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埋地热油管道启输热力数值模拟 被引量:39
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作者 李长俊 骆建武 陈玉宝 《油气储运》 CAS 北大核心 2002年第12期16-19,共4页
在综合考虑预热介质、管道、管道覆盖层以及半无穷大土壤的情况下,提出了埋地热油管道启输传热的数学模型,并在该模型中,将土壤物性参数视为随温度变化的函数,应用保角变换将半无穷大土壤区域变换成有限矩形区域。由Keller盒式积分法构... 在综合考虑预热介质、管道、管道覆盖层以及半无穷大土壤的情况下,提出了埋地热油管道启输传热的数学模型,并在该模型中,将土壤物性参数视为随温度变化的函数,应用保角变换将半无穷大土壤区域变换成有限矩形区域。由Keller盒式积分法构造出了问题的差分格式,采用广义阻尼牛顿一拉夫逊法求解非线性差分方程组,得到了问题的数值解,并由算例验证了所述方法的正确性。 展开更多
关键词 热力数值模拟 输油管道 埋地热油管道 启输 传热 保角变换 数值模拟
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洋壳渗透率结构对其内部热液对流的影响研究——基于热力学数值模拟
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作者 范庆凯 李江海 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2020年第5期1986-1997,共12页
洋底特殊环境的限制使数值模拟成为研究海底热液对流与成矿机制的有效方法.本文通过数值模拟的方法,研究洋壳渗透率单因素变化对热液对流系统的形态和输出参数(热液喷发温度和热流值)进行研究.模拟结果表明,洋壳平均渗透率分别与热液喷... 洋底特殊环境的限制使数值模拟成为研究海底热液对流与成矿机制的有效方法.本文通过数值模拟的方法,研究洋壳渗透率单因素变化对热液对流系统的形态和输出参数(热液喷发温度和热流值)进行研究.模拟结果表明,洋壳平均渗透率分别与热液喷发温度和热量输出呈反相关和正相关关系,符合达西流体热对流的基本解析规律.另外,洋壳渗透率的垂向变化不会使洋壳内部的对流系统产生明显的横向偏移,只使热液羽规模在垂向上产生规律性变化,且渗透率越大,热液羽规模越小.渗透率在水平方向的变化则是引发热液羽和热液喷发位置横向偏移的主要因素,且只有在特定的渗透率水平变化率范围内,上涌热液羽才会发生向高渗区的明显偏移,这也从一定程度上解释了现今拆离断层相关的热液系统均未发育于断层终止线上的事实.以大西洋Trans-Atlantic Geotraverse(TAG)热液区为例,断裂带高渗区必然影响相邻洋壳内部热液的上涌路径,但受区内拆离断裂带周缘的渗透率水平变化规律的影响,上涌热液羽不至于完全偏移至断裂带,从而产生拆离断层上盘的热液活动. 展开更多
关键词 热力数值模拟 热液对流 喷发温度 热流值 相位差
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厚壁管张力减径过程数值模拟
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作者 李华奎 《甘肃科技》 2014年第24期72-75,共4页
通过对影响厚壁管张力减径工艺参数的研究,用有限元软件ANSYS/LS-DYNA对厚壁管张力减径过程进行热力耦合数值模拟,分析了张力减径时钢管的应力与应变分布、温度分布、壁厚分布以及轧制力分布情况,为钢管张力减径工艺的优化提供了依据。
关键词 厚壁管 张力减径 热力耦合数值模拟
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铝合金圆锥形零件粘性介质温成形研究 被引量:3
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作者 刘建光 王忠金 +1 位作者 李毅 刘岩 《锻压技术》 CAS CSCD 北大核心 2007年第5期33-36,共4页
采用热力耦合有限元数值模拟方法对铝合金圆锥形零件粘性介质温成形过程进行了模拟分析,研究了成形过程粘性介质和板材的温度分布、不同温度条件下成形零件壁厚分布、成形载荷等。结果表明,圆锥形零件的底部圆角区域为成形危险区域。非... 采用热力耦合有限元数值模拟方法对铝合金圆锥形零件粘性介质温成形过程进行了模拟分析,研究了成形过程粘性介质和板材的温度分布、不同温度条件下成形零件壁厚分布、成形载荷等。结果表明,圆锥形零件的底部圆角区域为成形危险区域。非等温粘性介质温成形过程中,在粘性介质内部形成的非均匀温度场影响了板材的温度分布。当粘性介质温度略低于板材温度时,坯料中心区域温度较低,有利于延迟底部圆角成形时的破裂,提高了零件壁厚的均匀性。分别进行了室温和加热时铝合金圆锥形零件粘性介质压力成形试验,试验结果与数值模拟具有相同的规律。 展开更多
关键词 粘性介质压力成形 温成形 热力耦合数值模拟 铝合金
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Furnace structure analysis for copper flash continuous smelting based on numerical simulation 被引量:7
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作者 汪金良 陈亚州 +1 位作者 张文海 张传福 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第12期3799-3807,共9页
According to the innate characteristic of four types of furnace, the copper flash continuous smelting (CFCS) furnace can be considered a synthetic reactor of two relatively independent processes: flash matte smelti... According to the innate characteristic of four types of furnace, the copper flash continuous smelting (CFCS) furnace can be considered a synthetic reactor of two relatively independent processes: flash matte smelting process (FMSP) and copper continuous converting process (CCCP). Then, the CFCS thermodynamic model was proposed by establishing the multi-phase equilibrium model of FMSP and the local-equilibrium model of CCCP, respectively, and by combining them through the smelting intermediates. Subsequently, the influences of the furnace structures were investigated using the model on the formation of blister copper, the Fe3O4 behavior, the copper loss in slag and the copper recovery rate. The results show that the type D furnace, with double flues and a slag partition wall, is an ideal CFCS reactor compared with the other three types furnaces. For CFCS, it is effective to design a partition wall in the furnace to make FMSP and CCCP perform in two relatively independent zones, respectively, and to make smelting gas and converting gas discharge from respective flues. 展开更多
关键词 furnace structure copper flash continuous smelting numerical simulation thermodynamic analysis
