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Investigations on High-Speed Flash Boiling Atomization of Fuel Based on numerical simulations

Computer Modeling in Engineering & Sciences 2024年第5期139卷 1427-1453页

作者： Wei Zhong Zhenfang Xin Lihua Wang Haiping Liu School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai200092China Beijing Mechanical Equipment Research Institute Beijing100854China

Flash boiling atomization(FBA)is a promising approach for enhancing spray atomization,which can generate a fine and more evenly distributed spray by increasing the fuel injection temperature or reducing the ambient pressure.However,when the outlet speed of the nozzle exceeds 400 m/s,investigating high-speed flash boiling atomization(HFBA)becomes quite challenging.This difficulty arises fromthe involvement ofmany complex physical processes and the requirement for a very fine mesh in numerical simulations.In this study,an HFBA model for gasoline direct injection(GDI)is established.This model incorporates primary and secondary atomization,as well as vaporization and boilingmodels,to describe the development process of the flash boiling spray.Compared to lowspeed FBA,these physical processes significantly impact HFBA.In this model,the Eulerian description is utilized for modeling the gas,and the Lagrangian description is applied to model the droplets,which effectively captures the movement of the droplets and avoids excessive mesh in the Eulerian coordinates.Under various conditions,numerical solutions of the Sauter mean diameter(SMD)for GDI show good agreement with experimental data,validating the proposed model’s performance.simulations based on this HFBA model investigate the influences of fuel injection temperature and ambient pressure on the atomization process.numerical analyses of the velocity field,temperature field,vapor mass fraction distribution,particle size distribution,and spray penetration length under different superheat degrees reveal that high injection temperature or low ambient pressure significantly affects the formation of small and dispersed droplet distribution.This effect is conducive to the refinement of spray particles and enhances atomization.

关键词： High-speed flash boiling atomization numerical simulations Eulerian description Lagrangian description gasoline direct injection

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numerical simulations of One-Directional Fractional Pharmacokinetics Model

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Computers, Materials & Continua 2022年第12期73卷 4923-4934页

作者： Nursyazwani Mohamad Noor Siti Ainor Mohd Yatim Nur Intan Raihana Ruhaiyem School of Distance Education Universiti Sains MalaysiaUSM PenangPenang11800Malaysia School of Computer Science Universiti Sains MalaysiaUSM PenangPenang11800Malaysia

In this paper,we present a three-compartment of pharmacokinetics model with irreversible rate constants.The compartment consists of arterial blood,tissues and venous blood.Fick’s principle and the law of mass action were used to develop the model based on the diffusion process.The model is modified into a fractional pharmacokinetics model with the sense of Caputo derivative.The existence and uniqueness of the model are investigated and the positivity of the model is established.The behaviour of the model is investigated by implementing numerical algorithms for the numerical solution of the system of fractional differential equations.MATLAB software is used to plot the graphs for illustrating the variation of drug concentration concerning time.Therefore,the numerical simulations of the model are presented for different values ofαwhich verified the theoretical analysis.Besides,we also observed the pattern of the simulations at the three-compartment of the model by using different values of initial conditions.

关键词： Pharmacokinetics model Irreversible rate Fractional order numerical simulations

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Vertical impedance functions of pile groups under low-to-high loading amplitudes:numerical simulations and experimental validation

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Earthquake Engineering and Engineering Vibration 2023年第3期22卷 647-666页

作者： Usama Zafar Chandra Shekhar Goit Masato Saitoh Riku Fukuda School of Science and Engineering Saitama University255 Shimo-OkuboSaitamaJapan

Piles in a group experience additional displacements in soil due to pile-to-pile interactions apart from those resulting from the external loading.The effect of these interactions determined assuming soil as an elastic and/or viscoelastic material on pile head impedance functions of the pile group is studied by relating the group stiffness to the static stiffness of a single pile.However,the prevailing elastic solutions may misestimate the resulting pile group response due to the lack of consideration for either soil(material)and/or soil-pile interface nonlinearities.It is well established that soil behaves nonlinearly under moderate-to-high loading amplitudes,and besides,the soil-pile interface nonlinearity can exist even at small loading amplitudes.This study addresses the effects of these nonlinearities on the vertical impedance functions of a 3×3-pile group using numerical methods by direct analyses and superposition using pile-to-pile interaction factors.The numerical results are validated using scaled model tests under 1 g conditions.The results highlight the overestimation of pile-to-pile interactions in the pile group when assuming elastic soil conditions.The cases either by direct analyses or superposition approach involving soil and soil-pile interface nonlinearities agree well with the experimental pile group responses under close-to-elastic and nonlinear conditions.

