Centrifugal impeller with forward and reverse flow paths

Abstract

A centrifugal impeller having an inlet and a plurality of outlets the outlets including at least one outlet in a forward direction of the Impeller and at least one outlet in a rearward direction of the impeller. A flow path distance of the outlet in the forward direction can be greater than a flow path distance of the outlet in the rearward direction in order to provide a greater pressure in the outlet having the greater flow path distance. In another embodiment, the flow path volume in the forward direction can be greater than the flow path volume in the rearward direction in order to provide a greater flow volume in the forward direction In another embodiment, the number of flow paths in the forward direction can be greater than the number of flow paths in the rearward direction in order to provide a greater flow volume in the forward direction. The impeller is also used in a gas turbine engine in which the impeller also includes a turbine blade, and the forward directing outlets deliver compressed air to a combustor while the rearward directed outlets bypass the combustor.

1 . A centrifugal impeller, comprising:
 a common inlet;   a plurality of flow paths in communication with the common inlet;   a plurality of outlets, each outlet associated with a respective flow path; and,   at least one of the plurality of outlets being arranged to direct fluid flow substantially in a forward direction of the impeller, and at least one of the plurality of outlets being arranged to direct fluid flow substantially in a rearward direction of the impeller.   
   
   
       2 . The centrifugal impeller of  claim 1 , and further comprising;
 the at least one outlet in the forward direction has a flow path distance through the impeller greater than a flow path distance through the impeller of the outlet in the rearward direction.   
   
   
       3 . The centrifugal impeller of  claim 1 , and further comprising:
 a number of forward flow paths is equal to a number of rearward flow paths.   
   
   
       4 . The centrifugal impeller of  claim 1 , and further comprising:
 a number of forward flow paths is greater than a number of rearward flow paths.   
   
   
       5 . The centrifugal impeller of  claim 1 , and further comprising:
 a number of forward flow paths is less than a number of rearward flow paths.   
   
   
       6 . The centrifugal impeller of  claim 1 , and further comprising:
 a size of the forward flow path is greater than a size of the rearward flow path such that a greater volume of fluid flows in the forward flow path than does in the rearward flow path.   
   
   
       7 . The centrifugal impeller of  claim 1 , and further comprising:
 the forward flow paths and the rearward flow paths are all formed in the same rotor disk and discharge near the outer disk end.   
   
   
       8 . The centrifugal impeller of  claim 1 , and further comprising:
 the forward flow paths are separated within the rotor disk by the rearward flow paths.