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Effects of static magnetic fields on melt flow in detached solidification 被引量:3
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作者 彭岚 龚欢 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第3期936-943,共8页
A series of three-dimensional numerical computations were conducted to understand the effects of different static magnetic fields on thermal fluctuation and melt flow during the detached solidification of CdZnTe. Nume... A series of three-dimensional numerical computations were conducted to understand the effects of different static magnetic fields on thermal fluctuation and melt flow during the detached solidification of CdZnTe. Numerical calculations were carried out by three different configurations of magnetic field: without magnetic field, with an axial magnetic field (AMF) and with a cusp-shaped magnetic field (CMF). The results reveal that the magnetic fields can effectively suppress the melt flow and thermal fluctuation and the suppression effect of the AMF is stronger than that of the CMF. Besides, the physical mechanism of thermocapillary?buoyancy convection instability was discussed and the effects of magnetic field on the critical Marangoni number were also obtained. 展开更多
关键词 detached solidification static magnetic field thermocapillary-buoyancy convection numerical simulation CDZNTE
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Simulation on flow, heat transfer and stress characteristics of large-diameter thick-walled gas cylinders in quenching process under different water spray volumes 被引量:2
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作者 GAO Jing-na GAO Ying +2 位作者 XU Qin-ran WANG Ge LI Qiang 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第11期3188-3199,共12页
Cooling strength is one of the important factors affecting microstructure and properties of gas cylinders during quenching process,and reasonable water spray volume can effectively improve the quality of gas cylinders... Cooling strength is one of the important factors affecting microstructure and properties of gas cylinders during quenching process,and reasonable water spray volume can effectively improve the quality of gas cylinders and reduce production costs.To find the optimal water spray parameters,a fluid-solid coupling model with three-phase flow was established in consideration of water-vapor conversion.The inner and outer walls of gas cylinder with the dimensions of d914 mm×38 mm×12000 mm were quenched using multi-nozzle water spray system.The internal pressure,average heat transfer coefficient(have)and stress of the gas cylinder under different water spray volumes during quenching process were studied.Finally,the mathematical model was experimentally verified.The results show that both the internal pressure and have increase along with the increase of spray volume.The internal pressure increases slowly first and then rapidly,but have increases rapidly first and then slowly.To satisfy hardenability of gas cylinders,the minimum spray volume should not be less than 40 m^3/(h·m).The results of stress indicate that water spray quenching will not cause deformation of bottle body in the range of water volume from 40 to 290 m^3/(h·m). 展开更多
关键词 large-diameter thick-walled gas cylinders QUENCHING water spray volume heat transfer STRESS numerical simulation
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NUMERICAL SIMULATION EXPERIMENTS OF THE IMPACTS OF LOCAL LAND-SEA THERMODYNAMIC CONTRASTS ON THE SCS SUMMER MONSOON ONSET 被引量:2
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作者 任雪娟 钱永甫 《Journal of Tropical Meteorology》 SCIE 2003年第1期1-8,共8页
