Question

A turbine disk with 24 blades has a combined mass of 30 kg and a combined centroidal radius of gyration of 175 mm. The turbine is rotating clockwise at a constant rate of 60 rpm when one of the blades (point A) becomes loose and is thrown off. Each blade has a mass of 51 grams. Neglecting friction, determine the change in the angular velocity of the turbine disk after it has rotated through (a) 90 ̋, (b) 270 ̋.

radius= 300mm

Hints

1. You may treat the turbine blades as remote point masses rotating about an axis.
2. You will need to consider how the center of mass of the assembly shifts with the blade missing and it will be different

for the 90 ̋ and 270 ̋ positions. Recall from your Statics class that the centroid of a composite part can be found as

where mi and y ̄i are the mass and centroid of each individual component making up the assembly respectively.

Answer 1