检索结果-南通市图书馆

浮力作用下上升气泡的变形和驻涡形成机理研究

在线全文

学校读者我要写书评

暂无评论

工程热物理学报 2009年第1期30卷 76-80页

作者：倪明玖中国科学院研究生院物理科学学院北京100049

采用直接模拟方法,研究气泡在浮力作用下的变形机理及气泡尾部驻涡形成机理。用二阶时空精度的变密度投影方法解Navier-Stokes方程,用VOF(volume of fluid)方法捕捉界面。获得了气泡平衡时的上升速度,并探讨气泡内部环流和气泡尾部驻涡... 详细信息

采用直接模拟方法,研究气泡在浮力作用下的变形机理及气泡尾部驻涡形成机理。用二阶时空精度的变密度投影方法解Navier-Stokes方程,用VOF(volume of fluid)方法捕捉界面。获得了气泡平衡时的上升速度,并探讨气泡内部环流和气泡尾部驻涡间的关系。

关键词：驻涡 VOF(volume of fluid)方法气泡变形

在线全文

学校读者我要写书评

暂无评论

水平磁场对液态金属自然对流的影响

工程热物理学报 2018年第6期39卷 1366-1372页

作者：陈龙倪明玖中国科学院大学工程科学学院北京101408

在聚变堆中,由于大温差和强磁场的影响,液态金属自然对流呈现出了不同于常见流体的流动和换热特征。本文基于自主研发的磁流体计算程序,通过三维直接数值模拟,研究了平行于温度梯度的水平磁场对封闭方腔中液态金属流动与传热的影响。分... 详细信息

在聚变堆中,由于大温差和强磁场的影响,液态金属自然对流呈现出了不同于常见流体的流动和换热特征。本文基于自主研发的磁流体计算程序,通过三维直接数值模拟,研究了平行于温度梯度的水平磁场对封闭方腔中液态金属流动与传热的影响。分析了不同磁场强度下,方腔内的流动与传热,包括主环流、二次流、温度分布及Nu数分布等,并从机理上解释了磁场的影响。结果表明平行温度梯度的水平磁场对自然对流有抑制作用,磁场越强,抑制越明显,传热效率越低。

关键词：水平磁场自然对流三维数值模拟

Elastic three-dimensional phononic topological insulators with Dirac hierarchy

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第5期67卷 54-62页

作者： Shao-Yong Huo Qiu-Shuang Yang jiu-jiu Chen Hong-Kang Li Long-Chao Yao Fu-Chun He Chun-ming Fu College of Mechanical Engineering University of South ChinaHengyang 421001China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China

Three-dimensional(3D)phononic topological insulators(TIs)featuring two-dimensional(2D)surface states and one-dimensional(1D)hinge states have opened up a new route for multi-dimensional robust wave transport,providing unprecedented methods for integrated acoustic sensors and energy harvesting ***,aiming at the elastic 3D phononic TI with gapless surface states and hinge states,the realization of elastic 3D phononic TIs with gapless surface states and hinge states is a significant challenge due to the complicated multi-mode polarization of elastic waves in 3D *** this study,we demonstrate an elastic 3D phononic TI with a Dirac hierarchy by elaborately operating the corresponding spatial symmetries of the chiral honeycomb ***,a 3D double Dirac cone of elastic wave can be achieved by doubling the lattice along the outof-plane direction to fold two iso-frequency Weyl *** topological phase transitions and 2D gapless two-fold Dirac surface states of elastic wave are realized by breaking the half-lattice spatial translation ***,based on the Brillouin zone folding along the in-plane direction,the 2D gapless two-fold surface Dirac cones are folded into four-fold surface Dirac ***,by inducing the relative radius of adjacent holes to break the in-plane spatial inversion symmetry,the fourfold surface Dirac cones are gapped and associated with a surface state inversion,in which the gapless 1D hinge Dirac dispersion is *** research offers a route for engineering the hierarchies of TIs in 3D elastic wave systems and provides new possibilities for designing 3D ultrasonic devices with unconventional functions.

