High pressure testing of see-through labyrinth seals

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 69-70).Issued also on microfiche from Lange Micrographics.Detailed results are presented for teeth-on-stator labyrinth seals tested under high pressure of 70 bar-a (1015 psi-a) and 52 bar-a (754 psi-a) in the centered position. The seals were tested at pressure ratios of 0.52, 0.36 and 0.16, speeds of 10,200, 15,200 and 20,200 rpm and clearances of 0.1 and 0.2 mm. The effects of changes in radial clearance and pressure differential across the seal are studied for various inlet tangential velocities. The results confirm the existence of negative direct stiffness, positive cross-coupled stiffness as shown by Benckert and Wachter and low direct damping (when compared to hole-pattern seals). Experimental results are compared with predictions from the one-control-volume model (Childs and Scharrer) and two-control-volume model (Scharrer). Results show that both models under-predict the rotordynamic coefficients significantly. Leakage is also under predicted by both the codes. However, the effective damping and whirl frequency ratio (wfr) predicted by the one-control volume theory is comparable with the test results