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Effect of Bowed/Leaned Vane on the Unsteady Aerodynamic Excitation in Transonic Turbine

Journal of Thermal Science 2019年第1期28卷 133-144页

作者： LIU Jian QIAO Weiyang DUAN Wenhua turbomachinery Aerodynamics and Acoustics lab.(TAAL) School of Power and Energy Northwestern Polytechnical University

To investigate the effect of bowed/leaned vane configurations on the aerodynamic performance and aerodynamic excitation in transonic high-pressure turbine, the full three-dimensional viscous unsteady numerical simulation was performed by solving N-S equations based on SAS SST *** influence of bowed/leaned vanes on turbine efficiency and efficiency fluctuation was investigated. The action of vane modelling to the overall aerodynamic fluctuation level and the amplitude of each vane passing frequency were analyzed. By comparing instantaneous pressure fluctuation contours in the blade passage with space-time maps, the link of the pressure fluctuation on blade surface with flow distortions was achieved, which can reveal the mechanism of the impact of the vane modelling. As the results suggest, the turbine efficiency is promoted with positively leaned and bowed vane modelling, and the fluctuation of stage turbine efficiency is repressed, which contributes to the smooth running of the turbine stage. The blade aerodynamic excitation on the rotor blade is characterized by the motion of vane trailing edge shock system, and the vane configurations can reduce the fluctuation level on the rotor blade surface effectively. For the positively leaned vane configuration, the aerodynamic excitations at the root and tip region are affected by the impact of the amplitude of the first harmonic, whereas they are reduced with the decrease of the amplitude of the second and higher harmonics at midspan. For the positively bowed vane, aerodynamic excitation is repressed by reducing the amplitude of the third harmonic at the root region, and the first harmonic at the tip region, and the amplitude of each harmonic is reduced at the middle region.

关键词： transonic turbine leaned bowed aerodynamic performance aerodynamic excitation numerical simulation

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Effects of Freestream Turbulence,Reynolds Number and Mach Number on the Boundary Layer in a Low Pressure Turbine

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Journal of Thermal Science 2023年第4期32卷 1393-1406页

作者： DUAN Wenhua QIAO Weiyang CHEN Weijie ZHAO Xinyu turbomachinery Aerodynamics and Acoustics lab.TAAL) School of Power and EnergyNorthwestern Polytechnical UniversityXi’an710129China

In order to investigate the aerodynamics of a high speed low pressure turbine works in high Mach number and low Reynold number environment,the effect of freestream turbulence(FST)on the boundary layer development on the high speed low pressure turbine under different Reynolds numbers(Re)is numerically *** eddy simulation is adopted here with a subgrid scale model of Wall Adapting Local Eddy viscosity(WALE).Cases with Re ranging from 100000 to 400000 under an exit Mach number(Ma)of 0.87 have been considered at low and high FST levels.A low Ma case(0.17)under very low Re has also been studied under both low and high *** is found that higher Re or FST level leads to earlier *** has a greater effect than FST on the development of boundary *** effect of FST on the boundary layer depends on the *** boundary layer development shows totally different behaviors under different Ma.A separation bubble could be formed under low Ma while no attachment could be detected under high *** FST has a stronger effect on the separated boundary layer under low Ma,which could eliminate the separation in the present *** all the cases under low FST,the Kelvin-Helmholtz instability is the dominate mechanism in the transition *** the low Ma case with high FST,the streamwise streaks play a dominant role in the transition *** the high Ma cases with high FST,both the streamwise streaks and Kelvin-Helmholtz instability work in the transition *** streamwise streaks play a more important role when the Re increased.

关键词： freestream turbulence Reynolds number Mach number low pressure turbine boundary layer

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The Tip Leakage Flow Structure of an Axial Fan with Tip Clearance

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Journal of Shanghai Jiaotong university(Science) 2003年第1期8卷 75-79页

作者：竺晓程杜朝辉林万来 turbomachinery lab. Shanghai Jiaotong Univ. Emerson Electric Corporation 10048 Industrial Blvd

Experiment and numerical simulation technique are used to investigate the tip leakage flow in an axial fan with tip clearance at the design condition. The flow field in the tip region of fan is measured using a PDA (Particle Dynamics Analysis) system. The flow is surveyed across the whole passage at fifteen axial locations (from the 100% axial chord in front of the leading edge to the 100% axial chord behind the trailing edge), mainly focusing on the outer 90% blade span. Both experiment measurement and numerical simulation indicates the leakage flow originated from the tip clearance along the chord rolls up into three dimensional spiral structure to form leakage flow vortex. The interaction of leakage flow and main flow will produce the low velocity zone, and block the flow. The leakage flow almost occupies the most part of flow passage behind the trailing edge.

