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Supercritical Carbon Dioxide Power Cycles
Published in Viorel Badescu, George Cristian Lazaroiu, Linda Barelli, POWER ENGINEERING Advances and Challenges, 2018
Rotating equipment requires both internal and external seals. Internal seals are primarily required to reduce inter-stage leakage, and can take the form of labyrinth, hole-pattern or honeycomb seals. External seals are necessary to reduce overboard leakage of CO2, which must be recovered and/or replenished to maintain the total closed-loop fluid inventory. The current state-of-the-art is the dry gas seal, which operate with micron-level running gaps that are created by hydrodynamic forces. These were developed originally for compressor service, but their adaptation to turbine seals is relatively straightforward. The main areas of design concern are thermal management in the higher-temperature turbine environment due to secondary elastomer seals, and fluid conditioning and buffering to prevent contamination and condensation in the leak gap.
Enhancing Film Stiffness of Spiral Groove Dry Gas Seal via Shape Modification at Low Speed: Numerical Results and Experiment
Published in Tribology Transactions, 2019
Jinbo Jiang, Xudong Peng, Cong Zong, Wenjing Zhao, Yuan Chen, Jiyun Li
Dry gas seal (DGS), as a typical kind of noncontacting mechanical seal, meets satisfactorily the requirements of low leakage rate, wear-free operation, and low power consumption for industrial centrifugal compressors, pumps, fans and other turbomachines with medium speed (1–5). Dry gas seal technology has now been extended into the area of low-speed services, including mixers and agitators used in food and pharmaceutical areas, which always require absolute purity of product by eliminating wear or unwanted seal lubricant leaking into the process (6). However, sufficient hydrodynamic force is hard to generate with dry gas seals when operating at low speed. Too little hydrodynamic force may result in seal face wear.