ケーシングの無い短スパン貫流羽根車のアスペクト比効果とレイノルズ数効果(流体工学,流体機械)

概要

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The purpose of this experimental research is to clarify both the aspect-ratio effect and the Reynolds-number effect, especially for the flow of cross-flow impellers with shorter axes. Particle-image-velocimetry (PIV) technique and a hot-wire anemometer are used for measurements of flow velocity. The impeller rotates without any casings. The authors study two kinds of the impellers, that is, one with forward-cambered blades and the other with radial-flat blades. As a result, observing eccentric-vortex revolution by using hot-wire measurements and flow visualisations, the flow can be classified into three modes. According to this classification, the authors show flow-regime maps for both impellers. Using PIV results, the authors define outflow rate Q from the impeller. Outflow-rate coefficient C_Q is independent of the Reynolds number for both impellers. For the radial-flat-blade impeller, C_Q is not affected by aspect ratio L/D_2. But, for the forward-cambered-blade impeller, C_Q increases with L/D_2.
2007-12-25