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Dynamic characteristics and application of dual throat fluidic thrust vectoring nozzle

CHINESE JOURNAL OF AERONAUTICS 2024年第9期37卷 85-99页

作者： Xu, Buxian Hu, Dongping Feng, Lihao Beihang Univ Fluid Mech Key Lab Minist Educ Beijing 100191 Peoples R China dongfang turbine co ltd State Key Lab Clean & Efficient Turbomachinery Pow Dongfang Elect Corp Deyang 618000 Peoples R China

Thrust vectoring technology plays an important role in improving the maneuverability of aircraft. In order to overcome the disadvantages of mechanical thrust vectoring nozzles, such as complications of structure and significant increases in weight and cost, fluidic thrust vectoring nozzles are proposed. Dual Throat fluidic thrust vectoring Nozzle (DTN) has received wide attention due to its excellent thrust vectoring efficiency and minimal thrust loss. In this study, three-dimensional unsteady numerical simulations of a single axisymmetric DTN are conducted first to analyze its dynamic response. Then the pitch and yaw control characteristics of DTN equipped on a flying-wing aircraft are investigated. It is found that the dynamic response will experience three stages: rapid-deflecting stage, oscillating stage, and steady stage. A complete recirculation zone forms at the end of the rapid-deflecting stage, which pushes the primary flow to attach to the wall opposite the secondary injection. Meanwhile, the exhaust flow is deflected. In terms of DTN's application, the DTN equipped on the flying-wing aircraft is capable of providing effective pitch and yaw moments at all angles of attack and Mach numbers. In addition, continuous pitch and yaw moments can be obtained by adjusting the secondary mass flow ratios. The control moment is generated due to the asymmetrical pressure distribution of nozzle surface, which is mainly contributed by the pressure decrease on the secondary injection surface. Moreover, the DTN equipped on the flying-wing aircraft has a relatively high thrust vectoring efficiency of around 5 degrees/% and a thrust coefficient of around 0.95 when nozzle pressure ratio equals 4. These results provide an important theoretical basis for the practical application of DTN. (c) 2024 Production and hosting by Elsevier ltd. on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://creativecommo

关键词： Dual throat nozzle Dynamic response characteristic Flow control Flying-wing aircraft

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Oxidation behavior of 4774DD1 Ni-based single-crystal superalloy at 980℃ in air

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China Foundry 2024年第2期21卷 116-124页

作者： Yu Fang Ya-zhou Li Qiang Yang Qun-gong He Xiu-fang Gong Qian Duan Hai-yang Song Fu Wang Qiong-yuan Zhang Hong Zeng State Key Laboratory of Long-Life High Temperature Materials Dongfang Turbine Co.Ltd.Deyang 618000SichuanChina State Key Laboratory for Manufacturing System Engineering School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China

The oxidation behavior of a novel Ni-based single-crystal 4774DD1 superalloy for industrial gas turbine applications was investigated by the isothermal oxidation at 980℃ and discontinuous oxidation weight gain *** phase constitution and morphology of surface oxides and the characteristics of the crosssection oxide film were analyzed by XRD,SEM and *** show that the oxidation kinetics of the 4774DD1 superalloy follows the cubic law,indicating its weak oxidation resistance at this *** the oxidation time increases,the composition of the oxide film evolves as following:One layer consisting of a bottom Al_(2)O_(3)sublayer and an upper(Al_(2)O_(3)+NiO)mixture sublayer after oxidized for 25 ***,two layers composed of an outermost small NiO discontinuous grain layer and an internal layer for 75 *** internal layer is consisted of the bottom Al_(2)O_(3)sublayer,an intermediate narrow CrTaO_(4)sublayer,and an upper(Al_(2)O_(3)+NiO)mixture *** two layers comprising an outermost relative continuous NiO layer with large grain size and an internal layer as the oxidation time increases to 125 *** internal layer is composed of the upper(Al_(2)O_(3)+NiO)mixture sublayer,an intermediate continuous(CrTaO_(4)+NiWO_(4))mixture sublayer,and a bottom Al_(2)O_(3)***,three layers consisting of an outermost(NiAl2O_(4)+NiCr2O_(4))mixture layer,an intermediate(CrTaO_(4)+NiWO_(4))mixture layer,and a bottom Al_(2)O_(3)layer for 200 h.