The important effects of local land-sea thermodynamic contrast between the South China Sea (SCS) and Indochina Peninsula on SCS summer monsoon onset are preliminarily studied by using two sets of SSTA tests and two id... The important effects of local land-sea thermodynamic contrast between the South China Sea (SCS) and Indochina Peninsula on SCS summer monsoon onset are preliminarily studied by using two sets of SSTA tests and two ideal tests in s-p regional climate model. The result shows that warm SST in the SCS in winter and spring is favorable for the formation of monsoon circulation throughout all levels of the atmosphere over the sea, which hastens the onset of SCS summer monsoon. The effects of cold SST are generally the opposite. The local land-sea contrast in the SCS is one of the possible reasons for SCS summer monsoon onset. Superposed upon large-scale land-sea thermodynamic differences, it facilitates the formation of out-breaking onset characteristics of SCS summer monsoon in the SCS area. 展开更多
关键词 local land-sea thermodynamic contrast SCS summer monsoon p-σregional climate model
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Hot tearing susceptibility of Mg-xZn-2Y alloys 被引量:3
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作者 Zhi WANG Yi-zhou LI +4 位作者 Feng WANG Yuan-ding HUANG Jiang-feng SONG Ping-li MAO Zheng LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第12期3115-3122,共8页
Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The exp... Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The experimental results indicate thatthe hot tearing susceptibility (HTS) is affected by the content of Zn. The Zn-free base alloy shows the lowest HTS. The HTS ofMg?xZn?2Y alloys increases with increasing Zn content, reaches the maximum at 1.5% Zn, and then decreases with further Znaddition. The high HTS observed in the alloy with 1.5% Zn is attributed to its high force release rate and large force drop duringsolidification. The hot cracks of casting are initiated and propagate along the dendritic or grain boundaries. The predictions of HTS ofMg?xZn?2Y alloys using ProCAST software are in good agreement with the results obtained by experimental measurements. 展开更多
关键词 Mg-xZn-2Y alloy hot tearing susceptibility solidification contraction force numerical simulation
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Numerical Study on Heat Transfer Enhancement for Use of Corrugated, Nodal and Horizontal Grain Tubes 被引量:1
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作者 朱家玲 王钰沛 +1 位作者 张伟 刘雪玲 《Transactions of Tianjin University》 EI CAS 2014年第5期385-392,共8页
With isopentane as working fluid, the heat transfer performances for corrugated, nodal and horizontal grain tubes are simulated. The structural parameters of the three kinds of tubes are compared with those of the pla... With isopentane as working fluid, the heat transfer performances for corrugated, nodal and horizontal grain tubes are simulated. The structural parameters of the three kinds of tubes are compared with those of the plain tube. The numerical results using computational fluid dynamics are validated with theoretical values. For the corrugated, nodal and horizontal grain tubes, the heat transfer enhancements(HTEs) are 2.31—2.53, 1.18—1.86 and 1.02—1.31 times of those of the plain tube, respectively. However, the improved HTEs are at the expense of pressure losses. The drag coefficients are 6.10—7.09, 2.06—11.03 and 0.53—1.83 higher, respectively. From the viewpoint of comprehensive heat transfer factor, the corrugated tube is recommended for engineering applications, followed by the horizontal grain tube. 展开更多
关键词 corrugated tube nodal tube horizontal grain tube heat transfer
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Fluid-solid coupling numerical simulation of charge process in variable-mass thermodynamic system 被引量:8
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作者 胡继敏 金家善 严志腾 《Journal of Central South University》 SCIE EI CAS 2012年第4期1063-1072,共10页
