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Investigation of control effects of end-wall selfadaptive jet on three-dimensional corner separation of a highly loaded compressor cascade

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Chinese Journal of Aeronautics 2024年第6期37卷 109-126页

作者： Hejian WANG Bo LIU Xiaochen MAO Botao ZHANG Zonghao YANG School of Power and Energy Northwestern Polytechnical UniversityXi’an 710129China The National Key Laboratory of Science and Technology on Aerodynamic Design and Research Xi’an 710129China Taihang Laboratory Chengdu 610000China

To overcome the limitations posed by three-dimensional corner separation,this paper proposes a novel flow control technology known as passive End-Wall(EW)self-adaptive *** single EW slotted schemes(EWS1 and EWS2),alongside a combined(COM)scheme featuring double EW slots,were *** results reveal that the EW slot,driven by pressure differentials between the pressure and suction sides,can generate an adaptive jet with escalating velocity as the operational load *** high-speed jet effectively re-excites the local low-energy fluid,thereby mitigating the corner ***,the EWS1 slot,positioned near the blade leading edge,exhibits relatively low jet velocities at negative incidence angles,causing jet separation and exacerbating the corner ***,the EWS2 slot is close to the blade trailing edge,resulting in massive low-energy fluid accumulating and separating before the slot outlet at positive incidence *** contrast,the COM scheme emerges as the most effective solution for comprehensive corner separation *** can significantly reduce the total pressure loss and improve the static pressure coefficient for the ORI blade at 0°-4° incidence angles,while causing minimal negative impact on the aerodynamic performance at negative incidence ***,the corner stall is delayed,and the available incidence angle range is broadened from -10°--2°to -10°-4°.This holds substantial promise for advancing the aerodynamic performance,operational stability,and load capacity of future highly loaded compressors.

关键词： Three-dimensional corner separation End-wall adaptive jet Total pressure loss Highly loaded compressor cascade Compressors

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Effect of anisotropic resistance characteristic on boundary-layer transitional flow

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Applied Mathematics and Mechanics(English Edition) 2022年第12期43卷 1935-1950页

作者： Zheng HONG Zhengyin YE Kangling WU Kun YE National Key Laboratory of Science and Technology on Aerodynamic Design and Research Northwestern Polytechnical UniversityXi'an 710072China

It is observed that the feather surface exhibits anisotropic resistances for the streamwise and spanwise *** obtain a qualitative understanding about the effect of this anisotropic resistance feature of surface on the boundary-layer transitional flow over a flat plate,a simple phenomenological model for the anisotropic resistance is established in this *** means of the large eddy simulation(LES)with high-order accurate finite difference method,the numerical investigations are *** numerical results show that with the spanwise resistance hindering the formation of vortexes,the transition from laminar flow to turbulent flow can be delayed,and turbulence is weakened when the flow becomes fully turbulent,which leads to significant drag reduction for the *** the contrary,the streamwise resistance renders the flow less stable,which leads to the earlier transition and enhances turbulence in the turbulent region,causing a drag increase for the ***,it is indicated that a surface with large resistance for spanwise flow and small resistance for streamwise flow can achieve significant drag *** present results highlight the anisotropic resistance characteristic near the feather surface for drag reduction,and shed a light on the study of bird’s efficient flight.

关键词： anisotropic resistance transitional flow drag reduction numerical simulation

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A novel high-order scheme for numerical simulation of wake flow over helicopter rotors in hover

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Chinese Journal of Aeronautics 2022年第5期35卷 260-274页

作者： Shaoqiang HAN Wenping SONG Zhonghua HAN Institute of Aerodynamic and Multidisciplinary Design Optimization National Key Laboratory of Science and Technology on Aerodynamic Design and ResearchSchool of AeronauticsNorthwestern Polytechnical UniversityXi’an 710072China

