搜索到10450篇“ DISKS“的相关文章
Analyzing Thermal Stratification and Nanoparticle Shapes Influence on an EMHD Ternary Nanofluid Flow amidst Two Spinning Disks
2024年
The present study examines the thermal distribution of ternary nanofluid flow amid two spinning disks influenced by electric and magnetic fields. Keeping in view the shape of the particles, the electrically conducting ternary nanofluid is analyzed with variable thermophysical features. Three types of nanoparticles namely Copper, Aluminum Oxide, and Graphene with spherical, cylindrical, and platelet shapes are taken respectively and are immersed in a (50-50)% ratio of water and ethylene glycol mixture which acts as a base fluid. The anticipated problem is addressed by employing a reliable and user-friendly numerical bvp4c built-in collocation scheme. This solution is then showcased through illustrations and tables. Strengthening the radiation results in an enhanced heat transfer rate. Radial and azimuthal velocities once rotation of disks is enhanced. The key findings provide a strong theoretical background in photovoltaic cells, solar collectors, radiators, solar water heaters, and many other applications.
Muhammad RamzanSaima Riasat
大尺寸低损耗金刚石窗片制备及微波窗口封接
2024年
为满足长脉冲大功率回旋管研制需求,采用直流电弧等离子体喷射化学气相沉积法合成大尺寸低损耗金刚石厚膜窗片;通过表面金属化和钎焊工艺进行微波窗口的封接。采用法布里-玻罗(Fabry-Perot)开放激励腔、激光导热仪、三维轮廓仪、激光干涉仪等对金刚石窗片介电损耗、热导率、表面平坦度、粗糙度等性能参数进行了表征;采用氦质谱检漏仪、高功率长脉冲微波测试平台测试了窗口气密性和微波吸收特性。实验结果表明,抛光厚度1.36 mm的金刚石窗片具有高尺寸精度,热导率达到17.9~18.7 W·cm^(-1)·K^(-1);波导窗片介电损耗tanδ=1.76×10^(-4),回旋管窗片tanδ=2.6×10^(-4)。计算结果表明,在1 MW微波输入功率下波导窗损耗功率约2.34 kW,窗片中心热应力在安全数值内,相同损耗功率条件下回旋管窗口可承受至少680 kW的输出功率。
李义锋姜龙安晓明葛新岗张雅淋仝婷婷张平伟刘晓晨郭辉任斌孙振路
双刀盘铣齿机床与Free-form型机床的加工运动等效转换
2024年
为了实现在国产数控螺旋锥齿轮加工机床上采用单刀盘加工直齿锥齿轮,基于空间运动学原理,在保证工件轴线与刀盘轴线相对位置及相对运动关系不变的前提下,将双刀盘铣齿机床中刀盘与工件的相对位置和相对运动关系等效转换至Free-form型机床,得到以时间为自变量的Free-form型机床各数控轴的运动表达式;通过Matlab计算每个加工时刻Free-form型机床运动轴的位置坐标点并编写数控加工程序;基于Vericut仿真软件,建立了Free-form型机床加工环境并对加工过程进行仿真,仿真结果验证了运动转换方法和数控加工程序的正确性;在实际Free-form型机床上进行了铣齿加工实验,利用齿轮测量中心对实验工件的实际齿面相对于理论齿面的齿形误差进行了检测,齿形误差在10.8μm以内;利用滚动检查机对齿轮副的接触区进行检验,实际啮合接触区与TCA结果基本一致。仿真加工和实际切齿加工实验的结果验证了机床加工运动等效转换方法的正确性。
王志永李文强张宇
关键词:直齿锥齿轮
Unsteady squeezing flow and heat transport of SiO_(2)/kerosene oil nanofluid around radially stretchable parallel rotating disks with upper disk oscillating
2024年
In this study,we have analyzedfluid mobility and thermal transport of the SiO_(2)/kerosene nanofluid within two rotating stretchable disks.The top disk is simulated to be oscil-lating with a periodic velocity and squeezing continuously the nanofluid within a porous me-dium and making thefluid toflow perpendicularly to the situated magneticfield.Thermal radiation effects are considered in the heat transfer model.The non-linear(NL)PDEs that describe the nanofluid mobility structure and thermal transport are transformed into system of NL-ODEs by introducing adequately suitable non-dimensional variables after which the NL-ODEs were numerically solved via spectral quasi-linearization method(SQLM)on over-lapping grids.The consequences of several pertinent parameters of the model on pressure,tem-perature,velocity,skin drag coefficient and thermal transport rate are examined and elucidated in detail with the aid offigures and tables.It was found that theflow structure with prescribing conditions develops negative pressure situation which has vast applications in modern day medical engineering,especially in the construction of air pressure stabilizers used in medical isolation and wound therapy physiology.
