Conjugated Heat Transfer in a Laminar Boundary Layer With Heat Source at the Wall

1982 ◽  
Vol 104 (1) ◽  
pp. 90-95 ◽  
Author(s):  
A. Brosh ◽  
D. Degani ◽  
S. Zalmanovich
Keyword(s):  
Boundary Layer ◽  
Heat Conduction ◽  
Heat Source ◽  
Flow Direction ◽  
Boundary Layer Separation ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Line Heat Source ◽  
Solid Plate ◽  
Conjugated Heat Transfer

This work presents the solution of the temperature field in a two-dimensional laminar incompressible flow over a conducting solid plate with a line heat source located at the fluid-solid interface perpendicular to the flow direction. A numerical scheme was used to obtain the temperature profiles as a function of the source strength, and of the properties of the fluid and the solid. The heat conduction and forced convection in the fluid and the heat conduction in the solid were solved for the case of moderate temperature rise, where the assumption of constant properties applies. The model enables the improvement of an instrument for the detection of boundary layer separation. It was found that for the actual parameters of the separation detector, a distance of 4 to 24 mm between the sensors gives an indication of 70 percent of the maximum temperature difference.

Optical Effects Induced by the Multilayer Nature of SOI Films During Transient Thermal Processing with a Radiant Line Heat Source.

1990 ◽  
Vol 201 ◽  
Author(s):  
Peter Y. Wong ◽  
Ioannis N. Miaoulis ◽  
P. Zavracky
Keyword(s):  
Heat Source ◽  
Radiation Effects ◽  
Silicon Oxide ◽  
Silicon Film ◽  
Radiation Heat Transfer ◽  
Linear Increase ◽  
Maximum Temperature ◽  
Line Heat Source ◽  
Silicon Oxide Layer ◽  
Optical Effects

AbstractRadiation heat transfer has been found to have the greatest Impact on the quality of the thin recrystalllzed silicon film during zone-melting recrystallizatlon (ZMR) processing. This study focused on the radiation effects during ZMR with an Infrared radiant line heat source such as a graphite strip heater. The multilayer nature of the capped sllicon-on-tnsulator (SOI) structure Induces complex optical effects which affect the temperature distribution during processing. A two dimensional numerical model of the ZMR process has been developed using a finite difference scheme. The effect of the radiant line heat source’s emission into the wafer has been modeled with a matrix method using Fresnel coefficients. A numerical parametric study was conducted to observe the effects of varying the thickness of the different layers In a capped SOI wafer on the maximum temperature and melt width attained. Results indicate that the variation of either the capping or insulating silicon oxide layer causes significant fluctuations of the reflectivity and temperature profile of the film. Increasing the thickness of the Si layer results in a nearly linear increase in temperature and melt width after complete melting. Layering schemes that are sensitive to small variations In thickness that may result in large changes in reflectivity were Identified.

scholarly journals Constructal Design of an Arrow-Shaped High Thermal Conductivity Channel in a Square Heat Generation Body

Entropy ◽  
2020 ◽  
Vol 22 (4) ◽  
pp. 475 ◽  
Author(s):  
Fengyin Zhang ◽  
Huijun Feng ◽  
Lingen Chen ◽  
Jiang You ◽  
Zhihui Xie
Keyword(s):  
Thermal Conductivity ◽  
Heat Conduction ◽  
Heat Generation ◽  
Degrees Of Freedom ◽  
High Thermal Conductivity ◽  
Maximum Temperature ◽  
Thermal Conductivity Ratio ◽  
Maximum Temperature Difference ◽  
Conduction Model ◽  
Three Degrees Of Freedom

