ターボ型遠心送風機の全閉時における騒音発生源の探索

抄録

We are researching centrifugal blowers used for dust collection and air conditioning in homes and factories. In this study, we targeted turbo type. It is characterized by high efficiency and high pressure air. However, the downside is that there is a lot of noise. In this study, we focused on the high pressure of the rear edge of the blade due to the collision of the rear edge of the blade. As a result, there is a pressure difference before and after the blade, which interferes with each other as it passes through the tongue and generates noise. This noise is the BPF noise represented by the actual rotational speed x blade. By reducing the flow of this collision, we thought that we could reduce the pressure difference before and after the blade and reduce the noise generated. Therefore, focusing on the slowdown of the vortex generated between the impeller and the circulation flow near the cutoff, we took measures. The vortex that occurs between the blades expands the wrap gap to generate a flow through the blade, reducing the scale of the vortex. As a result, the collision flow to the rear edge of the blade is relaxed, it was revealed that BPF noise was reduced. Decrease in circulation flow is alleviated by attaching a projection to the bottom of the casing. This slowdown reduces the collision flow to the rear edge of the blade and reduces BPF noise.