Closure to “Discussion of ‘Measured and Predicted Secondary Flows in a Centrifugal Impeller’” (1971, ASME J. Eng. Power, 93, p. 132)

Abstract

Howard and Lenneman have done an excellent job of getting secondary flow measurements in centrifugal impellers. The results certainly show the importance of secondary flow and also that qualitative results may be obtained even with a one-dimensional calculation.It would be of great interest to see a comparison of the calculated primary flow with the measured velocities of Figs. 6 to 10. Also, a comparison of the calculated secondary flow with the experimental results would be informative.Very little comment was made in the paper on the flow visualization results.Based on primary potential flow on a two-dimensional blade to blade plane for the radial impeller, I would expect cross passage velocities from pressure to suction surface near the inlet and from suction to pressure near the outlet. This trend is observed in Figs. 7 to 10. Fig. 9 is noteworthy in that the cross flow varies so much near the shroud. Since this impeller is shrouded and the flow is reasonably symmetrical from hub to shroud at station