关键词： nickel-base single crystal superalloy oxidation kinetics oxide film microstructure mechanism

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Optimization of the co-closing law of guide vanes and blades for bulb turbines based on CFD

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Journal of Hydrodynamics 2024年第2期36卷 363-377页

作者： Hui Liu Yun-fa Lin Yong-guang Cheng Song Xue Mao-jia Tang Jian Zhang Jia-yi Fan State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China dongfang Electric Machinery co. Ltd.Deyang618000China

The load rejection transient process of bulb turbine units is critical to safety of hydropower stations,and determining appropriate closing laws of guide vanes(GVs)and runner blades(RBs)for this process is of *** this study,we proposed a procedure to optimize the co-closing law of GVs and RBs by using computational fluid dynamics(CFD),combined with the design of experiment(DOE)method,approximation model,and genetic optimization *** sensitivity of closing law parameters on the histories of head,speed,and thrust was analyzed,and a two-stage GVs’closing law associating with a linear RBs’closing law was *** results show that GVs dominate the transient characteristics by controlling the change of *** GVs’first-stage closing speed while shortening first-stage closing time can not only significantly reduce the maximum rotational speed but also suppress the water hammer pressure;slowing GVs’second-stage closing speed is conducive to controlling the maximum reverse axial *** directly affect the runner *** RBs’closing speed can further reduce the rotational speed and the maximum reverse axial *** safety margin of each control parameter,flow patterns,and pressure pulsations of a practical hydropower station were all improved after optimization,demonstrating the effectiveness of this method.

关键词： Bulb turbine load rejection transient process double regulation closing law optimization computational fluid dynamics(CFD)

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Preparation and property of seal coating for gas turbine compressor

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China Welding 2024年第1期33卷 60-64页

作者：余沛坰刘中华郑健生徐伏根陈千宝 Zhejiang Rancon turbine Machinery co. Ltd.Hangzhou 310020China Hangzhou Steam turbine Power Group co. Ltd.Hangzhou 310020China

Double-layer structure of seal coating which consisted of a Ni5Al bond coating and a Ni25 graphite top coating were prepared on steel substrate of gas turbine compressor cylinder *** coating was prepared by atmospheric plasma spraying and top coating was prepared by flame *** microstructure,mechanical properties and abradability of the coating were characterized by scanning elec-tron microscope(SEM),hardness tester,universal testing machine,thermal shock testing machine and abradability testing *** res-ults show that the overall spraying structure of the seal coating is uniform,the nickel metal phase is the skeleton supporting the entire coat-ing,and the coating is well bonded without *** seal coating has a bonding strength of not less than 7.7 MPa,excellent thermal stability,and thermal shock resistance cycle numbers at 500℃more than 50;the scratch length,deepest invasion depth and wear amount of the coating increase with rise of test temperature,with almost no coating adhesion,indicating that the seal coating has excellent abradability.

关键词： gas turbine compressor seal coating microstructure mechanical property abradability

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An improved deviation model for transonic stages in axial compressors

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Chinese Journal of Aeronautics 2024年第7期37卷 93-108页

作者： Xiaochen WANG Xuesong LI Xiaodong REN Chunwei GU Xiaobin QUE Guoyu ZHOU Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China China United Gas turbine Technology co.ltd. Beijing 102209China

Deviation model is an important model for through-flow analysis in axial *** analysis in classical deviation models is developed under the assumption of onedimensional flow,which is controlled by the continuity *** consider three-dimensional characteristics in transonic flow,this study proposes an improved theoretical analysis method combining force analysis of the blade-to-blade flow with conventional analysis of the continuity *** of shock structures on transverse force,streamwise velocity and streamline curvature in the blade-to-blade flow are analyzed,and support the analytical modelling of density flow ratio between inlet and outlet ***,a novel deviation model for transonic stages in axial compressors is proposed in this *** empirical coefficients are corrected based on the experimental data of a linear cascade,and the prediction accuracy is validated with the experimental data of a three-stage transonic *** novel model provides accurate predictions for meridional flow fields at the design point and performance curves at design speed,and shows obvious improvements on classical models by Carter and C¸etin.

