液体射流在不均匀速度横流中的轨迹和穿透研究

Investigation on trajectory and penetration of liquid jet in non-uniform velocity crossflow

实验研究了横流速度分布不均匀时液体射流的轨迹和穿透。利用多孔板实现速度分布不均匀,射流液体为水,用激光片光照相结合相位多普勒粒子分析仪进行研究。主要关注平均射流动量比、局部韦伯数和横流速度分布不均匀度等参数。不均匀横流对射流的影响主要体现为破碎模式沿射流流向的转变。提出表征射流受横流影响范围的无量纲数L,并构造常温常压下适用于不均匀度为−2~2且射流动量比为10~40的射流轨迹经验公式。以是否存在“初级抬升段”作为判定是否进行分段拟合的准则。对于不均匀度小于1,结合经验公式与不均匀度和L的线性函数图对射流轨迹进行预测;对于不均匀度大于1,以射流首次发展为复合式破碎的位置作为“抬升段”和“偏转段”的分界点对射流轨迹进行分段拟合。

The trajectory and penetration of liquid jet in crossflow with non-uniform velocity distribution were studied experimentally.Using specifically designed perforated plates to realize several non-uniform velocity distributions,water was used as the jet liquid,and the research was carried out by laser sheet combined with phase doppler particle Analyzer.The main concerns involved the average jet momentum flux ratio,the local Weber number and non-uniformity of the transverse velocity distribution.The influence of the crossflow with non-uniform velocity distribution on the liquid jet was mainly reflected in the transformation of the breakup mode along the liquid flow direction.A dimensionless parameter L characterizing the influence range of liquid jet by cross flow was proposed,and an empirical formula suitable for jet trajectory with non-uniformity of−2—2 and jet momentum flux ratio of 10—40 at normal temperature and pressure was constructed.The existence of“primary uplift section”was taken as the criterion to determine whether the subsection fitting was carried out.For non-uniformity less than 1,the jet trajectory was predicted by combining the empirical formula with the linear function diagram of nonuniformity and L.For non-uniformity greater than 1,the location where the liquid jet first developed into composite breakup was taken as the dividing point of“uplift section”and“deflection section”,and the jet trajectory was fitted by segments.