小型二冲程直喷发动机爆震燃烧特性数值模拟  

Numerical simulation on characteristics of knock combustion of small two-stroke direct injection engine

作　　者：贝太学[1] 魏民祥[1] 刘锐[1] 常诚[1] 

机构地区：[1]南京航空航天大学能源与动力学院,江苏南京210016

出　　处：《华中科技大学学报（自然科学版）》2017年第2期34-39,共6页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国防预研基金资助项目(513250203);江苏省高校研究生科研创新计划资助项目(KYLX-0244)

摘　　要：为了了解点火参数对小型二冲程直喷发动机爆震燃烧的影响,利用GT-Power和AVL Fire软件对该发动机整机及燃烧室分别建立了仿真模型,选取扭矩、功率等数据验证了模型的正确性,并对发动机在5 000r/min、大负荷工况下的缸内平均压力和温度、放热率、累积放热量以及爆震强度分布等特性进行了研究.结果表明:在点火提前角由15℃A逐渐增加至35℃A的过程中,小型二冲程直喷发动机的扭矩、功率、缸内混合气燃烧放热量、放热率、缸内平均压力和温度的峰值均呈现出逐渐增大的趋势,而且会伴随着爆震强度表征物的浓度增大,二冲程直喷发动机的爆震倾向加强;当异步点火相位由0℃A逐渐增加至5℃A时,二冲程直喷发动机的扭矩、功率呈现出略微减小的趋势,两个火花塞附近由于湍动能增大,加快了火焰传播速度,使得末端混合气低温反应时间变短,爆震强度表征物的浓度逐步减小,二冲程直喷发动机爆震发生的倾向有所减小.In order to understand the impact of ignition parameters on the knock of two-stroke kerosene aero-piston engine,the calculation model of the engine and the combustion chamber was established by using GT-Power and AVL Fire software.And the validity of the model was verified by the test data.The characteristics of average pressure and temperature,heat release rate,cumulative heat release rate and knock intensity distribution in the cylinder under 5 000r/min and large load conditions were studied.The simulation and test results show that when angle of ignition advance changes from15 ℃A to 35℃A,the torque,power,and average pressure,mean pressure and temperature,heat release rate and the accumulated heat release rate increase,accompanied by knock intensity tends to increase.When the asynchronous ignition phase changes from 0 ℃A to 5 ℃A,the torque and power shows slightly decreasing trend.Due to the turbulent kinetic energy near the spark plug increases,the flame propagation speed up,the reaction time at the end of the mixed gas becomes shorter,and the knock tendency of the two-stroke engine decreases.

关 键 词：二冲程发动机 缸内直喷 数值模拟 燃烧 爆震 点火提前角 异步点火相位 

分 类 号：V233.7[航空宇航科学与技术—航空宇航推进理论与工程]