Based on a small perturbation stability model for periodic flow,the effects of inlet total temperature ramp distortion on the axial compressor are investigated and the compressor stability is quantitatively evaluated....Based on a small perturbation stability model for periodic flow,the effects of inlet total temperature ramp distortion on the axial compressor are investigated and the compressor stability is quantitatively evaluated.In the beginning,a small perturbation stability model for the periodic flow in compressors is proposed,referring to the governing equations of the Harmonic Balance Method.This stability model is validated on a single-stage low-speed compressor TA36 with uniform inlet flow.Then,the unsteady flow of TA36 with different inlet total temperature ramps and constant back pressure is simulated based on the Harmonic Balance Method.Based on these simulations,the compressor stability is analyzed using the proposed small perturbation model.Further,the Dynamic Mode Decomposition method is employed to accurately extract pressure oscillations.The two parameters of the temperature ramp,ramp rate and Strouhal number,are discussed in this paper.The results indicate the occurrence and extension of hysteresis loops in the rows,and a decrease in compressor stability with increasing ramp rate.Compressor performance is divided into two phases,stable and limit,based on the ramp rate.Furthermore,the model predictions suggest that a decrease in period length and an increase in Strouhal number lead to improved compressor stability.The DMD results imply that for compressors with inlet temperature ramp distortion,the increase of high-order modes and oscillations at the rotor tip is always the signal of decreasing stability.展开更多
This Special Column of Journal of Thermal Science(JTS)contains a selection of peer-reviewed papers from AJWTF 2022,held in Utsunomiya,Japan during 27 to 30November,2022.The Asian Joint Workshop and Thermophysics is a ...This Special Column of Journal of Thermal Science(JTS)contains a selection of peer-reviewed papers from AJWTF 2022,held in Utsunomiya,Japan during 27 to 30November,2022.The Asian Joint Workshop and Thermophysics is a biennial international conference facilitating cooperation between scientists of Asian nations.The conference was founded by three renowned academicians Prof.Heuy Dong Kim,from South Korea,Prof.Shen YU from China and Prof.Toshiaki Setoguchi from Japan.The inaugural edition of the conference was held at Qufu,China in 2006.This was followed by Luoyang,China(2008),Matsue,Japan(2010),Busan,Korea(2012),Nagasaki,Japan(2014),Guilin,China(2016),Trivandrum,India(2018),Daegu,Korea(2020).The ninth edition of the conference,held at Utsunomiya,Japan in November,2022 was chaired by Prof.Makoto Yamamoto of the Department of Mechanical Engineering,Tokyo University of Science,Japan.The conference involved keynote lectures and talks from distinguished academicians and professionals from the industry.Progress made and future directions on research involving fluid and thermal sciences and engineering were part of the deliberations.The conference also provided an opportunity for cultural exchanges and promotion of soft power of participating nations.展开更多
The present work is about the stall margin enhancement ability of a kind of stall precursor-suppressed（SPS） casing treatment when fan/compressor suffers from a radial total pressure inlet distortion.Experimental res...The present work is about the stall margin enhancement ability of a kind of stall precursor-suppressed（SPS） casing treatment when fan/compressor suffers from a radial total pressure inlet distortion.Experimental researches are conducted on a low-speed compressor with and without SPS casing treatment under radial distorted inlet flow of different levels as well as uniform inlet flow.The distorted flow fields of different levels are generated by annular distortion flow generators of different heights.The characteristic curves under these conditions are measured and analyzed.The results show that the radial inlet distortion could cause a stall margin loss from 2%to30%under different distorted levels.The SPS casing treatment could remedy this stall margin loss under small distortion level and only partly make up the stall margin loss caused by distortion in large level without leading to perceptible additional efficiency loss and obvious change of characteristic curves.The pre-stall behavior of the compressor is investigated to reveal the mechanism of this stall margin improvement ability of the SPS casing treatment.The results do show that this casing treatment delays the occurrence of rotating stall by weakening the pressure perturbations and suppressing the nonlinear amplification of the stall precursor waves in the compression system.展开更多
A stability model for multi-stage compressor is developed on the basis of the eigenvalue approach.This model assumes that the unsteady flow field can be decomposed into pressure,vortex and entropy waves.Besides,a line...A stability model for multi-stage compressor is developed on the basis of the eigenvalue approach.This model assumes that the unsteady flow field can be decomposed into pressure,vortex and entropy waves.Besides,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 model.The 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 eigenvalue.The 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 fan.The 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.展开更多
