Use of Streamline Analysis Method to Model Aerodynamic Forces in Axial Compressors

Within the field of rotor dynamics, the aerodynamic loading on turbomachinery blades is an important factor for calculating the overall stability of these machines. In order to determine the magnitude of this force, it is necessary to analyze the flow of the fluid through the turbomachinery. With respect to modern jet engines, an axial compressor is the component through which the incoming air passes first. As the performance of the compressor often determines the efficiency of the overall engine, it is crucial to analyze and understand the fluid effects in the compressor properly. Therefore, the goal of this thesis is to develop a tool for determining the aerodynamic forces on the blades of axial compressors in jet engines for further use in rotor dynamic calculations.

To avoid a time consuming and computationally expensive procedure, a two-dimensional “streamline” or “through-flow” analysis is adopted, in which various assumptions are used to simplify the Navier-Stokes equations. For the streamline model, the flow between blades is divided into “annuli”, and fluid properties are calculated from hub to casing while marching axially downstream through the multiple stages making up the compressor. The streamline analysis method was coded in Matlab as a software package called CompFlow. Computational results are then compared with experimental values available in literature. Cases studied include a single-stage rotor case called Stage 37, and a multistage compressors case called NASA 74A. A case study was also conducted on the GEnx-2B, a current jet engine consisting of a low-pressure compressor and high-pressure compressor that was developed by GE Aviation.