Mixed Quasi-Steady and Transient Modeling of Radioisotope Thermoelectric Generators via the Applied Energy and Power Library

Radioisotope thermoelectric generators (RTGs) typically have life spans measured in decades. For this reason, life performance modeling of RTGs tend to be quasi-steady state rather than fully transient. The Applied Energy and Power Library (AEPL), developed by the Applied Research Laboratory at Penn State University, was designed to model a variety of steady, quasi-steady, and fully transient energy and power systems. A key feature of AEPL is a variable state temporal solver capable of dynamically switching between quasi-steady state and fully transient solutions within a simulation. To demonstrate AEPL's ability to model such variable state temporal problems, a simplified RTG was modeled within AEPL focusing upon the entry, descent, and landing stage of the Curiosity rover's mission profile. Results show the impact of a transient induced increased cold side temperature and the asymptotic approach to steady state after landing. Other features of AEPL to model radioisotope power systems, including dynamic systems, are also discussed in the paper.