Abstract: A joint solution model of variabk:-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated... Abstract: A joint solution model of variabk:-mass flow in two-phase region and fluid-solid coupling heat transfer, concerned about the charge process of variable-mass thermodynamic system, is built up and calculated by the finite element method (FEM). The results are basically consistent with relative experimental data. The calculated average heat transfer coefficient reaches 1.7~105 W/(m2. K). When the equal percentage valve is used, the system needs the minimum requirements of valve control, but brings the highest construction cost. With the: decrease of initial steam pressure, the heat transfer intensity also weakens but the steam flow increases. With the initial water filling coefficient increasing or the temperature of steam supply decreasing, the amount of accumulative steam flow increases with the growth of steam pressure. When the pressure of steam supply drops, the steam flow gradient increases during the maximum opening period of control valve, and causes the maximum steam flow to increase. 展开更多
关键词 steam accumulator variable-mass control valve fluid-solid coupling numerical simulation
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Thermal stress in SiC element used in heat exchanger
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作者 李贺松 梅炽 《Journal of Central South University of Technology》 EI 2005年第6期709-713,共5页
An especial snake SiC pipe was designed for collecting losing heat from furnaces. The three-dimensions thermal, fluid and thermal stress coupled field of heat exchanger was analyzed by using the commercial engineering... An especial snake SiC pipe was designed for collecting losing heat from furnaces. The three-dimensions thermal, fluid and thermal stress coupled field of heat exchanger was analyzed by using the commercial engineering computer package ANSYS. The structural and operational parameters of heat exchanger, the junction between standpipe and snake pipe, the diameter of snake pipe, ratio of thickness to diameter of pipe, velocity of inlet air were optimized for thermal stress. The computed results show that the large thermal stress exits in the SiC, and the stand pipe should be ellipse for the least thermal stress; the optimal ratio of thickness to diameter of pipe is 6, the velocity of inlet air is 25 m/s. The most thermal stress is in inverse proportion to diameter of pipe and velocity of inlet air. 展开更多
关键词 finite element method SIMULATION heat exchanger element thermal stress
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Numerical Simulation of New Friction Welded Joints
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作者 Takeshi Higashi Ryoji Tsujino +2 位作者 Kiyoshi Matsuura Yoshiaki Ueda Manabu Iguchi 《Journal of Mechanics Engineering and Automation》 2013年第10期595-601,共7页
In developing the new friction welding technology, the thermal elastic-plastic stress analysis by the finite element method was carried out to seek the suitable welding conditions such as the friction pressure, the fr... In developing the new friction welding technology, the thermal elastic-plastic stress analysis by the finite element method was carried out to seek the suitable welding conditions such as the friction pressure, the friction speed and the upset pressure. The results obtained are as follows: Heat transfer to the specimens and the intermediate material during friction process was made clear; The operational conditions such as the rotation number of the intermediate material and the friction pressure to reach the liquidus in the interface could be estimated; Further, as the overhang length near the interface is well related to the joint efficiency, we tried to obtain the operational conditions by numerical analysis to acquire a certain length of the overhang length near the interface. 展开更多
关键词 Numerical simulation friction welding intermediate material thermal elastic-plastic stress analysis aluminum alloy steel.
