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temperature distribution study during the friction stir welding process of Al2024-T3 aluminum alloy

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International Journal of Minerals,Metallurgy and Materials 2013年第8期20卷 779-787页

作者： Y.H.Yau A.Hussain R.K.Lalwani H.K.Chan N.Hakimi Department of Mechanical Engineering University of Malaya50603 KLMalaysia

Heat flux characteristics are critical to good quality welding obtained in the important engineering alloy A12024- T3 by the friction stir welding （FSW） process. In the present study, thermocouples in three different configurations were amxed on the welding samples to measure the temperatures： in the first configuration, four thermocouples were placed at equivalent positions along one side of the welding direction; the second configuration involved two equivalent thermocouple locations on either side of the welding path; while the third configuration had all the thermocouples on one side of the layout but with unequal gaps from the welding line. A three-dimensional, non-linear ANSYS computational model, based on an approach applied to A12024-T3 for the first time, was used to simulate the welding temperature profiles obtained experimentally. The experimental thermal profiles on the whole were found to be in agreement with those calculated by the ANSYS model. The broad agreement between the two kinds of profiles validates the basis for derivation of the simulation model and provides an approach for the FSW simulation in A12024-T3 and is potentially more useful than models derived previously.

关键词： aluminum alloys friction stir welding welds temperature distribution

temperature distribution of fluids in a two-section two-phase closed thermosyphon wellbore

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Petroleum Science 2014年第2期11卷 287-292页

作者： Zhang Yufeng Zhao Lun Fan Zifei Wu Xiaodong Fu Libing Xu Bifeng Kong Fanshun Jiang Shengdong Research Institute of Petroleum Exploration & Development MOE Key Laboratory of Petroleum Engineering China University of Petroleum School of Energy Resources China University of Geosciences Exploration and Development Research Institute Petrochina Daqing Oilfield Company Northeast Petroleum University

Compared with a conventional single section two-phase closed thermosyphon （TPCT） wellbore, a two-section TPCT wellbore has better heat transfer performance, which may improve the temperature distribution of fluid in wellbores, increase the temperature of fluid in wellheads and even more effectively reduce the failure rate of conventional TPCT wellbores. Heat transfer performance of two-section TPCT wellbores is affected by working medium, combination mode and oil flow rate. Different working media are introduced into the upper and lower TPCTs, which may achieve a better match between the working medium and the temperature field in the wellbores. Interdependence exists between the combination mode and the flow rate of the oil, which affects the heat transfer performance of a two-section TPCT wellbore. The experimental results show that a two-section TPCT wellbore, with equal upper and lower TPCTs respectively filled with Freon and methanol, has the best heat transfer performance when the oil flow rate is 200 L/h.

关键词： Two-section two-phase closed thermosyphon temperature distribution combination mode,heat transfer performance

temperature distribution and Heat Flux on the EAST Divertor Targets in H-Mode

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Plasma Science and Technology 2013年第3期15卷 225-229页

作者：王福敏甘开福龚先祖 Institute of Plasma Physics Chinese Academy of Sciences

An infrared camera （IR） has been put into operation in the Experimental Advanced Superconducting Tokamak （EAST）, which is used to measure the temperature distribution on the surface of lower divertor target plates. With a finite difference method, the heat flux onto the divertor target plates is calculated from the surface temperature profile. The high confinement mode （H-mode） with type-III edge localized modes （ELMs） has been obtained with about 1 MW lower-hybrid wave power on the EAST in the autumn experiment in 2010. The analyzed H-mode discharges were lower single null X-point diverted discharges with a density range of 〈 ne 〉（1 - 4） × 10^19 m-3. The surface temperature of the inner target plate increases with heating power. The peak temperature on the surface of target plates is lower than 200 ~C with about 2.4 MW heating power. Comparison among the heat flux profiles occurring in different phases in the same discharge has been performed. It indicates that the heat flux profile obviously changes from the ohmic phase to the H-mode phase, and the full width at half maximum （FWHM） of the heat flux profile is the narrowest during the ELM-free H-phase. On the outer target plate, the peak heat flux exceeds 2 MW/m2 during the ELMy H-mode phase, whereas it is only about 0.8 MW/m2 during the ELM-free phase in the same discharge.

