Integration and validation of some modules for modelling of high-speed chemically reactive flows in two-phase gas-droplet mixtures

• Published in: Computers & fluids Vol. 277; no. C; p. 106282
• Main Authors: Zhu, Ruixuan, Huang, Zhiwei, Xu, Chao, Wu, Bifen, Davy, Martin
• Format: Journal Article
• Language: English
• Published: United Kingdom Elsevier Ltd 15-06-2024; Elsevier
• Subjects: Detonation wave; Dynamic adaptive hybrid integration; Eulerian–Lagrangian solver; Multi-component diffusion; Sparse ODE solver; Two-phase reacting flow; Eulerian–Lagrangian solver; Dynamic adaptive hybrid integration; Sparse ODE solver; Two-phase reacting flow; Multi-component diffusion; Detonation wave
• ISSN: 0045-7930; 1879-0747
• DOI: 10.1016/j.compfluid.2024.106282

Three modules are integrated into the built-in OpenFOAM rhoCentralFoam solver towards accurate and efficient modelling of high-speed chemically reactive flows in two-phase gas-droplet mixtures within the OpenFOAM 10.0 framework. The first module is the mixture-averaged diffusion model. The second module is the built-in OpenFOAM Lagrangian solver coupled with optimised droplet drag coefficient and convective heat transfer coefficient sub-models. The last module is a sparse stiff chemistry solver based on dynamic adaptive hybrid integration (AHI-S). The optimised droplet sub-models are first verified in correct implementation for subsequent simulations in this work. They show good accuracy against experimental and analytical data in the modelling of ammonia droplet acceleration and cooling in the flowing and/or low-temperature air. The accuracy and efficiency gains related to the mixture-averaged diffusion model and the AHI-S chemistry solver are examined by simulating 1-D detonation propagation in ammonia droplet-free/laden ammonia-oxygen mixtures. Numerical results of detonation propagation speed, gaseous temperature, density, and species distributions around the induction zone show good agreement with experimental data and analytical solutions. Compared to the built-in OpenFOAM diffusion model, the mixture-averaged diffusion model provides different numerical predictions of pulsating instabilities in detonation propagation. It shows better accuracy in depicting the detonation structure within the droplet-free section attributed to improved multi-component diffusion modelling. Compared to the built-in OpenFOAM solver EulerImplicit (backward Euler), the AHI-S chemistry solver reduces the computational cost by around 50%. It achieves satisfactory accuracy in calculating detonation propagation speed within the droplet-free section with the optimal efficiency when the safety factor, β, equals 0.5.
•Some modules are integrated towards accurate and efficient modelling of high-speed chemically reactive two-phase gas-droplet flows.•Optimised droplet sub-models are verified in correct implementation by simulating ammonia droplet acceleration and cooling in the flowing air.•The accuracy and efficiency gains are examined by simulating 1-D detonation propagation in ammonia droplet-free/laden ammonia-oxygen mixtures.•The mixture-averaged and built-in OpenFOAM diffusion models provide different predictions of pulsating detonation instabilities.•A sparse stiff chemistry solver based on dynamic adaptive hybrid integration reduces the computational cost by around 50%.