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Recent development of casing treatments for aeroengine compressors

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Chinese Journal of Aeronautics 2019年第1期32卷 1-36页

作者： xiaofeng sun Xu DONG Dakun sun Fluid and Acoustic Engineering Laboratory Beihang University Collaborative Innovation Center for Advanced Aero-Engine Beihang University

Casing treatment is a mature stabilization technique which has been widely applied on aero-engines for modern aircrafts and turbo-chargers for automobiles. After the investigations of half century since the 1960 s, this technique has been well developed for various configurations with different effectiveness. From the perspective of stabilization mechanism, this paper roughly categorizes the configurations of casing treatment into two types: traditional ones which work by affecting the flow structure of blade tip region; a novel one named as Stall Precursor-Suppressed(SPS) casing treatment. The effectiveness of both types will be demonstrated for their applications on axial compressors and centrifugal compressors with uniform or distorted inlet. And the stabilization mechanism of casing treatments for regular types and SPS one will also be explained respectively. In addition, this review will summarize the methodologies of casing treatments with the numerical simulations for regular grooved configurations and the eigenvalue approach for SPS casing *** forward to the future of compressor stabilization, casing treatment technique will still exist as a general and inexpensive option, and the exploration for its effectiveness and mechanism will be deeper with the development of computational fluid dynamics and advanced measurement techniques.

关键词： Casing treatment Compressor Compressor stability Rotating stall Stall margin

A Model to Predict Stall Inception of Transonic Axial Flow Fan/Compressors

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Chinese Journal of Aeronautics 2011年第6期24卷 687-700页

作者： sun xiaofeng sun Dakun YU Weiwei School of Jet Propulsion Beihang University Beijing 100191 China

A stall inception model for transonic fan/compressors is presented in this paper. It can be shown that under some assumptions the solution of unsteady flow field consists of pressure wave which propagates upstream or downstream, vortex wave and entropy wave convected with the mean flow speed. By further using the mode-matching technique and applying the conservation law and conditions reflecting the loss characteristics of a compressor in the inlet and outlet of the rotor or stator blade rows, a group of homogeneous equations can be obtained from which the stability equation can be derived. Based on the analysis of the unsteady phenomenon caused by casing treatments, the function of casing treatments has been modeled by a wall impedance condition which has been included in the stability model through the eigenvalues and the corresponding eigenfunctions of the system. Besides, the effect of shock waves in cascade channel on the stability prediction is also considered in the stall inception model. Finally, some numerical analysis and experimental investigation are also conducted with emphasis on the mutual comparison.

关键词： stability model rotating stall stall inception transonic compressor unsteady flow

Calibration of S-duct Swirl Distortion Based on Vortex Identification Methods

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Journal of Thermal Science 2022年第1期31卷 35-46页

作者： sun Dakun LI Zhenyu DONG Xu sun xiaofeng School of Energy and Power Engineering Beihang UniversityBeijing 100191China Research Institute of Aero-engine Beihang UniversityBeijing 100191China Beihang Hangzhou Innovation Institute Yuhang Hangzhou 310023China Shen Yuan Honors College Beihang UniversityBeijing 100191China

The S-shape inlet has been widely used in advanced military aircraft due to their advantage of reducing radar ***,the curvature of the inlet usually causes different kinds of intake distortion at the aerodynamic interface plane(AIP).Among them,the swirl distortion has been seriously concerned because of its great impact on the performance and stability of *** is still no universal criterion for assessing the stability of compressors in the condition of strong swirl *** an approach of assessing the swirl intensity and pattern,vortex identification method may be used as an auxiliary method for stability *** this paper,numerical and experimental investigations on different S-ducts were carried *** axial vorticity component and g criterion were used to analyze the quantitative correlation between geometry and swirl *** was found that there is a relatively strong correlation between the geometry,the axial vorticity component and the Q *** present investigation may provide a quick reconstruction method to model the effect of S-ducts for compressor stability prediction.

关键词： S-inlet swirl distortion vortex identification

The precipitation and effect of topologically close-packed phases in Ni-based single crystal superalloys

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Journal of Materials Science & Technology 2024年第6期173卷 149-169页

作者： Jinguo Li Jingxia sun Jinlai Liu xiaofeng sun Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The precipitation of topologically close-packed(TCP)phases is the result of microstructure instabilities of Ni-based *** review seeks to comprehensively collate all the available information on TCP phases in SX superalloys based on the latest ***,the thermodynamics and kinetics of the TCP phase precipitation are ***,the morphology,composition and orientation of TCP phases and their sequential transformation are summarized in ***,the factors affecting the precipitation of these phases are sorted ***,the proposed damage mechanisms of TCP phases are ***,several control and prediction methods of the TCP phase precipitation are reviewed,so the alloy designer can better balance the relationship between microstructure stabilities and properties of the superalloy.

关键词： Ni-based superalloys Topologically close packed(TCP)phases Precipitation Microstructure stability Properties

Effect of solidification rate on competitive grain growth in directional solidification of a nickel-base superalloy

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Science China(Technological Sciences) 2012年第5期55卷 1327-1334页

作者： ZHOU YiZhou sun xiaofeng Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

The mechanism of grain structure evolution during directional solidification is a fundamental subject in material science. Within the published research there exist conflicting views on the mechanism of grain overgrowth. To study the effect of solidification rate on grain structure evolution, bi-crystals samples were produced in a nickel-base superalloy at different solidification rates. It was found that at the convergent grain boundaries those grains better aligned with respect to the heat flux more readily overgrew neighbouring grains with misaligned orientations and the effect became more pronounced as solidification rate was increased. However, at diverging grain boundaries the rate of overgrowth was invariant to the solidification rate. These experimental results were compared with models in the literature. Thus, a better insight into competitive grain growth in directional solidification processes was obtained.

