Network flow solver for modern fluid systems engineering.
FSAP is the host of a seven-program desktop suite for liquid-rocket propulsion. Size your injector, thrust chamber, tanks, and feed lines in focused tools — then wire them together and solve the whole engine, with real propellant properties and the cited textbook physics your course already teaches. Free for educational and nonprofit use throughout the beta.
One host. Six sizers. Your whole engine.
FSAP doesn't stop at the feed system. It's the hub of a desktop suite that takes a student team from propellant choice to a complete, analyzed pressure-fed engine — size each part in its own focused tool, then drop it into FSAP and solve the system as one model. Every tool runs standalone, so you install only what you need.
A solver, not a black box.
FSAP is built around an explicit conservation formulation with a sparse Jacobian — what's happening at every node is inspectable, and every correlation has a reference. Engineers can swap models, override correlations, and verify against papers.
Steady & transient
Backward-Euler integration with SASS-style Newton-Raphson. Successive-substitution outer loop handles energy and equation-of-state coupling.
Any CoolProp fluid
Water, helium, oxygen, nitrogen, hydrogen, methane, refrigerants, propellants. Mix fluids in a single network and let FSAP track each branch.
Two-phase & boiling
Lockhart-Martinelli and Friedel pressure drop. Chen and Shah boiling correlations for vaporizers, chilldown, and cryogenic two-phase flow.
Conjugate heat transfer
Solid nodes, ambient nodes, and solid-fluid conductors. Resolve wall temperature evolution during chilldown without an external FEA tool.
Schematic editor
Blank-canvas drag-and-drop. Connect branches between nodes, inspect every property in unit-aware fields, watch results overlay live on the network.
Headless CLI
Run any deck from the command line. Sweep parameters, drive Monte Carlo studies, and integrate FSAP into your CI for design-of-experiments work.
Three networks, one solver.
A few representative systems FSAP is being used to model. Every diagram below is a real, solvable deck.