Flow Field and Temperature Field of Water-Cooling-Type Magnetic Coupling

At present, the water-cooling simulation of the water-cooled magnetic coupler is based on the water-cooled motor and the hydraulic coupler, which cannot accurately characterize the temperature distribution of the rotating watercooled coupling of the coupler. Focusing on rotating water cooling radiating, the present paper proposes simulating the water cooling temperature field as well as the flow field through the method of combining fluid-solid coupled heat transfer and MRF(Multiphase Reference Frame). In addition, taking an 800 kW magnetic coupling as an example, the paper optimizes the shape, number, cooling water inlet speed? and so on? of the cooling channel. Considering factors such as the complete machine’s temperature, and drag torque, it is proved that the cooling e ect is best when there are 36 involute curved channels and when the inlet speed is 3 m/s. Further, through experiments, the actual temperature values at six di erent positions when 50 kW and 70 kW thermal losses di er are measured. The measured values agree with the simulation results, proving the correctness of the proposed method. Further, data have been collected during the entire experimental procedure? and the variation in the coupling’s temperature is analyzed in depth, with the objective of laying a foundation for the estimation of the inner temperature rise as well as for the optimization of the structural design.

MATHEMATICAL MODEL OF MILLING TEMPERATURE AND TEMPERATURE FIELD ANALYSIS FOR THREE-DIMEN-SIONAL COMPLEX GROOVE MILLING INSERT

The mathematical model on the temperature of the waved-edge is constructedaccording to Jaeger's theory of moving solid and based on the used temperature model of the flatinsert. It is possible to forecast the milling temperature through programming. The comparableexperiments have been done between the two new three-dimension groove inserts (waved-edge insert,great edge insert) and flat fake insert. The theoretic forecast is in good agreement with theexperimental result. According to the cutting conditions, the boundary condition of finite elementanalysis on cutting temperature field is established, and the three-dimensional temperature fieldsof inserts with grooves are analyzed by FEM, so as to offer a reference basis for the design andoptimization of insert grooves.

Temperature Field Reconstruction in High-Temperature Gas by Using the Colored Background Oriented Schlieren Method

A 3D temperature field reconstruction method using the colored background oriented schlieren(CBOS)method is proposed to address image blurring due to the different refractive index of the multi-wavelength light and significant errors produced when the traditional background oriented schlieren(BOS)method is applied to high-temperature gas.First,the traditional method is employed to reconstruct the non-uniform 3D temperature field.Second,the CBOS method is applied to correct the distortion.Then,by analyzing the correlation coefficient among different color points of the colored background pattern,the non-uniform temperature field is reconstructed much more accurately.Finally,the experimental results are verified by applying the Runge-Kutta ray-tracing method and the thermocouple contact measurement method.The maximum average temperature error of the CBOS-reconstructed temperature field is 12.92°C,compared with the thermocouples.Therefore,an accurate three-dimensional reconstruction of the temperature field can be achieved by the proposed method effectively.

Reconstruction of Temperature Field in 3-D, Absorbing, Emitting, and Anisotropically Scattering Medium

The soft measurement technology of flame temperature field is an efficient method to learn the combustion status in furnace. Generally, it reconstructs the temperature field in furnace through the image of flame, which is a process to solve radiative inverse problem. In this paper, the flame of pulverized coal is considered as 3-D, absorbing, emitting, and anisotropically scattering non-gray medium. Through the study on inverse problem of radiative heat transfer, the temperature field in this kind of medium has been reconstructed. The mechanism of 3-D radiative heat transfer in a rectangular media, which is 2 m×3 m× 5 m and full of CO2, N2 and carbon particles, is studied with Monte Carlo method. The 3-D temperature field in this rectangular space is reconstructed and the influence of particles density profile is discussed.

Study on the computation method of temperature field of RCC dam

According to the construction characteristic of RCC dam cast by layers, three-dimensional finite element relocating mesh method is developed to simulate construction process and compute temperature field. The computation model of relocating mesh method is expatiated in detail; based on the thermodynamic properties of RCC materials, the feasibility and error of relocating mesh method are analyzed and demonstrated; The computation results in this article are verified by means of the temperature observation data of certain RCC gravity dam. The results show that the temperature field computed by three-dimensional finite element relocating mesh method can not only ensure the computation precision, but also improve the calculation efficiency greatly. This provides an effective method for simulating construction process and computing temperature field of RCC dam.