关键词： Dirac topological hierarchy

在线全文

学校读者我要写书评

暂无评论

强磁场对突扩管中液态金属剪切层的影响

工程热物理学报 2021年第10期42卷 2672-2680页

作者：王赵波陈龙倪明玖中国科学院大学工程科学学院北京101408

在聚变堆中,由于强磁场的影响,液态金属流动呈现准二维流动的特征。本文基于SM82模型,对不同磁场强度下突扩管内的流动进行数值研究。计算结果表明,随着磁场强度增大,流动从不稳定状态向稳定状态转变,剪切涡脱落逐渐消失,并伴随着剪切... 详细信息

在聚变堆中,由于强磁场的影响,液态金属流动呈现准二维流动的特征。本文基于SM82模型,对不同磁场强度下突扩管内的流动进行数值研究。计算结果表明,随着磁场强度增大,流动从不稳定状态向稳定状态转变,剪切涡脱落逐渐消失,并伴随着剪切涡纵向尺寸变窄,横向关联尺度变长,剪切层脉动特征频率趋于一致。同时,脱落后的剪切涡与壁面相互作用是影响管道换热的主要因素,随着磁场强度增加,壁面平均努塞尔数逐渐减小,换热效率降低。

关键词：强磁场突扩管流动准二维流动

在线全文

学校读者我要写书评

暂无评论

MHD膜流数值计算平台的发展

中国科学：物理学、力学、天文学 2022年第10期52卷 131-136页

作者：潘君华倪明玖中国科学院大学工程科学学院北京101408

简述了磁约束热核聚变反应堆的关键部件液态锂偏滤器研发中所涉及的流体力学研究背景,主要研究问题为液态金属在磁场环境下的薄膜流动稳定性.为了解磁流体动力学效应对薄膜流动稳定性的影响,本文发展了线性稳定性分析数值计算平台和直... 详细信息

简述了磁约束热核聚变反应堆的关键部件液态锂偏滤器研发中所涉及的流体力学研究背景,主要研究问题为液态金属在磁场环境下的薄膜流动稳定性.为了解磁流体动力学效应对薄膜流动稳定性的影响,本文发展了线性稳定性分析数值计算平台和直接数值模拟计算平台,采用数值模拟手段,揭示磁场对膜流流动稳定性作用的物理机制,指导液态锂偏滤器的设计和实现.

关键词：磁流体动力学膜流线性稳定性分析直接数值模拟

Multi-Fidelity Simulation of Gas Turbine Overall Performance by Directly Coupling High-Fidelity Models of Multiple Rotating Components

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第4期33卷 1357-1378页

作者： DENG Weimin XU Yibing ni ming WEI Zuojun GAN Xiaohua REN Guangming Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen518055China School of Aerospace Engineering Tsinghua UniversityBeijing100084China Shenzhen Key Laboratory of Wide-Speed-Range and Variable-Density Continuous Wind Tunnel Shenzhen Science and Technology Innovation CommitteeShenzhen518000China

Multi-fidelity simulations incorporate computational fluid dynamics(CFD) models into a thermodynamic model,enabling the simulation of the overall performance of an entire gas turbine with high-fidelity *** iterative coupled methods rely on characteristic maps,while fully coupled methods directly incorporate high-fidelity ***,fully coupled methods face challenges in simulating rotating components,including weak convergence and complex *** address these challenges,a fully coupled method with logarithmic transformations was developed to directly integrate high-fidelity CFD models of multiple rotating *** developed fully coupled method was then applied to evaluate the overall performance of a KJ66 micro gas turbine across various off-design *** developed fully coupled method was also compared with the traditional iterative coupled ***,experimental data from ground tests were conducted to verify its *** convergence history indicated that the proposed fully coupled method exhibited stable convergence,even under far-off-design *** experimental verification demonstrated that the multi-fidelity simulation with the fully coupled method achieved high accuracy in off-design *** analysis revealed inherent differences in the coupling methods of CFD models between the developed fully coupled and traditional iterative coupled *** inherent differences provide valuable insights for reducing errors between the component-level model and CFD models in different coupling *** developed fully coupled method,introducing logarithmic transformations,offers more realistic support for the detailed and optimal design of high-fidelity rotating components within the overall performance platform of gas turbines.

关键词： multi-fidelity fully coupled method iterative coupled method gas turbine component-level model

在线全文

学校读者我要写书评

暂无评论

耦合物理场中包层的流动传热和结构安全分析

工程热物理学报 2015年第6期36卷 1339-1344页

作者：李明健陈龙倪明玖张年梅中国科学院大学物理学院北京100190

包层结构是国际热核聚变实验堆(ITER)中的重要组件,它的力学行为与磁-热-流-固多物理场的耦合效应密切相关。本文采用有限体积法和有限元方法,分析了磁场强度和流体入口速度对包层内流动传热效应和包层中流道插件(FCI)结构安全性的影响... 详细信息

