基于CFD的风琴管喷嘴结构优化

Optimization of Organ Pipe Nozzle Structure Based on CFD

对风琴管喷嘴的谐振腔顶端、底端和圆柱段起点处增加曲面过渡,利用Fluent进行数值计算,对各喷嘴的气相体积分布、气相生成速率、静压力、流速和湍动能进行对比分析。结果表明:气相主要在圆柱段和扩散段近壁面产生,在圆柱段起点和扩散段起点处气相生成速率最高;在谐振腔顶端增加曲面过渡会降低空化效果,在谐振腔底端增加曲面过渡可提高空化效果,在圆柱段起点处增加曲面过渡能显著提高空化效果;对喷嘴圆柱段起点处采用45°角过渡、圆形过渡和椭圆形过渡并进行数值计算,发现圆形曲面过渡的喷嘴产生的空化效果优于其他两种形状。

In this paper,a circular transition surface was added at resonator's top,bottom and starting point of the organ pipe nozzle,and Fluent was employed in numerical calculation to comparatively analyze gas volume distribution,gas phase generation rate,static pressure,flow rate and turbulent kinetic energy of each nozzle.The results show that,the gas phase mainly generates in cylinder section and near the wall of diffusion section,the gas phase generation rate is highest at the beginning of both the cylinder section and the diffusion section.Adding a curved transition at the cavity top can reduce cavitation effect and adding that at the resonator bottom can improve cavitation effect as well as adding a curved transition at the beginning of the cylinder can significantly improve cavitation effect.Numerically simulating transition surfaces of circular,elliptical and 45° chamfering at the starting point of the nozzle's cylindrical section respectively show that,the cavitation effect incurred by the circular transition surface outperforms those of other shapes.