Session: 23-11 Seal Rotordynamics

Paper Number: 152582

Static and Rotordynamic Characteristics for a Novel Helical Damper Seal Operating in a Liquid Hydrogen Turbopump 

In this paper, a novel helical damper seal was invented and assessed for application at the inter-stage location in a cryogenic liquid hydrogen turbopump, focusing on the improvement of the seal leakage and rotordynamic performances. This novel helical damper seal (HDS) was designed with the hole-pattern on stator and the helical-groove on rotor, derived from the conventional straight-through hole-pattern seal (HPS) with the same sealing clearance, diameter, axial length, hole diameter and depth. To enhance the seal net damping capability at high inlet preswirl condition, a straight swirl brake was also designed at seal entrance. A comprehensive assessment and comparison on the static and rotordynamic characteristics was conducted for the conventional HPS and the present novel HDS. The leakage flow rates, rotordynamic force coefficients, cavity dynamic pressure, and swirl velocity developments were calculated and analyzed for two seals with/without inlet swirl brake, using a proposed transient computational fluid dynamic (CFD)-based perturbation method based on the multiple-frequency elliptical-orbit rotor whirling model. To take into account of the thermodynamic effect and the weak compressibility of the liquid hydrogen, a table look-up procedure based on the National Institute of Standards and Technology (NIST) reference fluid properties database was implemented, using an in-house code, for the fluid properties of liquid hydrogen in supercritical and high pressure difference conditions. Results show that the present novel HDS has the better sealing capability and rotordynamic stability, especially at high rotational speed case.

Presenting Author: Zhigang Li Xi'an Jiaotong University

Presenting Author Biography: Zhigang Li is a professor in the Institute of Turbomachinery at Xi’an jiaotong University. His research interests are in advanced sealing and gas bearing techniques of turbomachinery. He has over 50 peer reviewed publications on AIAA Journals and ASME Journals, and has given several invited, keynote, and plenary lectures at international conferences.

Authors:

Xiaoqiang Ye National Key Laboratory of Aerospace Liquid Propulsion
Haiyan Luo Xi'an Jiaotong University
Wei Shen Nuclear and Radiation Safety Center
Zhigang Li Xi'an Jiaotong University
Jun Li Xi'an Jiaotong University