Infrared Thermal Image on Vapor-Liquid Interface in Capillary Microgrooves Heat Sink

2009 ◽  
Author(s):  
Tao Wang ◽  
Xuegong Hu ◽  
Dawei Tang ◽  
Chaohong Guo
Keyword(s):  
Temperature Distribution ◽  
Heat Sink ◽  
Solid Wall ◽  
Thermal Image ◽  
Liquid Interface ◽  
Liquid Interfaces ◽  
Average Temperature ◽  
Solid Walls ◽  
Working Liquid ◽  
Vapor Liquid

An infrared thermoviewer is utilized to measure the temperature distribution on solid walls and vapor-liquid interfaces of the rectangular capillary microgrooves heat sink, which is made of borosilicate glass. The infrared thermal image clearly shows that the solid wall temperature of microgroove top is lower than the average temperature of vapor-liquid interface. The results indicate that heat source position has a significant influence on the microgrooves surface temperature distribution, besides working liquid, tilt angle (the angle between microgroove surface and gravity direction) and heat flux.

Infrared thermal image of vapor–liquid interface in capillary microgroove heat sink

2011 ◽  
Vol 50 (3) ◽  
pp. 274-279 ◽  
Author(s):  
Tao Wang ◽  
Xuegong Hu ◽  
Dawei Tang ◽  
Chaohong Guo
Keyword(s):  
Heat Sink ◽  
Thermal Image ◽  
Liquid Interface ◽  
Vapor Liquid

Correlation of Electronic and Thermal Properties of Short Channel nMOSFETS

1999 ◽  
Author(s):  
M. Palaniappan ◽  
V. Ng ◽  
R. Heiderhoff ◽  
J.C.H. Phang ◽  
G.B.M. Fiege ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Temperature Distribution ◽  
Heat Generation ◽  
Hot Spots ◽  
Light Emission ◽  
Photon Emission ◽  
Thermal Image ◽  
Short Channel ◽  
Physical Phenomena ◽  
Backside Illuminated

Abstract Light emission and heat generation of Si devices have become important in understanding physical phenomena in device degradation and breakdown mechanisms. This paper correlates the photon emission with the temperature distribution of a short channel nMOSFET. Investigations have been carried out to localize and characterize the hot spots using a spectroscopic photon emission microscope and a scanning thermal microscope. Frontside investigations have been carried out and are compared and discussed with backside investigations. A method has been developed to register the backside thermal image with the backside illuminated image.

scholarly journals Hydrodynamic Boundary Layers at Solid Wall—A Tool for Separation of Fine Solids

2021 ◽  
Vol 5 (1) ◽  
pp. 11
Author(s):  
Ljubomir Nikolov
Keyword(s):  
Relative Density ◽  
Hydrodynamic Interaction ◽  
Theoretical Study ◽  
Solid Wall ◽  
Separation Processes ◽  
Starting Point ◽  
Potential Applications ◽  
Neutrally Buoyant ◽  
Solid Walls ◽  
Solid Spheres

A theoretical study is performed about the hydrodynamic interaction of fine species entrapped in the boundary layer (BL) at solid wall (plate). The key starting point is the analysis of the disturbance introduced by solid spheres in the background fluid flow. For a neutrally buoyant entity, the type of interaction is determined by the size of the spheres as compared to the thickness of the BL region. The result is granulometric separation of the solids inside the BL domain at the wall. The most important result in view of potential applications concerns the so-called small particles Rp < L/ReL5/4 (ReL is the Reynolds number of the background flow and Rp is the radius of the entrapped sphere). In the case of non-neutrally buoyant particles, gravity interferes with the separation effect. Important factor in this case is the relative density of the solid species as compared to this of the fluid. In view of further practical uses, particles within the range of Δρ/ρ < Fr2/ReL1/2 (Fr is Froude number and Δρ/ρ is the relative density of the entrapped solids) are systematically studied. The trajectories inside the BL region of the captured species are calculated. The obtained data show that there are preferred regions along the wall where the fine solids are detained. The results are important for the assessment of the general efficiency of entrapment and segregation of fine species in the vicinity of solid walls and have high potential for further design of industrial separation processes.

scholarly journals An analytical method to estimate temperature distribution of typical radiant floor cooling systems with internal heat radiation

2021 ◽  
pp. 014459872199800
Author(s):  
Xiaolong Wang ◽  
Wenke Zhang ◽  
Qingqing Li ◽  
Zhenqiang Wei ◽  
Wenjun Lei ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Internal Heat ◽  
Single Layer ◽  
Heat Radiation ◽  
Transfer Model ◽  
Cooling Systems ◽  
Average Temperature ◽  
Floor Surface ◽  
Floor Structure

