Test results are presented for the High Pressure Oxygen Turbopump (HPOTP) Turbine Interstage Seal in the folloiwing configurations: (1) no swirl brake, (2) Rocketdyne (current) swirl brake, (3) a TAMU aerodynamically-designed swirl brake. Tests were conducted at speeds out to 16,000 rpm, supply pressures up to 250 psi, and the following three inlet-tangential-velocity conditions: no preswirl, intermediate preswirl in the direction of rotation, and high preswirl in the direction of rotation. The back pressure can be controlled independently and was varied to yield the following four pressure ratios: 0.4, 0.45, 0.56, and 0.67. The central and simplest conclusion to be obtained from the first series is that the TAMU swirl brake consistently outperformed the Rocketdyne swirl brake in terms of stability performance. The TAMU whirl-frequency-ratio was generally about one half or less than corresponding values for the Rocketdyne design. In many cases, the TAMU design yielded negative whirl-frequency-ratio values in comparison to positive values for the Rocketdyne design. The TAMU design can be directly substituted into the space currently occupied by the Rocketdyne design. There is no change in leakage performance. Unexplained and peculiar results were obtained for tests with no swirl brakes. In some cases, the no-swirl-brake tests showed highly negative cross-coupled stiffness values corresponding to highly prerotated flows. These tests suggest that the original, no-swirl-brake configuration would be more stable than either swirl brake design. If time becomes available, retesting of this configuration is advisable.
Rotordynamic-Coefficient Test Results for the SSME (Space Shuttle Main Engine) HPOTP (High Pressure Oxygen Turbopump) Turbine Interstage Seal for the Current and an Improved Swirl Brake
1989
94 pages
Report
Keine Angabe
Englisch