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为研究挤流对进气道喷射汽油机燃烧过程的影响,应用三维CFD软件AVL-FIRE对具有三种不同顶面形状活塞的燃烧室的进气及燃烧过程进行了多维数值模拟计算。计算研究了挤气面积和挤气间隙对缸内速度场、浓度场、湍动能场及放热率、平均有效压力、燃烧持续期等缸内燃烧特征参数的影响。CFD分析表明:合理设计燃烧室活塞顶面形状,可以在压缩上止点附近形成较强挤流,促进缸内燃烧。挤流对组织缸内气流运动、提高点火时刻火花塞附近湍流强度以及改善发动机燃烧都有较大作用。
In order to study the effect of squish flow on the combustion process of air-injected gasoline engine, three-dimensional CFD software AVL-FIRE was used to simulate the intake and combustion process of the combustion chamber with three different top-shape pistons. The influence of squish area and squish gap on the in-cylinder combustion parameters such as in-cylinder velocity field, concentration field, turbulent kinetic energy field and heat release rate, mean effective pressure and combustion duration were studied. CFD analysis shows that: Reasonable design of the combustion chamber piston top shape, can form a strong squeeze near the compression top dead center, and promote combustion in the cylinder. Squish flow on the organization of air flow within the cylinder to improve the intensity of turbulence near the spark plug ignition time and improve the engine combustion have a greater role.