It is well known that the output of a centrifugal pump or compressor can be increased by altering the impeller blade tip profiles but very little is said in the literature on how this comes about, or how much improvement is possible.nThe increase of output that can be obtained is of the order of 5 or 10％, depending on blade thickness, and at the same time shaft power increases by about the same amount so that little or no improvement in efficiency takes place.nThis report describes work done to investigate the pos¬sibility of a "separation bubble" occurring at an impeller blade trailing tip, with flow re-attachment on its cylindrical surface. In such a case, the blade thickness would not be reflected in a thick wake (Pig. 3, blade (l)) and the flow would be more like that in Pig. 3, blade (2).
展开▼
