This paper analyses the effect of injection pressures on spray and flame structures under high-pressure diesel spray conditions using a three-dimensional Reynolds-Average Navier-Stokes (RANS) model. The simulations are conducted using three kinetic mechanisms known as Luo (106 species), Cai (57 species) and Yao (54 species). Tabulation and Dynamic Adaptive Chemistry (TDAC) solver is adopted to reduce the computational cost. The reacting results obtained using the Luo kinetic mechanism demonstrate the best agreement with the experiment. The Cai and Yao chemistry models overpredict and underpredict the ignition delay time respectively, whereas both mechanisms overpredict the flame lift-off length, particularly at higher injection pressures. It is found that the error for the ignition delay time is larger at higher injection pressures while the opposite is true for the flame lift-off length. The results reveal that at lower injection rates, the cool flame, represented by the CH₂O, occurs at richer mixture closer to the nozzle. On the other hand, the heat release rate is lower while the CO emission is higher. Detailed analysis on scalar fields shows that the Cai and Yao mechanisms lead to more consistent results in capturing the temperature field in terms of high-temperature reaction zone while Yao and Luo mechanisms result in a more consistent trend in producing the C₂H₂ species.

本文使用三维雷诺平均Navier-Stokes（RANS）模型分析了高压柴油喷射条件下喷射压力对喷射和火焰结构的影响。模拟使用三种动力学机制进行，分别称为Luo（106种），Cai（57种）和Yao（54种）。采用列表和动态自适应化学（TDAC）求解器可降低计算成本。使用罗动力学机理获得的反应结果表明与实验的最佳吻合。Cai和Yao化学模型分别高估和低估了点火延迟时间，而这两种机制都高估了火焰抬起长度，特别是在较高的喷射压力下。已经发现，在较高的喷射压力下，点火延迟时间的误差较大，而对于火焰起燃长度则相反。结果表明，在较低的注入速率下，以CH为代表的冷火焰₂ O发生在靠近喷嘴的浓混合气中。另一方面，放热率较低，而CO排放较高。对标量场的详细分析表明，在高温反应区方面，Cai和Yao机理导致捕获温度场的结果更加一致，而Yao和Luo机理导致产生C ₂ H ₂物种的趋势更加一致。