Effects of Tapered Diffuser Vane on the Flow Field and Noise of a Centrifugal Compressor

从一台离心的压缩机散发的流动地和噪音上的三维的逐渐变细的更弥漫的翼的效果被 CFD 分析和实验调查。逐渐变细的更弥漫的翼不仅为相互作用音调噪音的减小而且为在更弥漫的经过以内的压力恢复特征的改进是很有用的。由使用逐渐变细的更弥漫的翼，在推动分泌物流动和更弥漫的翼之间的相互作用区域变得小，然后分离音调的噪音水平能作为结果显著地被减少。由基于 CFD 结果利用旋涡的结构的可视化技术，而且，旋涡流从更弥漫的翼的前缘离开的规模被发现被收缩，为到减少的骚乱水平的一个趋势被观察。这可以是宽带噪音部件的变细的原因。第二等的流动，被认为是更弥漫的压力恢复的阻塞，能被逐渐变细的更弥漫的翼，和在更弥漫的经过的喉咙部分观察的压力减少也压制是进一步可约的。

The effects of a three-dimensional tapered diffuser vane on the flow field and noise radiated from a centrifugal compressor are investigated by both CFD analyses and experiments. Tapered diffuser vanes are very useful not only for the reduction of the interaction tone noise but also for the improvement of the pressure recovery characteristics within the diffuser passage. By using tapered diffuser vanes, the interaction area between the impeller-discharge flow and diffuser vanes becomes small, and then the noise level of the discrete tone can be reduced remarkably as a result. Furthermore, by utilizing the visualization technique of vortical structures based on the CFD results, the scale of vortex shedding leaving from the leading edge of the diffuser vanes is found to be contracted and a tendency for the turbulence level to decrease is observed. This may be the cause of the attenuation of broadband noise components. The secondary flow, which is considered to be an obstruction of diffuser pressure recovery, can also be suppressed by the tapered diffuser vanes, and the pressure decrease observed in the throat part of the diffuser passage is further reducible.