基于DDES方法的汽油机进气流动湍流特性  

Turbulence Characteristics of Gasoline Engine Intake Flow Based on DDES

作　　者：李卫 刘大明[3] 田福全[2] 王天友 Li Wei;Liu Daming;Tian Fuquan;Wang Tianyou(Engine R&D Center,Weichai Power Company Limited,Weifang 261061,China;State Key Laboratory of Engines,Tianjin University,Tianjin 300350,China;School of Automotive and Transportation,Tianjin University of Technology and Education,Tianjin 300222,China)

机构地区：[1]潍柴动力股份有限公司发动机研究院,山东潍坊261061 [2]天津大学内燃机燃烧学国家重点实验室,天津300350 [3]天津职业技术师范大学汽车与交通学院,天津300222

出　　处：《内燃机学报》2023年第4期298-306,共9页Transactions of Csice

基　　金：国家自然科学基金资助项目(51921004,51706155).

摘　　要：采用基于切应力输运(SST)耦合延迟分离涡模拟(DDES)方法,对某汽油机进行了稳流试验条件下的数值模拟,并采用光学发动机上3D-粒子图像测速(PIV)试验数据对结果进行了验证,在此基础上研究了缸内湍流场的空间域及频域特征.通过与试验及雷诺平均(RANS)数值模拟结果的对比发现,DDES方法对发动机缸内复杂流动模拟有明显优势.结果表明:滚流中心面内高气门升程下缸内流动对称趋势较低气门升程工况更好,三维流动区域主要集中在燃烧室及进气门下方区域.平均流雷诺数决定了缸内流场湍流能谱的整体特征,平均流雷诺数越高的区域,湍流能量进入惯性输运的涡团尺度越小.湍流雷诺数主要影响惯性子区长度,湍流雷诺数越高,湍流发展越充分,惯性子区越明显.湍流脉动强度的平方代表湍流能谱所包围的面积;相对湍流脉动强度则影响低频湍流能量密度的高低.The delayed detached eddy simulation(DDES)based on shear stress transport(SST)model was performed to simulate the flow filed in a gasoline engine under steady state.The simulation results were first validated against the experimental data measured by 3D-particle image velocimetry(PIV)on an optical engine.Then,the spatial domain and frequency domain of turbulent flow in cylinder were analyzed.The comparisons of simulation results of DDES with experimental data and calculation results of Reynolds-averaged navier-stokes(RANS)indicate that the DDES has great advantages in simulating the complex flow in the cylinder.The results show that the flow symmetry trend in tumble center plane under high valve lift condition is better than that under low valve lift condition,and three-dimensional flow concentrates in the combustion chamber and the region under intake valves.The Reynolds number of mean flow determines the overall characteristics of turbulent energy spectrum in the cylin-der.In the region with higher Reynolds number of mean flow,the scale of vortex whose turbulent energy enters in-ertial transport becomes smaller.Turbulent Reynolds number mainly affects the length of inertial sub-region.The turbulence develops more fully and the inertial sub-region becomes more obvious at higher turbulent Reynolds number.The square of turbulence intensity represents the area surrounded by the turbulence spectrum,and relative turbulence intensity affects the turbulence energy density in low frequency.

关 键 词：汽油机 延迟分离涡模拟 湍流特性 粒子图像测速 

分 类 号：TK411[动力工程及工程热物理—动力机械及工程]