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A Computational Study of Thrust Vectoring Control Using Dual Throat Nozzle

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Journal of Thermal Science 2010年第6期19卷 486-490页

作者： Choon Sik Shin Heuy Dong Kim Toshiaki Setoguchi Shigeru Matsuo department of mechanical engineering Andong National University department of mechanical engineering Saga University

Dual throat nozzle (DTN) is fast becoming a popular technique for thrust vectoring. The DTN is designed with two throats, an upstream minimum and a downstream minimum at the nozzle exit, with a cavity in between the upstream throat and exit. In the present study, a computational work has been carried out to analyze the performance of a dual throat nozzle at various mass flow rates of secondary flow and nozzle pressure ratios (NPR). Two-dimensional, steady, compressible Navier-Stokes equations were solved using a fully implicit finite volume scheme. The present computational results were validated with available experimental data. Based on the present results, the control effectiveness of thrust-vectoring is discussed in terms of the thrust coefficient and the coefficient of discharge.

关键词： Compressible Flow Dual Throat Nozzle Thrust Vector Control Shock Wave Supersonic Flow

Recent progress in constructing fluorinated solid-electrolyte interphases for stable lithium metal anodes

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 270-291页

作者： Di Zhang Pengfei Lv Wei Qin Xin He Yuanhua He Civil Aircraft Fire Science and Safety engineering Key Laboratory of Sichuan Province College of Civil Aviation Safety EngineeringCivil Aviation Flight University of ChinaGuanghan 618307China School of Chemical engineering Sichuan UniversityChengdu 610065China

Lithium metal batteries(LMBs)are emerging as a promising energy storage solution owing to their high energy density and specific ***,the non-uniform plating of lithium and the potential rupture of the solid-electrolyte interphase(SEI)during extended cycling use may result in dendrite growth,which can penetrate the separator and pose significant short-circuit *** a stable SEI is essential for the long-term operation of the ***-rich SEI has garnered significant attention for its ability to effectively passivate electrodes,regulate lithium deposition,and inhibit electrolyte *** the structural components and preparation methods of existing fluorinated SEI is crucial for optimizing lithium metal anode *** paper reviews the research on optimizing LiF passivation interfaces to protect lithium metal *** focuses on four types of compositions in fluorinated SEI that work synergistically to enhance SEI *** instance,combining compounds with LiF can further enhance the mechanical strength and ionic conductivity of the *** metals with LiF significantly improves electrochemical performance at the SEI/anode interface,with a necessary focus on reducing electron tunneling ***,incorporating polymers with LiF offers balanced improvements in interfacial toughness and ionic conductivity,though maintaining structural stability over long cycles remains a critical area for future *** alloys combined with LiF increase surface energy and lithium affinity,challenges such as dendrite growth and volume expansion *** summary,this paper emphasizes the crucial role of interfacial structures in LMBs and offers comprehensive guidance for future design and development efforts in battery technology.

关键词： LiF lithium metal anodes solid-electrolyte interphase interface cycling stability

A review:On path planning strategies for navigation of mobile robot

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Defence Technology（防务技术） 2019年第4期15卷 582-606页

作者： B.K. Patle Ganesh Babu L Anish Pandey D.R.K. Parhi A. Jagadeesh department of mechanical engineering CVR College of Engineering Hyderabad India department of Mechatronics engineering Tishik International University Erbil Iraq department of mechanical engineering KITS University Bhubaneshwar India department of mechanical engineering NIT Rourkela India department of mechanical engineering KL University Guntur India

This paper presents the rigorous study of mobile robot navigation techniques used so *** step by step investigations of classical and reactive approaches are made here to understand the development of path planning strategies in various environmental conditions and to identify research *** classical approaches such as cell decomposition(CD),roadmap approach(RA),artificial potential field(APF);reactive approaches such as genetic algorithm(GA),fuzzy logic(FL),neural network(NN),firefly algorithm(FA),particle swarm optimization(PSO),ant colony optimization(ACO),bacterial foraging optimization(BFO),artificial bee colony(ABC),cuckoo search(CS),shuffled frog leaping algorithm(SFLA)and other miscellaneous algorithms(OMA)are considered for *** navigation over static and dynamic condition is analyzed(for single and multiple robot systems)and it has been observed that the reactive approaches are more robust and perform well in all terrain when compared to classical *** is also observed that the reactive approaches are used to improve the performance of the classical approaches as a hybrid ***,reactive approaches are more popular and widely used for path planning of mobile *** paper concludes with tabular data and charts comparing the frequency of individual navigational strategies which can be used for specific application in robotics.

