Development of Numerical Method for the Analysis of Low Emission Combustion using Artificial Turbulence Stimulation

本文提出了一种新的预混压燃燃烧计算分析方法。该方法采用超大涡模拟（VLES）结合化学反应，解决时间和空间波动的速度和温度的数值细胞大小，并模拟随机性质的外观自燃点。采用一种新的思想，在模拟的实施，我们给了统计上合理的初始条件，在进气门关闭时的脉动湍流流场。压缩过程中的平均流量、平均温度、缸内平均湍流动能和压力等参数的相平均计算结果与k-S模型的计算结果吻合较好。的VLES表现出空间随机外观的自燃点，这是类似的文献中所示的实验观察。分析表明，自燃的空间随机发生是由于局部壁面传热的随机变化和产生的温度波动。本研究提供了一种新的计算方法来分析预混充量压缩着火燃烧的机理。

A new method for the computational analysis of premixed charge compression ignition combustion has been developed. The method employs Very Large Eddy Stimulation (VLES) in conjunction with chemical reactions, solving temporal and spatial fluctuations of velocities and temperatures in a numerical cell size, and simulating the random nature of the appearance of auto-ignition spots. Using a novel idea in the implementation of the simulation, we give statistically reasonable initial condition for a fluctuating turbulent flow field at intake valve closing time. The phase-averaged result of the VLES and the result of the k-epsilon model are well in agreement with respect to mean flow, mean temperature, cylinder-averaged turbulence kinetic energy and pressure during compression. The VLES exhibits the spatially random appearance of auto-ignition sites, which is similar to experimental observations shown in the literature. The analysis shows that the spatially random occurrence of the auto-ignition is due to the local wall heat transfer which changes randomly and generates temperature fluctuations. This study presents a new computational approach to analyze the mechanism of the premixed charge compression ignition combustion.