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应用粒子图像测速技术(PIV)对定容弹内多种试验条件下压电晶体控制的外开轴针式喷油器的喷雾场速度特性进行测量与分析.试验结果表明,油嘴附近的大尺度气体涡流A和涡流B不仅对油气掺混和喷雾雾化起到关键作用,对于点火时刻火花塞附近的混合气特性也具有重要影响.将喷射压力、环境压力、轴针升程及轴针座锥角对喷雾场内涡流运动的影响作为重点进行分析.结果表明,环境压力增加促进了涡流A和涡流B的增长,同时使涡流的位置更加靠近喷油器.轴针座锥角的变化显著改变了喷雾场内的气流运动特征,94°轴针座锥角的喷雾出现了明显的冲向油嘴的气体回流.通过对喷雾场各节点的速度结果进行标准差计算,得到了喷雾场的速度标准偏差.以此为基础,对喷雾场内涡流的运动特性及其对混合气分布的影响做了进一步的分析.
The velocity field characteristics of the spray nozzle controlled by the piezo-electric crystal controlled by Piezoelectric crystal under various test conditions in the constant volume bomb were measured and analyzed by the particle image velocimetry (PIV). The experimental results show that the large scale Gas swirl A and swirl B play a key role not only in the mixing of oil and gas and spray atomization, but also in the ignition characteristics of the mixture near the spark plug.The injection pressure, ambient pressure, The results show that the increase of ambient pressure promotes the increase of eddy current A and eddy current B, and at the same time makes the eddy current position closer to the injector.The change of the conical angle of the needle hub significantly changes The gas flow motion in the spray field and the gas flow to the nozzle of the 94 ° needle hub taper obviously. By calculating the standard deviation of the velocity results of each node in the spray field, the velocity standard deviation of the spray field was obtained Based on this, further analysis is made on the movement characteristics of the vortex in the spray field and its influence on the distribution of the mixture.