关键词： EAST tokamak IR camera temperature distribution lower targets heat flux

temperature distribution of Iron Ore Pellet Bed in Grate

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Journal of Iron and Steel Research(International) 2012年第2期19卷 7-11页

作者： FENG Jun-xiao XIE Zhi-yin CHEN Yan-mei School of Mechanical Engineering University of Science and Technology Beijing Beijing 100083 China

The temperature distribution of iron ore pellet bed in grate has a significant effect on pellet production and quality control, but the related work is scarce. A well-designed test was successfully carried out by means of tracking measurement and the temperature distribution and variation in pellet layers were obtained. The effects of blast tem- perature, blast velocity and oxidation reaction on the pellet layer temperature were studied. According to the analy- sis, the inlet air temperature in the up-draught drying zone （UDD） and blast temperature in the Preheating I （PH I） zone should be raised, and the length of the down-draught drying zone （DDD） should be properly increased.

关键词： grate iron ore pellet bed temperature distribution industrial test

Non-uniform operative temperature distribution characteristics and heat-source-controlled core-area range of local heating radiators

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Building Simulation 2023年第1期16卷 87-103页

作者： Dengjia Wang Weijia Li Yanfeng Liu Yaowen Chen Liang Hu Hu Du State Key Laboratory of Green Building in Western China Xi'an University of Architecture and TechnologyXi'an 710055China School of Building Services Science and Engineering Xi'an University of Architecture and TechnologyXi'an 710055China Welsh School of Architecture Cardiff UniversityCardiffCF103NBUK

Heating the whole space,which is currently used in northern China,leads to high energy consumption and substantial pollution.A transition to local heating has the potential to help address this problem.In this paper,the effects of radiator-related parameters(position,power,and size)and room-related parameters(aspect ratio and height)on local heating were studied.Two evaluation indices,the effective coefficient of operative temperature(OTEC)and the effective coefficient of local heating(LHEC),were proposed.In addition,the heat source-control core-area(HSCCA)was proposed,and the effect range of heat sources in the space was evaluated by the attenuation of operative temperature.The findings demonstrated that the radiator position has a greater influence on local heating than size.When the position of the radiator was changed from"close to the inner wall"to"close to the outer wall",the LHEC(the interior one-quarter of room is a local heating zone)was found to decrease by 73%.The size of the radiator,which is close to the inner wall,doubled or quadrupled,and the LHEC increased by 9%and 18%.Moreover,rooms with a larger aspect ratio or small room height were found to be the most optimal for local heating applications.The area of the HSCCA decreased as the position of the radiator approached the outer wall.The findings of this study can be used as a design reference for the radiator when the heating mode changes from"full-space heating"to"local heating".

关键词： local heating radiator non-uniform thermal environment operative temperature mean radiant temperature temperature distribution

Real-time monitoring of raster temperature distribution and width anomalies in fused filament fabrication process

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Advances in Manufacturing 2022年第4期10卷 571-582页

作者： Feng Li Zhong-Hua Yu Hao Li Zhen-Sheng Yang Qing-Shun Kong Jie Tang The State Key Laboratory of Fluid Power Transmission and Control College of Mechanical EngineeringZhejiang UniversityHangzhou310027People’s Republic of China

The aim of this study is to monitor the raster temperature distribution and width anomalies in a fused filament fabrication(FFF)process by an infrared(IR)array sensor.To achieve this goal,two experiments were conducted on a desktop FFF machine.For the first experiment,three normal samples with different raster widths were fabricated,and thermal images of the newly deposited rasters were collected during the process.To process the low-resolution images,a segmentation-based image processing method was proposed.The temperature distributions along the horizontal direction of the raster section and along the raster length were obtained.The temperature features that could indicate the raster widths were extracted and then fed to recognition models for training and testing.The classification performance of the models were evaluated based on the F-score.The models with high F1-scores could be used to recognise width anomalies online.For the second experiment,an abnormal sample with raster width anomalies was fabricated.The temperature features were extracted from the collected experimental data.The obtained features were then fed to the built and evaluated models to recognise the width anomalies online.The effectiveness of the monitoring method was validated by comparing the recognition results with the actual optical images.The support vector machine(SVM)and k-nearest neighbour(KNN)were adopted to build the recognition models.The F1-score and online recognition results of the models were compared.The comparison study shows that SVM is more suitable for our situation than KNN.A method for monitoring the temperature distribution and width anomalies of the FFF raster is provided in this paper.To the best of the authors’knowledge,this is the first study to explore the actual temperature distribution along the horizontal direction of the raster section,and the first study to monitor the width anomalies of the raster in the FFF process.

