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Integrated optimization analyses of aerodynamic/stealth characteristics of helicopter rotor based on surrogate model

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Chinese Journal of Aeronautics 2015年第3期28卷 737-748页

作者： Jiang Xiangwen Zhao qijun Zhao Guoqing Li Peng National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics

Abstract Based on computational fluid dynamics （CFD） method, electromagnetic high-frequency method and surrogate model optimization techniques, an integration design method about aerody- namic/stealth has been established for helicopter rotor. The developed integration design method is composed of three modules： integrated grids generation （the moving-embedded grids for CFD sol- ver and the blade grids for radar cross section （RCS） solver are generated by solving Poisson equa- tions and folding approach）, aerodynamic/stealth solver （the aerodynamic characteristics are simulated by CFD method based upon NavieStokes equations and Spalart-Allmaras （S-A） tur- bulence model）, and the stealth characteristics are calculated by using a panel edge method combining the method of physical optics （PO）, equivalent currents （MEC） and quasi-stationary （MQS）, and integrated optimization analysis （based upon the surrogate model optimization technique with full factorial design （FFD） and radial basis function （RBF）, an integrated optimization analyses on aerodynamic/stealth characteristics of rotor are conducted. Firstly, the scattering characteristics of the rotor with different blade-tip swept and twist angles have been carried out, then timfrequency domain grayscale with strong scattering regions of rotor have been given. Meanwhile, the effects of swept-tip and twist angles on the aerodynamic characteristic of rotor have been performed. Furthermore, by choosing suitable object function and constraint condition, the compromised design about swept and twist combinations of rotor with high aerodynamic performances and low scattering characteristics has been given at last.

关键词： Aerodynamic characteristicsEquivalent currents Physical optics Quasi stationary Rotor Radar cross section Stealth characteristics Surrogate model

A New Single-blade Based Hybrid CFD Method for Hovering and Forward-flight Rotor Computation

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Chinese Journal of Aeronautics 2011年第2期24卷 127-135页

作者： SHI Yongjie ZHAO qijun FAN Feng XU Guohua National Key Laboratory of Rotorcraft Aeromechanics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

A hybrid Euler/full potential/Lagrangian wake method,based on single-blade simulation,for predicting unsteady aerodynamic flow around helicopter rotors in hover and forward flight has been *** this method,an Euler solver is used to model the near wake evolution and transonic flow phenomena in the vicinity of the blade,and a full potential equation（FPE） is used to model the isentropic potential flow region far away from the rotor,while the wake effects of other blades and the far wake are incorporated into the flow solution as an induced inflow distribution using a Lagrangian based wake *** further reduce the execution time,the computational fluid dynamics（CFD） solution and rotor wake analysis（including induced velocity up-date） are conducted parallelly,and a load balancing strategy is employed to account for the information exchange between two *** the developed method,several hover and forward-flight cases on Caradonna-Tung and Helishape 7A rotors are *** agreements of the loadings on blade surface with available measured data demonstrate the validation of the ***,the CPU time required for different computation runs is compared in the paper,and the results show that the pre-sent hybrid method is superior to conventional CFD method in time cost,and will be more efficient with the number of blades increasing.

关键词： hybrid CFD method Euler equations full potential equations wake model rotor helicopters

Calculations of β-decay half-lives of proton-rich nuclei

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Science China(Physics,Mechanics & Astronomy) 2012年第12期55卷 2397-2406页

作者： NI DongDong REN ZhongZhou ZHI qijun Department of Physics Nanjing UniversityNanjing 210093China Kavli Institute for Theoretical Physics China Beijing 100190China Center of Theoretical Nuclear Physics National Laboratory of Heavy-Ion AcceleratorLanzhou 730000China GSI Helmholtzzentrum für Schwerionenforschung DarmstadtGermany School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China

We investigate the half-lives of β + /EC(electron capture) decay using the proton-neutron quasiparticle random-phase approximation(pnQRPA) with a δ-form Gamow-Teller residual *** particle-hole and particle-particle residual interactions are consistently introduced in dealing with the pnQRPA matrix *** sensitivity of the calculated half-lives to some physical quantities used in the calculations is *** are performed for even-even neutron-deficient isotopes ranging from Z = 10 to Z = *** agreement between experiment and theory is achieved especially for the nuclei far from stability,and the results of our calculations are discussed with comparison with other theoretical *** on the β-decay half-lives of some very neutron-deficient nuclei are also given for reference in future experiments.

