柴油喷雾火焰撞壁瞬时传热仿真与辐射传热特性

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

    • 摘要: 基于3D-CFD软件构建高精度喷雾燃烧与壁面传热模型,系统分析了喷雾火焰与壁面相互作用时壁面平均辐射热流的时空演化规律。结果表明,喷雾火焰撞壁前辐射热流可忽略,撞壁后辐射热流随火焰发展明显上升,喷油结束后达到峰值。此外,撞壁面辐射热流最高,达到1.4 MW/m2,其热流峰值首先出现在火焰扩散半径处,尾燃阶段在驻点附近形成第二个峰值并沿壁面径向扩散。上壁面的辐射热流较小,为0.7 MW/m2,其热流峰值分布在喷嘴附近。侧壁面辐射热流最小,为0.3 MW/m2,其热流峰值位于火焰反弹高度处。

       

      Abstract: 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.

       

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