however, peak pressure rise in ETFC matches the experiment, yet TFC has 8 times lower value. This reveals that TFC with gravity had realistic pressure rise only coincidentally, due to gravity inducing turbulence, thus accelerating the flame and increasing pressure rise to realistic level only by chance. The conclusion of our study is that the ETFC outmatches the TFC model in slow combustion, yet further validation work is required to understand its advantages and domain of applicability.