Accurate prediction of tip vortices is crucial for predicting the hovering performance of a helicopter rotor.A new high-order scheme(we call it WENO-K)proposed by our research group is employed to minimize numerical dissipation and extended to numerical simulation of unsteady compressible viscous flows dominated by tip vortices over hovering ***-K is referred to as an adaptively optimized WENO scheme with Gauss-Kriging reconstruction,and its advantage is to reduce dissipation in smooth regions of flow while preserving high-resolution around *** WENO-K scheme is adopted to reconstruct left and right state values within the Roe Riemann solver updating the inviscid fluxes on a structured dynamic overset *** minimize the accuracy loss for high-order reconstruction on artificial boundaries of overset grid,a method of multilayer fringes is proposed to carry out interpolation between background grid and blade *** parallel computing considering automatic load balance on averagely partitioned overset grid is developed to reduce the wall-clock time of an unsteady *** results for Caradonna-Tung(C-T)rotor in hover at the conditions of subsonic and transonic tip Mach numbers show that the thrust coefficient error for the result of WENO-K scheme is no more than 3%.Compared with WENO-JS scheme,WENO-K scheme achieves about 40%improvement on accuracy of predicting rotor thrust with only 4.1%extra computational *** importantly,WENO-K scheme can capture more sophisticated unsteady flow structures and resolve tip vortices to a larger wake age with an increment of about 270°compared to WENO-JS scheme.

关键词： Dynamic overset grid Helicopter rotors High-order scheme Unsteady flow Vortex flow WENO scheme

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Reconstruction of particle distribution for tomographic particle image velocimetry based on unsupervised learning method

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Particuology 2024年第10期93卷 349-363页

作者： Duanyu Zhang Haoqin Huang Wu Zhou Mingjun Feng Dapeng Zhang Limin Gao School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai200093China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer for Power Engineering University of Shanghai for Science and TechnologyShanghai200093China National Key Laboratory of Aerodynamic Design and Research Northwestern Polytechnical UniversityXi'an710072China

The development of deep learning has inspired some new methods to solve the 3D reconstruction problem for Tomographic Particle Image Velocimetry (Tomo-PIV). However, the supervised learning method requires a large number of data with ground truth as training information, which is very difficult to gather from experiments. Although synthetic datasets can be used as alternatives, they are still not exactly the same with the real-world experimental data. In this paper, an Unsupervised Reconstruction Technique based on U-net (UnRTU) is proposed to reconstruct volume particle distribution explicitly. Instead of using ground truth data, a projection function is used as an unsupervised loss function for network training to reconstruct particle distribution. The UnRTU was compared with some traditional algebraic reconstruction algorithms and supervised learning method using synthetic data under different particle density and noise level. The results indicate that UnRTU outperforms these traditional approaches in both reconstruction quality and noise robustness, and is comparable to the supervised learning methods AI-PR. For experimental tests, particles dispersed in cured epoxy resin are moved by an electric rail with a certain speed to obtain the ground truth data of particle velocity. Compared with other algorithms, the reconstructed particle distribution by UnRTU has the best reconstruction fidelity. And the accuracy of the 3D velocity field estimated by UnRTU is 12.9% higher than that from the traditional MLOS-MART algorithm. It demonstrates significant potential and advantages for UnRTU in 3D reconstruction of particle distribution. Finally, UnRTU was successfully applied to the high-speed planar cascade airflow field, demonstrating its applicability for measuring complex fluid flow fields at higher particle density.

关键词： Tomographic particle image velocimetry 3D reconstruction Unsupervised learning Convolutional neural network

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design strategy and relevant flow mechanisms of highly loaded 3D compressor tandem cascades

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Chinese Journal of Aeronautics 2024年第7期37卷 220-235页

作者： Xiaochen MAO Yunyu WANG Zhihua DING Hao CHENG Bo LIU School of Power and Energy Northwestern Polytechnical UniversityXi’an 710129China The National Key Laboratory of Science and Technology on Aerodynamic Design and Research Xi’an 710129China Xi’an Thermal Power Research Institute Co.Ltd Xi’an 710072China