Folarin OluwaseunSicelo GoqoHiranmoy Mondal
关键词:UNSTEADYSQUEEZINGSTRETCHABLEKEROSENE
分辨超大质量黑洞吸积盘的结构被引量:1
2024年
超大质量黑洞吸积盘是活动星系核的中心引擎.理解超大质量黑洞吸积盘的结构对认识超大质量黑洞的质量演化、活动星系核的反馈和引力透镜宇宙学等重大天体物理问题有着重要的意义.利用射电干涉技术,天文学家已经能对银河系和M87中心超大质量黑洞周围的吸积气体进行空间分辨,进而对黑洞“成像”.然而,绝大部分超大质量黑洞吸积盘太小且距离地球过于遥远,无法被现有空间和地面望远镜直接进行空间分辨.天文学家借助时域观测,利用微引力透镜和连续谱反响映射来研究超大质量黑洞吸积盘的结构.上述两种方法给出的超大质量黑洞吸积盘的尺寸都显著大于标准薄盘的预期.这一观测与理论的矛盾被称为“吸积盘尺寸超出”问题.本文从观测和理论的角度,综述“吸积盘尺寸超出”问题研究方面取得的进展、面临的问题以及可能的解决方案.我们认为,只有在正确理解活动星系核光变的物理起源后,天文学家才能正确分辨超大质量黑洞吸积盘的结构.
孙谋远周淑英
关键词:超大质量黑洞活动星系核
基于热-固耦合作用的泄压箱爆破片疲劳寿命研究
2024年
爆破片作为核反应堆泄压箱关键的安全设备,主要功能是在系统超压时迅速破裂,释放多余的压强,以保证反应堆冷却剂系统的正常运行和安全。在复杂的工作环境中,爆破片会同时受到循环压强载荷和温度载荷的作用,因此研究在热-固耦合作用下爆破片的应力分布和疲劳寿命具有重要意义。首先利用有限元方法建立泄压箱爆破片的数值分析模型,其次基于热-固耦合分析爆破片在循环压强载荷和温度循环载荷共同作用下的应力,对爆破片进行疲劳分析和疲劳寿命预测分析,最后基于几何尺寸对爆破片疲劳寿命的影响对爆破片进行结构优化。通过优化设计,延长了爆破片的疲劳寿命,增强了其在复杂工作环境下的稳定性和可靠性。
岳景辉李哲吴腾
关键词:爆破片有限元分析
高速列车碳陶制动盘制动性能对比研究
2024年
针对碳陶制动盘在全制动工况下制动能力不明的问题,提出了一种基于匹配参数表征的制动盘制动性能对比分析方法。分别考虑以制动减速度为特征的动力学性能,和以盘面最大温升累积为特征的热力学性能,建立适用于多种线路工况的碳陶制动盘制动性能仿真分析模型。仿真实验结果表明,在设定工况下碳陶制动盘的紧急制动距离最高可达6726 m,盘面最高温度可达941.4℃;在紧急制动模式下实施制动,盘体温升速率明显提升,对高速列车制动单元的安全性产生威胁。
徐忠宣单昌胜梁海泉
关键词:制动性能制动距离
修正q-Szász-Kantorovich算子在紧圆盘的复逼近(q>1)
2024年
本文给出了修正q-Szász-Kantorovich算子在复空间的定义,参照Gal S G等人在文献[10]的方法,研究了当q>1时修正q-Szász-Kantorovich算子在紧圆盘对解析函数的逼近性质,获得了Voronovskaja结果,并给出其精确估计,丰富了修正q-Szász-Kantorovich算子在复空间的逼近性质.
