期刊文献+
共找到809篇文章
< 1 2 41 >
每页显示 20 50 100
Research on Leading Edge Erosion and Aerodynamic Characteristics of Wind Turbine Blade Airfoil
1
作者 Xin Guan Yuqi Xie +2 位作者 Shuaijie Wang Mingyang Li Shiwei Wu 《Fluid Dynamics & Materials Processing》 EI 2024年第9期2045-2058,共14页
The effects of the erosion present on the leading edge of a wind turbine airfoil(DU 96-W-180)on its aerodynamic performances have been investigated numerically in the framework of a SST k–ωturbulence model based on ... The effects of the erosion present on the leading edge of a wind turbine airfoil(DU 96-W-180)on its aerodynamic performances have been investigated numerically in the framework of a SST k–ωturbulence model based on the Reynolds Averaged Navier-Stokes equations(RANS).The results indicate that when sand-induced holes and small pits are involved as leading edge wear features,they have a minimal influence on the lift and drag coefficients of the airfoil.However,if delamination occurs in the same airfoil region,it significantly impacts the lift and resistance characteristics of the airfoil.Specifically,as the angle of attack grows,there is a significant decrease in the lift coefficient accompanied by a sharp increase in the drag coefficient.As wear intensifies,these effects gradually increase.Moreover,the leading edge wear can exacerbate flow separation near the trailing edge suction surface of the airfoil and cause forward displacement of the separation point. 展开更多
关键词 Wind energy wind turbine EROSION AIRFOIL leading edge erosion characteristics aerodynamic performance numerical simulation
下载PDF
Numerical Study on the Duct Noise Control of Single-Stage Axial Flow Fan with Wave Leading Edge Stator Blade Configurations 被引量:1
2
作者 Jianxin Lian Hang Tong +2 位作者 Liangji Zhang Weiyang Qiao Weijie Chen 《Journal of Applied Mathematics and Physics》 2023年第8期2503-2514,共12页
This study focuses on a single-stage axial flow fan, investigating the effect of three kinds of wave leading edge stator blades on its noise reduction. The DDES method and the duct acoustic analogy theory based on the... This study focuses on a single-stage axial flow fan, investigating the effect of three kinds of wave leading edge stator blades on its noise reduction. The DDES method and the duct acoustic analogy theory based on the penetrable data surface were used for noise prediction. The results showed that the three kinds of wave leading edge blades were effective in reducing the rotor-stator interaction tonal noise and also have a certain inhibitory effect on broadband noise. The A10W15 stator blade can effectively reduce broadband noise in the frequency range of 2200 - 4200 Hz. When the amplitude is increased to 20, the noise reduction effect is further enhanced. However, when the amplitude is increased to 30, the broadband noise reduction effect is no longer significant. Further research shows that the wave leading edge stator blades can significantly change the pressure fluctuation distribution on the leading edge and suction surface, which control the modal energy distribution. Finally, this paper analyzed multiple factors affecting the broadband noise reduction, such as the noise source cut-off and cut-on effect and correlation. The purpose of this paper is to explore the laws of the influence of wave leading edge blades on the duct noise of real fan, and to reveal its noise control mechanism. . 展开更多
关键词 FAN Wave leading edge Blade Duct Noise Broadband Noise Noise Source Analysis
下载PDF
A Large-scale Tertiary Salt Nappe Complex in the Leading Edge of the Kuqa Foreland Fold-Thrust Belt, the Tarim Basin, Northwest China 被引量:7
3
作者 TANGLiangjie JINZhijun +4 位作者 JIAChengzao PIXuejun CHENShuping XIEHuiwen WANGZiyu 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2004年第3期691-700,共10页