关键词： particle dynamics analysis (PDA) tip clearance flow tip clearance vortex

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Wave Energy Assessment Along the Moroccan Atlantic Coast

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Journal of Marine Science and Application 2019年第2期18卷 142-152页

作者： Hafsa Bouhrim Abdellatif El Marjani EMISys Team Research E3S Research Center Turbomachinery Lab Mohammadia School of Engineers Mohammed V University in Rabat

The aim of the present work is to assess the offshore wave energy potential along the Atlantic coast of *** works of this paper focus on the identification of the most energetic sites for wave energy converters(WECs)*** this purpose,11 sites have been explored;all of them are located at more than 40m depth on the Moroccan Atlantic *** wave power at each site is computed on the basis of wave data records in terms of significant wave height and energy period provided by theWaveWatch three(WW3)*** indicate that the coast sites located between latitudes 30°30′N and 33°N are the most energetic with an annual average wave power estimated at about 30 kW?m^-1,whereas,in the other sites,the wave power is significantly ***,the study of the monthly and seasonal temporal variability is found to be uniform in the powerful sites with values four times greater in winter than in *** directional investigation on the significant wave height has shown that for almost all the powerful sites,the incoming waves have a dominant sector ranging between Northern(N)and Western-Northern-Western(WNW)directions.

关键词： Wave energy Moroccan Atlantic coast Wave energy converter(WEC) Wave Watch 3(WW3) Seasonal and temporal variability Directional wave height investigation Power roses Occurrence bivariate distributions

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Thermal stability improvement of sprayable fast-responding pressure-sensitive paint for measurement above 100℃

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Chinese Journal of Aeronautics 2021年第1期34卷 320-326页

作者： Di PENG Feng GU Zhe ZHONG Yingzheng LIU Key lab.of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Gas Turbine Research Institute Shanghai Jiao Tong UniversityShanghai 200240China

The thermal stability of sprayable fast-responding Pressure-Sensitive Paint(fast PSP)was investigated to explore the possibility for application in turbomachinery and hypersonic research with temperature above 100℃.The first part of the study focused on a widely-used Polymer Ceramic PSP(PC-PSP).The effects of thermal degradation on its key sensing properties,including luminescent intensity,pressure sensitivity and response time,were examined for a temperature range from 60 to 100℃.Severe degradation in intensity and pressure sensitivity was found as temperature reached 70℃or higher,which would cause failure of PSP application in these ***,a fast-responding Mesoporous-Particle PSP(MP-PSP)was developed which did not show degradation effects until 140℃.The greatly improved thermal stability of MP-PSP was attributed to:selection of polymer with higher glass transition temperature(polystyrene)to delay the saturation effect of oxygen quenching as temperature increased;porous and hollow structure of particles for luminophore deposition that minimizes polymer–luminophore *** new paint formulation has significantly raised the upper temperature limit of fast PSP and offers more opportunities for applications in harsh environment.

关键词： Dynamic response Polymer–luminophore interaction Pressure sensitivity Pressure-sensitive paint Thermal degradation

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A novel none once per revolution blade tip timing based blade vibration parameters identification method

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Chinese Journal of Aeronautics 2020年第7期33卷 1953-1968页

作者： Weimin WANG Xulong ZHANG Dongfang HU Dengpeng ZHANG Paul ALLAIRE Key lab.of Engine Health Monitoring-Control and Networking Beijing University of Chemical TechnologyBeijing 100029China Beijing Key lab.ratory of Health Monitoring Control and Fault Self-recovery for High-end Machinery Beijing University of Chemical TechnologyBeijing 100029China Rotor Bearing Solutions International LLCCharlottesvilleVA 22911USA

The vibration caused blade High Cycle Fatigue(HCF)is seriously affects the safety operation of turbomachinery especially for ***,it is crucial important to identify the blade vibration parameters and then evaluate the dynamic stress *** Tip Timing(BTT)method is one of the promising method to solve these ***,it need a high resolution Once Per Revolution(OPR)signal which is difficult to get for the ***,a Coupled Vibration Analysis(CVA)method for identifying blade vibration parameters by a none OPR BTT is *** method assumes that every real blade has its own vibration performance at a given ***,it can take any blade as the reference blade,and the other blades using the reference blade as the OPR for vibration displacement calculating and further parameter *** proposed method is validated by numerical ***,experimental studies are carried out on a straight blade and a twisted three dimensional blade test rig as well as a large industrial axial compressor *** results show that the proposed method can accurately identify the blade synchronous vibration parameters and quantitatively evaluate the mistuning in bladed disks,which lays a foundation for the reliability improvement of aero-engine.

关键词： Blade tip timing Blade vibration Parameter identification turbomachinery blades Vibration analysis

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