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Numerical and Experimental Study on Dynamic Performance of Heat Pump Water Heater with Electronic Expansion Valve
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作者 Liang Zhang Xianmin Guo Weiguo Li Weihua Wang 《Journal of Energy and Power Engineering》 2012年第10期1582-1588,共7页
A series of experiments on the dynamic performance of the HPWH (heat pump water heater) unit with EXV (electronic expansion valve) under different environmental conditions were conducted. The dynamic heating capac... A series of experiments on the dynamic performance of the HPWH (heat pump water heater) unit with EXV (electronic expansion valve) under different environmental conditions were conducted. The dynamic heating capacity and COP (coefficient of performance) of the HPWH unit under different EXV openings were measured. The effects of the EXV opening on the performance of the HPWH unit were analyzed. Meanwhile, the dynamic performance of the HPWH with EXV was simulated and the results were compared with the experimental one. The experimental results indicate that during heating process, the COP increases firstly and then decreases for a fixed EXV opening, which is in good agreement with the numerical result. For different EXV openings, the COP and heating capacity of the system using larger EXV opening are superior to those using the smaller one in the initial heating stage. While in the late stage, the performance of system using smaller EXV opening is better. It is found that the system performance is improved significantly by changing the EXV opening in the different heating period and the average COP of the HPWH system is increased by 7.6%. 展开更多
关键词 Heat pump water heater electronic expansion valve experimental investigation simulation.
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滚轧轮运动方式对减速机蜗杆滚轧成形的影响 被引量:1
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作者 苑文婧 邢子文 +2 位作者 曹建文 张琦 田浩彬 《锻压技术》 CAS CSCD 北大核心 2017年第10期106-112,共7页
研究了减速机蜗杆零件滚轧成形过程中滚轧轮运动方式对成形的影响。首先根据蜗杆零件特点,设计了轴线平行的两滚轧轮滚轧方式,并确定了滚轧轮的具体结构参数。然后进行了蜗杆材料20Cr Mn Ti钢的热压缩实验,在应变速率分别为0.1,1,10和30... 研究了减速机蜗杆零件滚轧成形过程中滚轧轮运动方式对成形的影响。首先根据蜗杆零件特点,设计了轴线平行的两滚轧轮滚轧方式,并确定了滚轧轮的具体结构参数。然后进行了蜗杆材料20Cr Mn Ti钢的热压缩实验,在应变速率分别为0.1,1,10和30 s^(-1),实验温度分别为800,900和1000℃的情况下,得到了材料的应力-应变曲线。最后通过数值模拟研究了蜗杆滚轧过程中两种滚轧轮运动方式的成形结果,并进行了实验验证。结果表明:当两个滚轧轮顺时针单向旋转时,数值模拟中工件轴向位移达到6.48 mm,实验件达到2.66 mm;当两个滚轧轮先顺时针、再逆时针往复旋转时,工件的轴向位移矢量和接近零。滚轧轮往复旋转的滚轧方式能够有效避免蜗杆工件轴线位移严重的问题,保证了滚轧的顺利进行。 展开更多
关键词 蜗杆 滚轧成形 热压缩实验 热力耦合数值模拟 滚轧轮运动方式
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Numerical Simulation of Air-cooling Tower 被引量:1
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作者 Lijuan Hao Huanzhi Li Zhaohu Sun Lige TongThermal Energy Department, Beijing University of Science and Technology, Beijing 100083, China 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第3期264-269,共6页
A mathematic model for packed air-cooling tower thermodynamic calculation is set up in this paper on the basis of fundamental heat and mass transfer equations. Based on the Double Film theory, direct equation-solving ... A mathematic model for packed air-cooling tower thermodynamic calculation is set up in this paper on the basis of fundamental heat and mass transfer equations. Based on the Double Film theory, direct equation-solving method is used to simulate air-cooling tower, and variation of parameters is taken to analyze the data and results of the program. 展开更多
关键词 packing air-cooling tower computer simulation mathematic model
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Analysis of Particle Behavior in High-Velocity Oxy-Fuel Thermal Spraying Process 被引量:3
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作者 Hiroshi Katanoda Kazuyasu Matsuo 《Journal of Thermal Science》 SCIE EI CAS CSCD 2003年第3期279-282,共4页
