搜索结果: 31-45 共查到“知识库 工程热力学”相关记录66条 . 查询时间(3.8 秒)
PERSISTENCE OF THE LAMINAR REGIME IN A FLAT PLATE BOUNDARY LAYER AT VERY HIGH REYNOLDS NUMBER
transition flow control boundary layer theory
2009/10/13
Starting from the Navier-Stokes and the continuity equations of a viscous incompressible fluid, a statistical theory is developed for the prediction of transition and break down to turbulence in a lam...
NUMERICAL EXPERIMENTS ON WALL TURBULENCE AT LOW REYNOLDS NUMBER
turbulence flow control transition
2009/10/13
A direct numerical simulation of a turbulent channel ?ow, with regularly spaced two-dimensional roughness elements mounted at the wall and perpendicular to the ?ow direction, was performed at a very l...
ADVANCED THERMODYNAMICS METRICS FOR SUSTAINABILITY ASSESMENTS OF OPEN ENGINEERING SYSTEMS
thermodynamics metrics manufacturing sustainability
2009/10/13
This paper offers a verification of the following hypotheses. Advanced thermodynamics metrics based on entropy generation assessments indicate the level of sustainability of transient open systems, su...
THERMODYNAMIC ANALYSIS OF AIR REFRIGERATOR ON ENERGY GRAPH
thermodynamic analysis exergy efficiency
2009/10/13
Improving me chanical system efficiency is the goal of many engineers and scientists. Commonly, the solutions to these types of problems are uncovered using thermodynamic analysis and optimization. An...
MICROCHANNELS IN MACRO THERMAL MANAGEMENT SOLUTIONS
micro-channels roughness computational fluid dynamics
2009/10/13
Modern progress in electronics is associated with increase in computing ability and processing speed, as well as decrease in size. Future applications of electronic devices in aviation, aero space and...
RELIABLE SIMPLE ZONAL METHOD OF THE FURNACE THERMAL CALCULATION
thermal calculation boiler furnace zonal method
2009/10/13
The calculation of the furnace in the industrial and power boilers is the most important and the most responsible part of the thermal calculation, and it has important influence on the rationalization...
EMPIRICAL CORRELATION FOR PREDICTION OF THE ELUTRIATION RATE CONSTANT
EMPIRICAL CORRELATION PREDICTION ELUTRIATION RATE CONSTANT
2009/10/13
In vessels containing fluidized solids, the gas leaving carries some suspended particles. This flux of solids is called entrainment, E or carryover and the bulk density of solids on this leaving gas s...
EXPERIMENTAL STUDIES AND ECONOMIC CONSIDERATIONS ON A THERMOSOLAR PILOT SYSTEM DESTINED FOR HOUSE TEMPERATURE MAINTENANCE
solar energy efficiency solar collectors
2009/10/13
The "Politehnica" University of Timisoara has built a thermo solar system implemented on the ground floor and first floor of a building. The system is made up of solar water collectors, an air-water h...
Last ten years the attention of the research and development efforts in developed countries has been moved from bubbling FBC to circulating FBC. Low prices of the liquid fuel and gas and more stringen...
高通量循环流化床上升管气固流动特性实验研究
循环流化床 高通量 上升管
2009/9/17
以直径0.06 m、高5 m的高通量循环床提升管中气固两相流大量试验数据为基础，考察在高颗粒循环量和较高气体表观流速下，平均粒径为140 mm、密度为2 700 kg/m3的Geldart B 类颗粒气固流动特性。试验发现，截面平均颗粒浓度分布总体上为下浓上稀，并随操作气速的增大而减小，悬浮上升流动结构区域随着颗粒循环速率的增大而向上延伸。滑移因子、截面平均颗粒浓度与无量纲滑移速度之间...
气液两相流并列双方柱绕流涡脱特性数值研究
气液两相流 并列双方柱 旋涡脱落
2009/9/17
采用有限容积法，综合考虑了由剪切引起的紊流和由气泡引起的紊流关系式，基于双流体模型，对不同含气率、不同间距比下气液两相流并列双方柱绕流旋涡脱落特性进行了数值模拟。通过计算发现：气液两相流并列方柱绕流，在间距比T/D<2.0时，双方柱尾迹模式是偏流模式，且宽窄尾迹流是通过中间模式(非偏流)相互转化的；在偏流模式中，拥有宽尾迹模式的柱体具有更小的阻力，拥有窄尾迹模式的柱体具有更大的阻力，而中间模式...
根据热挤压模具的工作特点,基于热弹性力学和有限应变理论,建立了三维热力耦合弹塑性有限元方程。用该方程研究方管铝型材平面分流组合模的三维数值分析,在确定边界条件和计算挤压力的基础上,通过合理设计单元类型,计算了模具在挤压过程中的温度场和应力场。通过分析模具应力,发现在模桥与模芯相接处有较大的应力集中,与出现裂纹的位置相吻合,说明应力集中是模具桥裂的主要原因之一。
以有限元分析软件ANSYS为平台，建立导流槽半槽有限元模型，对普通炭块、半石墨质、半石墨化和石墨化4种阴极炭块在燃气预热过程中的温度、位移与热应力分布进行数值模拟研究。研究结果表明：炭块表面的高温区位于燃气的射流区域；炭块两侧的位移都呈对称分布，x，y和z方向位移较大的区域分别位于边部聚铝沟、中部聚铝沟及烟道端聚铝沟附近；热应力集中的区域位于中央聚铝沟下方的阴极炭块与钢棒接触处。随着石墨含量的增加...
光纤耦合器熔融拉锥粘弹性建模与分析
光纤耦合器 熔融拉锥 粘弹流变 有限元
2009/8/26
根据热粘弹流变理论和时温等效原理,以广义Maxwell模型模拟高温下熔融光纤玻璃的粘弹特性,建立了光纤耦合器熔融拉锥过程热粘弹数值分析模型;采用热电偶和电位差计测定了气体火焰的温度;并以此温度场作为边界条件,结合有限元软件对光纤耦合器熔融拉锥过程进行热瞬态数值分析,得到了光纤耦合器在熔融拉伸过程中的应力应变场。实验结果表明:当最高温度为1 171℃,拉伸速度为0.15μm/s时,最大拉应力为20....