关键词： proton-rich nuclei β-decay half-lives quasiparticle random-phase approximation

一体化压裂液对佳县区块致密气储层伤害实验研究

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油气井测试 2024年第2期33卷 9-14页

作者：卢军凯曾祺俊李云子罗成孙宏晶卢聪中国石油冀东油田分公司钻采工艺研究院河北唐山063000 西南石油大学“油气藏地质及开发工程”全国重点实验室四川成都610500

为分析压裂液对J区块致密气储层的伤害,采用压裂液评价实验方法,从压裂液性能参数、对储层基质的伤害、对填砂裂缝伤害三个方面进行实验评价,研究了压裂液基液对致密储层基质和填砂裂缝的影响。结果表明,鄂尔多斯盆地J区块现场所用的一... 详细信息

为分析压裂液对J区块致密气储层的伤害,采用压裂液评价实验方法,从压裂液性能参数、对储层基质的伤害、对填砂裂缝伤害三个方面进行实验评价,研究了压裂液基液对致密储层基质和填砂裂缝的影响。结果表明,鄂尔多斯盆地J区块现场所用的一体化变黏压裂液对致密气储层的伤害率为19.83%~2..32.,伤害还表现出渗透率越低岩心损害率越大的特征;随着返排压差的增大,压裂液对岩心的伤害程度明显降低,返排压差大于6 MPa时,损害率降低缓慢,最大可降低至10.96%;裂缝导流能力伤害率随着闭合应力逐渐增加,在高闭合应力条件下裂缝导流能力伤害程度大于低闭合应力条件;低铺砂浓度的裂缝导流能力对压裂液敏感性较强,相同条件下低铺砂浓度导流能力伤害率更大。研究为鄂尔多斯盆地J区块致密储层改造压裂液体系优化有一定实际意义。

关键词：鄂尔多斯盆地致密气储层一体化压裂液渗透率储层伤害导流能力返排压差

The function-oriented precursor selection for the preparation of carbon dots

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Nano Research 2023年第8期16卷 11221-11249页

作者： Yalan Xu Chan Wang Huan Zhuo Dongrun Zhou qijun Song Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi 214122China

As a new type of fluorescent nanomaterials,carbon dots(CDs)have exhibited excellent photoluminescence properties with tunable emission and high quantum yields,hence they have attracted an increasing interest in diverse research *** photoluminescence performance of CDs is primarily influenced by their precursors,which directly or indirectly determine the structures and specific functions of the resultant *** this review,we aim to summarize the recent progress on synthesis of CDs using small aliphatic molecules,anilines,polyphenol,polycyclic aromatic hydrocarbons,organic dyes,or biomass as *** associations of the physical and chemical properties of the CDs with their respective precursors are comprehensively investigated,and the potential applications and future development of CDs are discussed in *** is hoped that this review will open new horizons for CDs preparation by rational selection of the precursors from the vastly available carbon sources and the critical comments presented,here could inspire and guide future research in the design of multifunctional CDs.

关键词： carbon dots precursors photoluminescence fluorophore sensing imaging

基于CFD/CSD耦合的TEF旋翼气弹特性高精度模拟

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航空学报 2024年第18期45卷 147-162页

作者：王华龙张夏阳赵国庆招启军马砾南京航空航天大学直升机动力学全国重点实验室南京210016

为分析前飞状态带有后缘小翼的旋翼的气弹特性,建立了一套基于计算流体力学/计算结构动力学(CFD/CSD)耦合的高精度分析方法。基于参数化建模发展了一套含动态后缘小翼的旋翼运动嵌套网格方法。在气动分析方面,在传统气动模型的基础上引... 详细信息

为分析前飞状态带有后缘小翼的旋翼的气弹特性,建立了一套基于计算流体力学/计算结构动力学(CFD/CSD)耦合的高精度分析方法。基于参数化建模发展了一套含动态后缘小翼的旋翼运动嵌套网格方法。在气动分析方面,在传统气动模型的基础上引入高精度CFD方法,可以精确模拟旋翼非定常流场和气动特性。在结构方面,建立了刚性后缘小翼动力学模型,以附加质量、阻尼、刚度等矩阵的形式考虑刚性后缘小翼运动对旋翼系统的影响,基于Hamilton原理和Timoshenko梁模型建立了系统的非线性动力学方程。采用基于代数变换的弹性网格变形方法,在此基础上发展流固非定常耦合策略。通过对比模型旋翼和SA349/2.翼气弹响应的计算结果,验证了CFD/CSD耦合方法的有效性。以带后缘小翼的SMART旋翼为算例,与桨叶剖面等效法向力系数的计算结果进行了对比;着重开展Fulton模型旋翼的计算分析,分别研究悬停状态下桨根扭矩和前飞状态下挥舞弯矩幅值的变化规律,并与文献结果进行对比。结果表明:所建立的CFD/CSD耦合方法可以提高旋翼非定常气弹载荷的分析精度,精确捕捉低速前飞旋翼的桨-涡干扰(BVI)现象,挥舞弯矩平均误差可控制在11.68%;同时计算得到的带后缘小翼的桨叶固有频率误差不超过4.0%,桨根挥舞弯矩幅值平均误差为15.15%,能够有效模拟后缘小翼的气弹特性。在单一后缘小翼操纵规律下,Fulton旋翼的桨毂垂向力Fz能够得到有效控制,载荷幅值的降幅可达80%以上。