This paper analyzes the behavior of coating particle as Well as the gas flow both of inside and outside the High-Velocity Oxy-Fuel (HVOF) thermal spraying gun by using quasi-one-dimensional analysis and numerical simu... This paper analyzes the behavior of coating particle as Well as the gas flow both of inside and outside the High-Velocity Oxy-Fuel (HVOF) thermal spraying gun by using quasi-one-dimensional analysis and numerical simulation. The HVOF gun in the present analysis is an axisymmetric convergent-divergent nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. In the present analysis it is assumed that the influence of the particles injected in the gas flow is neglected, and the interaction between the particles is also neglected. The gas flow in the gun is assumed to be quasi-one-dimensional adiabatic flow. The velocity, temperature and density of gas in the jet discharged from the barrel exit are predicted by solving Navier-Stokes equations numerically. The particle equation of motion is numerically integrated using three-step Runge-Kutta method. The drag coefficient of the particle is calculated by linear interpolation of the experimental data obtained in the past. Particle mean temperature is calculated by using Ranz and Marchalls' correlation for spherical particles. From the present analysis, the distributions of velocity and temperature of the coating particles flying inside and outside the HVOF gun are predicted. 展开更多
关键词 supersonic nozzle supersonic jet thermal spraying gas-particle flow.
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Percolation Phase Transitions from Second Order to First Order in Random Networks
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作者 贾啸 洪劲松 +4 位作者 杨宏春 杨春 付传技 胡建全 史晓红 《Communications in Theoretical Physics》 SCIE CAS CSCD 2015年第4期515-519,共5页
We investigate a percolation process where an additional parameter q is used to interpolate between the classical Erd¨os–R′enyi(ER) network model and the smallest cluster(SC) model. This model becomes the ER ne... We investigate a percolation process where an additional parameter q is used to interpolate between the classical Erd¨os–R′enyi(ER) network model and the smallest cluster(SC) model. This model becomes the ER network at q = 1, which is characterized by a robust second order phase transition. When q = 0, this model recovers to the SC model which exhibits a first order phase transition. To study how the percolation phase transition changes from second order to first order with the decrease of the value of q from 1 to 0, the numerical simulations study the final vanishing moment of the each existing cluster except the N-cluster in the percolation process. For the continuous phase transition,it is shown that the tail of the graph of the final vanishing moment has the characteristic of the convexity. While for the discontinuous phase transition, the graph of the final vanishing moment possesses the characteristic of the concavity.Just before the critical point, it is found that the ratio between the maximum of the sequential vanishing clusters sizes and the network size N can be used to decide the phase transition type. We show that when the ratio is larger than or equal to zero in the thermodynamic limit, the percolation phase transition is first or second order respectively. For our model, the numerical simulations indicate that there exists a tricritical point qcwhich is estimated to be between0.2 < qc< 0.25 separating the two phase transition types. 展开更多
关键词 PERCOLATION NETWORKS
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Influence of the heating rate on the critical Marangoni number of oscillatory thermocapillary convection in the floating half zone
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作者 LI Kai TANG ZeMei HU WenRui 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第1期102-107,共6页
In the present study, numerical simulations were conducted on thermocapillary convection in floating half zones of 5 cSt silicone oil of different scales in comparison with the experimental studies in the microgravity... In the present study, numerical simulations were conducted on thermocapillary convection in floating half zones of 5 cSt silicone oil of different scales in comparison with the experimental studies in the microgravity conditions. The effect of heating rate on the marginal instability boundaries is indicated as a possible explanation for the significant quantitative discrepancies between the experimental results in the terrestrial conditions and in the microgravity conditions. 展开更多
关键词 thermocapillary convection flow instability finite element methods
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