GFSSP (Generalized Fluid System Simulation Program) is a general purpose, user friendly software for analyzing steady state and transient flow in a complex fluid network. The computer program employs a finite volume procedure for flow network analysis. The program is capable of modeling compressibility, fluid transient, phase change, mixture of multiple species and external body forces such as gravity and centrifugal. The program's graphical user interface allows the user to interactively develop a fluid network simulation consisting of nodes and branches. It also provides the capability to run the model and view the results in the interface. Mass, energy and specie conservation equations are solved at the nodes; the momentum conservation equations are solved in the branches. The system of equations describing the fluid network is solved by a hybrid numerical method that is a combination of the Newton-Raphson and successive substitution methods. The program has integrated thermodynamic property programs that have a library of thirty-six fluids including cryogenic propellant, water, RP-1, refrigerants and hydrogen per oxide solution. Eighteen different resistance/source options are provided for modeling momentum sources or sinks in the branches. The program also provides flexibility to add new capabilities. Additional capabilities, such as new resistance options, new fluids and non-linear boundary conditions can be added through the use of user subroutines.

GFSSP has been primarily developed to analyze various propulsion systems including turbopump and engine feed systems. However, the code's structure and user interface have been made very general such that its use is not restricted for any specialized applications. During the last several years, this package has been used to gain solutions to engineering problems that were not solvable by other means. An engineer with an undergraduate background in fluid mechanics and thermodynamics can use this program to model complex flow circuits in a very short time. For advanced users, the code provides the flexibility to enhance its capability through User Subroutines. There is no known alternative to this easy to use software in industry or academic institutions which has similar capabilities. GFSSP has been used on various NASA/MSFC programs including: Space Shuttle Main Engine, Columbia Accident Investigation, MC-1 Engine, X-33, X-34, International Space Station, Solar Thermal Propulsion, Propulsion Test Article and Safe Affordable Fission Engine (SAFE). GFSSP is the recipient of NASA Software of the Year Award. MSFC has submitted a patent application for this technology and license for commercialization was awarded to CONCEPTS/NREC. The code has extensive documentation; more than twenty five technical papers have been published to describe GFSSP’s capability and applications. An audio-visual training CD has been developed for new users.

Licensing Information

Contact: Sammy Nabors NASA/Marshall Space Flight Center

Point of Contact

Sammy Nabors
Phone: (256) 544-5226
NASA/Marshall Space Flight Center
FAX: (256) 544-1815
George C. Marshall Space Flight Center MSFC, AL 35812

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