TY - GEN A1 - Özgünoğlu, Mehmet A1 - Mouokue, Gerard A1 - Oevermann, Michael A1 - Bensow, Rickard E. T1 - Numerical investigation of cavitation erosion in high-pressure fuel injector in the presence of surface deviations T2 - Fuel N2 - This study investigates cavitation-induced erosion in high-pressure fuel injectors using numerical simulations, focusing on the effects of surface deviations, turbulence modeling, and a refined approach for the erosion assessment. The proposed erosion model combines advanced erosion indicators to enhance predictive accuracy while addressing limitations in existing methodologies. Cavitation dynamics are simulated with the modified Zwart–Gerber–Belamri model, employing Reynolds-averaged Navier–Stokes (RANS) and Large Eddy Simulation (LES) approaches. Numerical results for a high-lift needle position are validated against experimental data, providing insights into erosion behavior in industrial heavy-duty injectors. Both Computer-Aided Design (CAD) and Tomography Scan (TS) models are used to evaluate the impact of surface deviations on erosion patterns. Results reveal that incorporating surface deviations reduces the vapor volume and alters the erosion patterns. LES simulations exhibit enhanced sensitivity to the surface deviations, capturing finer turbulence structures and local pressure fluctuations, whereas RANS provides reasonable accuracy with lower computational cost. KW - Fuel injector KW - CFD KW - Cavitation erosion KW - Surface deviations Y1 - 2025 U6 - https://doi.org/10.1016/j.fuel.2024.134174 SN - 0016-2361 VL - 386 SP - 1 EP - 21 PB - Elsevier BV ER - TY - GEN A1 - Menon, Abhilash M. A1 - Kerstein, Alan A1 - Oevermann, Michael T1 - Investigation of coarse-graining parameters for super-grid LEM closure applied to LES of practical bluff-body flames T2 - Combustion Theory and Modelling N2 - Large Eddy Simulation (LES) coupled with the Linear Eddy Model (LEM) provides a robust method for studying turbulent combustion, but it is computationally expensive due to the need for highly resolved sub-grid LEM domains. These domains simulate sub-grid stirring through stochastic rearrangements of scalar fields, while large-scale transport is modelled using a Lagrangian ‘splicing’ scheme. To address the computational cost of LES-LEM, a super-grid (SG) framework for LEM closure was developed by the authors (Comb. Theor. Model. 28, 2024), which uses coarse-graining, on-the-fly chemistry tabulation and a presumed PDF approach to reconstruct thermochemical fields at LES resolution. This study applies SG-LEM to a challenging setup, Case 1 of the Volvo Validation Rig, which involves a bluff-body-stabilised turbulent premixed propane-air flame, as a stress test to identify limitations that were not revealed by the previous application, in particular that of the coarse-graining parameters used to generate the super-grid. The intent is to yield a more realistically constrained assessment of the current capabilities of the method, and insight into possible ways for improving it. Four simulations were conducted using three SG cluster sizes. The finest resolution was tested with a global 2-step mechanism, showing good agreement with experimental data for temperature and velocity, particularly near the bluff body. The two larger cluster sizes used a 66-step skeletal mechanism for more detailed chemical closure but led to unphysical quenching due to splicing inaccuracies. To mitigate these issues, two novel additions were introduced: an intra-cluster-stirring routine and a method to control SG cluster shapes to reduce numerical dissipation. These methods improved flame stability with coarser SG clusters and more detailed mechanisms. Comparison with experiments showed good agreement for temperature and velocity, though elevated CO levels were observed in the recirculation region. Potential methods for further improving SG-LEM's capabilities are discussed. KW - LES-LEM KW - Premixed flames KW - Stabilised flames KW - Turbulence modelling KW - Subgrid-scale closure Y1 - 2024 U6 - https://doi.org/10.1080/13647830.2024.2428156 SN - 1364-7830 VL - 2024 SP - 1 EP - 22 PB - Taylor&Francis ER -