The tectono-stratigraphic sequences of the Kuqa foreland fold-thrust belt in the northern Tarim basin, northwest China, can be divided into the Mesozoic sub-salt sequence, the Paleocene-Eocene salt sequence and the Ol... The tectono-stratigraphic sequences of the Kuqa foreland fold-thrust belt in the northern Tarim basin, northwest China, can be divided into the Mesozoic sub-salt sequence, the Paleocene-Eocene salt sequence and the Oligocene-Quaternary supra-salt sequence. The salt sequence is composed mainly of light grey halite, gypsum, marl and brown elastics. A variety of salt-related structures have developed in the Kuqa foreland fold belt, in which the most fascinating structures are salt nappe complex. Based on field observation, seismic interpretation and drilling data, a large-scale salt nappe complex has been identified. It trends approximately east-west for over 200 km and occurs along the west Qiulitag Mountains. Its thrusting displacement is over 30 km. The salt nappe complex appears as an arcuate zone projecting southwestwards along the leading edge of the Kuqa foreland fold belt. The major thrust fault is developed along the Paleocene-Eocene salt beds. The allochthonous nappes comprise large north-dipping faulting monoclines which are made up of Paleocene-Pliocene sediments. Geological analysis and cross-section restoration revealed that the salt nappes were mainly formed at the late Himalayan stage (c.a. 1.64 Ma BP) and have been active until the present day. Because of inhomogeneous thrusting, a great difference may exist in thrust displacement, thrust occurrence, superimposition of allochthonous and autochthonous sequences and the development of the salt-related structures, which indicates the segmentation along the salt nappes. Regional compression, gravitational gliding and spreading controlled the formation and evolution of the salt nappe complex in the Kuqa foreland fold belt. 展开更多
关键词 salt nappe structure thrust fault leading edge of the Kuqa foreland fold-thrust belt Tarim Basin
下载PDF
Effect of Flat Plate Leading Edge Pattern on Structure of Streamwise Vortices Generated in Its Boundary Layer 被引量:6
4
作者 Seyed Mohammad Hasheminejad Hatsari Mitsudharmadi Sonny Handojo Winoto 《Journal of Flow Control, Measurement & Visualization》 2014年第1期18-23,共6页
The use of leading edge with different geometrical patterns will affect the development of boundary layer flow on a flat plate and its heat transfer properties. In this work, the effects of three patterns namely saw-t... The use of leading edge with different geometrical patterns will affect the development of boundary layer flow on a flat plate and its heat transfer properties. In this work, the effects of three patterns namely saw-tooth, semicircular and slots with same wavelength and amplitude were examined. The experiments were carried out for Reynolds number based on wavelength of patterns ranging from 1540 to 3850. For all cases, after each valley, an oval shape region was formed containing a counter- rotating vortex pair. It is also shown that for the flat plate with slots, another vortex was visualized between each valley. 展开更多
关键词 leading edge PATTERN COUNTER Rotating Vortex Pair Saw-Tooth Semi-Circle SLOT
下载PDF
Aerodynamic improvement of a delta wing in combination with leading edge flaps 被引量:1
5
作者 Tadateru Ishide Mao Itazawa 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2017年第6期357-361,共5页
