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Numerical Investigation of Flow and Heat Transfer in Vane Impingement/Effusion Cooling with Various Rib/Dimple Structure

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Journal of Thermal Science 2023年第4期32卷 1357-1377页

作者： wang Mingrui ZHU Huiren LIU Cunliang wang Rui WU Zhuang YAO Chunyi School of Power and Energy Northwestern Polytechnical UniversityXi’an710129China

By investigating heat transfer and flow structures of dimples,orthogonal ribs,and V-shaped ribs in the impingement/effusion cooling,the article is dedicated to selecting a best-performing internal cooling structure for a turbine *** overall cooling effectiveness and coolant consumption are adopted to evaluate the cooling *** analyze the influence of structural modification,the flow field is investigated on chordwise/spanwise sections and the target *** blockage effect on crossflow can protect jet flow,resulting in higher heat transfer performance of the target *** own a stronger blockage effect than *** with the blockage effect,the influence of the rib shape is *** installing dimples between ribs,heat transfer is augmented *** introduction of ribs/dimples leads to higher discharge coefficients of jet nozzles but lower discharge coefficients of film ***,the film cooling ***,the installation of the ribs and dimples decreases total coolant *** effect of ribs/dimples on heat transfer and effusion condition of internal and external cooling is *** best-performing cooling structure is the target surface with dimples and orthogonal ribs,which decreases the wall temperature and coolant consumption by 14.57-28.03 K and 1.19%-1.81%*** article concludes the flow mechanism for dimples and influence factors on the cooling performance,which may serve as guidance for the turbine vane design.

关键词： conjugate heat transfer impingement cooling dimple V-shape rib discharge coefficient

Enhanced extraction of essential oil from Cinnamomum cassia bark by ultrasound assisted hydrodistillation

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Chinese Journal of Chemical Engineering 2021年第8期34卷 38-46页

作者： Guanghui Chen Fengrui Sun Shougui wang Weiwen wang Jipeng Dong Fei Gao Key Laboratory of Mutiphase Flow Reaction and Separation Engineering of Shandong Province College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China Fundamental Chemistry Experiment Center(Gaomi) Qingdao University of Science and TechnologyGaomi 261500China

Cinnamon essential oil with many bioactivities is an important raw material for the production of various chemicals,and the conventional hydrodistillation(HD)for cinnamon oil extraction always require a longer extraction *** this work,ultrasound-assisted hydrodistillation extraction(UAHDE)technique was employed to enhance the extraction efficiency of essential oils from cinnamon *** parameters with significant effects on the essential oil extraction efficiency(ultrasound time,ultrasound power,extraction time,liquid–solid ratio)were optimized,and the proposed UAHDE was compared with the conventional HD extraction in terms of the extraction time,extraction yield,and physicochemical properties of extracted *** to the HD extraction,the UAHDE resulted in a shorter extraction time and a higher extraction *** GC–MS analysis,the UAHDE provided more valuable essential oil with a high content of the vital trans-cinnamaldehyde compounds compared with the *** electron micrograph(SEM)confirmed the efficiency of ultrasound irradiation for cinnamon oil *** addition,the analysis of electric consumption and CO_(2) emission shows that the UAHDE process is a more economic and environment-friendly ***,UAHDE is an efficient and green technology for the cinnamon essential oil extraction,which could improve the quantity and quality of cinnamon oils.

