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Sun D.,Beihang University | Nie C.,CAS Institute of Engineering Thermophysics | Liu X.,Engine Certification Center | Lin F.,CAS Institute of Engineering Thermophysics | Sun X.,Beihang University
Journal of Turbomachinery | Year: 2016

A kind of casing treatment, named as stall precursor-suppressed (SPS), has been developedrecently, which was proved to be able to effectively improve stall margin (SM) withoutsignificant efficiency loss in low-speed axial flow compressors and a transoniccompressor rotor. In this paper, the effectiveness of the SPS casing treatment is investigatedin a single-stage transonic compressor. Based on an extended stall inceptionmodel, the quantitative evaluation of the SM enhancement by the SPS casing treatment ispresented for the transonic compressor stage. The model predicts that a 2.5-6.8% of stallmargin improvement (SMI), which is defined in terms of mass flow rate at stall inception, can be achieved at the design rotational speed. The experimental results show that theSPS casing treatment can achieve 3.5-9.3% of the SMI at 95% design rotationalspeed. Due to the fact that the distributions of the total pressure ratio along the spanwisedirection are kept the same as those of the solid wall casing at the same mass flow rate, the SPS casing treatments with a small open area ratio and large backchamber enhancethe SM without a recognizable efficiency loss and a migration of the pressure-rise characteristics. Furthermore, the mechanism of SMI with the SPS casing treatment is investigatedin the experiments. In comparison with the solid wall casing, the emergence andthe evolution of the stall inception waves are suppressed and the nonlinear developmentof the stall process is delayed with the SPS casing treatment. © 2016 by ASME.

Ma Y.,Beihang University | Liu X.,Engine Certification Center | Sun D.,Beihang University | Sun X.,Beihang University
Proceedings of the ASME Turbo Expo | Year: 2015

This paper is concerned with the prediction of stability inception of centrifugal compreßor based on eigenvalue theory. A body force model has been developed to simulate the impellers of the compreßor by applying the effect of the blade force on momentum change and energy loß and geometries of blades. Using spectrum method, the stability equations can be precisely transformed into a very large matrix equation due to the compreßor configuration. Before computing with spectrum method, it is available to use Jacobi Transform when making a transformation between physical and computational regions. Afterwards, the Singular Value Decomposition is adopted to solve the resultant eigenvalue matrix, the roots of which can conveniently predict whether the flow is stable or not. It is found that the relative error of the computational model is smaller in comparison with CFD steady results, which indicates that the model can be used as a practical and reliable theoretical criterion during the compreßor design phase without requiring any experiential formulas and data. Copyright © 2015 by ASME.

Sun D.,Beihang University | Sun D.,Co Innovation Center for Advanced Aerospace Engine | Liu X.,Engine Certification Center | Sun X.,Beihang University | Sun X.,Co Innovation Center for Advanced Aerospace Engine
Journal of Fluids Engineering, Transactions of the ASME | Year: 2015

It is known that a kind of stall precursor-suppressed (SPS) casing treatment can be used to enhance compressor stall margin (SM) without recognizable efficiency loss. The further requirement in this regard is to develop an effective way to determine the variation range of the SM improvement during the design of such SPS casing treatment. In this investigation, based on the extrapolation hypothesis and the existing work, an extended stall inception model for quantitative evaluation of the SM enhancement is presented for both subsonic and transonic compressors with the SPS casing treatment. The capability of the extended model to quantitatively evaluate the SM enhancement with the SPS casing treatment is validated against the experimental data. The quantitative evaluation results show that the SPS casing treatments with different geometric parameters can improve the SM by a diverse percentage. In particular, for the facilities used in the present investigation, the experiments show that the SPS casing treatments can cause relevant increases of the SM. The change trend of the SM enhancement with various design parameters of the SPS casing treatment is in line with the corresponding theoretical results. Copyright © 2015 by ASME.

Zhang G.,Engine Certification Center | Zhang G.,China Academy of Civil Aviation Science and Technology | Zhou Y.-P.,Engine Certification Center | Zhou Y.-P.,China Academy of Civil Aviation Science and Technology | Ding S.-T.,Beihang University
Hangkong Dongli Xuebao/Journal of Aerospace Power | Year: 2015

In order to meet the requirement of airworthiness regulations on engine life limited parts (ELLPs), a theoretical model integrating stress-strength interference model, linear elastic fracture mechanics and zone based probabilistic analysis was established to assess the failure risk of ELLPs. The numerical algorithm and the computer program were also developed. The method was calibrated by the test case provided in the advisory circular. The assessment results are 1.45×10-9 times/cycle without any non-destructive inspection and 1.0×10-9 times/cycle with an inspection at 10000 cycles, respectively. The results measure up to the calibration test case very well, indicating the method to meet the terms of the regulation, thus is applicable to the current civil engine type certification. ©, 2015, BUAA Press. All right reserved.

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