A. Forberger ,
 Gamax Laboratory Solutions Ltd., Budapest, Hungary
Introduction Present paper gives a comparison of the Upperconvected Maxwell (UCM) and the Oldroyd-B model for the calculation of dissipation in high shear-rate cases of viscodampers. When polymeric liquid is considered that part of energy that is irreversible can not be calculated in the typical way. For fluids where the separation into a solvent and a polymer part is not available the ...
S. Thennavarajan, P. Jeyaraj , L. P. Manikandan , S. S. Kulkarni , S. Jana ,
Department of Mechanical Engineering, NITK, Surathkal, Mangalore, Karnataka, India
CSIR- National Aerospace Laboratories, Bengalore, Karnataka, India
The high speed gas turbine is a power plant developed for modern aircrafts. It is widely used and developed because it can meet the high power to weight ratio. The rotor system of modern small gas turbine works above the critical speeds. Hence, there is a stricter requirement for the control and isolation of vibration magnitude under heavy unbalance load and passing through critical speeds. An ...
C. Belavý, G. Hulkó, S. Lipár, B. Barbolyas
Institute of Automation, Measurement and Applied Informatics, Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava, Bratislava, Slovak Republic
In the paper, first a basic concept of the engineering approach for modeling and control of distributed parameter systems (DPS) based on interpretation of controlled systems as lumped input and distributed output systems (LDS) is introduced. Next, FEM modeling of temperature fields in casting mould and extruder body as real DPS by means of the software environment COMSOL Multiphysics® is ...
D. Groulx, A. Bharath, S. Campbell
Department of Mechanical Engineering, Dalhousie University, Halifax, NS, Canada
The field of underwater acoustics research is constantly growing with the ongoing improvement of acoustic measuring techniques. An acoustic hydrophone receiver is a passive listening device which is widely used in biological research and sonar technology. The hydrophone however suffers from turbulence generated noise created by its presence in ever faster flow. This work aims to analyze the ...
P. Lin, C. Chang, H. Huang, and B. Zheng
Mechanical and Aerospace Eng., Rutgers, The State University of New Jersey, Piscataway, NJ
FTR Systems (Shanghai) Inc., Shanghai, China
PolarOnyx, Inc., San Jose, CA
School of Mechatronics Eng., University of Electronic Science and Technology of China, Chengdu, China
The heat sink designs using impinging liquid jets, which form stagnation flows, feature uniform heat transfer coefficients, and provide thin thermal boundary layers, are studied to reduce the heat from GPUs. Three different designs using central, micro, and uniform-cross-section (UCS) central jets are studied and simulated in COMSOL. The efficiency factors, defined as the ratio of total ...
R. V. Arimilli, A. H. Nejad, K. Ekici
The University of Tennessee, Knoxville, TN, USA
A new simple air-cooled inverter design is numerically investigated using COMSOL Multiphysics® software. The thermal-fluid analysis is based on a three-dimensional conjugate heat transfer model in which the flow field is assumed to be laminar. A rigorous mesh convergence was performed to ensure that the overall energy balance error is within engineering accuracy while the computational cost is ...
D. Kekejian, Y. Martinez
ITESO, Tlaquepaque, Jalisco, Mexico
In this work, a new design is suggested which functions both as a pipe for fluid transfer and as a valve which decreases the flow of the fluid in the opposite direction in case there are pressure fluctuations in the pipe. Therefore, we call it a "Deformed Valve". To design the structure, we had to use different geometric shapes and calculate the velocity of the fluid for each shape to determine ...
F. Boukrouche, C. Moreau, W. Frelin
EDF R&D, Moret-sur-Loing, France
Electric power, in cities or for power plant outflow, is most often transmitted through underground cables. Due to increased electricity demands power suppliers make large investments to house these cables in deep or shallow tunnels. The thermal environment is complex, with different kind of cables placed in different configurations, transmitting different powers. These are hard to take into ...
E. Luz, D. M. P. Cunha, V. H. C. Lemos
Universidade Federal do Pará - UFPA, Belém, PA, Brasil; Centro de Instrução Almirante Braz de Aguiar - CIABA, Belém, PA, Brasil
Centro de Instrução Almirante Braz de Aguiar - CIABA, Belém, PA, Brasil
The phenomenon of cavitation can severely affect the working of valves used to control liquid flow. Cavitation occurs when the pressure is reduced and the water evaporates, forming bubbles. When bubbles pass into an area of higher pressure, they condense and collapse, releasing a large amount of energy able to removing the surface layers of the material. In this work, we model the effects of ...
赵旭山 , 郝雷 , 蒋利军 , 米菁 , 杨海龄 ,
随着能源紧张、油价攀升，环境污染严重，利用可再生绿色能源又成为不懈努力的方向。槽式太阳能热发电技术具有兼容性强、对电网冲击小、性价比高、发电成本低、可存储可调度等特点，近年来得到了迅猛发展，其核心部件为高温太阳能真空集热管，如图1所示。本研究利用 COMSOL Multiphysics® 针对真空集热管真实工况下的动态过程开展研究，并在此基础上开展集热管结构的优化设计。 由图1可知：集热管在电站中服役工况下，槽面会聚的太阳光主要集中于集热管下半面，上半面接收的会聚太阳光较少；导热工质自吸收管一端进入，接收会聚太阳光辐照能量，从吸收管另一端流出，流入→流出过程中，导热工质被加热；集热管外表面与外部环境通过热辐射和对流两种方式换热；吸收管与玻璃罩管间形成的环形密闭高真空区域各内表面通过热辐射换热，不考虑对流；集热管两端支撑固定于聚光器上，由于本身自重和热应力 ...