离心喷嘴喷口结构参数对雾化性能的影响分析

Effects of Structure Parameters of Centrifugal Nozzle on Atomization Performance

关键词:  离心喷嘴  结构参数  流体体积  正交试验  雾化锥角  液膜厚度  流量系数

Key words:  Centrifugal nozzle  Structure parameters  Volume of fluid（VOF）  Orthogonal experiment  Spray angle  Liquid film thickness  Flow coefficient

摘要:

为了提高航空发动机离心喷嘴的雾化性能，优化喷嘴喷口结构参数，基于两相界面追踪流体体积（Volume of fluid，VOF）方法对离心喷嘴进行了仿真分析，并通过实验验证了VOF方法的可靠性。采用正交试验方法完成以喷嘴出口直径、出口直管段长度、扩张角、扩张段长度为优化参数，以雾化锥角、液膜厚度和流量系数作为雾化性能指标的试验设计。通过极差方差分析讨论各个参数对雾化性能指标影响的显著性并利用回归分析得到规律曲线，获得最佳参数组合。结果表明：4个结构参数中扩张角是对喷嘴雾化性能影响最大的因素；扩张角和喷口直径的增大可以明显地增大雾化锥角，减小液膜厚度和流量系数；扩张段长度的增大会使雾化锥角减小，同时减小液膜厚度和流量系数；直管段长度的变化对各指标的影响不大；当扩张角θ为60°，出口直径D为0.6mm，出口直管段长度L₁为0.3mm，扩张段长度L₂为0.4mm时，雾化性能最佳。

Abstract:

In order to improve the atomization performance of the aero-engine centrifugal nozzle and optimize the structure parameters， the volume of fluid （VOF） method was adopted to simulate the nozzle with experimental validation. An orthogonal experiment design was conducted by selecting the nozzle outlet diameter， the length of straight pipe， the divergent angle and the divergent length as the design parameters and the spray angle， the liquid film thickness and the flow coefficient as the atomization characteristics. Through the range variance analysis and regression analysis， the statistical significance of each parameter to the atomization characteristics and their regression curves were obtained to determine the optimal parameter combination. The results show that the divergent angle dominants the influence of the four structural parameters on the atomization performance. Increasing the divergent angle and the outlet diameter can increase spray angle but decrease liquid film thickness and flow coefficient remarkably. The extention of the divergent length decreases spray angle， liquid film thickness and flow coefficient significantly. The length of the straight pipe barely affects the three atomization characteristics. When the divergent angle θ is 60°， the outlet diameter D is 0.6mm， the length of straight pipe L₁ is 0.3mm and the divergent length L₂ is 0.4mm， the three atomization characteristics are well.