A stall warning approach based on aero-acoustic theory is studied in this paper. For this stall warning approach, a parameter Rc is defined to measure the periodicity of the blade-passing signal. Signal simulation is ...A stall warning approach based on aero-acoustic theory is studied in this paper. For this stall warning approach, a parameter Rc is defined to measure the periodicity of the blade-passing signal. Signal simulation is used to investigate the mechanism of the stall warning approach. The results suggest that the value of Rc is influenced by the power of the perturbations. The experiments on a two-stage compressor indicate this stall warning approach can generate a warning signal several seconds before the stall. It is demonstrated in this paper that the stall warning approach can detect the distribution and evolution of stall precursors. According to the distribution of the stall precursors, the partial stall precursor-suppressed casing treatment is applied and realized a stabilization of compressor.展开更多
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 met...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 treatment.It 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.展开更多
The S-shape inlet has been widely used in advanced military aircraft due to their advantage of reducing radar signature.However,the curvature of the inlet usually causes different kinds of intake distortion at the aer...The S-shape inlet has been widely used in advanced military aircraft due to their advantage of reducing radar signature.However,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 aero-engines.There is still no universal criterion for assessing the stability of compressors in the condition of strong swirl distortion.As an approach of assessing the swirl intensity and pattern,vortex identification method may be used as an auxiliary method for stability analysis.In this paper,numerical and experimental investigations on different S-ducts were carried out.The axial vorticity component and g criterion were used to analyze the quantitative correlation between geometry and swirl intensity.It was found that there is a relatively strong correlation between the geometry,the axial vorticity component and the Q criterion.The present investigation may provide a quick reconstruction method to model the effect of S-ducts for compressor stability prediction.展开更多
基金supported by National Natural Science Foundation of China(NSFC Grant Nos.52306036,52325602)Science Center for Gas Turbine Project(P2022-A-Ⅱ-002-001,P2022-C-Ⅱ-003-001)+3 种基金Project funded by China Postdoctoral Science Foundation(2022M720346)National Science and Technology Major Project(Y2022-Ⅱ-0003-0006,Y2022-Ⅱ-0002-0005).Alsothe research is supported by the Key Laboratory of Pre-Research Management Centre(No.6142702200101)the Fundamental Research Funds for the Central Universities(YWF-23-Q-1009,YWF-23-Q-1065)。
文摘Based on a small perturbation stability model for periodic flow,the effects of inlet total temperature ramp distortion on the axial compressor are investigated and the compressor stability is quantitatively evaluated.In the beginning,a small perturbation stability model for the periodic flow in compressors is proposed,referring to the governing equations of the Harmonic Balance Method.This stability model is validated on a single-stage low-speed compressor TA36 with uniform inlet flow.Then,the unsteady flow of TA36 with different inlet total temperature ramps and constant back pressure is simulated based on the Harmonic Balance Method.Based on these simulations,the compressor stability is analyzed using the proposed small perturbation model.Further,the Dynamic Mode Decomposition method is employed to accurately extract pressure oscillations.The two parameters of the temperature ramp,ramp rate and Strouhal number,are discussed in this paper.The results indicate the occurrence and extension of hysteresis loops in the rows,and a decrease in compressor stability with increasing ramp rate.Compressor performance is divided into two phases,stable and limit,based on the ramp rate.Furthermore,the model predictions suggest that a decrease in period length and an increase in Strouhal number lead to improved compressor stability.The DMD results imply that for compressors with inlet temperature ramp distortion,the increase of high-order modes and oscillations at the rotor tip is always the signal of decreasing stability.
文摘This Special Column of Journal of Thermal Science(JTS)contains a selection of peer-reviewed papers from AJWTF 2022,held in Utsunomiya,Japan during 27 to 30November,2022.The Asian Joint Workshop and Thermophysics is a biennial international conference facilitating cooperation between scientists of Asian nations.The conference was founded by three renowned academicians Prof.Heuy Dong Kim,from South Korea,Prof.Shen YU from China and Prof.Toshiaki Setoguchi from Japan.The inaugural edition of the conference was held at Qufu,China in 2006.This was followed by Luoyang,China(2008),Matsue,Japan(2010),Busan,Korea(2012),Nagasaki,Japan(2014),Guilin,China(2016),Trivandrum,India(2018),Daegu,Korea(2020).The ninth edition of the conference,held at Utsunomiya,Japan in November,2022 was chaired by Prof.Makoto Yamamoto of the Department of Mechanical Engineering,Tokyo University of Science,Japan.The conference involved keynote lectures and talks from distinguished academicians and professionals from the industry.Progress made and future directions on research involving fluid and thermal sciences and engineering were part of the deliberations.The conference also provided an opportunity for cultural exchanges and promotion of soft power of participating nations.