Recently, various studies of micro air vehicle (MAV) and unmanned air vehicle (UAV) have been reported from wide range points of view. The aim of this study is to research the aerodynamic improvement of delta wing... Recently, various studies of micro air vehicle (MAV) and unmanned air vehicle (UAV) have been reported from wide range points of view. The aim of this study is to research the aerodynamic improvement of delta wing in low Reynold's number region to develop an applicative these air vehicle. As an attractive tool in delta wing, leading edge flap (LEF) is employed to directly modify the strength and structure of vortices originating from the separation point along the leading edge. Various configurations of LEF such as drooping apex flap and upward deflected flap are used in combination to enhance the aerodynamic characteristics in the delta wing. The fluid force measurement by six component toad ceil and particle image velocimetry (PIV) analysis are performed as the experimental method. The relations between the aerodynamic superiority and the vortex behavior around the models are demonstrated. 展开更多
关键词 Delta wing leading edge flap PIV analysis leading edge vortex Aerodynamic characteristics
下载PDF
Research on Aerodynamic Characteristics of Hovering Rotor Based on Leading Edge Droop 被引量:1
6
作者 LI Congcong SHI Yongjie +1 位作者 XU Guohua MA Taihang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2021年第S01期10-16,共7页
In view of the reduction of hovering efficiency near high tension when a helicopter rotor hovers,a numerical simulation method of lifting rotor hovering aerodynamic characteristics based on leading edge droop is estab... In view of the reduction of hovering efficiency near high tension when a helicopter rotor hovers,a numerical simulation method of lifting rotor hovering aerodynamic characteristics based on leading edge droop is established in this paper. It is dominated by Reynolds average N-S equation in integral form. Firstly,VR-12 airfoil is taken as the research object,and the influence of leading edge droop angle on the aerodynamic characteristics of two-dimensional airfoil is studied. Secondly,the modified 7 A rotor is taken as the research object,and the effects of different leading edge droop angles at the position of blade r/R=0.75—1 on the aerodynamic characteristics in hover are explored. It is found that the leading edge droop can significantly improve the aerodynamic characteristics of two-dimensional airfoil and three-dimensional hovering rotor near high angle of attack,and can effectively inhibit the generation of stall vortex. 展开更多
关键词 helicopter rotor hovering leading edge droop aerodynamic characteristics
下载PDF
Effect of leading edge roughness on cavitation inception and development on thin hydrofoil 被引量:2
7
作者 TAO Ran XIAO Ruofu FARHAT Mohamed 《排灌机械工程学报》 EI CSCD 北大核心 2017年第11期921-926,940,共7页
The cavitation incipience and development of water flow over a thin hydrofoil placed in the test section of high-speed cavitation tunnel were investigated.Hydrofoils with smooth and rough leading edge were tested for ... The cavitation incipience and development of water flow over a thin hydrofoil placed in the test section of high-speed cavitation tunnel were investigated.Hydrofoils with smooth and rough leading edge were tested for different upstream velocities and incidence angles.The observations clearly revealed that cavitation incipience is enhanced by roughness at incidence angle below 2°.This is in line with the former reports,according to whose roughness element decreases the wettability and traps a larger amount of gas.As a result,surface nucleation is enhanced with an increased risk of cavitation.Surprisingly,for higher incidence angles(>3°),it was found that cavitation incipience is significantly delayed by roughness while developed cavitation is almost the same for both smooth and rough hydrofoils.This unexpected incipience delay is related to the change in the boundary layer structure due to roughness.It was also reported a significant influence of roughness on the dynamic of developed cavitation and shedding of transient cavities. 展开更多
