EFFECT OF SURFACE PATTERNING ON THE DYNAMIC RESPONSE OF ANNULAR HOLE-PATTERN SEALS

摘要

The performance of annular seals depends on the geometry of the leakage path as it facilitates the dissipation of the fluid kinetic energy. The goal of this study is to investigate potential correlations between the characteristics of the alternately arranged surface pattern and the corresponding rotor dynamic properties of the seal in addition to mapping its performance. Various patterning arrangements lining the stator surface are considered and the relative seal performance change is investigated using a hybrid method that calculates the seal dynamic response for each point in the design space. The design parameters selected in this DOE study are: the diameters of alternately arranged holes that are replicated in both axial and circumferential direction to construct the pattern, the hole depths for both types of holes, and the number of holes in both axial and circumferential directions. A sensitivity study is conducted to analyze the influence of each geometrical parameter on the seal response. Regression models are then generated for each response, including the leakage rate and the rotor dynamic coefficients. Quadratic regression models are used in this study to represent the relationship between the objective functions and the design parameters. The goal is to achieve a minimum leakage rate as well as an improved dynamic response. The results of the baseline model and the best performing design are compared. The results show that the patterning arrangements have crucial effects on the leakage rate as well as the dynamic coefficients of the seal. The results of this study are found to be helpful in designing a hole-pattern seal that can concurrently satisfy constraints on both the leakage rate and the rotor dynamic response while maintaining same design envelope.