Investigation of Lower Thermal Conductivity Ni-Cu Wicks for Loop Heat Pipes

2012 ◽  
Author(s):  
Gongming Xin ◽  
Lin Cheng
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Effective Thermal Conductivity ◽  
Heat Pipes ◽  
Loop Heat Pipes ◽  
Steady State Method ◽  
Copper Powders ◽  
Nickel Copper ◽  
State Method ◽  
Thermal Conductivities

In this study, a series of sintered nickel-copper wicks with different ratios of copper powders in the mixture of wicks were fabricated, with the effective thermal conductivities (ETC) experimentally investigated by using the steady-state method. The ETC of wick with composition of 60% nickel and 40% copper presents the lowest value among the tested range. Comparisons of some existing models for predication of porous effective thermal conductivity to experiment results were performed, but no reasonable accurate predictions were found for the tested Ni-Cu wicks.

Steady-State Investigation of Vapor Deposited Micro Heat Pipe Arrays

1995 ◽  
Vol 117 (1) ◽  
pp. 75-81 ◽  
Author(s):  
A. K. Mallik ◽  
G. P. Peterson
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Surface Temperature ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Heat Pipes ◽  
Temperature Gradients ◽  
Bottom Surface ◽  
Micro Heat Pipe ◽  
Micro Heat Pipes

An experimental investigation of vapor deposited micro heat pipe arrays was conducted using arrays of 34 and 66 micro heat pipes occupying 0.75 and 1.45 percent of the cross-sectional area, respectively. The performance of wafers containing the arrays was compared with that of a plain silicon wafer. All of the wafers had 8 × 8 mm thermofoil heaters located on the bottom surface to simulate the active devices in an actual application. The temperature distributions across the wafers were obtained using a Hughes Probeye TVS Infrared Thermal Imaging System and a standard VHS video recorder. For wafers containing arrays of 34 vapor deposited micro heat pipes, the steady-state experimental data indicated a reduction in the maximum surface temperature and temperature gradients of 24.4 and 27.4 percent, respectively, coupled with an improvement in the effective thermal conductivity of 41.7 percent. For wafers containing arrays of 66 vapor deposited micro heat pipes, the corresponding reductions in the surface temperature and temperature gradients were 29.0 and 41.7 percent, respectively, and the effective thermal conductivity increased 47.1 percent, for input heat fluxes of 4.70 W/cm2. The experimental results were compared with the results of a previously developed numerical model, which was shown to predict the temperature distribution with a high degree of accuracy, for wafers both with and without the heat pipe arrays.

scholarly journals Numerical Simulation of Thermal Conductivity of Foam Glass Based on the Steady-State Method

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 54 ◽  
Author(s):  
Zipeng Qin ◽  
Gang Li ◽  
Yan Tian ◽  
Yuwei Ma ◽  
Pengfei Shen
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Heat Flow ◽  
Thermal Resistance ◽  
Thermal Insulation ◽  
Foam Glass ◽  
Orthogonal Experimental Design ◽  
Carbonate Content ◽  
Steady State Method ◽  
State Method

The effects of fly ash, sodium carbonate content, foaming temperature and foaming time on foam glass aperture sizes and their distribution were analyzed by the orthogonal experimental design. Results from the steady-state method showed a normal distribution of the number of apertures with change in average aperture, which ranges from 0.1 to 2.0 mm for more than 93% of apertures. For a given porosity, the thermal conductivity decreases with the increase of the aperture size. The apertures in the sample have obvious effects in blocking the heat flow transmission: heat flow is quickly diverted to both sides when encountered with the aperture. When the thickness of the sample is constant, the thermal resistance of the foam glass sample increases with increasing porosity, leading to better thermal insulation. Furthermore, our results suggest that the more evenly distributed and orderly arranged the apertures are in the foam glass material, the larger the thermal resistance of the material and hence, the better the thermal insulation.

A Spherical Steady-State Method to Measure Soil Thermal Conductivity

2019 ◽  
Vol 52 (12) ◽  
pp. 1572-1576
Author(s):  
S. M. Mahdavi ◽  
M. R. Neyshabouri ◽  
H. Fujimaki
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Soil Thermal Conductivity ◽  
Steady State Method ◽  
State Method

Film Cooling Performance for Combustor Wavy Liner-wall Evaluated by Steady-state Method Using Two Different Thermal-conductivity Materials

2017 ◽  
Vol 2017.23 (0) ◽  
pp. 517
Author(s):  
Hitoshi Taniguchi ◽  
Ryosuke Kondo ◽  
Akira Murata ◽  
Hiroshi Saito ◽  
Kaoru Iwamoto ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Film Cooling ◽  
Cooling Performance ◽  
Steady State Method ◽  
State Method
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