关键词 cavitation inception surface roughness sheet cavitation cloud cavitation HYDROFOIL
下载PDF
CHARACTER OF SIMPLIFIED NAVIER-STOKES EQUATIONS FOR NEAR THE LEADING EDGE PART OF TWO-DIMENSIONAL LAMINAR FLOW PAST A FLAT PLATE
8
作者 田纪伟 王新生 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 1994年第4期351-360,共10页
Starting from the Simplified Navier-Stokes(SNS)equations presented at first by Godovachev-Kuzmin-Tsopov,and Gao Zhi,Davis,the authors analyze the character of the SNS equations for the laminarflow near the leading edg... Starting from the Simplified Navier-Stokes(SNS)equations presented at first by Godovachev-Kuzmin-Tsopov,and Gao Zhi,Davis,the authors analyze the character of the SNS equations for the laminarflow near the leading edge of a flat plate and far away from the plate by using the Weiner—Hopf meth-od and Fourier transform.It is proved that the solution of the SNS equations agree with the solution of the Navier-Stokes equations for flow near the leading edge of the plate and far away from the plate.How to match the solution of the SNS equations to the Blasius solution of the boundary layer equationsis also discussed. 展开更多
关键词 simplified NAVIER-STOKES equations Weiner-Hope method leading edge of a flat plate
原文传递
Proof of Concept in a Case Study of Glioblastoma Multiforme Successfully Treated with IV Quercetin in Combination with Leading Edge Gamma Knife and Standard Treatments
9
作者 M. A. Nezami Christopher Duma 《Journal of Cancer Therapy》 2018年第6期522-528,共7页
The Stupp protocol has become standard of care for the treatment of glioblastoma (GBM) (since its publication in 2005) and has led to some limited survival improvements. This protocol, consists of radiotherapy and con... The Stupp protocol has become standard of care for the treatment of glioblastoma (GBM) (since its publication in 2005) and has led to some limited survival improvements. This protocol, consists of radiotherapy and concomitant chemotherapy with temozolomide, an alkylating agent. Temozolomide + radiation, compared to radiation alone had added in average 3 months additional life span, 16 percent improved survival at 2 years. That said since 2005, the standard of care has not changed in regards to the treatment of early diagnosed aggressive or multifocal GBM, and unfortunately the expected survival is still poor with 75 percent of patients dying in less than 2 years and average survival of 15 months. In patients with multifocal tumors (such as the case below) the average survival is even worse with less than 4 months at her age [1]. Here we present a case study of a patient with advanced multifocal, and rapidly progressing Glioblastoma Multiforme treated with STUPP protocol in combination with IV Quercetin. The patient experienced improved quality of life and response, compared to historical data. It is our recommendation to investigate such combinational approach in patients with Glioblastoma, as in our case it proved to be safe and effective with improved quality of life and performance as well as clinical response and survival. 展开更多
关键词 QUERCETIN GLIOBLASTOMA leading edge GAMMA KNIFE
下载PDF
Selection and Impact of an Aerofoil Leading Edge on Boundary Layer Transition
10
作者 Dinesh Bhatia Devinder Kumar Yadav +2 位作者 Guangjun Yang Jian Wang Henrik Hesse 《Journal of Transportation Technologies》 2022年第4期778-803,共26页