Radiant floor cooling systems are increasingly used in practice. The temperature distribution on the floor surface and inside the floor structure, especially the minimum and average temperature of floor surface, determines the thermal performance of radiant floor systems. A good temperature distribution of the floor structure is very important to prevent occupant discomfort and avoid possible condensation in summer cooling. In this study, based on the heat transfer model of the single-layer homogeneous floor structure when there is no internal heat radiation in the room, this paper proposes a heat transfer model of single-layer floor radiant cooling systems when the room has internal heat radiation. Using separation variable methods, an analytical solution was developed to estimate temperature distribution of typical radiant floor cooling systems with internal heat radiation, which can be used to calculate the minimum temperature and the average temperature of typical composite floor structure. The analytical solution was validated by experiments. The values of the measured experiments are in a good agreement with the calculations. The absolute error between the calculated and the measured floor surface temperatures was within 0.45°C. The maximum relative error was within 2.31%. Prove that this model can be accepted. The proposed method can be utilized to calculate the cooling capacity of a typical multi-layer composite floor and will be developed in the future study for design of a typical radiant floor cooling system.

Stability Analysis of Thermocapillary Convection of B2O3/Sapphire Melt in an Annular Pool

2021 ◽  
Vol 1036 ◽  
pp. 175-184
Author(s):  
Dong Ming Mo
Keyword(s):  
Stability Analysis ◽  
Temperature Distribution ◽  
Thermocapillary Convection ◽  
Silicone Oil ◽  
Liquid Interface ◽  
Sapphire Crystal ◽  
Neutral Stability ◽  
Unstable Flow ◽  
Fluid Layers ◽  
Lower Fluid

Aiming at the thermocapillary convection stability of sapphire crystal grown by liquid-encapsulated Czochralski method, by non-linear numerical simulation, obtained the flow function and temperature distribution of R-Z cross section, as well as the velocity and temperature distribution at liquid-liquid interface and monitoring point of B2O3/sapphire melt in annular two liquid system, covered with solid upper wall and in microgravity. By means of linear stability analysis, obtained the neutral stability curve and critical stability parameters of the system, and revealed the temperature fluctuation of the liquid-liquid interface. The calculated results of B2O3/sapphire melt were compared with 5cSt silicone oil/HT-70. The results show that under the same geometrical conditions, the flow of B2O3/sapphire melt system is more unstable than 5cSt silicone oil/HT-70, there are two unstable flow patterns, radial three-dimensional steady flow cell and hydrothermal waves near the hot wall. The larger the ratio of Pr number of upper and lower fluid layers is, the better the effect of restraining the flow of lower fluid layers is.

A Molecular Dynamics Study on Effects of Nanostructural Clearances at an Interface on Thermal Resistance

2008 ◽  
Author(s):  
Masahiko Shibahara ◽  
Kosuke Inoue ◽  
Kiyomori Kobayashi
Keyword(s):  
Molecular Dynamics ◽  
Temperature Gradient ◽  
Thermal Resistance ◽  
Solid Wall ◽  
Middle Layer ◽  
Dynamics Simulation ◽  
Nanometer Scale ◽  
Liquid Density ◽  
Solid Interface ◽  
Solid Walls

The classical molecular dynamics simulation was conducted in order to clarify the effects of structural clearances in nanometer scale on thermal resistance at a liquid-solid interface. A liquid molecular region confined between the solid walls, of which the interparticle potential was Lennard-Jones type, was employed as a calculation system. The solid walls consisted of three atomic layers where the temperature of the middle layer was controlled by the Langevin method. Heat flux in the system was calculated numerically by integrating the forces that acted on the temperature controlled atoms by the Langevin method. The temperature jump between the solid wall and the liquid molecular region was calculated numerically. The thermal resistance at a liquid-solid interface was calculated numerically with changing the surface structural clearances in nanometer scale. Temperature gradient and liquid density were also changed as calculation parameters. With changing the surface structural clearances from 0nm to 2.5nm the thermal resistance at the interface once decreased and became the minimum value when the structural clearances were between 0.6 to 1.0 nm. The thermal resistance between the solid and the liquid increased when the structural clearances were more than 1.0nm. With the increase of the liquid density the thermal resistance between the solid and the liquid substantially decreased regardless of the temperature gradient and the surface structures in nanometer scale.

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