关键词： Mobile robot navigation Path planning Classical approaches Reactive approaches Artificial intelligence

Experimental Study on Cross-Flow Induced Vibrations in Heat Exchanger Tube Bundle

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China Ocean engineering 2017年第1期31卷 91-97页

作者： KHUSHNOOD Shahab NIZAM Luqman Ahmad department of mechanical engineering University of Engineering and Technology Taxila Pakistan department of mechanical engineering HITEC University Taxila Pakistan

Vibration in heat exchangers is one of the main problems that the industry has faced over last few decades. Vibration phenomenon in heat exchangers is of major concern for designers and process engineers since it can lead to the tube damage, tube leakage, baffle damage, tube collision damage, fatigue, creep etc. In the present study, vibration response is analyzed on single tube located in the centre of the tube bundle having parallel triangular arrangement （60-） with P/D ratio of 1.44. The experiment is performed for two different flow conditions. This kind of experiment has not been reported in the literature. Under the first condition, the tube vibration response is analyzed when there is no internal flow in the tube and under the second condition, the response is analyzed when the internal tube flow is maintained at a constant value of 0.1 rn/s. The free stream shell side velocity ranges from 0.8 rn/s to 1.3 m/s, the reduced gap velocity varies from 1,80 to 2.66 and the Reynolds number varies from 44500 to 66000. It is observed that the internal tube flow results in larger vibration amplitudes for the tube than that without internal tube flow. It is also established that over the current range of shell side flow velocity, the turbulence is the dominant excitation mechanism for producing vibration in the tube since the amplitude varies directly with the increase in the shell side velocity. Damping has no significant effect on the vibration behavior of the tube for the current velocity range.

关键词： cross-flow tube bundle parallel Iriangular internal tube flow damping

Numerical solutions to heat transfer of nanofluid flow over stretching sheet subjected to variations of nanoparticle volume fraction and wall temperature

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Applied Mathematics and Mechanics(English Edition) 2014年第1期35卷 63-72页

作者： M.SALARI M.MOHAMMADTABAR A.MOHAMMADTABAR department of mechanical engineering Imam Hussein University department of mechanical engineering University of Alberta department of mechanical engineering Islamic Azad University

The numerical analysis of heat transfer of laminar nanofluid flow over a fiat stretching sheet is presented. Two sets of boundary conditions （BCs） axe analyzed, i.e., a constant （Case 1） and a linear streamwise variation of nanopaxticle volume fraction and wall temperature （Case 2）. The governing equations and BCs axe reduced to a set of nonlinear ordinary differential equations （ODEs） and the corresponding BCs, respectively. The dependencies of solutions on Prandtl number Pr, Lewis number Le, Brownian motion number Nb, and thermophoresis number Nt are studied in detail. The results show that the reduced Nusselt number and the reduced Sherwood number increase for the BCs of Case 2 compared with Case 1. The increases of Nb, Nt, and Le numbers cause a decrease of the reduced Nusselt number, while the reduced Sherwood number increases with the increase of Nb and Le numbers. For low Prandtl numbers, an increase of Nt number can cause to decrease in the reduced Sherwood number, while it increases for high Prandtl numbers.

关键词： stretching sheet nanofluid laminar boundary layer Brownian motion,thermophoresis partial differential equation numerical solution

Study of microstructure and flexural properties of microcellular acrylonitrile-butadiene-styrene nanocomposite foams: experimental results

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Applied Mathematics and Mechanics(English Edition) 2015年第4期36卷 487-498页

作者： A.MOHYEDDIN A.FEREIDOON I.TARAGHI department of mechanical engineering Parand BranchIslamic Azad University department of mechanical engineering Semnan University

In this paper, acrylonitrile-butadiene-styrene （ABS） nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative density ranging from 0.38 to 0.97. The effects of the processing conditions on the density, morphology, and flexural properties of ABS and its nanocomposite foams are studied. It is found that nanoclay particles, as nucleating sites, play an important role in reducing the size of cells and increasing their number in the unit volume of foamed polymer, as well as increasing the flexural modulus of foam through reinforcing its matrix.