包层结构是国际热核聚变实验堆(ITER)中的重要组件,它的力学行为与磁-热-流-固多物理场的耦合效应密切相关。本文采用有限体积法和有限元方法,分析了磁场强度和流体入口速度对包层内流动传热效应和包层中流道插件(FCI)结构安全性的影响。对磁场效应的分析表明,虽然MHD效应对流体存在不利影响,但磁场效应引起的M型速度分布改变了流体的传热形式,可以增加流体出口平均温度,提高热效率;同时,射流可降低第一壁最高温度,减小FCI最大结构热应力。此外,磁场效应还降低了FCI的热膨胀趋势,使得侧壁和Hartmann壁的法向位移有所减小。对于入口流速的分析表明,当速度增加时,PbLi流体出口平均温度降低,使其热效率降低,但流道向氦气中的热泄露有所减少,增加了出口输出热功率。当速度超过0.06 m/s时,出口热功率占中子生成热功率的比例将稳定在85%左右,同时考虑到第一壁和FCI的结构安全性,入口速度选择在0.06~0.10 m/s间可使包层达到良好的传热性能和安全性能。

关键词：多物理场流道插件传热热应力

Mechanism of Qili Qiangxin Capsule for Heart Failure Based on miR133a-Endoplasmic Reticulum Stress

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第5期30卷 398-407页

作者： JI Xiao-di YANG Ding CUI Xi-yuan LOU Li-xia niE Bo ZHAO jiu-li ZHAO ming-jing WU Ai-ming Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine Key Laboratory of Chinese Internal Medicine of Ministry of Education and BeijingBeijing 100700China Department of Traditional Chinese Medicine Fuwai HospitalChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100037China

Objective:To investigate the pharmacological mechanism of Qili Qiangxin Capsule(QLQX)improvement of heart failure(HF)based on miR133a-endoplasmic reticulum stress(ERS)***:A left coronary artery ligation-induced HF after myocardial infarction model was used in this *** were randomly assigned to the sham group,the model group,the QLQX group[0.32 g/(kg·d)],and the captopril group[2.25 mg/(kg·d)],15 rats per group,followed by 4 weeks of *** function such as left ventricular ejection fraction(EF),fractional shortening(FS),left ventricular systolic pressure(LVSP),left ventricular end diastolic pressure(LVEDP),the maximal rate of increase of left ventricular pressure(+dp/dt max),and the maximal rate of decrease of left ventricular pressure(–dp/dt max)were monitored by echocardiography and *** and eosin(HE)and Masson stainings were used to visualize pathological changes in myocardial *** m RNA expression of mi R133a,glucose-regulated protein78(GRP78),inositol-requiring enzyme 1(IRE1),activating transcription factor 6(ATF6),X-box binding protein1(XBP1),C/EBP homologous protein(CHOP)and Caspase 12 were detected by *** protein expression of GRP78,p-IRE1/IRE1ratio,cleaved-ATF6,XBP1-s(the spliced form of XBP1),CHOP and Caspase 12 were detected by Western *** T-mediated d UTP nick-end labeling(TUNEL)staining was used to detect the rate of ***:QLQX significantly improved cardiac function as evidenced by increased EF,FS,LVSP,+dp/dt max,-dp/dt max,and decreased LVEDP(Pning showed that QLQX ameliorated cardiac pathologic damage to some *** staining indicated that QLQX significantly reduced collagen volume fraction in myocardial tissue(Pnificantly increased the expression of mi R133a and inhibited the m RNA expressions of GRP78,IRE1,ATF6 and XBP1,as well as decreased the protein expressions of GRP78,cleave

关键词： heart failure Qili Qiangxin Capsule miR133a endoplasmic reticulum stress apoptosis

在线全文

学校读者我要写书评

暂无评论

交错网格下MHD相容守恒格式的发展

核聚变与等离子体物理 2011年第3期31卷 219-223页

作者：李俊峰倪明玖中国科学院研究生院物理科学学院北京100049

在低磁场雷诺数条件下,基于电势泊松方程,发展了交错网格下可以精确计算电流和洛伦兹力（电磁力）的相容守恒格式。采用压力为变量的原始变量法求解不可压缩Navier-Stokes方程,所计算的电流满足电荷守恒定律,所计算的电磁力满足动量守... 详细信息

在低磁场雷诺数条件下,基于电势泊松方程,发展了交错网格下可以精确计算电流和洛伦兹力（电磁力）的相容守恒格式。采用压力为变量的原始变量法求解不可压缩Navier-Stokes方程,所计算的电流满足电荷守恒定律,所计算的电磁力满足动量守恒定律。对金属流体在Hartmann数50~5000范围内验证了格式的精确性。交错网格下相容守恒格式的发展为后续MHD稳定性分析、湍流的大涡模拟及直接数值模拟提供很好的选择。

关键词：磁流体动力学相容守恒格式交错网格洛伦兹力