To investigate the design strategy of highly loaded tandem cascades at both the midspan and endwall,the overall performance and flow mechanisms of four typical tandem cascades based on the optimization were analyzed from multiple perspectives *** results show that the interference effects on the Front Blade(FB)and Rear Blade(RB)should not be overlooked during the design phase,and the design strategies at the midspan and endwall are completely *** the midspan,the optimization aims to increase the interference effects and the strength of the gap jet while maintaining the same load on the FB and ***,the endwall optimal airfoil exhibits weakening interference effects,advancement of the gap jet location,and load transfer from the FB to *** further analysis of flow characteristics,the midspan optimal airfoil is beneficial for inhibiting the low-energy fluid from interacting with the suction surface of RB under the design condition,but results in earlier occurrence of corner *** endwall optimal airfoil helps suppress the development of the secondary flow and delay the onset of corner ***,by combining the benefits of these two design approaches,additional forward sweep effects are achieved,further enhancing the performance of the tandem cascade.

关键词： Tandem cascade Interference effect Vortex structure Load split Compressor

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Optimal design Criteria of Tandem Configuration for High-Load Compressor Cascades

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Journal of Thermal science 2024年第6期33卷 2047-2058页

作者： MAO Xiaochen JIAO Yingchen CHENG Hao ZHANG Botao LIU Bo School of Power and Energy Northwestern Polytechnical UniversityXi'an 710129China The National Key Laboratory of Science and Technology on Aerodynamic Design and Research Xi'an 710129China Xi'an Thermal Power Research Institute Co. Ltd.Xi'an 710072China

Axial overlap(AO)and percent pitch(PP)are considered as key position configuration parameters that affect the tandem cascade *** objective of the current study is to investigate the optimal design criteria for these two parameters in tandem cascades of subsonic highly-loaded two-dimensional *** that,the influence mechanisms of AO and PP are explored *** results show that higher PP is beneficial for decreasing rear blade(RB)load,but an invalidity of gap flow occurs when it approaches *** change in AO has an influence on the adverse pressure gradient of the front blade(FB),and it also affects the gap flow strength and FB wake ***,the optimal design criteria for AO and PP are obtained in a large design space,which clarifies the matching relationship of the two parameters at different operating *** best global range of AO is about-0.05 to 0.05 while PP is between 0.85 to 0.92,and PP should be smaller to avoid performance degradation as AO *** to the fault tolerance in practical applications,PP should be closer to the lower bound to ensure that the deterioration boundary is wide enough.

关键词： axial compressor tandem cascade axial overlap percent pitch optimal design criteria

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Effect of longitudinal lift distribution on sonic boom of a canard-wing-stabilator-body configuration

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Chinese Journal of Aeronautics 2023年第6期36卷 92-108页

作者： Liwen ZHANG Zhonghua HAN Jianling QIAO Wenping SONG Yulin DING Xuehe WANG Institute of Aerodynamic and Multidisciplinary Design Optimization School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Research Center for Environment-friendly Supersonic Civil Transport Northwestern Polytechnical UniversityXi'an 710072China

After the last flight of the Concorde in 2003,sonic boom has been one of the obstacles to the return of a supersonic transport aircraft to *** reduce the sonic boom intensity to an acceptable level,it is of great significance to study the effect of lift distribution on far-field sonic boom,since lift is one of the most important contributors to an intense sonic *** studies on the longitudinal lift distribution used low-fidelity methods,such as Whitham theory,and in turn,only preliminary conclusions were obtained,such as that extending the lift distribution can reduce sonic *** paper uses a newly developed high-fidelity prediction method to quantitatively study the effect of longitudinal lift distribution on the sonic boom of a Canard-Wing-Stabilator-Body(CWSB)*** high-fidelity prediction method combines near-feld CFD simulation with far-field propagation by solving the augmented Burgers equation.A multipole analysis method is employed for the extraction of near-field waveform in order to reduce computational *** configurations with the same total lift but different distributions are studied,and the quantitative relationship between the longitudinal lift distribution and far-field sonic boom intensity is *** is observed that a small lift generated by the stabilator can prevent aft-stabilator and aft-fuselage shocks from merging,while the balanced lift generated by the canard and wing can effectively keep the corresponding shocks further apart,which is beneficial for reducing both the on-track and off-track sonic *** turn,the acoustic level perceived at the ground can be reduced by 5.9 PLdB on-track and 5.4 PLdB off-track,on average.