关键词： Fused filament fabrication(FFF) Process monitoring Infrared temperature distribution Width anomalies

Real-Time Calculation Method for temperature distribution of temperature-Controlled Radiofrequency Ablation

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上海交通大学学报:英文版 2023年第4期28卷 411-417页

作者：王雪维王逸飞张爱丽 School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Precise temperature control and temperature distribution prediction are of great significance forradiofrequency ablation.This research proposes a real-time calculation method for the temperature distribution of radiofrequency ablation combined with proportional-integral temperature control.The thermo-electricalcoupling was simplified into a linear relationship based on the study of the influence of temperature-dependentelectrical conductivity and thermal conductivity on the PI-controlled radiofrequency ablation temperature distribution,which increases the computational efficiency by 150 times.The average calculation time for radiofrequencyablation of 10 min is about 23 s,and the difference between the calculation results of this method and that fromCOMSOL Multiphysics is no more than 1?C.This method is not only used for single-probe,but also for doubleprobe radiofrequency ablation in this paper.

关键词： radiofrequency ablation temperature distribution proportional-integral(PI)controller

temperature distribution and control in liquefied petroleum gas fluidized beds

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Journal of University of Science and Technology Beijing 2004年第3期11卷 202-206页

作者： LiWang PingWu YanpingZhang JingYang LigeTong MechanicalEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China AppliedScienceSchool UniversityofScienceandTechnologyBeijingBeijing100083China

temperature distribution and control have been investigated in a liquefiedpetroleum gas (LPG) fluidized bed with hollow corundum spheres (A1_2O_3) of 0.867-1.212 mm indiameter at moderately high temperatures (800-1100℃). Experiments were carried out for the airconsumption coefficient α in the range of 0.3 to 1.0 and the fluidization number N in the range of1.3 to 3.0. Particle properties, initial bed height, α and N all affect temperature distribution inthe bed. Bed temperature can be adjusted about 200℃ by combined the adjusting of α and N.

关键词： liquefied petroleum gas fluidized bed temperature distribution

Simulation of temperature distribution and discharge crater of SiC_(p)/Al composites in a single-pulsed arc discharge

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Chinese Journal of Aeronautics 2021年第9期34卷 37-46页

作者： Jipeng CHEN Lin GU Wansheng ZHAO Mario GUAGLIANO School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037China State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering Politecnico Di MilanoPiazza Leonardo da Vinci32Italy

SiC_(p)/Al composites are difficult-to-cut materials.In recent years,electrical arc discharge machining has been developed to improve the machinability of these materials.However,there is a big challenge to build a satisfactory heat transfer model of SiC_(p)/Al composites in the arc machining.This is not only because of the material property difference between the reinforcement and matrix material but also because of the micro-dimension Si C reinforcements.This paper established a new heat conduction simulation model considering the Si C particle-Al matrix interface and the phase change effects in a single-pulsed arc discharge of SiC_(p)/Al composites.A novel Si C particle-Al matrix cell geometric model was designed firstly.Then,the temperature distribution at a different depth from the workpiece surface was analyzed,the influence of sic volume fraction on temperature field was studied,and the contribution of the interface thermal resistance and latent heat were explained.To demonstrate the validity of the new numerical model,comparisons and verifications were employed.Finally,the method of improving the model was proposed and the machining mechanism of arc discharge of SiC_(p)/Al matrix materials was discussed.It was found that high temperature is prone to concentrate on the surface layers of the workpiece especially when the Si C fraction is high,also,the temperature fluctuates respectively at the evaporation point of aluminum and Si C,and the Si C-Al resistance has less influence on temperature distribution compared to latent heat,etc.The model build in this work improves the simulation accuracy observably compared to the previous model,and the simulation work will help to acquire a detailed mechanism of material removal of SiC_(p)/Al composites in the arc discharge machining.

关键词： Arc discharge Discharge crater SiC_(p)/Al composites Single-pulsed temperature distribution