FRANCIS-TYPE RUNNER FOR A TURBINE, AND ENERGY CONVERSION PLANT COMPRISING SUCH A RUNNER

摘要

This Francis-type runner for a turbine includes a crown, a band and blades the number of which is not a prime number. These blades are made as one piece and extend between the crown and the band, and between a leading edge and a trailing edge each trailing edge has its concave face facing upstream over its entire length. In addition, first blades are uniformly distributed about a central axis of the runner in a number equal to a divisor of the total number of blades. Each of these first blades has a point of attachment of its trailing edge to the crown that is lowered by comparison with the point of attachment of the trailing edge to the crown of second blades, which are likewise part of the runner. Moreover, the ratio between, on the one hand, the radius of a circle centered on the central axis of the runner, perpendicular to this axis and passing through the point of attachment of the trailing edge of a first blade to the crown and, on the other hand, the radius of a circle centered on the central axis of the runner perpendicular to this axis and passing through the point of attachment of the trailing edge of the same blade to the band is less 0.15.