低压射流不同喷嘴参数及压力下破碎过程实验

Experiment on Breakup Process of Low-pressure Jets with Different Nozzle Parameters and Pressures

研究了不同低压下喷头喷嘴直径和喷嘴锥角对射流破碎的影响。采用高速摄像仪对低压圆柱射流的射流核心长度和射流破碎长度进行实验,测量了不同喷嘴结构的流量、射程和末端水滴直径。结果表明:同一压力下,当喷嘴锥角不变时,随着喷嘴直径的增大,喷头流量、射程和喷头末端水滴直径都变大,射流核心长度和破碎长度均增大;当喷嘴直径不变时,随着喷嘴锥角的增大,喷头流量逐渐减小,而喷头射程呈先增大后减小趋势,喷头末端水滴直径也变大,射流核心长度逐渐减小,射流破碎长度先减小后增大。综合考虑射程和雾化效果,直径为5 mm、锥角为45°的喷嘴为最优选择。同时通过对不同Re数和We数的实验和分析,给出了适合低压喷嘴的两种射流特征长度的拟合关联式。

In order to identify the two characteristic lengths of breakup process of low-pressure jets, the relationship between different diameters and angles of entrance of jet nozzle on the breakup of low- pressure jet under different pressures was studied. An experiment was conducted to investigate the core lengths and breakup lengths of a round water jet. The flow, ranges and ending raindrop diameters were measured under low jet velocity. The results showed that with the increase of nozzle diameter, the flow, ranges, ending raindrop diameters, core lengths and breakup lengths became larger. With the increase of nozzle cone angle, the flow became smaller, the ranges increased at first then decreased, the ending raindrop diameters increased and the core lengths decreased, but the breakup length decreased at first then increased. The ranges and the atomizing condition showed that the diameter of nozzle of 5 mm and cone angle of nozzle of 45° were the best. Correlation equation was proposed based on the analysis of effect of Re and We on the core length and breakup length.