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Efficiency and life requirements of advanced turbomachinery and the pollution demands of the Clean Air Act dictate the need for significant advances in seal technology [1]*. NASA is sponsoring a program to produce computer codes to be used by industry and government for analyzing and designing a wide variety of advanced seals for rotating machinery. A general computational fluid dynamics (CFD) code is being generated for accurate flow simulations, as well as simpler 2-D codes for expeditious application. A knowledge-based system (KBS) controls the codes and includes a user-friendly graphical user interface (GUI). A data base and an expert system to provide design guidance to the user will be added. This paper describes the codes and their application.

A forward integration in time analysis that traces dynamic response of a face seal in five degrees of freedom is developed. Both rotating and stationary types of seal rings are considered, The analysis accounts for Coulomb friction at both the seal interface and the secondary seal. Compression of the carbon element in axial and angular modes is also included. Interface fluid-film effects (stiffness, damping, viscous shear, load) are applied whenever face separation occurs. The analytical treatment was designed to produce a computer code that can be used efficiently as a design and/or diagnostic tool. Several examples of the use of the analysis are presented, and general conclusions regarding face seal performance are deduced as a result of the analysis.