Transient Heat Transfer Simulation and Radiative Heat Flux Characterization During Diesel Spray Flame Impinging on the Wall

Based on 3D-CFD software, a high-fidelity spray combustion and wall heat transfer model was developed, and the temporal and spatial evolution of the wall-averaged radiative heat flux was investigated. The results indicate that the radiative heat flux is negligible before flame impingement, then increases substantially with the flame development after impingement and ultimately reaches its peak during the late combustion phase. Besides, the impingement wall exhibits the highest radiative heat flux, peaking at 1.4 MW/m², with the localized heat flux peaks first showing at the flame diffusion radius, while a secondary peak emerges at the stagnation point during late combustion and expands radially along the wall. The injector-side wall shows lower heat flux of 0.7 MW/m², with localized peaks concentrated near the nozzle. The side wall shows the minimal radiative heat flux, approximately 0.3 MW/m², with its peak value aligning with the flame rebound height.