关键词： Computational fluid dynamics Longitudinal lift distribution Sonic boom Sonic boom reduction Supersonic transport

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Resonance mechanism of flapping wing based on fluid structure interaction simulation

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Chinese Journal of Aeronautics 2024年第5期37卷 243-262页

作者： Yueyang GUO Wenqing YANG Yuanbo DONG Dong XUE National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China Yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang 215400China

Certain insect species have been observed to exploit the resonance mechanism of their *** order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)***,there exists controversy among researchers regarding the relationship between frequency and aerodynamic *** that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant *** this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM *** performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic ***,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum ***,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible ***,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure *** paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.

关键词： Flexible Flapping Wing(FFW) Acoustic Structure Interaction Modal(ASIM) Fluid Structure Interaction(FSI) Resonance mechanism aerodynamic performance

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Far-field sonic boom prediction considering atmospheric turbulence effects: An improved approach

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Chinese Journal of Aeronautics 2022年第9期35卷 208-225页

作者： Jianling QIAO Zhonghua HAN Liwen ZHANG Wenping SONG Bifeng SONG Institute of Aerodynamic and Multidisciplinary Design Optimization School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710071China National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an710071China

Accurate prediction of sonic boom is one of key challenges for the design of a low-boom supersonic aircraft. For most of available far-field prediction methods, the effect of atmospheric turbulence appearing in the planetary boundary layer cannot be considered, which results in remarkable inaccuracy of predicting ground-level sonic boom waveform. Although some efforts have been made to overcome the shortcoming, the turbulence effects are not yet well described so far. This article proposes an improved method by extending the two-dimensional Heterogeneous One-Way Approximation for the Resolution of Diffraction(HOWARD) equation to account for the axial and transverse convections of wind fluctuation as well as the effect of temperature fluctuation. The proposed method is validated by comparing the predictions with the flight-test data of JAXA D-SEND#1 LBM, which shows that the result of the proposed method is in better agreement with the flight-test data than that of the method without considering atmospheric turbulence ***, distortion mechanism of sonic boom waveforms caused by atmospheric turbulence is analyzed by using the proposed method. It is indicated that the effect of turbulent convection makes uniform sonic-boom wavefronts irregular, which creates the condition of diffraction effect to perturb waveforms. Finally, the proposed method is applied to investigate the behavior of two types of waveforms given by the sonic boom minimization theory. Results show that a far-field waveform with a weaker initial shock is more beneficial for low-boom design of a supersonic aircraft.

关键词： Atmospheric turbulence Augmented Burgers equation HOWARD equation Sonic boom Supersonic transport

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Phase-field simulation of precipitation kinetics and creep properties of Ni-Al-Cr/Ta superalloys

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science China(Technological sciences) 2024年第4期67卷 1139-1150页

作者： YANG ShuaiGe ZHANG Zan ZHUO JiCheng LONG HongLi LI YongSheng National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China

The precipitation kinetics ofγ'-Ni_(3)(Al,Ta)phase and creep properties of Ni-15Al-x Ta at.%superalloys are investigated by the crystal plasticity phase-field *** results show that the high Ta content brings a lower creep strain for the deceleration and steady creep stage,while the creep lifetime is *** large external strain intensifies the creep damage and shortens the creep life of Ni-15Al-3Ta at.%*** kinetics evolution and elements distribution are revealed in the quaternary Ni-10Al-8.5Cr-xT a(x=1.5 at.%,2.0 at.%,2.5 at.%)superalloys by the multi-component phase-field *** anti-phase boundary(APB)changes the coarsening mechanism ofγ'phase,and Ta promotes the precipitation ofγ'phase with an increasing volume fraction and particle *** composition difference betweenγ'andγphases increases with the rising of Ta content,the strong partitioning of Ta toγ'phase strengthens the partitioning of Ni and Cr toγmatrix,and Ta shows a superiority than Al in the lattice site occupation of L1_(2)-Ni_(3)(Al,X)*** an importantγ'phase forming element,the optimization of Ta content is essential for improving the mechanical properties of Ni-based superalloys.

关键词： Ni-Al-Ta alloys creep properties kinetics phase-field

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