关键词：旋翼动力学后缘小翼气动弹性 CFD/CSD方法气弹载荷

Multi-Layered CPG for Adaptive Walking of Quadruped Robots

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Journal of Bionic Engineering 2018年第2期15卷 341-355页

作者： Chengju Liu Li Xia Changzhu Zhang qijun Chen School of Electronics and Information Engineering Tongji University Shanghai 201804 China

This work concerns biped adaptive walking control on slope terrains with online trajectory generation. In terms of the lack of satis- factory performances of the traditional simplified single-layered Central Pattern Generator （CPG） model in engineering applications where robots face unknown environments and access feedback, this paper presents a Multi-Layered CPG （ML-CPG） model based on a half-center CPG model. The proposed ML-CPG model is used as the underlying low-level controller for a quadruped robot to generate adaptive walking patterns. Rhythm-generation and pattern formation interneurons are modeled to promptly generate motion rhythm and patterns for motion sequence control, while motoneurons are modeled to control the output strength of the joint in real time according to feedback. Referring to the motion control mechanisms of animals, a control structure is built for a quadruped robot. Multi-sensor models abstracted from the neural reflexes of animals are involved in all the layers of neurons through various feedback paths to achieve adaptability as well as the coordinated motion control of a robot＇s limbs. The simulation experiments verify the effectiveness of the pre- sented ML-CPG and multi-layered reflexes strategy.

关键词： Multi-Layered CPG (ML-CPG) biological reflex quadruped robot adaptive walking

Aeroelastic analysis and structural parametric design of composite rotor blade

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Chinese Journal of Aeronautics 2021年第1期34卷 336-349页

作者： Li MA qijun ZHAO Kai ZHANG Xiayang ZHANG Mengmeng ZHAO National Key Laboratory of Science and Technology on Rotorcraft Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Based on FEM theory,a method of dynamic analysis for hingeless rotors considering anisotropic composite materials is established.A parametric modeling method of composite blade with typical profile and high simulation degree for design is *** the finite element method,the profile characteristics of rotor blade can be obtained efficiently and accurately,and the synchronization of parametric design and finite element analysis of structural characteristics can be *** a 2.-degrees of freedom non-linear beam element is used to simulate the extended one-dimensional beam,thereby a nonlinear differential equation describing the elastic motion of the rotor is *** obtain the crosssectional target characteristics of the blades,an inverse design method is proposed for cross-section components based on combinatorial optimization *** calculation and validation work show that the proposed model can effectively analyze the aeroelastic characteristics of general composite ***,the influence of cross-sectional parameters on the aeroelastic stability and hub loads of hingeless rotor is analyzed and some remarkable conclusions are obtained.

关键词： Aeroelastic stability Composite material Cross-section analysis Hub loads Inverse design Rotor

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高速直升机推力桨气动干扰特性研究

飞行力学 2024年第4期42卷 13-20页

作者：廖霆汉曹宸恺招启军陈希赵国庆南京航空航天大学直升机动力学全国重点实验室江苏南京210016

针对前飞状态高速直升机全机气动干扰特性开展了研究。首先,基于动量源方法建立共轴刚性旋翼气动分析模型,并通过与试验结果对比,验证了数值模拟方法的可靠性;然后,采用滑移网格方法建立推力桨干扰的数值计算模型,采用非结构网格对机身... 详细信息

针对前飞状态高速直升机全机气动干扰特性开展了研究。首先,基于动量源方法建立共轴刚性旋翼气动分析模型,并通过与试验结果对比,验证了数值模拟方法的可靠性;然后,采用滑移网格方法建立推力桨干扰的数值计算模型,采用非结构网格对机身进行划分;最后,开展了旋翼、机身、平/垂尾等对推力桨气动干扰的模拟,分析了平尾气动布局参数对推力桨气动特性的影响规律。结果表明:相较于孤立推力桨,全机干扰情况下推力桨推力系数降低、巡航效率提高;随着平尾负安装角增大,在相同推力桨总距情况下,推力桨推力系数和功率系数均增大。

关键词：高速直升机推力桨气动布局动量源方法滑移网格