抄録
A prototype pump performance converted from its model pump performance shows an increase in efficiency compared with that of the model pump. The increase is brought about by the decrease in friction loss in the pump. The friction force on impeller blades causes a part of peripheral motion of the outlet flow from the impeller, and accordingly the increase in prototype efficiency is related with the decrease in its input power. This paper analyses the behavior of the theoretical head or input power of the prototype pump, applying friction drag coefficient of a flat plate to blade passage friction. As a result it is revealed that the friction drag of a flat plate can be substituted for the friction drag of impeller blades to a certain degree as a means of analyzing the relationship between the efficiency increase and the power decrease of the prototype pump.