关键词： Cinnamon oil Extraction Ultrasound Distillation Optimization Chemical composition

Fast and accurate adaptive collocation iteration method for orbit dynamic problems

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Chinese Journal of Aeronautics 2023年第9期36卷 231-242页

作者： Honghua DAI Zhe ZHANG Xuechuan wang Haoyang FENG Changtao wang Xiaokui YUE National Key Laboratory of Aerospace Flight Dynamics(AFDL) Northwestern Polytechnical UniversityXi’an 710072China School of Astronautics Northwestern Polytechnical UniversityXi’an 710072China

For over half a century,numerical integration methods based on finite difference,such as the Runge-Kutta method and the Euler method,have been popular and widely used for solving orbit dynamic *** general,a small integration step size is always required to suppress the increase of the accumulated computation error,which leads to a relatively slow computation ***,a collocation iteration method,approximating the solutions of orbit dynamic problems iteratively,has been *** method achieves high computation accuracy with extremely large step *** efficient,the collocation iteration method suffers from two limitations:(A)the computational error limit of the approximate solution is not clear;(B)extensive trials and errors are always required in tuning *** overcome these problems,the influence mechanism of how the dynamic problems and parameters affect the error limit of the collocation iteration method is *** this basis,a parameter adjustment method known as the“polishing method”is proposed to improve the computation *** method proposed is demonstrated in three typical orbit dynamic problems in aerospace engineering:a low Earth orbit propagation problem,a Molniya orbit propagation problem,and a geostationary orbit propagation *** simulations show that the proposed polishing method is faster and more accurate than the finite-difference-based method and the most advanced collocation iteration method.

关键词： Collocation iteration method Numerical integration method Orbit dynamics Parameter adjustment method Polishing method

One-pot synthesis of arginine modified hydroxyapatite carbon microsphere composites for efficient removal of U(Ⅵ) from aqueous solutions

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Science Bulletin 2017年第23期62卷 1609-1618页

作者： Dongxu Yang Xiangxue wang Gang Song Guixia Zhao Zhe Chen Shujun Yu Pengcheng Gu Hongqing wang Xiangke wang College of Environmental Science and Engineering North China Electric Power University School of Chemistry and Chemical Engineering University of South China Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources Guangzhou University

Uranium was not only the main source of nuclear energy but also one of the long-lived ***, a novel arginine modified hydroxyapatite carbon microsphere composites(defined as C@HAp/Arg) obtained promptly via a one-step mild hydrothermal method, was applied to remove U(Ⅵ) from aqueous solutions. Based on the characterization of transmission electron microscopy(TEM), scanning electron microscopy(SEM), Fourier transformed infrared spectroscopy(FT-IR), X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS), the synthesized C@HAp/Arg presented globular morphology and abundant functional groups(e.g., —COO^-), which were beneficial to its combination with U(Ⅵ). The interaction mechanism and removal capability of U(Ⅵ) on C@HAp/Arg were studied by batch adsorption technique and spectroscopy analysis. The results implied that U(Ⅵ) can form strong surface complexes on C@HAp/Arg. The kinetics adsorption of U(Ⅵ) followed pseudo-second-order kinetic model with high removal efficiency($95% within 5h at pH 5.0). The adsorption isotherms were well fitted by Langmuir model, implying that U(Ⅵ) uptake on C@HAp/Arg was monolayer coverage. It was found that the maximum adsorption capacities of CSs, C@HAp and C@HAp/Arg toward U(Ⅵ) were calculated to be 23.16,72.09 and 569.66 mg/g, respectively, at 298.15 K and pH 5.0, and thermodynamic parameters revealed that the adsorption processes of U(Ⅵ) were spontaneous and endothermic. In addition, effect of co-existed ions and CO_3^(2-)concentrations demonstrated that U(Ⅵ) adsorption on C@HAp/Arg was weakly interfered by foreign ions and carbonate concentrations. More importantly, the adsorption performance of U(Ⅵ) on C@HAp/Arg was still over $87% after five cycles. Therefore, it was noted that the versatile C@HAp/Arg could be potentially used as a powerful building block for the enrichment and disposal of U(Ⅵ) from aqueous solutions, which could efficiently reduce the potential toxicity of U(Ⅵ) in the U(Ⅵ)-contaminated wate

关键词： U(Ⅵ) C@HAp/Arg composites Interaction mechanism Adsorption

Chirally assembled plasmonic metamolecules from intrinsically chiral nanoparticles

