Method of computation of gas-tube engines in windmill modes

Abstract

Providing the restart capability of engine in flight is an important certification requirement applied to engine units of manned and unmanned aerial vehicles oriented to ensuring flight safety with a given level of technical characteristics. It is important to perform preliminary analysis and evaluation of gas turbine engine parameters at the start-up and windmill modes before rig and flight tests. The work presents a method for computation of the windmill modes of gas turbine engines based on the use of analytical and numerical methods. The Numeca Fine/Turbo software package was used to calculate the maps of turbomachines at the sub-idle modes. The solution of the system of nonlinear equations for computing the start-up and windmill modes is carried out using the combined Newton-Nelder-Mead method. The application of the method is demonstrated by a mixed flow two-shaft turbojet.

Keywords

• gas turbine engine
• axial-flow compressor
• axial-flow turbine
• windmilling
• computational fluid dynamics