Experimental Investigation of Interfacial Thermal Conductance for Molten Metal Solidification on a Substrate

1996 ◽  
Vol 118 (1) ◽  
pp. 157-163 ◽  
Author(s):  
G.-X. Wang ◽  
E. F. Matthys
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Thermal Conductance ◽  
Measured Temperature ◽  
Solid Contact ◽  
Metal Solidification ◽  
Model Calculations ◽  
Interfacial Thermal Conductance ◽  
Cooling Phase

Experiments have been conducted to quantify the interfacial thermal conductance between molten copper and a cold metallic substrate, and in particular to investigate the heat transfer variation as the initial liquid/solid contact becomes a solid/solid contact after nucleation. A high heat transfer coefficient during the earlier liquid cooling phase and a lower heat transfer coefficient during the subsequent solid splat cooling phase were estimated through matching of model calculations and measured temperature history of the sample. The dynamic variations in the interfacial heat transfer resulting from the solidification process were quantified for splat cooling and were found to be affected by the melt superheat, the substrate material, and the substrate surface finish.

Physical Modeling and Simulation of the Cooling-Down of Fused-Cast Refractories

2020 ◽  
Vol 996 ◽  
pp. 142-150
Author(s):  
Run Feng Wang ◽  
Ao Huang ◽  
Yan Zhu Huo ◽  
Li Jun Mei ◽  
Hong Jin Rao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Physical Simulation ◽  
Temperature Record ◽  
Measured Temperature ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer ◽  
Cooling Process

The accurate description of the interfacial heat transfer coefficient is of great significance for the accurate measurement of the temperature field in the process of casting cooling. In this paper, the solidification process of metallic tin in refractory mould was studied by physical simulation experiment, and the on-site temperature measurement of the mold structure was carried out. According to the temperature record, the numerical simulation method is used to realize the fitting of the calculated temperature and the measured temperature. The reversible method was used to calculate the interfacial heat transfer coefficient between the casting and the mould, and then the evolution of the internal temperature field of the casting during the cooling process was determined. The results show that the melt has a large shrinkage during the cooling process, and the interface heat transfer coefficient can reach 300 W·m-2·K-1, which provides a mathematical model for the annealing process of fused-cast refractories.

Bio Inspired Particle Enhanced Capillary Heat Exchanger

2008 ◽  
Author(s):  
Fatemeh Hassanipour ◽  
Jose´ Lage
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Exchange Process ◽  
Heat Fluxes ◽  
Measured Temperature ◽  
Lung Capillaries ◽  
The Heat Transfer Coefficient

This study proposes a new cooling concept using encapsulated phase-change material particles in mini-channels. This novel method is inspired by the gas exchange process in the lung capillaries. An important characteristic of capillary blood flow is that the red blood cells fit very snugly into the capillary opening. Hence, it is conjectured that using particles with diameter similar to the channel diameter, in a manner similar to red blood cells in lung capillaries, is likely to enhance the heat transfer coefficient, even under laminar flow. Preliminary tests are performed with encapsulated Octadecan paraffin (C18H38) in a low-conductivity thin melamine shell, flowing through a test module. The effect of flow rate on the heat transfer coefficient and also the effect of using particles on enhancement of Nusselt number has been measured. Temperature distribution on the chip has also been investigated under various particle concentrations, heat fluxes and Reynolds numbers.

A Method of the Inverse Evaluation for Heat Transfer Coefficient between Al-Cu Alloys and Cooling Water

2011 ◽  
Vol 189-193 ◽  
pp. 2294-2299
Author(s):  
Zhong Lin Hou ◽  
Ting Li ◽  
Jun Qiao ◽  
Sheng Li Li
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cooling Water ◽  
Transfer Model ◽  
Inductive Heating ◽  
Measured Temperature ◽  
Cu Alloys ◽  
The Heat Transfer Coefficient ◽  
Peak Value

The heat transfer coefficient between the alloys and cooling water is affected by a lot of factors and hard to measure, a new method was investigated with a self-designed system ultilizing SP-15 high-frequency inductive heating unit. Based on measured temperature curves and Fourier heat transfer model, quantitative correlation between heat transfer coefficient and temperature was obtained by inverse algorithm method of iterative simulation and automatic optimization. The results showed that in submerged water-cooling process, the heat transfer coefficient reached to a peak value at the beginning and then decreased with increasing temperature. A decrease of cooling water temperature increased the peak value of the heat transfer coefficient, but did not change temperature range of the peak value from 200°C to 225°C . The heat transfer coefficient was mainly dependent of interfacial temperature between the Al-Cu alloys and the cooling water.The temperatures range from 200°C to 225°C gave the highest heat flux transfer.

scholarly journals Finite difference method for computer study of the interfacial heat transfer coefficient during rapid solidification of spherical samples on a metallic substrate

2007 ◽  
Vol 39 (2) ◽  
pp. 111-116 ◽  
Author(s):  
Z.S. Nikolic ◽  
M. Yoshimura ◽  
S. Araki ◽  
T. Fujiwara
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Rapid Solidification ◽  
Heat Transfer Process ◽  
Metallic Substrate ◽  
Temperature History ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer ◽  
Model Calculations

In this paper a numerical model will be adopted to analyze the heat transfer process during rapid solidification of a spherical sample placed on a metallic substrate cooled by water. The interfacial heat transfer coefficient between the sample and the substrate will be evaluated by matching model calculations with the surface temperature history recorded by a digital camera during solidification of a sample melted in an Arc-image furnace. .