The choice of leading-edge aspect ratio (AR) plays a crucial role when planning boundary layer wind tunnel tests on a flat plate. Poor selection of the leading-edge profile hampers effectiveness of the experiment and ... The choice of leading-edge aspect ratio (AR) plays a crucial role when planning boundary layer wind tunnel tests on a flat plate. Poor selection of the leading-edge profile hampers effectiveness of the experiment and increases testing costs associated with interchanging of leading edges to attain accurate results. Thus, the appropriate selection of the leading edge is a very crucial part of the wind tunnel experiment process. It is argued that the curvature of the leading edge and thus the AR is of paramount importance to achieve accurate results from the wind tunnel testing. In this project, seven different elliptical leading edges were tested, and their performance was compared with an ideal leading edge with zero thickness. Experiments and computation have been done for leading edges ranging from AR6 to AR20. Results were evaluated for boundary layer transition onset location, and it was found that AR20 has the least influence on the flow structure when compared to the ideal leading edge. A study of the flow structure at the stagnation point indicates an increase in adverse pressure gradient with an increase in the AR but also shows a decrease in the size of the stagnation region. The presence of a higher AR leading edge reduces the turbulent spot production rate, which is one of the primary causes of boundary layer transition. This paper presents a correlation that enables aerodynamicists to quantify the impact of the leading-edge AR on transition. A typical case is also presented to compare the relative performance of a wedge and the higher AR leading edge, which provides a choice between an elliptical or a wedge-shaped leading edge. 展开更多
关键词 Boundary Layer Transition leading edge Aspect Ratio CURVATURE Flow Structure Adverse Pressure Gradient
下载PDF
High-Velocity Impact Studies on Scaled Leading Edges of Horizontal Tail with Smart Composite Layers
11
作者 Basavanna Rangaiah Dhayanidhi Jeevarathinam +1 位作者 Raja Samikkannu Karisiddappa 《Advances in Aerospace Science and Technology》 2022年第1期32-51,共20页
Bird strike studies on typical aluminium leading edges of the Horizontal Tail (HT) with and without Glass Fibre Shape Memory Polymer (GF-SMP) layers are carried out. A one-fifth scaled model of HT is designed and fabr... Bird strike studies on typical aluminium leading edges of the Horizontal Tail (HT) with and without Glass Fibre Shape Memory Polymer (GF-SMP) layers are carried out. A one-fifth scaled model of HT is designed and fabricated. The parameters like bird dimension and energy requirements are accordingly scaled to conduct the bird strike tests. Two leading-edge components have been prepared, namely one with AL 2024-T3 aluminium alloy and the other specimen of the same dimension and material, additionally having GF-SMP composite layers inside the metallic leading edge, in order to enhance its impact resistance. Bird strike experiments are performed on both the specimens, impacting at the centre of the leading edge in the nose tip region with an impact velocity of 115 m/s. The test component is instrumented with linear post-yield strain gauges on the top side and the PZT sensors on the bottom. Furthermore, the impact scenario is monitored using a high-speed camera at 7000 fps. The bird strike event is simulated by an equation of state model, in which the mass of the bird is idealized using smooth particle hydrodynamics element in PAMCRASH<sup>?</sup><sup> </sup>explicit solver. The strain magnitude and its pattern including time duration are found to be in a good correlation between test and simulation. Key metrics are evaluated to devise an SHM scheme for the load and impact event monitoring using strain gauges and PZT sensors. GF-SMP layers have improved the impact resistance of the aluminium leading edge which is certainly encouraging towards finding a novel solution for the high-velocity impact. 展开更多
关键词 Glass Fibre Shape Memory Polymer (GF-SMP) Scaled Model High-Velocity Impact leading edge (le) Piezoelectric Sensor (PZT)
下载PDF