Simultaneous reconstruction of temperature distribution and radiative properties in participating media using a hybrid LSQR-PSO algorithm

A hybrid least-square QR decomposition （LSQR）-particle swarm optimization （LSQR-PSO） algorithm was devel- oped to estimate the three-dimensional （3D） temperature distributions and absorption coefficients simultaneously. The outgoing radiative intensities at the boundary surface of the absorbing media were simulated by the line-of-sight （LOS） method, which served as the input for the inverse analysis. The retrieval results showed that the 3D temperature distribu- tions of the participating media with known radiative properties could be retrieved accurately using the LSQR algorithm, even with noisy data. For the participating media with unknown radiative properties, the 3D temperature distributions and absorption coefficients could be retrieved accurately using the LSQR-PSO algorithm even with measurement errors. It was also found that the temperature field could be estimated more accurately than the absorption coefficients. In order to gain insight into the effects on the accuracy of temperature distribution reconstruction, the selection of the detection direction and the angle between two detection directions was also analyzed.

SIMULATION-MEASUREMENT INVERSION OF ENVIRONMENT PARAMETERS DURING WELDING

The manual selection of environment parameters during welding simulation will bring a significant error to the simulation result of welding temperature field. By a combination of finite element method （FEM） and infrared thermography, these environment parameters were inversed mathematically in place of previous manual selection. First, FEM model of the welding process was constructed, and the temperature field was computed with initial environment parameters. Then, a real welding process was conducted and the temperature field was measured by infrared thermography. Last, the simulation and measurement results were compared, and the environment parameters were adjusted continuously with the genetic algorithm （ GA ） until the simulation matched the measurement best. Parameters according to the best-matched simulation results were considered as the most appropriate parameters.

基于遗传算法的碾压混凝土重力坝温度场多测点反演

由于碾压混凝土重力坝施工现场条件复杂,实验获得的参数与实际参数存在一定的差异。为获得高精度的温度场仿真结果,根据某碾压混凝土重力坝现场实测温度数据,利用遗传算法反演该碾压混凝土坝的绝热温升Q 0、温升常数n和导热系数λ,并运用所得的反演参数进行温度场仿真模拟分析,对比不同测点个数下反演所得参数的可靠性和精确性。结果表明:通过遗传算法进行参数反演可有效提高反演的速度与精度,并且反演所依据的测点个数越多反演结果越接近实测数据,9个测点反演比3个测点反演误差减少了1.43%,比6个测点反演误差减少了0.44%。因此,在利用遗传算法进行参数反演时应尽量选择较多的测点个数,以提高仿真计算的精度。研究结果可为碾压混凝土重力坝热学参数反演提供理论指导和依据。

基于IABAP混合算法的混凝土坝浇筑仓温控措施智能优选

混凝土坝浇筑仓在施工期的温控措施选择不当会导致混凝土出现温度裂缝,将智能优化算法与温控措施结合进行多个温控因素联合分析,可实现大坝温控措施智能调控。提出了一种结合粒子群(PSO)与人工峰群(ABC)的混合优化算法IABAP,避免了单一算法后期收敛速度降低、易陷入局部最优等问题,并将其运用于白鹤滩拱坝典型坝段的参数反演,基于计算温度曲线与实测温度曲线对比结果,进行温控措施联合优选。结果表明,通过IABAP算法温控措施调整后的温度曲线预测结果与施工期采用实际温控措施参数值预测结果相比温升速率和浇筑温度更小,对控制混凝土早期拉应力更有利。研究结果为混合优化算法在大坝温控措施智能优选方面的运用提供了参考。

三芯电缆接头轴向温度反演模型及其材料参数敏感性分析

三芯电缆中间接头热点温度的实时感知对研究电缆安全运行、温升及动态载流能力评估具有重要意义。因此,以10 kV三芯电缆中间接头为研究对象,针对不同型号中间接头的结构、材料及现场工艺分散性的实际情况,构建了电缆接头温度场仿真模型,分析了中间接头的温度场分布规律。建立了基于轴向热流的导体轴向温度统一反演模型。采用单因子变化与正交组合方式,分析了材料参数分散性对接头导体轴向反演模型的拟合度及灵敏度的影响。仿真结果表明,轴向温度反演模型的灵敏度系数和拟合优度变化均较小,对于不同结构、材料及现场工艺分散性具有较好的鲁棒性。

Influence of Temperature on the Inverse Hall-Petch Effect in Nanocrystalline Materials:Phase Field Crystal Simulation

The influence of temperature on the inverse Hall-Petch effect in nanocrystalline （NC） materials is investigated using phase field crystal simulation method. Simulated results indicate that the inverse Hall-Petch effect in NC materials becomes weakened at low temperature. The results also show that the change in microscopic deformation mechanism with temperature variation is the main reason for the weakening of the inverse Hall-Petch effect. At elevated temperature, grain rotation and grain boundary （GB） migration seriously reduce the yield stress so that the NC materials exhibit the inverse Hall-Petch effect. However, at low temperature, both grain rotation and GB migration occur with great difficulty, instead, the dislocations nucleated from the cusp of serrated GBs become active. The lack of grain rotation and GB migration during deformation is mainly responsible for the weakening of the inverse Hall-Petch effect. Furthermore, it is found that since small grain size is favorable for GB migration, the degree of weakening decreases with decreasing average grain size at low temperature.

