Propulsion System Modelling for Condition Monitoring and Control: A Status Report

A rigorous propulsion system modelling method suitable for control and condition monitoring purposes is developed. Previously developed control oriented methods yielding nominal models for gaseous medium propulsion systems are extended to include both nominal and anomalous models for liquid mediums in the following two ways. First, thermodynamic and fluid dynamic properties for liquids such as liquid hydrogen are incorporated into the governing equations. Second, anomalous conditions are captured in ways compatible with existing system theoretic design and analysis tools so that anomalous models can be constructed. Applications to the nominal SSME HPFP and degraded HPFP are considered as an example.