M.Sc Thesis


M.Sc StudentRoman Shapiro
SubjectJet Engine Simulation with Optimal Reconstruction
of Its Compressor Characterisrics Maps
Characteristics Maps
DepartmentDepartment of Aerospace Engineering
Supervisor Professor Emeritus Levy Yeshayahou


Abstract

In the present study, a numerical method for jet engine performance prediction has been analyzed and implemented in a digital engine simulation program. Most of the engine components can be analytically analyzed and have been described through nonlinear algebraic equations. However, there is no way to find a general analytical formulation to express the compressor and turbine behavior in their entire operational envelope. One can experimentally test the performance of turbo components and build discrete low-resolution characteristics’ maps. However, such a representation of a compressor and a turbine is insufficient for a precise steady state and a transient simulation. Therefore, interpolation and extrapolation of the maps are needed. Three different techniques for the characteristics maps reconstruction have been considered while one of them is an analytical technique and two are numerical ones. The simulation algorithm uses the main laws of physics that must be satisfied in the jet engine in their simple form - equalizing the mass flow through the compressor, the turbine and the nozzle and balancing the power on the engine’s shaft. The mathematical model for nonlinear variation of thermodynamic properties of air and combustion products with gas temperature, chemical composition, the fuel type and the constantly changing fuel to air ratio was developed. Simulation program solves a set of nonlinear equations for both steady state and transient modes. The digital simulation has been implemented for AMT Olympus turbojet and covers a large domain of steady state and transient operation.

Results show good agreement between measured results and simulation.