Method of quantitative estimation of acoustic characteristics of the fan stage

Abstract

Modern engine manufacturing is closely connected with consideration of ecological parameters of engines, which allows their developers to be in great demand and be competitive on the world market [1]. One of the directions of improvement passenger airplanes is process development of noise reduction of power unit by the choice of the efficient methods of a noise decreasing, with using modeling process of fan structural elements, as a main source of engine noise. For quantitative impact assessment of structural elements geometry of the fan the assessment technique of a fan acoustic characteristics by means of noise formation coefficient is offered. Implemented blades modification for studying of geometry influence on indicators of fan acoustic characteristics is carried out. Results of calculations are given in a type of dependences which analysis allowed to define the modified blade with the lowest noise formation coefficient level. For this study the best profile was profile inclined by 5 degrees in the direction to the entrance section as has the best indicators in comparison with the others. For receiving a total characteristic, the efficiency of each modification is in addition calculated. Proceeding from the obtained data more effective is also the profile inclined by 5 degrees towards entrance section. The offered technique allows to estimate influence and quantitatively of a behavior mode and geometry on acoustic characteristics by means of noise formation coefficient