喷嘴结构对生物油喷雾特性的影响研究

EFFECT OF CENTRIFUGAL NOZZLE STRUCTURE ON BIO-OIL SPRAY CHARACTERISTICS

为更好地明确喷嘴结构参数对生物油雾化性能的影响规律,采用流体体积函数法(volume of fluid,VOF)在高喷射流量条件下对不同喷嘴结构内流场的雾化特性进行数值分析。结果表明:在喷嘴结构参数中,喷嘴常数及旋流室与出口段直径比是喷嘴雾化性能的主要影响因素,其值过大或过小均会偏离最优雾化效果;旋流室长径比、出口段长径比及收缩室半锥角分别为0.75°、3.00°和30.00°时生物油雾化性能最好;在经验公式基础上拟合出流量系数公式,可为喷嘴设计和试验优化提供参考。

In order to investigate the influence of nozzle structure parameters on the atomization performance of bio-oil,the atomization characteristics of the flow field in different nozzle structures were numerically analyzed under the condition of high injection flow velocity by fluid volume function(VOF). In the nozzle structure parameters,the nozzle constant and the diameter ratio of the swirl chamber and the outlet section are the main influencing factors of the nozzle atomization performance. When the values are too large or too small,the optimal atomization performance will be inhibited. With increasing L_s/D_s,the spray cone angle decreases,while the discharge coefficient and the film thickness increase. However,the atomization characteristics is optimal when length-to-diameter ratio of swirl chamber is 0.75,length-to-diameter ratio of the exit segment is 3 and semiconical angle of systolic chamber is 30°,respectively. Based on the empirical formula,the discharge coefficient formula is fitted to provide reference for nozzle design and experimental optimization.