大涵道比涡扇发动机总压进气畸变数值模拟

基于数值缩放理念,以一台大涵道比涡扇发动机为研究载体,将三维彻体力模型与二维多子平行发动机模型进行有机结合,初步搭建了适用于分析复杂进气畸变对航空发动机整机流场特性影响的多维耦合计算模型。利用该多维耦合模型定量分析了稳态周向总压畸变及插板式总压畸变进气下发动机内部的流场特性。计算结果表明即便是进口单纯的方波周向总压畸变进气,在经过大涵道比风扇转子作用后在下游内外涵进口的畸变流场特征也将具有显著差异;在内涵进口形成的总压/总温复合畸变在四级增压级中均得到不同程度的衰减;插板式总压畸变进气下风扇转子进口近轮毂处受周向静压梯度驱动将产生一定程度旋流,并导致风扇转子出口轮毂处形成低压区。

Numerical simulation of high bypass ratio turbofan engine with total pressure inlet distortion

Based on the concept of numerical zooming and taking a high bypass ratio turbofan engine as the research carrier, a mixed-dimension computational model to investigate the effect of complex inlet distortion on the characteristics of flow field in aero engines was preliminarily established by integrating a three-dimensional body force model and a two-dimensional multiple segment parallel engine model. The mixed-dimension model was utilized to analyze the characteristics of flow field in the engine under different forms of total pressure distortion, including steady circumferential total pressure distortion and flat baffle total pressure distortion. Results revealed that even if the total circumferential pressure distortion of the square wave at the inlet was simple, there were significant differences in the distortion flow field characteristics at the core and bypass inlet after the action of the fan rotor with high bypass ratio. The combined total pressure/total temperature distortion formed at the core inlet was attenuated under different degrees in the four-stage booster compressor. A certain degree of swirl was induced by the circumferential static pressure gradient near the hub region of the fan rotor inlet under the flat baffle total pressure distortion. Thus, the low pressure area was formed near the hub of the fan rotor outlet.