闫丽新韩领兄
Effects of multiple shapes for steady flow with transformer oil+Fe_(3)O_(4)+TiO_(2) between two stretchable rotating disks
2024年
In this study,we examine the effects of various shapes of nanoparticles in a steady flow of hybrid nanofluids between two stretchable rotating disks.The steady flow of hybrid nanofluids with transformer oil as the base fluid and Fe_(3)O_(4)+TiO_(2)as the hybrid nanofluid is considered.Several shapes of Fe_(3)O_(4)+TiO_(2)hybrid nanofluids,including sphere,brick,blade,cylinder,and platelet,are studied.Every shape exists in the same volume of a nanoparticle.The leading equations(partial differential equations(PDEs))are transformed to the nonlinear ordinary differential equations(ODEs)with the help of similarity transformations.The system of equations takes the form of ODEs depending on the boundary conditions,whose solutions are computed numerically by the bvp4c MATLAB solver.The outputs are compared with the previous findings,and an intriguing pattern is discovered,such that the tangential velocity is increased for the rotation parameter,while it is decreased by the stretching values because of the lower disk.For the reaction rate parameter,the concentration boundary layer becomes shorter,and the activation energy component increases the rate at which mass transfers come to the higher disk but have the opposite effect on the bottom disk.The ranges of various parameters taken into account are Pr=6.2,Re=2,M=1.0,φ_(1)=φ_(2)=0.03,K=0.5,S=-0.1,Br=0.3,Sc=2.0,α_(1)=0.2,γ=0.1,E_(n)=2.0,and q=1.0,and the rotation factor K is within the range of 0 to 1.
M.RAHMANM.TURKYILMAZOGLUZ.MUSHTAQ
A Catalog of Collected Debris Disks:Properties,Classifications and Correlations between Disks and Stars/Planets被引量:1
2023年
We have collected a catalog of 1095 debris disks with properties and classification(resolved,planet,gas)information.From the catalog,we defined a less biased sample with 612 objects and presented the distributions of their stellar and disk properties to search for correlations between disks and stars.We found debris disks were widely distributed from B to M-type stars while planets were mostly found around solar-type stars,gases were easier to detect around early-type stars and resolved disks were mostly distributed from A to G-type stars.The fractional luminosity dropped off with stellar age and planets were mostly found around old stars while gas-detected disks were much younger.The dust temperature of both one-belt systems and cold components in two-belt systems increased with distance while decreasing with stellar age.In addition,we defined a less biased planet sample with 211 stars with debris disks but no planets and 35 stars with debris disks and planets and found the stars with debris disks and planets had higher metallicities than stars with debris disks but no planets.Among the 35 stars with debris disks and planets,we found the stars with disks and cool Jupiters were widely distributed with age from 10 Myr to 10 Gyr and metallicity from-1.56 to 0.28 while the other three groups tended to be old(>4Gyr)and metal-rich(>-0.3).In addition,the eccentricities of cool Jupiters are distributed from 0 to 0.932,wider than the other three types of planets(<0.3).
Peng-Cheng CaoQiong LiuNeng-Hui LiaoQian-Cheng YangDong Huang

相关作者

任杰
作品数:158被引量:210H指数:7
供职机构:南京理工大学
研究主题:通路 车用 燃气射流 复合材料 碳纤维复合材料
施伯乐
作品数:380被引量:2,738H指数:26
供职机构:复旦大学
研究主题:数据库 XML 面向对象 数据挖掘 数据模型
陈二云
作品数:130被引量:260H指数:8
供职机构:上海理工大学能源与动力工程学院
研究主题:数值模拟 压力脉动 间断有限元方法 血管生成 气动噪声
刘淑艳
作品数:92被引量:431H指数:11
供职机构:北京理工大学宇航学院
研究主题:数值模拟 非结构网格 紧致 水翼 高分辨率格式
孙未未
作品数:119被引量:214H指数:8
供职机构:复旦大学
研究主题:自组织网络 路网 无线自组织网络 服务请求 历史轨迹