Abstract Understanding turbulent premixed flame propagation under engine-relevant conditions is crucial for advancing efficient combustion technologies. This study applies high-fidelity Large Eddy Simulation (LES) to support the design and optimization of a fan-stirred constant volume combustion chamber intended for future experiments on spherically propagating turbulent premixed flames. The design is representative of large-bore engine conditions: moderate to high turbulence intensities with integral length scales significantly larger than the characteristic flame thickness. The numerical analysis focuses on this flow regime by accurately resolving the incompressible, isothermal, transient flow field generated by six rotating fans operating at two different rotation speeds of 2000 and 10,000 rpm, aiming to achieve high turbulence intensities with minimal mean flow in the optical measurement region. The evaluation of the LES-predicted turbulence intensities and the mean velocities indicates that the flow field generated in the targeted central region is statistically stationary and spatially homogeneous. The analysis of the Reynolds stress tensor invariants in the Lumley triangle proves a nearly isotropic turbulence. Moreover, the computed turbulence intensities and integral length scales evaluated with velocity autocorrelation functions are in close agreement with target values representative of large-bore internal combustion engines. These findings confirm the viability of the proposed design for future experimental investigations of flame–turbulence interactions of different fuels like ammonia and ammonia-hydrogen mixtures under engine-like operating conditions.
Handle-Kesselring et al. (Fri,) studied this question.