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在一台经过改装的单缸四气门柴油机上,由电机倒拖,使用LDA测量了缸内上部若干测点的速度信号,使用集总平均法对进气和压缩过程中缸内的流场分析计算了涡流的平均流速和湍流强度。结果表明在压缩过程中,从缸心到缸壁,切向湍流强度值大体相同。在压缩过程的初期和中期,缸内流场的切向速度曲线从缸心到缸壁变化较大,存在尖点;在压缩过程的后期、接近上止点位置时,由于挤流的作用,气缸中心的气体旋转角速度较外围明显增大,气缸中的气体分为燃烧室中心的高速圆柱区域和活塞顶上部的低速环形区域。在单进气道工作方式下,只影响进气和压缩初期的缸内流场。
In a modified single-cylinder four-valve diesel engine, dragged by the motor, the use of LDA measured several points on the upper cylinder speed signal, the use of lumped averaging method of intake and compression during the cylinder flow field analysis The average velocity of turbulent flow and turbulent intensity were calculated. The results show that during the compression process, the tangential turbulence intensity values are roughly the same from the cylinder center to the cylinder wall. In the early and mid-stage of the compression process, the tangential velocity curve of the in-cylinder flow field varies greatly from the cylinder center to the cylinder wall, and there is a sharp point. In the later stage of compression, close to the top dead center position, due to the effect of squish flow, The angular velocity of the gas at the center of the cylinder is significantly increased compared to the outer periphery. The gas in the cylinder is divided into a high-speed cylindrical area in the center of the combustion chamber and a low-speed annular area in the top of the piston. In the single-inlet working mode, only affect the initial intake and compression of the cylinder flow field.