关键词： acrylonitrile-butadiene-styrene (ABS) polymer-clay nanocomposite mi-crocellular foam flexural property

Cutting and wear behaviors of TiC based cermets cutter with nano-TiN modification

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中国有色金属学会会刊：英文版 2003年第4期13卷 869-875页

作者：刘宁许育东李振红陈名海谢峰 department of Materials Science and engineering department of mechanical and Automobile engineering

Cutting and wear properties of the TiC based cermets cutter with nano TiN addition were discussed in order to provide a theoretical basis for the practical application of such cermets cutter. Wear surface and quantitative analysis of chemical composition were conducted using SEM and EDX. The results reveal that this kind of cermets cutter shows higher endurance than the conventional cermets cutter and cemented carbides cutter (YT15). Normal wear occurs under the condition of lower cutting parameters, and tipping will be the predominant failure mode when the parameters are higher. SEM analysis shows that the grain wear, oxidation wear and diffusion wear all exist. In addition, oxidation and diffusion become very obvious when the cutting parameters are large.

关键词：刀具金属陶瓷碳化钛氮化钛磨损切削

Study of Thermal and Hydraulic Performances of Circular and Square Ribbed Rough Microchannels Using LBM

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Journal of Thermal Science 2015年第6期24卷 549-556页

作者： M.A.Taher H.D.Kim Y.W Lee department of mechanical and Automotive engineering Pukyong National University department of mechanical engineering Andong National University

The effects of roughness geometries and relative roughness height at the slip flow regime to investigate the thermal and hydraulic performances of microchannel have been considered in the present article using a thermal Lattice Boltzmann Method(TLBM).A two dimensional 9-bit(D2Q9)single relaxation time(SRT)model is used to simulate this *** micro-flows,the local density variation is still relatively small,but the total density changes,therefore,in order to account this density variation and its effect on the kinematic viscosityν,a new relaxation time proposed by Niu et al.[13]is *** roughness geometry is modeled as a series of square and circular riblets with a relative roughness height from 0%to 10%of the channel *** friction coefficients in terms of Poiseuille number(Pn)and the dimensionless heat transfer rate in terms of Nusselt number(Nu)have been discussed in order to analyze the roughness *** thermal-hydraulic performance(η)is calculated considering the simultaneous effects of thermal and fluid friction(pressure drop)at the slip flow regime at Knudsen number,Kn,ranging from 0.01 to 0.10 with other controlling parameters for both kind of *** results have been compared with previous published works and it is found to be in very good agreement.

关键词： Lattice-Boltzmann Friction factor Knudsen number Surface Roughness

Microstructural Characterization and Tensile Behavior of Rutile(TiO_2)-Reinforced AA6063 Aluminum Matrix Composites Prepared by Friction Stir Processing

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Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 52-62页

作者： Sahayam Joyson Abraham Isaac Dinaharan Jebaraj David Raja Selvam Esther Titilayo Akinlabi department of mechanical engineering V V College of Engineering department of mechanical engineering Science University of Johannesburg Auckland Park Kingsway Campus department of mechanical engineering Karunya Institute of Technology and Sciences

Rutile(TiO_2) particle-reinforced aluminum matrix composites were prepared by friction stir processing. The microstructure was studied using conventional and advanced characterization techniques. TiO_2 particles were found to be dispersed uniformly in the composite. Clusters of TiO_2 particles were observed at a higher particle content of 18 vol%. The interface between the TiO_2 particle and the aluminum matrix was characterized by the absence of pores and reactive ***-grain boundaries, ultra-fine grains and dislocation density were observed in the composites. TiO_2 particles improved the mechanical properties of the composites. However, a drop in tensile strength was observed at a higher particle content due to cluster formation. All the prepared composites exhibited ductile mode of fracture.

关键词： Aluminum matrix composites Friction stir processing Rutile Microstructure Tensile strength