Hybrid thermodynamic and CFD modeling of a UAV-class micro gas turbine engine: performance validation and optimization

Abstract The presented study proposes a hybrid multi-resolution simulation framework for predicting and validating the performance of UAV-class micro gas turbine engines in the 4–6 kN thrust range. The approach integrates 1D thermodynamic cycle analysis using the Gas Turbine Simulation Program (GSP), intermediate system-level validation through Flownex, and high-fidelity 2D CFD simulations in ANSYS Fluent for component-level analysis. Parametric studies were conducted for pressure ratios between 1.3 and 1.5 and Mach numbers from 0.1 to 0.6, at a design thrust of 4.56 kN and turbine inlet temperature of 1053 K. CFD results predicted nozzle exit velocities exceeding 750 m/s with minimal flow separation. Temperature predictions across tools showed strong agreement within 5 %, while pressure and mass-flow deviations were observed in turbulence-dominated regions. The framework demonstrates a balanced trade-off between computational efficiency and fidelity, offering a reliable methodology for early-stage design and validation of compact UAV propulsion systems.