基于岩石物性引导的地球物理联合反演研究

多元地球物理勘探资料的联合处理和综合解释是深部地热资源勘探评价工作必不可缺的环节,联合反演和后反演地质分异技术是目前深部资源勘探领域的2个研究热点。为融合多元地球物理场信息,降低单一地球物理场反演的多解性,本文利用岩石物性先验信息作为引导,以地震解释地层结构信息建立结构模型,采用高斯混合模型约束地层的地球物理参数,将重力、磁法、大地电磁进行正则化联合反演,实现了多物性结构的耦合,最终形成了重、磁、电、震联合反演软件,基于多物性联合反演的结果,利用Arrhenius定律,通过电阻率实现对典型干热岩场地温度场的预测。通过对直立六面体理论模型正演结果进行联合反演计算,联合反演结果相对于单独反演,对异常体的空间形态刻画以及物性数值恢复具有较好的效果,而且能够充分融合地质、岩石物性和地球物理等多元数据,更加符合实际规律。

基于流线分析的10kV油浸式变压器绕组热点温度反演模型建立及验证研究

准确获取运行变压器绕组热点温度一直是电力行业的难点问题之一。源自变压器绕组热源区域的热流是导致变压器外场域温度升高的直接推动力,该文基于变压器温度流体场耦合数值计算,分析变压器内部热流扩散规律,通过提取流经绕组热点区域与外壳散热区域的典型热流流线,选取变压器外部可测并与绕组热点温度具有强关联关系的特征测温点,并采用网格搜索法优化的支持向量回归机构建特征测温点温度与绕组热点温度间的多维非线性关系,进而建立变压器绕组热点温度反演检测模型。为拓宽反演模型的普适性,采用正交设计法构建反演模型所需的训练样本和测试样本,采用变压器多工况温升试验验证变压器温度流体场仿真结果的准确性,并验证绕组热点温度反演模型的准确性,绕组热点温度反演平均绝对误差为1.82%,最大温差小于3℃。

基于稳态传热分析的高炉炉壁温度场建模方法

高炉炉壁温度场是掌握炉内热负荷状态和燃料燃烧情况、及时发现高炉异常工况、保障高炉稳定顺行的重要信息。针对现有炉壁温度场获取难及温度场建模过程中未考虑渣皮脱落与生成现象等问题,提出一种基于稳态传热分析的高炉炉壁温度场建模方法。首先,利用COMSOL仿真软件搭建炉壁三维仿真模型;其次,充分考虑渣皮对炉壁温度变化的影响,建立包含渣皮热源项的稳态传热模型,获得初始炉壁内表面温度场;然后,为提高温度场模型精度,基于热传导反问题理论,以冷却壁中热电偶的实测温度为参考,构建炉壁温度场修正模型,实现炉壁温度场数据的迭代修正。实验表明经温度场修正模型修正后,传热模型的计算误差控制在5%以内,满足现场检测精度要求,并能可视化展示炉壁温度场,为高炉调控操作提供了可靠的炉壁温度场数据。

基于PCA降维和迭代正则化的温度场重建

针对声学CT对温度场重建的不适定性,该文提出了一种基于PCA降维和迭代正则化的重建算法。通过径向基函数逼近声慢度分布建立声学CT正问题模型;用PCA降维改善逆问题的病态性;用迭代正则化法求解逆问题;利用声慢度与温度的关系得到温度分布。仿真和实际温度场重建实验表明,与常用的最小二乘法和基于奇异值分解的直接正则化法相比,所提算法的重建图像更接近真实分布,重建误差最高可降低86.62%和29.1%。因此基于PCA降维和迭代正则化的重建算法能够提供更高质量的重建温度场。

