A Study on Lean, Sweep and Chord Length Effects on Aerodynamic Performance of Axial Fan of a High-bypass ratio Turbofan Engine

Compared to the enormous costs of laboratory experiments, numerical approaches to improving the performance of turbomachines are less costly and more practical. In the present study, by using the Taguchi method and orthogonal arrays while doing a limited number of simulations (according to the Taguchi method), the sensitivity level of objective functions have been investigated to optimization variables in a fan of a high-bypass ratio turbofan engine (JT۹D-۷ Engine). a mathematical parameterized algorithm coupled to a computational fluid dynamic solution  is employed to modify the geometry and calculate the objective functions. ۱۵ optimization variables are defined by varying:The radial distribution of the chord length from the hub to the tip of the blade and alsoeach profile's lean and sweep in five control points compared to hub profile.The lean, sweep and chord length are parameterized by a spline algorithm. The objective functions included the pressure ratio, isentropic efficiency and mass flow rate of the fan in the design point. The results showed that the lean angle affects the isentropic efficiency, and the sweep angle affects the mass flow rate of the fan. The pressure ratio was sensitive to both variables. Concerning the design variables, ۲-level L۱۶ and L۳۲ arrays of the Taguchi method were used for running the sensitivity analysis. Assuming a fixed number of blades, a fixed angle of incidence, and a fixed camber angle, distributing the chord length did not significantly affect the objective functions compared to the lean and sweep distribution.

Keywords:

the Taguchi method , fan , Lean , Sweep , Chord