Zhiyi Li, Alberto Cuoci, Alessandro Parente (ULB)

The present work focuses on the validation with OpenFOAM for the numerical simulation of turbulent combustion under Moderate or Intense Low-oxygen Dilution (MILD) combustion. Results for a Jet-in-Hot-Coflow (JHC) burner using a mixture of CH4 and H2 50/50 on molar basis are presented and discussed, with the objective of showing the sensitivity of the results to modelling parameters and numerical approach. Simulation were performed using Eddy Dissipation Concept (EDC) combustion model combined with edcPimpleSMOKE, a RANS transient solver coupled to the OpenSMOKE tool for stiff chemistry management. A 2D mesh with 30,000 computational cells is used. The sensitivity of the simulation results to different modelling choices is presented. This includes the sensitivity to the choice of the k-epsilon model parameters, the choice of canonical reactor simulating the fine structures and the EDC model coefficient. Moreover, the impact of molecular and turbulent diffusion on the results will be assessed, by investigating the effect of turbulent Schmidt number and considering the unbalanced influence of thermal to mass diffusion with non-unity Lewis Number. Finally, the combination of EDC combustion model with in-situ adaptive tabulation (ISAT) is presented, to assess the potential of computational time reduction.

Jens Dedeyne, Laurien A. Vandewalle, David J. Van Cauwenberge, Kevin M. Van Geem, Guy B. Marin (UGhent)

Even though LES is being used extensively to evaluate flow features in many different applications, RANS simulations remain the industrial standard as it is less computationally demanding. This is especially the case for simulation of steam cracking, where detailed kinetics increase the computational demand even more. To reduce the computational cost of these simulations, the domain size can be decreased drastically by implementing streamwise periodic boundary conditions (SPBC). However, the underlying assumptions of constant property flows limit this to non-reactive systems.
A simulation approach was developed to extend the existing methodology to non-equilibrium kinetics. This novel methodology was validated by comparison with full-scale CFD simulations for an industrially applied propane pyrolysis reactor.

W.A. Breugem, B. Decrop, P. Rauwoens, K. Verelst and W. Van Hoydonck (IMDC)

Locks are key structures for the accessibility of ports and navigable waterways. The filling of the lock chamber has to be done with special precautions, taking into account the forces experienced by the moored vessels during the levelling process. In case of filling a lock with openings in the lock gate, one of the potential methods to minimize the hydrodynamic forces on the ships, is to insert breaking logs (i.e. energy dissipation bars) at the downstream side of the lock gate, aiming at an enhanced spreading and energy dissipation of the filling jets.
The present investigation studies the influence of breaking logs on the flow pattern in a lock chamber using OpenFOAM. Thereto, two different kinds of simulations were performed:
• Simulations  were performed of a configuration with a single opening in the lock gate with and without breaking logs using simpleFoam. The results were compared with data from physical model experiments of the same configuration.
• Simulations were performed  of the filling process of a complete lock chamber with six openings using interFoam. This was done for two different configurations of openings in the lock gate. Both configurations were simulated both with and without breaking logs.
In the presentation, the results of these simulations will be discussed.

F. D’Ambrosio, A. Cuoci, A. Parente (ULB)

The description of particular combustion phenomena, e.g. flameless combustion, pollutants formation etc., requires the use of large kinetic mechanisms. CFD simulations of a practical system that involve also complex geometry, heat exchange, radiation, and turbulent flows are prohibitive in industrial applications due to the high computational cost. Therefore, reduction of detailed kinetic mechanisms is necessary to allow the resolution of practical problem with the required accuracy and within an affordable computation time. Usually, kinetic mechanism reduction is performed via pre-processing methods based on the analysis of the kinetic mechanism in a range of operating conditions. However, during the simulation the kinetic scheme is not adapted to the local conditions. The present work aims to couple an on-the-fly reduction method for chemistry  with two combustion solvers edcSMOKE, an open solver for turbulent combustion, and laminarSMOKE, an open solver for laminar combustion. Validation is performed through a series of 2D simulations, using large kinetic mechanisms. The sensitivity of the reduction method to the modelling parameters is also presented.