A numerical methodology for investigating compressor instabilities in a multistage environment is presented. The method is based on a stage-by-stage dynamic compression model and considers air compressibility explicit...A numerical methodology for investigating compressor instabilities in a multistage environment is presented. The method is based on a stage-by-stage dynamic compression model and considers air compressibility explicitly throughout the compressor. It involves discretizing the compression system into distinct elements and a use of the local elemental characteristic of mean performance. The models are presented in both nonlinear and linearized forms. The linearised form permits well surge condition prediction for multistage axial compressors, while the non-linear form is able to investigate the growth of local flow disturbances, and helps to develop practical control strategy. Validations were carried out using the data from several aircraft engine compressors. A good experiment-model consistency is achieved.展开更多
The timely detection of stall inception is of great significance for safe operation and stability control of axial compressor. In the current study, a fast wavelet tool was selected to predict stall precursor in axial...The timely detection of stall inception is of great significance for safe operation and stability control of axial compressor. In the current study, a fast wavelet tool was selected to predict stall precursor in axial compressors with spike-type and modal-wave stall inception. Dynamic pressure was measured in the casing wall by using a collection of time-resolved pressure transducers with circumferential and chord-wise spatial resolution. Fast wavelet analysis with low frequency reconstruction results demonstrate that the initial inception can be detected 110 rotor revolutions prior to stall for modal-wave stall inception in a 1.5 stage axial compressor. For spike-type stall inception, despite the failure of early stall warning via low frequency reconstruction, an increase amplitude frequency band of 0.2–0.8 blade passing frequency was identified using high frequency reconstruction in an isolated-rotor axial compressor. Fast wavelet method can predict two kinds of stall inceptions simultaneously in advance and realize the early stall warning in axial compressors through a reasonable selection of reconstructed frequency.展开更多
This paper reviews the development in the research of flow instability and its control over the recent ten or more years. This development was largely stimulated by the novel idea of active control of the aerodynamic ...This paper reviews the development in the research of flow instability and its control over the recent ten or more years. This development was largely stimulated by the novel idea of active control of the aerodynamic instability in compressors. Three topics are covered in the paper, which appeared as the major themes towards the goal of stability enhancement. The first topic is the pre-stall behavior of rotating stall, which plays a vital role in designing the control scheme and discovering the convenient route to find the causal factors of flow disturbances potentially leading to stall. The second topic is the mechanism of blade passage flow during stall and its inception, which is the basic knowledge needed to manipulate the blade design for the stability improvement and eventually to predict the unsteady performance of the compressor system. The third topic is the recent trend of the control strategy based on the learning of active vs. passive methods. To introduce to the discussion of these topics, a brief description of the history of the recent development is given at the beginning of the paper. In discussing each topic, future works are also highlighted to enhance the further development of this long-standing problem in turbomachinery research and application.展开更多
基金This project is supported by National Natural Science Foundation of China (No.50146014) National Natural Science Foundation of Xi'an Jiaotong University, China (No.573023).
文摘A numerical methodology for investigating compressor instabilities in a multistage environment is presented. The method is based on a stage-by-stage dynamic compression model and considers air compressibility explicitly throughout the compressor. It involves discretizing the compression system into distinct elements and a use of the local elemental characteristic of mean performance. The models are presented in both nonlinear and linearized forms. The linearised form permits well surge condition prediction for multistage axial compressors, while the non-linear form is able to investigate the growth of local flow disturbances, and helps to develop practical control strategy. Validations were carried out using the data from several aircraft engine compressors. A good experiment-model consistency is achieved.
基金support of the National Natural Science Foundation of China with Project No. 51676183 and No. 51727810the National Science and Technology Major Project (2017-II0004-0017)the Special Fund for the Member of Youth Innovation Promotion Association of CAS (2018173)
文摘The timely detection of stall inception is of great significance for safe operation and stability control of axial compressor. In the current study, a fast wavelet tool was selected to predict stall precursor in axial compressors with spike-type and modal-wave stall inception. Dynamic pressure was measured in the casing wall by using a collection of time-resolved pressure transducers with circumferential and chord-wise spatial resolution. Fast wavelet analysis with low frequency reconstruction results demonstrate that the initial inception can be detected 110 rotor revolutions prior to stall for modal-wave stall inception in a 1.5 stage axial compressor. For spike-type stall inception, despite the failure of early stall warning via low frequency reconstruction, an increase amplitude frequency band of 0.2–0.8 blade passing frequency was identified using high frequency reconstruction in an isolated-rotor axial compressor. Fast wavelet method can predict two kinds of stall inceptions simultaneously in advance and realize the early stall warning in axial compressors through a reasonable selection of reconstructed frequency.
文摘This paper reviews the development in the research of flow instability and its control over the recent ten or more years. This development was largely stimulated by the novel idea of active control of the aerodynamic instability in compressors. Three topics are covered in the paper, which appeared as the major themes towards the goal of stability enhancement. The first topic is the pre-stall behavior of rotating stall, which plays a vital role in designing the control scheme and discovering the convenient route to find the causal factors of flow disturbances potentially leading to stall. The second topic is the mechanism of blade passage flow during stall and its inception, which is the basic knowledge needed to manipulate the blade design for the stability improvement and eventually to predict the unsteady performance of the compressor system. The third topic is the recent trend of the control strategy based on the learning of active vs. passive methods. To introduce to the discussion of these topics, a brief description of the history of the recent development is given at the beginning of the paper. In discussing each topic, future works are also highlighted to enhance the further development of this long-standing problem in turbomachinery research and application.
