Abstract
High performance turbomachines such as the Space Shuttle Main Engine Turbopumps (SSME-HPOTP and HPFTP) are prone to experience severe vibration problems due to high operating pressures and speeds. The stability and response characteristics of these pumps depend significantly on the rotordynamic features of hardware elements such as the seals and bearings. The focus of this research effort is to develop a comprehensive thermo-elasto-hydrodynamic analysis of turbulent liquid annular seals and to understand the effects of annular seals on the pump rotordynamics. Seal eccentricity has been included for rigid seals. The eccentric seal analysis is based on the work of Nelson and Nguyen (1988), but a much simpler and effective method, namely the cubic spline interpolation method, is adapted to obtain the circumferential derivatives of the primitive variables. The bulk flow continuity, axial and circumferential momentum and the energy transport equations are utilized to model the flow field while Moody's friction factor model is adapted to account for the wall shear stresses. Wall flexibility of the seal can significantly impact rotordynamic coefficients of the turbopumps due to high pressures and low clearances. Linings of interstage annular seals in the SSME-HPOTP are made up of soft Silver alloys which can deform easily under the high pressures that are usually encountered. This study analyzes the effects of flexibility on the dynamic characteristics of concentric seals. The wall deformations are obtained using an iso-parametric, axi-symmetric Finite Element formulation of the seal wall. Numerical solution obtained by the current analysis compares wen with those of earlier researchers for the rigid as well as the flexible cases.
Venkataraman, Balaji (1995). Thermo-Hydrodynamic analysis of turbulent cryogenic eccentric annular seals and effects of seal flexibility. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1995 -THESIS -V46.