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本文介绍了作者等用粒子示踪法研究直接喷射式柴油机燃烧室中空气运动的理论及试验结果。研究结果表明,用具有导气屏的进气阀产生进气涡流时,在压缩开始前,气缸内的涡流既非自由涡流亦非强迫涡流,但更多地接近自由涡流。从进气终了至挤流开始之间的一般时间内,气流逐步趋近强迫涡流,特别在气缸的外围部分,本文提出的粒子在旋转气流中的运动轨迹方程与试验结果基本相符。它不仅表示示踪粒子的运动规律,而且可以用来了解燃油质点在燃烧室中的运动状态和混合气形成过程。研究结果还表明,只要仔细选择粒子,用粒子示踪法测量柴油机燃烧室中的空气运动是切实可行的。文中还提出了用粒子示踪法测量燃烧室中空气运动时的误差的理论分析及其控制方法。
This paper introduces the theory and test results of the particle tracer method used to study the air movement in a direct injection diesel engine combustion chamber. The results show that when the inlet vortex flow is generated by the intake valve with air-guide screen, the vortex flow in the cylinder is neither free vortex nor forced vortex before compression begins, but it approaches the free vortex more. During the normal time from the end of intake to the beginning of squish flow, the airflow gradually approaches the forced vortex. Especially in the peripheral part of the cylinder, the trajectory equation of the particles proposed in this paper is basically consistent with the experimental results. It not only shows the law of motion of tracer particles, but also can be used to understand the movement of fuel particles in the combustion chamber and the formation process of the mixture. The results also show that it is practicable to use particle tracer to measure air movement in the combustion chamber of a diesel engine by carefully selecting particles. The paper also presents the theoretical analysis and the control method of measuring the error of air movement in the combustion chamber by particle tracing method.