基金supported by National Natural Science Foundation of China(51236001 and 51576008)National Basic Research Program of China(2012CB720201)+1 种基金Aeronautical Science Foundation of China(2014ZB51018)Fundamental Research Funds for the Central Universities
文摘The present work is about the stall margin enhancement ability of a kind of stall precursor-suppressed（SPS） casing treatment when fan/compressor suffers from a radial total pressure inlet distortion.Experimental researches are conducted on a low-speed compressor with and without SPS casing treatment under radial distorted inlet flow of different levels as well as uniform inlet flow.The distorted flow fields of different levels are generated by annular distortion flow generators of different heights.The characteristic curves under these conditions are measured and analyzed.The results show that the radial inlet distortion could cause a stall margin loss from 2%to30%under different distorted levels.The SPS casing treatment could remedy this stall margin loss under small distortion level and only partly make up the stall margin loss caused by distortion in large level without leading to perceptible additional efficiency loss and obvious change of characteristic curves.The pre-stall behavior of the compressor is investigated to reveal the mechanism of this stall margin improvement ability of the SPS casing treatment.The results do show that this casing treatment delays the occurrence of rotating stall by weakening the pressure perturbations and suppressing the nonlinear amplification of the stall precursor waves in the compression system.
基金supported by the National Natural Science Foundation of China(Grant Nos.51576008&51236001)the National Basic Research Program of China(GrantNo.2012CB720201)+2 种基金Aeronautical Science Foundation of China(Grant No.2014ZB51018)the Collaborative Innovation Center for Advanced Aero-Engine of Chinathe Fundamental Research Funds for the Central Universities
文摘A stability model for multi-stage compressor is developed on the basis of the eigenvalue approach.This model assumes that the unsteady flow field can be decomposed into pressure,vortex and entropy waves.Besides,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 model.The 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 eigenvalue.The 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 fan.The 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.
基金supported by China Academy of Launch vehicle Technology (No.51606223)National Natural Science Foundation of China (Nos. 11661141020, 51576008, 51822601 and 51790514)
文摘A stall warning approach based on aero-acoustic theory is studied in this paper. For this stall warning approach, a parameter Rc is defined to measure the periodicity of the blade-passing signal. Signal simulation is used to investigate the mechanism of the stall warning approach. The results suggest that the value of Rc is influenced by the power of the perturbations. The experiments on a two-stage compressor indicate this stall warning approach can generate a warning signal several seconds before the stall. It is demonstrated in this paper that the stall warning approach can detect the distribution and evolution of stall precursors. According to the distribution of the stall precursors, the partial stall precursor-suppressed casing treatment is applied and realized a stabilization of compressor.
基金supported by National Natural Science Foundation of China (Nos. 51236001, 51406229 and 51106154)National Basic Research Program of China (No. 2012CB720201)+1 种基金Aeronautical Science Foundation of China (No. 2014ZB51018)Fundamental Research Funds for the Central Universities
文摘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 treatment.It 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.
基金This research is supported by National Natural Science Foundation of China(Nos.51906004,51822601 and 51790514)National Science and Technology Major Project(2017-11-0005-0018).
文摘The S-shape inlet has been widely used in advanced military aircraft due to their advantage of reducing radar signature.However,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 aero-engines.There is still no universal criterion for assessing the stability of compressors in the condition of strong swirl distortion.As an approach of assessing the swirl intensity and pattern,vortex identification method may be used as an auxiliary method for stability analysis.In this paper,numerical and experimental investigations on different S-ducts were carried out.The axial vorticity component and g criterion were used to analyze the quantitative correlation between geometry and swirl intensity.It was found that there is a relatively strong correlation between the geometry,the axial vorticity component and the Q criterion.The present investigation may provide a quick reconstruction method to model the effect of S-ducts for compressor stability prediction.