关键词： competitive grain growth structure evolution directional solidification nickel alloys

Prediction of stall inception in multi-stage compressors based on an eigenvalue approach

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Science China(Technological Sciences) 2017年第8期60卷 1132-1143页

作者： CHENG FanJie sun DaKun DONG Xu sun xiaofeng School of Energy and Power Engineering Beihang University Beijing 100191 China

A stability model for multi-stage compressor is developed on the basis of the eigenvalue *** model assumes that the unsteady flow field can be decomposed into pressure,vortex and entropy ***,a linear cascade of blades is modeled by three-dimensional semi-actuator disk theory and the characteristics of steady flow field are also considered in the present *** connection between the analytical solution for stator,rotor and gap can be established by applying mode matching approach,the relevant stability equation can be expressed in the form of matrix,while the compressor system stability can be judged by the imaginary part of the matrix *** capacity of the stall inception model to predict the stall inception point of multi-stage compressor is assessed against the experimental data of National Aeronautics and Space Administration(NASA) two stage *** theoretical results show that this model can predict the stall onset points of a two-stage fan at different operating speeds with a reasonable accuracy.

关键词： multi-stage compressor unsteady flow rotating stall stability model stall inception

Experimental investigation on SPS casing treatment with bias flow

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Chinese Journal of Aeronautics 2014年第6期27卷 1352-1362页

作者： Dong Xu Liu Xiaohua sun Dakun sun xiaofeng School of Energy and Power Engineering Beihang University Aeroengine Airworthiness Certification Center Preparatory Office China Academy of Civil Aviation Science and Technology

Generally, casing treatment（CT） is a passivity method to enhance the stall margin of fan/compressor. A novel casing treatment based on the small disturbance theory and vortex and wave interaction suggestion is a method combining passive control and active control, which has been proved effective at enhancing the stall margin of fan/compressor in experiment. In order to investigate the mechanism of this kind of casing treatment, an experimental investigation of a stall precursor-suppressed（SPS） casing treatment with air suction or blowing air is conducted in the present paper. The SPS casing treatment is designed to suppressing stall precursors to realize stall margin enhancement in turbomachinery. The experimental results show that the casing treatment with blowing air of small quantity can improve the stall margin by about 8% with about 1% efficiency loss. By contrast, the SPS casing treatment with micro-bias flow does not improve the stall margin much more than that without bias flow, even worse. Meanwhile, the present investigation has also attempted to reveal the mechanism of stall margin improvement with the casing *** is found that the stall margin improvements vary with the modification of the unsteady shedding flow and the unsteady wall boundary impedance. The experimental results agree fairly well with the theoretical prediction using a flow stability model of rotating stall.

关键词： Air blowing Air suction Casing treatment Fan stability Rotating stall

Flow Stability Model for Fan/Compressors with Annular Duct and Novel Casing Treatment

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Chinese Journal of Aeronautics 2012年第2期25卷 143-154页

作者： LIU Xiaohua sun Dakun sun xiaofeng WANG Xiaoyu School of Jet Propulsion Beihang UniversityBeijing 100191China

A three-dimensional compressible flow stability model is presented in this paper, which focuses on stall inception of multi-stage axial flow compressors with a finite large radius annular duct configuration for the first time. It is shown that under some assumptions, the stability equation can be obtained yielding from a group of homogeneous equations. The stability can be judged by the non-dimensional imaginary part of the resultant complex frequency eigenvalue. Further more, based on the analysis of the unsteady phenomenon caused by casing treatment, the function of casing treatment has been modeled by a wall impedance condition which is included in the stability model through the eigenvalues and the corresponding eigenfunctions of the system. Finally, some experimental investigation and two numerical evaluation cases are conducted to validate this model and emphasis is placed on numerically studying the sensitivity of the setup of different boundary conditions on the stall inception of axial flow fan/compressors. A novel casing treatment which consists of a backchamber and a perforated plate is suggested, and it is noted that the open area ratio of the casing treatment is less than 10%, and is far smaller than conventional casing treatment with open area ratio of over 50%, which could result in stall margin improvement without obvious efficiency loss of fan/compressors.

关键词： compressor stability rotating stall casing treatment eigenvalue

Numerical Investigation of an Oscillating Airfoil using Immersed Boundary Method

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Journal of Thermal Science 2011年第5期20卷 413-422页

作者： Guohua Zhong Lin Du xiaofeng sun Aviation China Engineering General Electric Co. Shanghai 201203 China School of Jet Propulsion Beihang University B eijing 100191 China

Based on the immersed boundary method, a numerical simulation for an oscillating airfoil is established and a preliminary analysis of the oscillating airfoil is presented with an emphasis on the physical understanding of fluid-structure interaction. In order to validate the method, two simulation cases： oscillating circular cylinder at low K-C number and two degrees of freedom oscillating cylinder are carded out first and the results are in good agreement with the previous re：searches. In the oscillating airfoil simulation, it is found that the reduced velocity U^＊. is a very sensitive factor and especially U^＊-2.8 is the critical stable boundary in the present work. The method shows the predominance of time saving in computational process for such a complicated fluid-structure interac- tion problem.

关键词： turbomachinery IB method fluid-structure interaction.