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Nano Research 2022年第10期15卷 9447-9453页

作者： Jiahao Pan Xiaoyao wang Jinjin Zhang Qin Zhang Qiangbin wang Chao Zhou School of Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China CAS Key Laboratory of Nano-Bio Interface Suzhou Key Laboratory of Functional Molecular Imaging TechnologyDivision of Nanobiomedicine and i-labSuzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou 215123China Nano Science and Technology Institute University of Science and Technology of ChinaSuzhou 215123China Jiangsu Key Laboratory of Thin Films School of Physical Science and TechnologySoochow UniversitySuzhou 215006China College of Materials Sciences and Opto-Electronic Technology University of Chinese Academy of SciencesBeijing 100049China

Significant chiroptical responses could be generated by chiral coupling of achiral plasmonic nanoparticles,or originated from intrinsically chiral plasmonic *** we create dimeric plasmonic metamolecules possessing both chiral coupling between nanoparticles and intrinsic chiroptical responses derived from nanoparticles *** plasmonic metamolecules are prepared by assembling helical plasmonic nanorods(HPNRs)with intrinsic chirality in chiral manners on DNA origami *** HPNRs with the same or opposite chirality,or one HPNR and one achiral gold nanorod,are coupled chirally into dimeric metamolecules with intriguing plasmonic circular dichroism(PCD).We found that both of the intrinsic chirality of constituent HPNRs and the chiral coupling contribute to the overall PCD while their weights are different in different metamolecules and vary in different wavelength range for a certain *** to conventional chiral plasmonic metamolecules from achiral nanoparticles,or discrete chiral nanoparticles,these metamolecules bring more dimensions for tailoring chiroptical responses and make it more flexible to design plasmonic nanodevices with custom PCD.

关键词： chiral plasmonics DNA origami plasmonic circular dichroism gold nanoparticle

Modeling radiative effects of haze on summer-time convective precipitation over North China： a case study

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Frontiers of Environmental Science & Engineering 2016年第4期10卷 105-114页

作者： Xuying wang Bin ZHANG School of Environment Tsinghua University Beijing 100084 China Chinese Academy for Environmental Planning Beijing 100012 China Ministry of Education Key Laboratory for Earth System Modeling Center for Earth System Science Institute for Global Change Studies Tsinghua University Beijing 100084 China

The impact of haze radiative effect on summertime 24-h convective precipitation over North China was investigated using WRF model （version 3.3） through model sensitivity studies between scenarios with and without aerosol radiative effects. The haze radiative effect was represented by incorporating an idealized aerosol optical profile, with AOD values around 1, derived from the aircraft measurement into the WRF shortwave scheme. We found that the shortwave heating induced by aerosol radiative effects would significantly reduce heavy rainfalls, although its effect on the post-frontal localized thunderstorm precipitation was more diverse. To capture the key factors that determine whether precipitation is enhanced or suppressed, model grids with 24-h precipitation difference between the ：two scenarios exceeding certain threshold （〉30 mm or〈 -30 mm） were separated into two sets. Analyses of key meteorological variables between the enhanced and suppressed regimes suggested that atmospheric convection was the most important factor that determined whether precipitation was enhanced or suppressed during summertime over North China. The convection was stronger over places with precipitation enhancement over 30 mm. Haze weakened the convection over places with precipitation suppression exceeding 30 mm and caused less water vapor to rise to a higher level and thus further suppressed precipitation. The suppression of precipitation was often accompanied with relatively high convective available potential energy （CAPE）, relative humidity （RH） and updraft velocities.

