A Novel Adaptive Generation Method for Initial Guess Values of Component-Level Aero-Engine Start-Up Models

Abstract

To solve the difficult problem of selecting initial guess values for component-level aero-engine start-up models, a novel method based on the flow-based back-calculation algorithm (FBBCA) is investigated. By exploiting the monotonic feature of low-speed aero-engine component characteristics and the principle of flow balance abided by components in the start-up process, this method traverses all the flows in each component characteristic at a given engine rotor speed. This method also limits the pressure ratios and flow rates of each component, along with the surplus power of the high-pressure rotor. Finally, a set of “fake initial values” for iterative calculation of the aero-engine start-up model can be generated and approximate true initial guess values that meet the accuracy requirement according to the Newton–Raphson iteration method. Extensive simulation verifies the low computational cost and high computational accuracy of this method as a solver for the initial guess values of the aero-engine start-up model.

Real-time improvement method of turbo-shaft engine component-level model based on dimensional reduction of residual iterative equation

“…The application of integration methods instead of algebraic equation iteration methods could eliminate iteration processes during the transient performance computation process, for example, the implementation of volumetric dynamics methods [8][9][10] . Optimizing iterative computation methods, such as quasi-Newton methods [11][12][13] and improved Broyden methods [14,15] , aim to reduce computation time per flow path calculation and lower the number of flow path calculations per step for transient performance calculations. Simplifying complex aerothermodynamic calculations by using numerous empirical formulas or analytical expressions and optimized interpolation methods [16] is of great importance in reducing model computation time.…”

“…Then, the relationship between inlet total pressure and outlet static pressure of power turbine is obtained as Equation (12).…”