Variable-Fidelity Toolset for Dynamic Thermal Modeling and Simulation of Aircraft Thermal Management System (TMSs)

ABSTRACT: A variable-fidelity toolset for conducting thermo-analysis of steady-state and transient behaviors of vapor compression systems (VCS) and generalized aircraft thermal management systems is proposed. Existing dynamic models of VCS components will be leveraged and development will concentrate on improving model accuracy and user-friendliness. To improve the accuracy of existing VCS models, high-order computational fluid dynamic (CFD) models will be used to generate tuning data for the lower-order moving boundary and finite control volume models used in the toolset. The use of CFD has four main advantages: 1) provides tuning data for components that have not been fabricated or instrumented, 2) permits validation of single component models rather than interconnected systems, 3) provides tuning data for many variables that would be expensive to measure (e.g. detailed temperature/pressure/heat flow gradients), and 4) provides noise-free data. The CFD models will be solved using the full Navier-Stokes equations with an Eulerian multiphase model. ATA will also adapt its commercial software tool Attune to allow automatic tuning of VCS systems or component models to test- or CFD-derived tuning data, using advanced gradient and genetic algorithms. This can reduce tuning time for VCS systems from weeks to hours, with a corresponding increase in model accuracy. BENEFIT: By integrating advanced automatic correlation algorithms with real-time capable switched moving-boundary models of vapor compression refrigeration components, this new toolset will do in hours what previously took weeks to do, namely, correlate full thermal management system models against transient test data spread over multiple experimental runs. In addition to analyzing aircraft thermal management systems, the new toolset will be useful to any group performing thermodynamic analysis of vapor compression cooling systems or more general thermal management systems. This will include applications in space, as well as terrestrial applications such as refrigeration systems for food storage or medical use. In addition, the new correlation algorithms developed under this SBIR will flow into a commercial release of ATA Engineering"s existing commercial software tool Attune, expanding its capabilities to include correlation against transient data. This will benefit existing Attune customers and expand the customer base to include potential customers who are interested in correlating analysis models to transient test data, regardless of the nature of the analysis. Finally, the two-phase computational fluid dynamics methods developed under this SBIR will be used by ATA Engineering to enhance its existing engineering services business.