Artificial heart pumps have attracted attention from researches worldwide as an efficient method for organ transplantation. In Europe, clinical trials of magnetically suspended centrifugal pumps have already been successfully performed, and these pumps have been commercialized. The aim of our research is to numerically examine the internal flow and the effect of the leakage flow through the gap between the impeller and the pump casing on the performance of the pump. The results obtained show that the pressure head increases due to the effect of the fluid passing through the gap. It was also observed that the leakage flow rate is sufficiently large, and that there is neither a stagnant nor a dead flow in the pump. Therefore, the present pump is very efficient in "wash-out" effect.

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Low specific speed Wedge type impellers with high performance are developed, which impellers are applied to high-pressure multistage compressors. Conventional low specific speed impellers have thin blades and small blade heights.Therefore, efficiency of low specific speed impellers is lower than that of high specific speed impellers, because the large wetted perimeter causes large skin friction loss. Wedge type impellers with thick blades and large blade heights are examined to reduce the skin friction loss. Designed Wedge type impellers were fabricated and tested. Results show that in case of Wedge type impeller the normalized stage efficiency increases by 6% and operating flow range expands significantly as compared with those of the conventional 2D impeller stage.

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A vertical bulb turbine unit with elbow type draft tube has been developed due to avoidance of complicated assembling and long standstill period at overhaul in comparison with conventional horizontal bulb turbine unit. Before designing the prototype vertical bulb unit, hydrographic model test was carried out to establish the ideal design concept for this innovative generating unit.
Froude similarity is not available for vortex occurrence. Consequently, an intake structure without air-entraining vortices under all the flow condition is developed, and it is confirmed that the surge wave at load rejection is not affected harmful influence for other constructions.

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