关键词： impedance functions numerical simulations model-scale experiment superposition approach soil-pile interface nonlinearity

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Image Representations of numerical simulations for Training Neural Networks

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Computer Modeling in Engineering & Sciences 2023年第2期134卷 821-833页

作者： Yiming Zhang Zhiran Gao Xueya Wang Qi Liu School of Civil and Transportation Engineering Hebei University of TechnologyTianjin300401China School of Computer and Software Nanjing University of Information Science&TechnologyNanjing210044China

A large amount of data can partly assure good fitting quality for the trained neural networks.When the quantity of experimental or on-site monitoring data is commonly insufficient and the quality is difficult to control in engineering practice,numerical simulations can provide a large amount of controlled high quality data.Once the neural networks are trained by such data,they can be used for predicting the properties/responses of the engineering objects instantly,saving the further computing efforts of simulation tools.Correspondingly,a strategy for efficiently transferring the input and output data used and obtained in numerical simulations to neural networks is desirable for engineers and programmers.In this work,we proposed a simple image representation strategy of numerical simulations,where the input and output data are all represented by images.The temporal and spatial information is kept and the data are greatly compressed.In addition,the results are readable for not only computers but also human resources.Some examples are given,indicating the effectiveness of the proposed strategy.

关键词： numerical simulations neural network pre-/post-processing data compression

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On the effect of pitch and yaw angles in oblique impacts of smallcaliber projectiles

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Defence Technology（防务技术） 2024年第1期31卷 73-94页

作者： Teresa Fras French-German Research Institute of Saint-Louis(ISL) Saint-LouisFrance

A terminal ballistic analysis of the effects of 7.62 mm × 51 AP P80 rounds on inclined high-strength armor steel plates is the focus of the presented study.The findings of an instrumented ballistic testing combined with 3D advanced numerical simulations performed using the IMPETUS Afea? software yielded the conclusions.The experimental verification proved that slight differences in the pitch-andyaw angles of a projectile upon an impact caused different damage types to the projectile’s core.The residual velocities predicted numerically were close to the experimental values and the calculated core deviations were in satisfactory agreement with the experimental results.An extended matrix of the core deviation angles with combinations of pitch-and-yaw upon impact angles was subsequently built on the basis of the numerical study.The presented experimental and numerical investigation examined thoroughly the influence of the initial pitch and yaw angles on the after-perforation projectile’s performance.

关键词： Ballistic impact Small-caliber projectile Pitch and yaw impact angles Shadowgraphy IMPETUS Afea numerical simulations

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numerical simulations AND DOPPLER RADAR DATA ANALYSIS OF A HAIL PROCESS IN HUAIHE RIVER BASIN

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Acta meteorologica Sinica 2002年第3期16卷 388-400,404页

作者：李柏许小峰周昆 Nanjing Institute of Meteorology Nanjing 210044 China Meteorological Administration Beijing 100081 Meteorological Observatory of Anhui Province Hefei 230061

A hail process in Huaihe River Basin observed by CINRAD Doppler radar on 12May 2000 has been simulated by using nonhydrostatic mesoscale numerical model MM5.The simulated wind field is analyzed and compared with Doppler radar wind data,both of them show that there was a meso-β cyclone around the hail region.Results show that this meso-β cyclone existed below 3 km in the troposphere and its cyclonic circulation was very obvious below 1 km.The temperature and moisture fields from the simulation are also analyzed.Furthermore,the storm-relative environmental helicity and CAPE(convective available potential energy)are discussed.

关键词： hail process numerical simulations radar observation meso-β cyclone

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Urban flood inundation and damage assessment based on numerical simulations of design rainstorms with different characteristics

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Science China(Technological Sciences) 2020年第11期63卷 2292-2304页

作者： MEI Chao LIU JiaHong WANG Hao LI ZeJin YANG ZhiYong SHAO WeiWei DING XiangYi WENG BaiSha YU YingDong YAN DianYi State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing 100038China Engineering and Technology Research Center for Water Resources and Hydroecology of the Ministry of Water Resources Beijing 100044China

In the context of global climate change and urbanization,urban flooding is an important type of natural disaster that affects urban development,especially in China,which is experiencing rapid urbanization.In the past 10 years,urban flooding events have caused huge disaster losses in Chinese cities.This has resulted in significant negative effects on the urban infrastructure,socioeconomic systems,and urban residents,thus causing widespread concern.Studies have confirmed the change in extreme rainstorms is due to the changing environments in many cities globally.Conducting studies on the impact of these rainstorms with different characteristics for urban flooding is valuable for coping with unfavorable situations.In addition,numerical simulations provide an economical and viable means to perform these studies.This paper presents a numerical model of Xiamen Island in China.simulations were conducted for 12 design rainstorm events with different return periods,rain patterns,and durations.The results indicate that,in the case of an equal rainfall amount,the rainfall intensity is the key factor that affects the inundated area,depth,and damages.However,the rainfall intensity is not the only determining factor;the rainfall pattern also affects the inundations.In regard to the rainfall pattern,a higher rainfall peak coefficient usually leads to severe urban inundation and damage.As a result,the lag time would be shorter,which may further exacerbate the impact of urban flood disasters.The results of this study provide insights into managing flood risks,developing urban flood prevention strategies,and designing flood prevention measures.

