A system includes a shaft body defining a longitudinal axis. A first internal fluid channel extends axially within the shaft body and includes an inlet opening through the shaft body for fluid communication of external fluid into the first internal fluid channel and an outlet opening through the shaft body for fluid communication of fluid from the first internal fluid channel to an area external of the shaft body. A second internal fluid channel extends axially within the shaft body and includes an inlet opening through the shaft body for fluid communication of external fluid into the second internal fluid channel and an outlet opening through the shaft body for fluid communication of fluid from the second internal fluid channel to an area external of the shaft body. The first and second internal fluid channels are in fluid isolation from one another within the shaft body.