外周リングを取付けた小型プロペラ水車の内部流れに関する研究

抄録

The authors focus on a small propeller turbine fabricating additive manufacturing technology represented by 3D printers. 3D printer runner fabrication is faster and cheaper than conventional manufacturing, but resin runner strength is not enough for utilization as it is. The authors proposed a ring runner integrated with a ring around the blade tip circumference to improve the strength of the runner vane and suppress blade tip leakage. This study conducted, CFD analyses for both the normal without ring and ring runner models to clarify the internal flow of the turbine and to elucidate the cause of the lower turbine efficiency in the ring runner model. As a result, it is found that the ring runner does not significantly improve the turbine efficiency compared to the normal one. Still, runner-only efficiency increased by approximately 2% because of increasing blade loading at the runner tip. Also, the circumference velocity downstream of the runner becomes larger near the shroud, so the ring runner model increases the loss downstream of the runner.