Search

This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s00340-023-08100-0, Simultaneous imaging of polycyclic aromatic hydrocarbons (PAHs), soot, and the flame zone formed around a single coal particle was conducted to investigate the flame structure of a single coal particle. The spatial distribution of PAHs, soot, and the flame zone was illuminated using PAHs and CH2O laser-induced fluorescence (LIF) and laser-induced incandescence (LII), respectively. Additionally, the spatial distribution of the primary soot particle size was evaluated using a combination of LII and laser-induced scattering (LIS). The results showed that the CH2O-LIF imaging was successful for the volatile flame of a single pulverized coal particle. The PAHs-LIF signal was found inside the region where the LII signal was measured, while the CH2O-LIF signal was detected outside of the LII signal. The size of soot particles increased, and the soot number density decreased from the interior to the exterior of the volatile flame. Furthermore, the structure of the volatile flame of a single coal particle was found to be identical to that of a diffusion flame.

In addressing the demands of industrial high-fidelity computation, the present study introduces a rapid and accurate customized solver developed on the OpenFOAM platform. To enhance computational efficiency, a novel integrated acceleration strategy is introduced. Initially, a sparse analytical Jacobian approach utilizing the SpeedCHEM chemistry library was implemented to increase the efficiency of the ODE solver. Subsequently, the Dynamic Load Balancing (DLB) code was employed to uniformly distribute the computational workload for chemistry among multiple processes. Further optimization was achieved through the introduction of the Open Multi-Processing (OpenMP) method to enhance parallel computing efficiency. Lastly, the Local Time Stepping (LTS) scheme was integrated to maximize the individual time step for each computational cell, resulting in a noteworthy minimum speed-up of over 31 times. The effectiveness and robustness of this customized solver were systematically validated against three distinct partially turbulent premixed flames, Sandia Flames D, E, and F. Additionally, a comparative analysis was conducted, encompassing different turbulence models, turbulent Prandtl numbers, and model constants, resulting in the recommendation of optimal numerical parameters for various conditions. The present study offers one viable solution for rapid and accurate calculations in the OpenFOAM platform, while also providing insights into the selection of turbulence models and parameters for industrial numerical simulation., Comment: 41 pages, 13 figures