【摘要】 在直喷式柴油机气缸及燃烧室中用热线风速仪研究了紊流场的发展变化规律。结果表明:在压缩行程的初期和中期,缸内的流场可近似当做均匀各向同性紊流场;在循环的大部分时间内,缸内和燃烧室中的紊流场则是非均匀、各向异性的。通过对压缩过程中缸内空气流动能量的转换分析,导出了估算压缩终了燃烧室内涡流转速的公式,计算结果与实验结果基本相符,并指出了燃烧室中涡流和紊流强度增强的原因及影响因素。更多还原

【Abstract】 An investigation of the development and variation of the turbulentflow field in the cylinder and combustion chamber of a D.I.diesel enginewas carried out by using the hot-wire anemometry.The results show that the turbulent flow field may be consideredapproximately as a homogeneous and isotropical one only in the early andmiddle stages of the compression stroke.In the other parts of the cycle,however,the turbulent flow field inside the cylinder and the combustionchamber is nonhomogeneous and nonisotropic.An analysis is made of the force and energy conversion for the airmotion in the cylinder and combustion chamber.A formula for predictingthe swirl speed at TDC in the combustion chamber is deduced.The resultsobtained by this formula agree quite well with the experimental results.The reasons for the increase in swirl speed and turbulence intensity insidethe chamber and the factors influencing them are also studied and discussed.更多还原