关键词： urban flood flood damage assessment flood disaster management numerical simulations design rainstorms

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New lump interaction complexitons to the(2+1)-dimensional Korteweg-de Vries equation with electrostatic wave potential in plasmas

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Journal of Ocean Engineering and Science 2024年第2期9卷 173-177页

作者： Tukur Abdulkadir Sulaiman Abdullahi Yusuf Alrazi Abdeljabbar Mustafa Bayram Department of Computer Engineering Biruni UniversityIstanbulTurkey Department of Mathematics Federal University DutseJigawaNigeria Department of Mathematics Near East University TRNCMersin 10Turkey Department of Mathematics Khalifa University for Science and TechnologyAbu DhabiUAE

A soliton is a packet of self-reinforcing waves that maintains its structure when moving at a constant speed.Solitons are caused by the cancellation of the medium’s nonlinear and dispersive effects.In plas-mas,the bilinear form of Hirota will be utilized to investigate the(2+1)-dimensional Korteweg-de Vries equation with electrostatic wave potential.Solutions for complexiton lump interaction have been devel-oped.To throw further light on the physical qualities of the recorded data,certain 3-dimensional and contour plots are presented to illustrate the interaction elements of these solutions.

关键词： (2+1)-dimensional Korteweg-de Vries equation Multi waves solutions Brether waves solutions numerical simulations

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STRESS-STRAIN HYSTERESIS OF Cu-Zn-Al POLYCRYSTALLINE SMAs─Ⅱ: EXPERIMENTS AND numerical simulations

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Acta Metallurgica Sinica(English Letters) 1999年第3期12卷 211-215页

作者： Y. Chen Y. Huo X. Zu M. Tu and Y. Gou ( Department of Metal Materials, Sichuan University, Chengdu 610065, China)( Department of Metal Materials, Sichuan University, Chengdu 610065, China)( Department of Metal Materials, Sichuan University, Chengdu 610 Sichuan Univ Chengdu China

In this paper, the stress-strain bys torests at various temperatures was investigated experimentally for Cu-Zn-Al polycrystalline shape memory alloys (SMAs). numerical simulations of the pseudoelastic hysteresis were performed based on a model, which had been proposed by the authors. As observed in the experiments, the shapes of the outer loops of the hysteresis varied strongly from specimen to specimen, which have the same chemical composition but different heat-treatment. Rather complicated inner hysteretic curves were obtained at testing temperatures higher than Af. The numerical simulations of the stress-strain hysteresis and the inner hysteretic curves agreed quite well with the experimental results.

关键词： shape memory alloys (SMAs) hystcresls inner hysteretic Beavior pseudoelasticity numerical simulations

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numerical simulations of kinetic formation mechanism of Tangjiashan landslide

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Journal of Rock Mechanics and Geotechnical Engineering 2012年第2期4卷 149-159页

作者： Gang Luo Xiewen Hu Chengzhuang Gu Ying Wang Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu610031China Aseismic Engineering Technology Key Laboratory of Sichuan Province Southwest Jiaotong UniversityChengdu610031China

Tangjiashan landslide is a typical high-speed landslide hosted on consequent bedding rock. The landslide was induced by Wenchuan earthquake at a medium-steep hill slope. The occurrence of Tangjiashan landslide was basically controlled by the tectonic structure, topography, stratum lithology, slope structure, seismic waves, and strike of river. Among various factors, the seismic loading with great intensity and long duration was dominant. The landslide initiation exhibited the local amplification effect of seismic waves at the rear of the slope, the dislocation effect on the fault, and the shear failure differentiating effect on the regions between the soft and the hard layers. Based on field investigations and with the employment of the distinct element numerical simulation program UDEC （universal distinct element code）, the whole kinetic sliding process of Tan iashan landslide was represented and the formation mechanism of the consequent rock landslide under seismic loading was studied. The results are helpful for understanding seismic dynamic responses of consequent bedding rock slopes, where the slope stability could be governed by earthquakes.

关键词： Tangjiashan high-speed landslide formation mechahism sliding process numerical simulations

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