A heat conduction model with an arrow-shaped high thermal conductivity channel (ASHTCC) in a square heat generation body (SHGB) is established in this paper. By taking the minimum maximum temperature difference (MMTD) as the optimization goal, constructal designs of the ASHTCC are conducted based on single, two, and three degrees of freedom optimizations under the condition of fixed ASHTCC material. The outcomes illustrate that the heat conduction performance (HCP) of the SHGB is better when the structure of the ASHTCC tends to be flat. Increasing the thermal conductivity ratio and area fraction of the ASHTCC material can improve the HCP of the SHGB. In the discussed numerical examples, the MMTD obtained by three degrees of freedom optimization are reduced by 8.42% and 4.40%, respectively, compared with those obtained by single and two degrees of freedom optimizations. Therefore, three degrees of freedom optimization can further improve the HCP of the SHGB. Compared the HCPs of the SHGBs with ASHTCC and the T-shaped one, the MMTD of the former is reduced by 13.0%. Thus, the structure of the ASHTCC is proven to be superior to that of the T-shaped one. The optimization results gained in this paper have reference values for the optimal structure designs for the heat dissipations of various electronic devices.

Numerical Simulation of Heat Conduction for Error Analysis on Heat Flux Sensor Embedded in Flat Steel Plate

2014 ◽  
Vol 563 ◽  
pp. 133-136
Author(s):  
Chun Lai Tian ◽  
Shan Zhou ◽  
Li Yong Han
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Heat Conduction ◽  
Temperature Difference ◽  
Heat Conduction Problem ◽  
Maximum Temperature ◽  
Heat Flux Sensor ◽  
Maximum Temperature Difference ◽  
Maximum Heat ◽  
Errors Analysis

A numerical simulation model of heat flux sensors embedded in a flat plate is established. Each sensor has four thermal couples and is inserted into the specified hole. The problem is defined as a steady heat conduction problem with specified boundary conditions and solved by the finite element method. The results of the simulation case demonstrate that the maximum heat flux appears near the sensor shell. The average heat flux of the plate is much smaller than the maximum. Due to exiting of the contact heat resistance, the temperature of the sensor is much lower than that of the plate at horizontal surface. The maximum temperature difference appears on the bottom shell of the sensor. The maximum temperature difference between the simulation results and the experimental data at test points is 1.5 K. The model is verified and could be accepted for the further errors analysis.

Nonequilibrium Thermal Response of Porous Media in Unsteady Heat Conduction With Sinusoidally Changing Boundary Temperature

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Huijin Xu ◽  
Liang Gong ◽  
Changying Zhao ◽  
Ying Yin
Keyword(s):  
Porous Media ◽  
Heat Conduction ◽  
Temperature Difference ◽  
Thermal Response ◽  
Porous Solid ◽  
Maximum Temperature ◽  
Maximum Temperature Difference ◽  
Boundary Temperature ◽  
Thermal Disturbance ◽  
Unsteady Heat Conduction

The thermal response of porous foam filled with a solid material was theoretically investigated under unsteady heat conduction with a sinusoidally changing boundary temperature. The local thermal nonequilibrium (LTNE) effect between the porous foam and the infill was obvious, and the two-equation model is employed for the unsteady heat conduction in porous-solid system. The temperature difference, which was defined as the time average of the absolute value of the difference between the temperatures of the porous solid and the infill, was proposed for quantitatively describing the LTNE effect in porous media. The LTNE phenomenon for unsteady heat conduction in porous media is influenced by the fluctuation period of the thermal boundary, foam morphology, and the thermal diffusivities of the porous solid and the infill. The LTNE effect of unsteady porous-media heat conduction was evident in the region near the thermal disturbance boundary. The maximum temperature difference was found on the curve of temperature difference versus fluctuation period, which means that the thermal response characteristics of porous composites resonate with periodically changing thermal disturbance. The fluctuation period corresponding to the maximum temperature difference has positive correlations with thermal diffusion resistance for unsteady porous-media heat conduction.

The boundary layer separation from streamlined surfaces and new ways of its prevention in diffusers

2017 ◽  
Author(s):  
Arkady Zaryankin ◽  
Andrey Rogalev ◽  
Ivan Komarov ◽  
V. Kindra ◽  
S. Osipov
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Separation ◽  
Layer Separation
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