流れ解析によるインデューサ付きディフューザポンプの設計流量ならびに部分流量における非定常流れ場の検討

概要

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This paper presents a numerical study of unsteady flow in a target pump with an inducer, an impeller and an axial diffuser. The objective of the present study was to clarify the flow field difference between the target pump and a newly designed one at design and off-design flow conditions. The target pump showed a positive slope in its head-flow curve (stall characteristic) at low flow rate, which was well suppressed in the newly designed pump. The numerical results of the target pump showed that stall characteristics were observed both in the inducer and the impeller, as well as in diffuser pressure recovery at the stall flow rate. It was predicted that the main cause of impeller stall of the target pump would be the impeller Euler head reduced by the strong interaction between the impeller exit flow and the reverse flow from the diffuser inlet at the hub. At the same time, occurrence of rotating stall was found in the diffuser. The stall characteristic in the inducer was found to be the large separation taking place near the inducer hub. This large separated region in the inducer also showed a behavior to propagate in the circumferential direction in a fashion similar to the rotating stall in the diffuser. The numerical results of newly designed pump showed improved flow field at the off-design flow and the stall characteristic was well-suppressed comparing to the target pump.
社団法人日本機械学会の論文
2009-05-25