A Non-Iterative Calculation Method for Zero-Dimensional Nozzle Model of Gas Turbine Engine

To address the real-time performance issue of the zero-dimensional nozzle model for gas turbine engines, a non-iterative computational method is proposed that determines the flow regime (subcritical vs. choked) via characteristic Mach number and characteristic flow factor. This method eliminates iterative solution procedures, thereby reducing computational time, and solves the problem of discontinuous throat mass flow rate calculation at the transition flow regime from subcritical to choked in traditional nozzle models. The method is applied to improve a component-level turbofan engine model and is validated through numerical simulation. Simulation results indicate that, compared with traditional nozzle models requiring two and eight iterations, the non-iterative nozzle model reduces computation time by 69.7% and 85.71%, respectively. The turbofan engine model incorporating the non-iterative nozzle model achieves a 24.58% reduction in maximum per-step computation time and a 13.7% reduction in average per-step computation time compared with the traditional model, while maintaining comparable simulation accuracy. The proposed method substantially enhances the real-time simulation performance of the component-level turbofan engine model, and can be readily extended to other component-level models—whether based on iterative-solution schemes or on volume-based modeling approaches.