基于不同压缩比的焦炉气与天然气混燃发动机燃烧特性的研究

摘要

In order to study different compression ratios on mixed natural gas and coke oven gas engine performance,we take a six-cylinder coke oven gas engine as the research object.We use CATIA 3D modeling software to establish four combustion chamber models with different compression ratio.With the limitations of the same boundary conditions,initial conditions and excess air system and other conditions,using AVL-FIRE fluid dynamics analysis software of different compression ratio to simulate engine compression and expansion process.The simulation results show that when the compression ratio is 12,the maximum flow velocity is the minimum in the cylinder at the ignition timing and creates favorable initial nucleus of a stable fire.Under the action of the strong squeezing flow the compression top dead point can generate the flow direction of the air flow to the spark plug which is favorable to the fire to spread away from the location of the spark plug.Compared the original machine with other machines,the engine which Compression ratio is 12 perform better.%为了研究不同压缩比对焦炉气与天然气混然发动机性能的影响,以一台6缸焦炉气发动机为研究对象.运用CATIA三维建模软件建立了4种不同压缩比的燃烧室模型,然后在相同的边界条件、初始条件及过量空气系数等条件下,利用AVL-FIRE流体力学分析软件对不同压缩比的发动机的压缩及膨胀过程进行了数值模拟.模拟结果表明:当压缩比为12时,在点火时刻缸内的最大气流流速最小,有利于初始稳定火核的形成,压缩上止点时在强挤流的作用下产生横向流动的气流流向火花塞的远处,有利于火焰向远离火花塞的位置传播;与原机和其他压缩比的发动机相比,压缩比为12的发动机性能较好.