回転体相対静止撮影技術を用いた汚水用水中ポンプの内部流れの可視化

Sewage submersible pumps are often used in situations where fluids containing various foreign objects, such as towels, plastic bottles, diapers, and toilet paper, are handled. To stabilize and efficiently transport such fluids containing foreign objects, numerous sewage submersible pumps with specially shaped impellers have been proposed. In these pumps, not only is the fluid transport efficiency improved, but the ability to pass foreign objects and resistance to clogging are also extremely important design elements.However, the environments in which these pumps are used are often highly specialized and harsh, and the physical properties of the fluid and the characteristics of the foreign objects are diverse, making it difficult for conventional pump design methods to adequately address these challenges. Additionally, the flow behavior inside the impeller is complex, and the detailed flow conditions remain poorly understood.In this study, we focused on a sewage submersible pump consisting of a two-blade non-clogging semi-open impeller and a suction cover with claw-like structures for crushing debris. To visualize the internal flow of the impeller during high-speed rotation, we applied rotating body relative stationary photography technology to capture images of the impeller in a relatively stationary state.This report presents the results of experiments conducted to clarify the flow state inside pumps with different suction cover and impeller shapes.