Study of Three-Dimensional Internal Flow Distribution Based on Measurements in a 48-inch Radial-Inlet Centrifugal Impeller

摘要

The flow distribution throughout the passage of a rotating impeller has been studied in detail, and the results are presented in the form of relative velocity and relative pressure loss contours. These were computed from total-pressure measurements taken at numerous positions from blade to blade and hub to shroud and from static pressures measured on the impeller hub. The loss and velocity distributions indicate that secondary flows in the boundary layer tend to shift the low-energy air toward the blade suction surface within the passage. There is a counter effect at the shroud apparently caused by leakage through the blade-to-shroud clearance space which moves the low-energy air toward the pressure surface. This results in a concentration of low-energy air at approximately 80 percent of the passage width from the pressure face at the shroud. Comparison of the data from the internal measurements made for the impeller of this investigation with hot-wire anemometer studies made at the outlet of a similar impeller indicates that much can be learned about the internal flow picture with hot-wire surveys alone.