Forming of Porous Micro-Features Using Hot Compaction

2007 ◽  
Author(s):  
Peng Chen ◽  
Gap-Yong Kim ◽  
Jun Ni
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Mass Production ◽  
Heat Transfer Characteristics ◽  
High Productivity ◽  
Powder Consolidation ◽  
Micro Scale ◽  
Hot Compaction ◽  
Micro Features ◽  
High Temperature Operation

Porous metallic micro-scale features are becoming important in the modern industry. However, a mass production of such features is a challenge when robustness, cost-effectiveness, and high productivity requirements are considered. In this study, the fabrication of such porous micro-features using hot compaction was investigated. A hot compaction experiment setup was designed and fabricated, which was capable of high temperature operation (up to 700 °C), quick heat-up, and avoiding oxidation of workpiece and tools. A 3D thermal simulation of the experiment setup was conducted to understand the heat transfer characteristics of the system, which was used as a reference for the experiment. The effects of compression loading force and temperature on the compact quality in terms of powder consolidation strength and porosity were studied.

scholarly journals Fabrication of High Aspect Ratio Porous Microfeatures Using Hot Compaction Technique

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Peng Chen ◽  
Gap-Yong Kim ◽  
Jun Ni
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Heat Transfer Performance ◽  
Experimental Setup ◽  
Production Environment ◽  
Taper Angle ◽  
High Productivity ◽  
Powder Consolidation ◽  
Hot Compaction ◽  
High Temperature Operation

High aspect ratio porous microfeatures are becoming more important in the modern industry. However, the fabrication of such features under a mass production environment remains a challenge when robustness, cost effectiveness, and high productivity requirements are required. In this study, the forming of such porous microfeatures using hot compaction was investigated. A hot compaction experimental setup was designed and fabricated that is capable of performing high temperature operation (700°C), quick heatup, and avoiding oxidation. 3D thermal simulation of the experimental setup was conducted to investigate the heat transfer performance and internal temperature distribution, which was then used as a reference for the experiment. Hot compaction experiments were carried out, and the effects of compression force and temperature on the quality in terms of powder consolidation strength and porosity were investigated. In addition, the achievable aspect ratio and taper angle were also discussed.

scholarly journals Performance of Siloxane Mixtures in a High-Temperature Organic Rankine Cycle Considering the Heat Transfer Characteristics during Evaporation

Energies ◽  
2014 ◽  
Vol 7 (9) ◽  
pp. 5548-5565 ◽  
Author(s):  
Theresa Weith ◽  
Florian Heberle ◽  
Markus Preißinger ◽  
Dieter Brüggemann
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Heat transfer characteristics during jet impingement on a high-temperature plate surface

2016 ◽  
Vol 100 ◽  
pp. 902-910 ◽  
Author(s):  
Bingxing Wang ◽  
Dong Lin ◽  
Qian Xie ◽  
Zhaodong Wang ◽  
Guodong Wang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Jet Impingement ◽  
Plate Surface ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics

Heat Transfer of Sprays of Large Water Drops Impacting on High Temperature Surfaces

1999 ◽  
Vol 121 (2) ◽  
pp. 446-450 ◽  
Author(s):  
T. L. Cox ◽  
S. C. Yao
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Current Data ◽  
Large Droplet ◽  
Heat Transfer Characteristics ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Water Drops ◽  
Large Water ◽  
Transfer Potential

Experiments were performed to evaluate the heat transfer of monodisperse sprays of large droplet diameters, ranging from 3 to 25 mm, on high temperature surfaces. This range of drop sizes has not previously been studied, and it was of interest to determine their heat transfer characteristics and how they relate to sprays of smaller drops. Parametric tests showed that the spray heat flux depends on mass flux with a power-law relationship, and that spray effectiveness, which relates the actual spray heat transfer to the maximum heat transfer potential, varies with d−1/2. There was no discernible relationship between the heat transfer and droplet velocity. These results agreed favorably with published results for smaller droplets. The current data was compared to previous tests with smaller droplets using the droplet Reynolds and Weber numbers. This analysis showed some grouping, with a marked separation at We = 80, where the dynamic behavior of droplets has been shown to change for nonwetting impaction.

scholarly journals Heat transfer in a novel microwave heating device coupled with atomization feeding

2021 ◽  
pp. 288-288
Author(s):  
Shangzhi Yu ◽  
Qinglong Xie ◽  
Xiaoning Mao ◽  
Ying Duan ◽  
Yong Nie
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
High Temperature ◽  
Microwave Heating ◽  
Flow Rate ◽  
Orifice Diameter ◽  
Spray Parameters ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Spray Flow Rate

The heat transfer characteristics of the microwave heating coupled with atomization feeding were investigated using ethanol as the spray medium on a pressure swirl nozzle. The effects of spray height, flow rate and temperature on the sauter mean diameter (SMD) of atomized droplets were examined. The results showed that the droplet SMD was 12-130 ?m, which increased with the spray height and decreased with the flow rate and temperature of spray medium. Through the fitting of the experimental data, the dimensionless correlation of the droplet SMD which was based on orifice diameter, Reynolds and Ohnesorge numbers was obtained. The calculated results were basically consistent with the experimental data within 15% error. The heat transfer characteristics of atomized droplets on high-temperature surface of SiC bed heated by microwave were then investigated. The effects of spray flow rate, spray height and spray temperature on the heat transfer characteristics were examined. The power of spray heat transfer decreased with the temperature and increased with the spray flow rate and spray height. The dimensionless correlation to describe the heat transfer characteristics of atomized droplets on the high-temperature SiC surface under the microwave heating was obtained which included thermophysical properties of spray medium, spray parameters, and temperatures of the high-temperature bed surface and spray medium, with the error of ?20%. These correlations can be used to predict the SMD of the atomized droplets and the power of spray heat transfer in the microwave heating process.

Manufacturing of Porous Coatings With Micro-Scale Features for Improved Boiling Heat Transfer

2006 ◽  
Author(s):  
Peng Chen ◽  
Muammer Koc¸ ◽  
Jun Ni
Keyword(s):  
Heat Transfer ◽  
Manufacturing Process ◽  
Boiling Heat Transfer ◽  
Micro Scale ◽  
Heat Transfer Efficiency ◽  
Porous Surfaces ◽  
Compaction Force ◽  
Micro Features ◽  
Interconnected Pore ◽  
Interconnected Pore Structure

Several recent heat transfer studies indicated that porous surfaces with modulated porous surface features lead to an improved boiling heat transfer efficiency. Thus, the aim of this study is to develop a novel manufacturing process that will produce the modulated porous surfaces cost-effectively. In this study, compaction and sintering experiment were conducted to investigate the consolidation performance of the powder into micro-scale features. The effects of compaction force and sintering on the pore size and mechanical strength of the formed micro-features were investigated. It was found that sintering at 800°C for 20 minutes can significantly increases the strength of the compacted part, while the interconnected pore structure was maintained.

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