A COUNTER-ROTATING TYPE PUMP-TURBINE AND A SELF GENERATING SYSTEM HAVING THE SAME AND AN OPTIMAL DESIGN METHOD OF A COUNTER-ROTATING TYPE PUMP-TURBINE

摘要

A counter-rotating pump turbine is provided. According to an exemplary embodiment of the present invention, the counter-rotating pump turbine comprises: a first impeller including a plurality of first blades; and a second impeller arranged to be spaced a certain distance apart from the first impeller and including a plurality of second blades, and operates in a turbine mode. The hub profile for the first blades has an angle difference (_F) of -6 to 2 degrees (excluding zero degree) from a reference blade, the hub profile for the second blades has an angle difference (_R) of -2 to 8 degrees (excluding zero degree), and interpolation is carried out from the hubs to tips of the first and second impellers by using a B-spline curve. At this time, the reference blade is defined by an NACA4409 hydrofoil and, after that, numerically redesigned to improve the performance of a pump using computational fluid dynamics (CFD).