关键词： Axial compressor Transonic flow Deviation model Through-flow method Aerodynamic performance

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Analytical Model and Topology Optimization of Doubly-fed Induction Generator

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 162-169页

作者： Lu Sun Haoyu Kang Jin Wang Zequan Li Jianjun Liu Yiming Ma Libing Zhou the State Key Laboratory of Advanced Electromagnetic Technology School of Electrical and Electronic EngineeringHuazhong University of Science and TechnologyWuhan 430074China IEEE dongfang Electric Machinery co. LtdDongfang Electric CorporationDeyangChina CSG PGC Energy Storage Research Institute Southern Power Grid Energy Storage Co.LtdGuangzhou 510630China

As the core component of energy conversion for large wind turbines,the output performance of doubly-fed induction generators (DFIGs) plays a decisive role in the power quality of wind *** realize the fast and accurate design optimization of DFIGs,this paper proposes a novel hybriddriven surrogate-assisted optimization *** firstly establishes an accurate subdomain model of DFIGs to analytically predict performance ***,taking the inexpensive analytical dataset produced by the subdomain model as the source domain and the expensive finite element analysis dataset as the target domain,a high-precision surrogate model is trained in a transfer learning way and used for the subsequent multi-objective optimization *** on this model,taking the total harmonic distortion of electromotive force,cogging torque,and iron loss as objectives,and the slot and inner/outer diameters as parameters for optimizing the topology,achieve a rapid and accurate electromagnetic design for ***,experiments are carried out on a 3MW DFIG to validate the effectiveness of the proposed method.

关键词： Doubly-fed induction generators Accurate subdomain model Surrogate-assisted Transfer learning

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Experimental study on secondary air mixing along the bed height in a circulating fluidized bed with a multitracer-gas method

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Chinese Journal of Chemical Engineering 2024年第6期70卷 54-62页

作者： Qingyu Zhang Leming Cheng Kun Li Qixun Kang Qiang Guo Chaogang Wu Institute for Thermal Power Engineering State Key Laboratory of Clean Energy UtilizationZhejiang UniversityHangzhou 310027China dongfang Boiler Group co.ltd. Zigong 643001China

A multitracer-gas method was proposed to study the secondary air(SA)mixing along the bed height in a circulating fluidized bed(CFB)using carbon monoxide(co),oxygen(O_(2)),and carbon dioxide(co_(2))as tracer *** were carried out on a cold CFB test rig with a cross-section of 0.42 m×0.73 m and a height of 5.50 *** effects of superficial velocity,SA ratio,bed inventory,and particle diameter on the SA mixing were *** results indicate that there are some differences in the measurement results obtained using different tracer gases,wherein the deviation between co and co_(2) ranges from 42%to 66%and that between O_(2) and co_(2) ranges from 45%to 71%in the lower part of the fluidized ***,these differences became less pronounced as the bed height ***,the high solid concentration and fine particle diameter in the CFB may weaken the *** measurement results of different tracer gases show the same trends under the variation of operating *** superficial velocity and SA ratio and decreasing particle diameter result in better mixing of the *** effect of bed inventory on SA mixing is not monotonic.

关键词： Circulating fluidized bed Secondary air injection Gas mixing Multitracer-gas method

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Effect of the grain boundary character distribution on the sulfur corrosion behaviour and mechanisms of copper windings under different high temperatures

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HIGH VOLTAGE 2024年第3期9卷 566-580页

作者： Dai, Xu Yuan, Yuan Zhou, Jiang Liu, Guoyong Zhu, Tao Xiang, Huiying Yu, Qi Gao, Xue Liao, Ruijin Chongqing Univ State Key Lab Power Transmiss Equipment & Syst Sec Chongqing Peoples R China Chongqing Univ Coll Mat Sci & Engn Chongqing Peoples R China dongfang Elect Machinery co ltd Deyang Peoples R China

As a typical failure phenomenon in transformers, sulfur corrosion has garnered significant attention in the field of high-voltage engineering. Grain boundary character distribution (GBCD) copper windings have been introduced to enhance sulfur corrosion resistance by slowing down intergranular corrosion. In this study, the sulfur corrosion behaviour and mechanisms of the GBCD copper windings under various temperatures were experimentally and theoretically studied. Results show that GBCD can enhance the corrosion resistance of copper in liquid environments. With the increase in temperatures, the insulating properties of oil and papers in traditional copper windings experience notable degradation, while GBCD copper windings show more stable insulating behaviours. In addition, modelling of grain boundary energy indicates that the grain boundary structure of GBCD copper windings has a lower average interface energy of 0.170 eV/angstrom 2. Calculations of reaction thermodynamics show that GBCD copper windings possess a higher failure temperature (135.2 degrees C) and inhibition degree (activation energy) of the sulfur corrosion (32,557.62 J/mol), revealing the stability and enhanced sulfur corrosion resistance at elevated temperatures.