Leading-edge receptivity of boundary layer to three-dimensional free-stream turbulence
12
作者 Luyu SHEN Changgen LU Xiaoqing ZHU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2019年第6期851-860,共10页
The laminar-turbulent transition has always been a hot topic of fluid mechanics. Receptivity is the initial stage and plays a crucial role in the entire transition process. The previous studies of receptivity focus on... The laminar-turbulent transition has always been a hot topic of fluid mechanics. Receptivity is the initial stage and plays a crucial role in the entire transition process. The previous studies of receptivity focus on external disturbances such as sound waves and vortices in the free stream, whereas those on the leading-edge receptivity to the three-dimensional free-stream turbulence (FST), which is more general in the nature, are rarely reported. In consideration of this, this work is devoted to investigating the receptivity process of three-dimensional Tollmien-Schlichting (T-S) wave packets excited by the three-dimensional FST in a flat-plate boundary layer numerically. The relations between the leading-edge receptivity and the turbulence intensity are established, and the influence of the FST directions on the propagation directions and group velocities of the excited T-S wave packets is studied. Moreover, the leading-edge receptivity to the anisotropic FST is also studied. This parametric investigation can contribute to the prediction of laminar-turbulent transition. 展开更多
关键词 leading-edge RECEPTIVITY free-stream turbulence (FST) boundary layer THREE-DIMENSIONAL Tollmien-Schlichting (T-S) wave
下载PDF
Piezoelectric resonant ice protection systems–Part1/2:Prediction of power requirement for de-icing a NACA 0024 leading edge 被引量:1
13
作者 Valerian PALANQUE Jason POTHIN +1 位作者 Vale′rie POMMIER-BUDINGER Marc BUDINGER 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第3期92-103,共12页
This paper proposes a numerical method to analyze the ice protection capability and predict the power requirements of a piezoelectric resonant de-icing system.The method is based on a coupled electro-mechanical finite... This paper proposes a numerical method to analyze the ice protection capability and predict the power requirements of a piezoelectric resonant de-icing system.The method is based on a coupled electro-mechanical finite element analysis which enables the fast computation of the modes of resonance of interest to de-ice curved surfaces and the estimation of the input voltage and current required for a given configuration(defined by its mode,actuator location,ice deposit,etc.).Eventually,the electric power to be supplied can be also assessed.The method is applied to a NACA 0024 leading edge equipped with piezoelectric actuators.First,two extension modes are analyzed and compared with respect to their efficiency and power requirements.Then,tests are carried out in an icing tunnel to verify the effectiveness of the piezoelectric ice protection system and the predictions of the maximal required power.The system allows de-icing the leading edge in less than 2 s for a glaze ice deposit. 展开更多
关键词 Ice protection system PIEZOEleCTRIC Resonance mode Ice fracture leading edge de-icing
原文传递
Heat Transfer and Flow Structure of a Turbine Blade's Air-cooled Leading Edge Considering Different Hole Shapes and Additional Flow Angles
14
作者 QIN Runxuan ZHOU Xun +1 位作者 WANG Songtao CAI Le 《Journal of Thermal Science》 SCIE EI CAS CSCD 2024年第4期1421-1442,共22页
