液压自由活塞柴油机缸内过程仿真研究  

In-Cylinder Simulation of Hydraulic Free-Piston Diesel Engine

作　　者：张栓录 赵振峰[1] 赵长禄[1] 

机构地区：[1]北京理工大学机械与车辆学院,北京100081

出　　处：《燃烧科学与技术》2015年第5期447-452,共6页Journal of Combustion Science and Technology

摘　　要：通过示功图计算和CFD数值模拟,针对液压自由活塞发动机燃烧过程的研究提出数值仿真迭代研究方法,从而分析控制参数与缸内工作过程的交互耦合影响关系.结果表明,与传统曲柄连杆发动机的活塞运动规律相比,当二者取相同喷油时刻或相同喷油位置时,在滞燃期内准备的混合气有所差异,HFPDE的滞燃期较短,从而造成预混燃烧阶段放热率的差异.HFPDE放热较快导致活塞加速较快,从而导致温度分布与传统发动机有所差异,温度随活塞快速膨胀而急剧下降导致了氮氧化物的产生主要集中在上止点附近,燃烧后期生成量较少;逆挤流对缸内空燃比的影响较大,使得碳烟生成在接近缸套附近的位置较为集中,而温度的快速下降使得其对碳烟的分布影响减弱.Through the calculation of indicator diagram and CFD numerical simulation, in order to study the incylinder combustion process of hydraulic free-piston engine, the numerical simulation iteration method is proposed. Thus the control parameters and the interactive relationship between in-cylinder coupling parameters in the working process can be analyzed. Results show that compared with the traditional crank-shaft engine, when the injection timing or the injection location is the same, the mixture prepared during ignition delay period is different. The ignition delay period of HFPDE is shorter, which leads to the difference in premixed combustion heat release rate. Rapid heat release causes fast piston movement, thus resulting in different in-cylinder temperature distribution. Lower temperature causes NOx to concentrate on TDC. NOx is hardly produced after combustion. On the other hand, the influence of inverse extrusion flow on in-cylinder air-fuel ratio is great, soot is mainly formed near the cylinder liner, and the rapid decline of temperature makes less contribution to soot distribution.

关 键 词：自由活塞发动机 喷油提前角 三维仿真 滞燃期 氮氧化物 

分 类 号：TK441[动力工程及工程热物理—动力机械及工程]