关键词： Haze Aerosol radiative effects Convective precipitation

Joint 2D DOA and Doppler frequency estimation for L-shaped array using compressive sensing

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Journal of Systems Engineering and Electronics 2020年第1期31卷 28-36页

作者： wang Shixin ZHAO Yuan LAILA Ibrahim XIONG Ying wang Jun TANG Bin School of Information and Communication Engineering University of Electronic Science and Technology of China

A joint two-dimensional(2D)direction-of-arrival(DOA)and radial Doppler frequency estimation method for the L-shaped array is proposed in this paper based on the compressive sensing(CS)*** from the conventional CS-based methods where the joint spatial-temporal parameters are characterized in one large scale matrix,three smaller scale matrices with independent azimuth,elevation and Doppler frequency are introduced adopting a separable observation ***,the estimation is achieved by L1-norm minimization and the Bayesian CS *** addition,under the L-shaped array topology,the azimuth and elevation are separated yet coupled to the same radial Doppler ***,the pair matching problem is solved with the aid of the radial Doppler ***,numerical simulations corroborate the feasibility and validity of the proposed algorithm.

关键词： electronic warfare L-shaped array joint parameter estimation L1-norm minimization Bayesian compressive sensing(CS) pair matching

Influence of deformation on the corrosion behavior of LZ91 Mg-Li alloy

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International Journal of Minerals,Metallurgy and Materials 2023年第1期30卷 72-81页

作者： Xueqin Liu Xuejian wang Enyu Guo Zongning Chen Huijun Kang Tongmin wang Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116024China Ningbo Institute of Dalian University of Technology Ningbo 315000China

The effect of rolling and forging on the microstructure and corrosion behavior of LZ91 alloy was investigated using an electron probe micro-analyzer,immersion and electrochemical *** showed that the area fraction of theβ-Li phase remained unchanged,and the grain size of theβ-Li phase decreased after *** as-rolled forged alloy(FR-LZ91)exhibited the highest area fraction of theβ-Li phase and the longest *** corrosion resistance of the forged LZ91 alloy increased due to grain refinement that prevented further corrosion during the immersion *** the experimental alloys,FR-LZ91 showed the highest resistance of corrosion film and charge transfer resistance values due to its protective film caused by the high area fraction of theβ-Li phase.

关键词： magnesium lithium alloy deformation electrochemical test corrosion behavior

Study of white-light flares observed by Hinode

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Chinese Journal of Astronomy and Astrophysics 2009年第2期9卷 127-132页

作者： Hai-Min wang Space Weather Research Lab Center for Solar Terrestrial Research New Jersey Institute of Technology Newark NJ 07102 USA

White-light flares are considered to be the most energetic flaring events that are observable in the optical broad-band continuum of the solar spectrum. They have not been commonly observed. Observations of white-light flares with sub-arcsecond resolution have been very rare. The continuous high resolution observations of Hinode provide a unique opportunity to systematically study the white-light flares with a spatial resolution around 0.2 arcsec. We surveyed all the flares above GOES magnitude C5.0 since the launch of Hinode in 2006 October. 13 of these kinds of flares were covered by the Hinode G-band observations. We analyzed the peak contrasts and equivalent areas （calculated via integrated excess emission contrast） of these flares as a function of the GOES X-ray flux, and found that the cut-off visibility is likely around M1 flares under the observing limit of Hinode. Many other observational and physical factors should affect the visibility of white-light flares; as the observing conditions are improved, smaller flares are likely to have detectable white-light emissions. We are cautious that this limiting visibility is an overestimate, because G-band observations contain emissions from the upper atmosphere. Among the 13 events analyzed, only the M8.7 flare of 2007 June 4 had near-simultaneous observations in both the G-band and the blue continuum. The blue continuum had a peak contrast of 94% vs. 175% in G-band for this event. The equivalent area in the blue continuum is an order of magnitude lower than that in the G-band. Very recently, Jess et al. studied a C2.0 flare with a peak contrast of 300% in the blue continuum. Compared to the events presented in this letter, that event is probably an unusual white-light flare： a very small kernel with a large contrast that can be detected in high resolution observations.

关键词： Sun activity - Sun flares - Sun magnetic fields