A numerical study is conducted to elucidate the impact of hole shapes and additional flow angles on the flow structure of the coolant and temperature field in the leading edge area of the gas turbine rotor.Four typica... A numerical study is conducted to elucidate the impact of hole shapes and additional flow angles on the flow structure of the coolant and temperature field in the leading edge area of the gas turbine rotor.Four typical hole shapes are considered for the GE-E3 blade.The impact of the additional flow angle(E)within each hole shape on the temperature field is investigated.The results indicate that for the leading edge area and suction surface,the fan-shaped hole case performs best in decreasing temperatures,with a decrease of about 43 K.This is mainly due to the fact that the fan-shaped hole has the maximum expansion in hole spanwise direction.For the pressure surface,the console hole case performs best in decreasing temperatures,with a maximum reduction of about 47.2 K.The influence of E on the surface temperature at leading edge area varied between the different hole shapes.For the cylinder hole and console hole,the E=-20°case has the lowest area-averaged temperature.Because both the fan-shaped hole and the 7-7-7 shaped hole are expansion holes,the pattern of variation of the leading edge area temperature with increasing E is similar for the fan-shaped hole case and 7-7-7 shaped hole case.The E=20°case shows the lowest spanwise-averaged temperature near the hole outlet,and the E=-20°case shows the lowest spanwise-averaged temperature further downstream. 展开更多
关键词 film cooling GE-E3 turbine rotor blade conjugate heat transfer leading edge
原文传递
Effects of Bionic Leading Edge on the Aerodynamic Performance of a Compressor Cascade at a Low Reynolds Number
15
作者 XU Huafeng ZHAO Shengfeng +1 位作者 WANG Mingyang YANG Chengwu 《Journal of Thermal Science》 SCIE EI CAS CSCD 2024年第4期1272-1285,共14页
To achieve high-performance compressor cascades at low Reynolds number(Re),it is important to organize the boundary layer transition and separation processes efficiently and reasonably.In this study,the airfoil is foc... To achieve high-performance compressor cascades at low Reynolds number(Re),it is important to organize the boundary layer transition and separation processes efficiently and reasonably.In this study,the airfoil is focused on at a 5%blade height at the root of the orthogonal blade in the downflow passage of the high-load booster stage.The bionics modeling design is carried out for the leading edge of the original blade cascade;the response characteristics of laminar transition and separation to blades with different leading edge shapes at low Reynolds numbers are studied by using large eddy simulations combined with Omega vortex identification.The findings of this study demonstrate that bionic leading edge modeling can significantly improve the aerodynamic performance of blades at low Reynolds numbers.The blades effectively suppress the formation of separation bubbles at low Reynolds numbers and weaken or even eliminate large-scale flow separation at the trailing edge.In addition,the blades can weaken the vortex intensity on the blade surface,reduce the areas of high-velocity fluctuations,and minimize aerodynamic losses caused by turbulence dissipation.These results should serve as a valuable reference for the aerodynamic design and flow control of the high-load booster stage blade at low Re. 展开更多
关键词 low Reynolds number booster stage bionic leading edge large eddy simulation
原文传递
Origin of Luminescent Centers and Edge States in Low-Dimensional Lead Halide Perovskites:Controversies,Challenges and Instructive Approaches 被引量:3
16
作者 Jiming Bao Viktor G.Hadjiev 《Nano-Micro Letters》 SCIE EI CAS CSCD 2019年第2期109-126,共18页
