To accurately model the Direct Injection Spark Ignition (DISI) combustion process, it is important to account for the effects of the spark energy discharge process. The proximity of the injected fuel spray and spark electrodes leads to steep gradients in local velocities and equivalence ratios, particularly under cold-start conditions when multiple injection strategies are employed. The variations in the local properties at the spark plug location play a significant role in the growth of the initial flame kernel established by the spark and its subsequent evolution into a turbulent flame. In the present work, an ignition model is presented that is compatible with the G-Equation combustion model, which responds to the effects of spark energy discharge and the associated plasma expansion effects. The model is referred to as the Plasma Velocity on G-surface (PVG) model, and it uses the G-surface to capture the early kernel growth. The model derives its theory from the Discrete Particle Ignition (DPIK) model, which accounts for the effects of electrode heat transfer, spark energy, and chemical heat release from the fuel on the early flame kernel growth. The local turbulent flame speed has been calculated based on the instantaneous location of the flame kernel on the Borghi-Peters regime diagram. The model has been validated against the experimental measurements given by Maly and Vogel,¹ and the constant volume flame growth measurements provided by Nwagwe et al.² Multi-cycle simulations were performed in CONVERGE³ using the PVG ignition model in combination with the G-Equation-based GLR⁴ model in a RANS framework to capture the combustion characteristics of a DISI engine. Good agreements with the experimental pressure trace and apparent heat-release rates were obtained. Additionally, the PVG ignition model was observed to substantially reduce the sensitivity of the default G-sourcing ignition method employed by CONVERGE.

为了精确地模拟直接喷射火花点火（DISI）燃烧过程，重要的是要考虑火花能量放电过程的影响。喷射的燃料喷雾和火花电极的接近导致局部速度和当量比的陡峭梯度，特别是在采用多种喷射策略的冷启动条件下。火花塞位置处局部特性的变化在由火花建立的初始火焰核的生长及其随后演变成湍流火焰中起着重要作用。在本工作中，提出了一种与G方程燃烧模型兼容的点火模型，该模型响应火花能量放电的影响以及相关的等离子膨胀效应。该模型称为G表面等离子体速度（PVG）模型，它使用G表面捕获早期的籽粒生长。该模型的理论源于离散粒子点火（DPIK）模型，该模型解释了电极传热，火花能量以及燃料中化学放热对火焰核早期生长的影响。已经基于Borghi-Peters态图上火焰核的瞬时位置计算了局部湍流火焰速度。该模型已针对Maly和Vogel给出的实验测量结果进行了验证，以及燃料的化学热在火焰核早期生长时释放出来。已经根据Borghi-Peters态图上火焰核的瞬时位置计算了局部湍流火焰速度。该模型已针对Maly和Vogel给出的实验测量结果进行了验证，以及燃料的化学热在火焰核早期生长时释放出来。已经根据Borghi-Peters态图上火焰核的瞬时位置计算了局部湍流火焰速度。该模型已针对Maly和Vogel给出的实验测量结果进行了验证，¹和Nwagwe等人提供的恒定体积火焰生长测量值。²在CONVERGE ^3中使用PVG点火模型与基于G方程的GLR ⁴模型在RANS框架中进行了多周期仿真，以捕获DISI发动机的燃烧特性。获得了与实验压力迹线和表观放热率的良好协议。此外，观察到PVG点火模型大大降低了CONVERGE使用的默认G源点火方法的灵敏度。