基于主被动层析融合的碳烟火焰多参数场重建

为克服实际工程应用中火焰辐射特性未知导致对火焰温度和辐射特性协同重建的低效率和低精度难题,结合主动激光层析吸收光谱和被动辐射成像技术,提出一种基于主被动层析融合的高温碳烟火焰多物理场协同重建的新方法。结合多谱段下激光层析透射测量信号和火焰自发辐射光场测量信号,根据火焰弥散介质辐射传输机理建立主被动层析的多场协同重建模型,对数值模拟高温碳烟火焰和耶鲁大学实验燃烧火焰的三维辐射物性场、温度场及气固两相燃烧产物组分浓度场的协同重建进行模拟研究,并对多种测量信号的随机误差进行误差传递分析。结果表明:当激光信噪比大于25 dB时,模拟火焰衰减系数场重建的相关系数接近1,重建的温度场与真值吻合较好;当激光信噪比大于30 dB时,实验火焰碳烟颗粒浓度场重建的相关系数接近1,温度场重建相关系数约为0.83;光场信号测量噪声对温度重建精度的影响比激光测量噪声显著,应尽可能保证激光与光场测量系统的标定精度。

井筒温压场下微型测量器运移模型及校正研究

目前微型测量器在随钻测量中只记录物理场参数和对应参数的时间参数,没有记录与井深相关的参数。为此,在相关研究的基础上,考虑井筒温压场的影响,建立微型测量器在井筒中的运移模型,并对其在井筒中运移的时间-深度关系进行校正研究。研究结果表明:微型测量器在井筒中的运移需要考虑井筒温压场的影响;校正后的微型测量器在井筒中运移的时间-深度关系的计算精度受校正次数影响较大,校正次数越多,反演得到的校正系数越趋于稳定;建立的微型测量器在井筒中运移的校正模型不仅能够较准确地计算出其在井筒中运移的校正系数,而且能够根据井下情况实时调整计算结果。所得结论可为微型测量器的现场应用提供理论指导。

大型复线船闸闸室底板混凝土热学参数优化反演

为探讨大型复线船闸闸室底板混凝土绝热温升参数和表面放热系数,建立了组合指数式绝热温升的水管冷却等效热传导有限元模型,基于临淮岗复线船闸闸室底板混凝土内部和表面实测温度,采用正交设计-BP神经网络-数值计算相结合的方法反演获得了混凝土的热学参数。结果表明:采用正交设计-BP神经网络-数值计算的方法较室内试验获取的混凝土热学参数更快速、更符合工程实际;混凝土最终绝热温升为62.06℃,3 d前后混凝土表面放热系数分别为34.43 kJ/(m^(2)·h·℃)和47.52 kJ/(m^(2)·h·℃),侧表面放热系数为19.42 kJ/(m^(2)·h·℃);由于没有模拟底板混凝土浇筑过程,导致前3 d混凝土表面温度计算值和实测值存在一定的差异,但底板内部温度和3 d后的表面温度的计算值与实测值变化规律基本一致,反演的闸室底板混凝土热学参数是可靠的。

感兴趣未知红外波段遥感图像超分辨率反演重构

提出了感兴趣未知波段遥感图像超分辨率反演重构算法。基于已有波段的多光谱图像,根据构建的地物光谱反射率数据库,利用高斯混合聚类算法和相关距离法,对辐射定标和大气校正后的场景光谱反射率图像的物质进行分类与类别判定。基于流形空间约束的图像解混算法得到场景图像的地物分布,据此,反演重构感兴趣未知波段地物光谱反射率图像。基于已有波段的远红外图像,利用温度反演算法与插值算法,反演重构感兴趣未知波段高分辨率地物温度场分布。根据地物光谱反射率信息和地物温度场信息,利用遥感链路成像模型,超分辨率反演重构出感兴趣未知红外波段高分辨率遥感图像。实验结果表明,本文算法能够超分辨率反演重构出感兴趣未知红外波段不同场景的高分辨率遥感图像,重构图像与场景实况图像的相似度很高,提升图像的目标检测识别能力。

开关柜内部热点温度非接触反演计算研究

内部过热是开关柜运维过程中的常见缺陷。现有的开关柜内部接触式测温技术在可靠性与安全性方面不足,存在着推广的局限;外部非接触式红外巡检则具有难定量诊断缺陷的问题。本文以KYN28-12A型630 A的自冷型开关柜作为研究对象,建立其温度流体场仿真模型,通过流线分析寻找合适的表面测温点,并通过正交计算得出不同工况、缺陷下开关柜负荷电流,将表面测点温度与内部热点温度之间的关系作为反演样本,最后基于支持向量机回归方法完成样本训练,形成反演计算用的降阶模型并进行了现场验证。研究成果实现了在无需内置温度传感器条件下开关柜内部热点温度的定量测算方法,在实施环节具有安全性与便捷性,尤其适用于大量难以停电改造的存量开关柜。