With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects,the defect-tolerant electronic and optical properties of lead halide perovskites have made ... With only a few deep-level defect states having a high formation energy and dominance of shallow carrier non-trapping defects,the defect-tolerant electronic and optical properties of lead halide perovskites have made them appealing materials for high-efficiency,low-cost,solar cells and light-emitting devices.As such,recent observations of apparently deep-level and highly luminescent states in low-dimensional perovskites have attracted enormous attention as well as intensive debates.The observed green emission in 2D CsPb2Br5 and 0 D Cs4PbBr6 poses an enigma over whether it is originated from intrinsic point defects or simply from highly luminescent CsPbBr3 nanocrystals embedded in the otherwise transparent wide band gap semiconductors.The nature of deep-level edge emission in 2D Ruddlesden–Popper perovskites is also not well understood.In this mini review,the experimental evidences that support the opposing interpretations are analyzed,and challenges and root causes forthe controversy are discussed.Shortcomings in the current density functional theory approaches to modeling of properties and intrinsic point defects in lead halide perovskites are also noted.Selected experimental approaches are suggested to better correlate property with structure of a material and help resolve the controversies.Understanding and identification of the origin of luminescent centers will help design and engineer perovskites for wide device applications. 展开更多
关键词 LOW-DIMENSIONAL perovskites LUMINESCENT CENTERS edge STATES Cesium leAD halides Deep-level STATES Ruddlesden–Popper perovskites
下载PDF
钛合金包边复合材料风扇叶片的鸟撞数值仿真
17
作者 金峰 刘璐璐 +3 位作者 朱信颖 罗刚 赵振华 陈伟 《航空发动机》 北大核心 2024年第4期107-113,共7页
为降低鸟体撞击航空发动机中带钛合金包边树脂基复合材料风扇叶片的试验成本,开展了数值仿真研究,为钛合金包边在航空发动机风扇叶片上的应用提供参考和依据。对风扇叶片进行简化,采用ABAQUS有限元软件构建了鸟撞带钛合金包边和不带钛... 为降低鸟体撞击航空发动机中带钛合金包边树脂基复合材料风扇叶片的试验成本,开展了数值仿真研究,为钛合金包边在航空发动机风扇叶片上的应用提供参考和依据。对风扇叶片进行简化,采用ABAQUS有限元软件构建了鸟撞带钛合金包边和不带钛合金包边的风扇叶片模型,其中,钛合金包边和复合材料叶片之间用粘结界面单元进行粘接,研究了不同鸟体冲击角度和速度下2种风扇叶片的损伤。结果表明:在鸟体冲击速度相同时,随着冲击角度的增大,风扇叶片的损伤增大且能量吸收率提高,在冲击角度也相同时,带钛合金包边的风扇叶片损伤更小且能量吸收率更高;在鸟体冲击角度相同时,随着冲击速度的加快,风扇叶片的损伤增大且能量吸收率提高;在鸟体冲击下,粘结界面单元最终发生拉伸破坏,在低速度冲击下还会发生剪切损伤。 展开更多
关键词 复合材料 风扇叶片 钛合金包边 鸟撞 数值仿真 航空发动机
下载PDF
随机加工偏差下前缘超差对高亚声速叶栅性能一致性影响
18
作者 高丽敏 杨光 +2 位作者 王浩浩 但玥 涂盼盼 《空气动力学学报》 CSCD 北大核心 2024年第10期109-118,共10页
针对叶片实际加工前缘易超差,但叶片其他区域满足加工容差的情况,本文构建了耦合前缘超差的叶型全弧长范围内带有随机轮廓加工偏差的数学模型,并通过基于稀疏网格的非嵌入混沌多项式方法,研究了加工偏差不确定性对高亚声速扩压叶栅气动... 针对叶片实际加工前缘易超差,但叶片其他区域满足加工容差的情况,本文构建了耦合前缘超差的叶型全弧长范围内带有随机轮廓加工偏差的数学模型,并通过基于稀疏网格的非嵌入混沌多项式方法,研究了加工偏差不确定性对高亚声速扩压叶栅气动性能一致性的影响。结果显示,在设计攻角下,叶型损失系数和静压比的一致性最高;在较大正攻角下,叶型性能参数一致性最低。造成性能一致性低的原因为前缘超差导致叶型前缘边界层内流动损失的平均水平和波动程度增大。当以设计叶型损失系数为±5%作为衡量标准时,在设计攻角和较大正攻角下,叶型性能一致性概率分别为99%和79.4%,此时因叶片几何轮廓不符合容差而舍弃叶片会导致较高的误判率。 展开更多
关键词 前缘 加工误差 不确定性量化 一致性 压气机叶栅
下载PDF
基于驻留时间控制的压气机叶片前缘砂带磨削研究
19
作者 黄云 桂林 +3 位作者 秦涛 王文玺 邹莱 李恒 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第4期1-9,共9页
提出了一种面向叶片前缘廓形精准控制的机器人砂带磨削加工方法.以轴流压气机叶片为研究对象,结合半赫兹接触理论和有限元仿真获取了柔性磨具和叶片前缘的接触区域内的应力分布,基于Preston方程求解材料去除函数.遍历刀位点对控制点的... 提出了一种面向叶片前缘廓形精准控制的机器人砂带磨削加工方法.以轴流压气机叶片为研究对象,结合半赫兹接触理论和有限元仿真获取了柔性磨具和叶片前缘的接触区域内的应力分布,基于Preston方程求解材料去除函数.遍历刀位点对控制点的磨削深度,建立全局材料去除矩阵,搭建驻留时间求解非线性方程组.采用带有阻尼因子的Tikhonov正则化消除大型稀疏病态矩阵对求解精度波动的影响,将所求驻留时间转换为对应刀位点的进给速度,生成机器人加工代码.磨削试验结果表明,基于驻留时间控制的机器人砂带磨削方法能够实现给定允差范围内叶片前缘廓形的精准加工,型面误差可以控制在0.02mm以内. 展开更多
关键词 压气机 砂带 柔性磨削 前缘廓形 驻留时间
下载PDF
高速平板边界层中定常条带的前缘感受性
20
作者 刘洋 赵磊 《空气动力学学报》 CSCD 北大核心 2024年第4期14-26,I0001,共14页
来流湍流度较高时,自由流涡波可在边界层内激发流向条带结构,并引起边界层的旁路(bypass)转捩。本文采用调和线性化Navier-Stokes方程(harmonic linearized Navier-Stokes,HLNS)方法模拟平板边界层条带对自由流涡波的前缘感受性,并通过... 来流湍流度较高时,自由流涡波可在边界层内激发流向条带结构,并引起边界层的旁路(bypass)转捩。本文采用调和线性化Navier-Stokes方程(harmonic linearized Navier-Stokes,HLNS)方法模拟平板边界层条带对自由流涡波的前缘感受性,并通过直接数值模拟验证了HLNS方法的可靠性。针对马赫数4.8的高速平板边界层,分析了零频涡波激发定常条带的前缘感受性过程及定常条带的演化规律。研究结果表明,边界层外的自由流涡扰动对边界层条带的发展存在持续的激励作用;对于固定展向波数的自由流涡波,法向波数为0时激发的条带幅值最大;自由流涡波的法向波数在小于临界角度时仅影响条带的幅值,而不影响条带扰动的形函数剖面。随着当地雷诺数的增加,条带的幅值演化和形函数剖面呈现出很好的相似性;当地无量纲展向波数β=0.18时,归一化幅值最大。 展开更多
关键词 定常条带 前缘感受性 自由流涡波 HLNS方法 高速边界层
下载PDF
上一页 1 2 41 下一页 到第
使用帮助 返回顶部