关键词： OIL-PAPER INSULATION DIBENZYL DISULFIDE POWER TRANSFORMERS STAINLESS-STEEL STRENGTH

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Local tetragonal distortion of Pt alloy catalysts for enhanced oxygen reduction reaction efficiency

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Carbon Energy 2024年第7期6卷 41-52页

作者： Xiaoke Li Xiao Duan Kang Hua Yongkang Wu Zhiyan Rui Rui Ding Aidong Li Chen Ouyang Jia Li Ting Li Jianguo Liu National Laboratory of Solid-State Microstructures College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjingChina Long-Life Fuel Cell Key Laboratory in Sichuan Province Dongfang Electric(Chengdu)Hydrogen Fuel Cell Technology Co.Ltd.ChengduChina Institute of Energy Power Innovation North China Electric Power UniversityBeijingChina

Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and catalytic performance is still ***,we present a synthetic strategy that uses transition-metal oxide-assisted thermal ***/C catalysts with localized tetragonal distortion were obtained by controlling the thermal diffusion process of transition-metal *** localized structural distortion induced a significant strain effect on the nanoparticle surface,which further shortened the length of the Pt-Pt bond,improved the electronic state of the Pt surface,and enhanced the performance of the ***/C catalysts with special short-range structures achieved excellent mass activity(2.27 Amg_(Pt)^(-1))and specific activity(3.34 A cm^(-2)).In addition,the localized tetragonal distortion-induced surface compression of the Pt skin improved the stability of the *** mass activity decreased by only 13%after 30,000 *** catalyst activity and excellent durability have also been demonstrated in the proton exchange membrane fuel cell *** study provides valuable insights into the development of advanced Pt-based nanocatalysts and paves the way for reducing noble-metal loading and increasing the catalytic activity and catalyst stability.

关键词： electrocatalysts fuel cells local tetragonal distortion oxygen reduction

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High toughness and CMAS resistance of REAlO_(3)/RE_(2)Zr_(2)O_(7)(RE=La,Nd,Sm,Eu,Gd,and Dy)composites with eutectic composition for thermal barrier coatings

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Journal of Advanced Ceramics 2024年第6期13卷 800-809页

作者： Zijian Zhang Jian Sun Guanghua Liu Yi Han Wei Liu Yi Li Wei Wang Xiangyang Liu Peng Zhang Wei Pan Chunlei Wan State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China China United Gas turbine Technology co. Ltd.Beijing 100015China college of Mathematics and Physics Beijing University of Chemical TechnologyBeijing 100029China college of Materials Science and Engineering Beijing University of TechnologyBeijing 100124China

Although rare earth zirconates(RE_(2)Zr_(2)O_(7))have garnered attention as viable candidates for thermal barrier coatings(TBCs),they suffer from low fracture toughness and accelerated calcium–magnesium–alumina–silicate(CMAS)melt corrosion at high service temperatures,which impedes their practical *** this work,we developed a series of REAlO_(3)/RE_(2)Zr_(2)O_(7)(RE=La,Nd,Sm,Eu,Gd,and Dy)composites with a eutectic composition that not only significantly enhanced the fracture toughness by more than 40%relative to that of RE_(2)Zr_(2)O_(7)but also exhibited improved resistance to CMAS *** increase in toughness arises from multiple mechanisms,such as ferroelastic toughening,fine-grain strengthening,and residual stress toughening,all of which trigger more crack defects and energy ***,the CMAS penetration depth of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites is approximately 36%lower than that of RE_(2)Zr_(2)O_(7).Al–O constituents in composites can capture CaO,SiO_(2),and MgO in CMAS melts and increase their viscosity,resulting in enhanced CMAS corrosion *** thermophysical properties of the REAlO_(3)/RE_(2)Zr_(2)O_(7)composites were also investigated,and their coefficient of thermal expansion and thermal conductivity are comparable to those of 7–8 wt%Y_(2)O_(3)partially stabilized ZrO2(YSZ),indicating their potential as TBC materials.

关键词： fracture toughness thermal property calcium-magnesium-alumina-silicate(CMAS)corrosion REAlO_(3)/RE_(2)Zr_(2)O_(7) eutectic composition

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