Study On The Influence Of Rain Injection And Rain Injection Distortion On Compressor Performance

The aero engine must have the ability to work under all-weather flight conditions,and all-weather flight requires the aircraft to ensure the safety of the entire flight process in rainy weather.A large amount of rainwater will be inhaled at the entrance of the engine of an aircraft sailing in rainy weather,which will change the performance and matching relationship of each engine component.Compressor is one of the most important parts of an aero engine.Excessive rain water intake can induce stalls and surges.The performance changes of compressor components after absorbing rain directly affect the reliability and airworthiness of the aero engine.The distribution of rainwater at the compressor inlet is one of the important factors that cause its performance changes.The characteristic distribution of rainwater may cause the compressor intake distortion.Therefore,this article takes the rainwater distribution at the compressor inlet as the starting point,and is typical for a multi-stage compressor.The change of flow characteristics and overall characteristics under rain swallowing conditions are studied.Aiming at the phenomenon of compressor rain swallowing and rain swallowing distortion,using ANSYS CFX software,based on Euler-Lagrangian two-phase flow theory,a single-channel compressor rain swallowing and whole week rain swallowing abnormal gas-liquid two-phase coupling process is established The calculation model of the compressor pays attention to the internal two-phase flow process of the raindrop-air two-phase heat transfer,mass transfer and evaporative phase change during the compressor working process,and fully considers the raindrop motion characteristics.In the case of uniform and non-uniform rain swallowing,according to the different spatial distribution characteristics of raindrops at the compressor inlet,the change of rain swallowing characteristics and the influence mechanism of rain swallowing distortion of a three-stage compressor are mainly studied.The research results show that the characteristics of the compressor change significantly after swallowing rain,its working performance is reduced,and the stable working margin is reduced.Under the same rain swallowing conditions,the degree of influence of raindrops at the compressor near stall operating point,design operating point and near clogged operating point is different,so the performance change range of the compressor at different operating conditions after rain swallowed There are also differences.And when raindrops enter the multi-stage compressor to participate in the compression process,the shape,distribution,and movement characteristics of the raindrops will change.Therefore,there are differences in the characteristics of each stage of the compressor,which will lead to changes in the characteristics of the entire compressor components.In the study of rain swallowing distortion throughout the week,by defining the rain swallowing distortion index DCWR_θand simulating and analyzing the rain swallowing process under the influence of this parameter,the results show that the larger the rain swallowing distortion index DCWR_θ,the worse the compressor performance and its performance.The more obvious,the narrower the stable working range of the compressor.Compared with uniform rain swallowing and dry conditions,the uneven distribution of raindrops after non-uniform swallowing of rain results in the distortion of the internal flow field of the compressor,which further reduces the work and expansion capacity of the compressor cascade,and the flow loss gradually increases.The inter-stage parameter matching characteristics deteriorate,which reduces the efficiency of the compressor components and the stable working margin.