The Comparison of Moisture Balance of Diffusion-Open and Diffusion-Closed Structure of a Building Envelope

2018 ◽  
Vol 776 ◽  
pp. 23-28
Author(s):  
Katarína Hellová ◽  
Alena Struhárová ◽  
Michaela Kostelecká
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Building Envelope ◽  
Model Calculations ◽  
Open Structure ◽  
Moisture Balance ◽  
Closed Structure ◽  
And Diffusion ◽  
The Heat Transfer Coefficient

This article is oriented toward the heat-moisture behaviour of the wooden construction sheeting. The behaviour of building envelope is evaluated according to the heat transfer coefficient and foremost from the view of the condensed vapour amount inside the building envelope structure. For exemplary building envelope will be elaborated model calculations and then they will be compared. The results have shown that diffusion-open structure has the best characteristics concerning the heat-humidity behaviour and ecology of wooden constructions.

scholarly journals Experimental Verification of the Inverse Method of the Heat Transfer Coefficient Calculation

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1440
Author(s):  
Piotr Duda ◽  
Mariusz Konieczny
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Balance ◽  
Inverse Method ◽  
Unknown Boundary ◽  
Laboratory System ◽  
Measured Temperature ◽  
Coefficient Distribution ◽  
The Heat Transfer Coefficient

The purpose of this work is to formulate a method which can be used to solve nonlinear inverse heat conduction problems and to calculate the heat transfer coefficient distribution on the unknown boundary. The domain under consideration is divided into control volumes in polar coordinates, and heat balance equations are written. Based on temperature transients measured in selected points on the outer surface, temperature values in other points of the domain are determined. Finally, the heat transfer coefficient distribution on the inner surface with the unknown boundary condition is calculated from the presented heat balance equation. The proposed inverse method was verified experimentally using a collector that is part of a semi-industrial laboratory system. This collector is a horizontal, cylindrical thick-walled tank with flat side walls with outlets that enable oil supply and removal. Each side wall has an additional connector to ensure venting. The calculations made it possible to identify the phenomena occurring inside the collector during the experiment. The transient temperature distribution identified by the proposed inverse method was verified by a comparison of the calculated and the measured temperature transients in points inside the collector wall. Very good agreement is observed between the calculated and the measured temperature transients, which confirms the correctness of the identification. This proposed inverse method of the temperature and the heat transfer coefficient calculation is fast enough to apply in online thermal state monitoring systems. The proposed algorithm presented in this paper can easily be implemented industrially.

Research on Simplified Reverse Method for Interfacial Heat Transfer Coefficient (IHTC)

2012 ◽  
Vol 268-270 ◽  
pp. 974-977
Author(s):  
Li Ping Su ◽  
Jian Min Zeng ◽  
Jun Chen ◽  
Wu Kui Gan
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Solidification Process ◽  
Cooling Curve ◽  
Measured Temperature ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer ◽  
Reverse Method

The success of numerical simulation of solidification process depends to a large extent on boundary condition. Interfacial heat transfer coefficient (IHTC) can be used to measure heat resistance between casting and mold. Boundary condition of casting and mold varies with the temperatures during solidification process. However, determination of heat exchange on the boundary is very complicated. A new simple reverse method has been introduced in this paper. A casting with simple geometry acts as the standard sample and a thermal couple records the temperature history at the center of the casting during solidification. The solidification simulation of the casting was conducted with different IHTCs. The equivalent IHTC that best fits the measured temperature can be determined by comparing the measured cooling curve with the calculated one.

Evaporation of lignin-lean black liquor

TAPPI Journal ◽  
2015 ◽  
Vol 14 (7) ◽  
pp. 441-450
Author(s):  
HENRIK WALLMO, ◽  
ULF ANDERSSON ◽  
MATHIAS GOURDON ◽  
MARTIN WIMBY
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Black Liquor ◽  
Salt Content ◽  
Solubility Limit ◽  
Lignin Removal ◽  
Kraft Black Liquor ◽  
Black Liquors ◽  
The Heat Transfer Coefficient

Many of the pulp mill biorefinery concepts recently presented include removal of lignin from black liquor. In this work, the aim was to study how the change in liquor chemistry affected the evaporation of kraft black liquor when lignin was removed using the LignoBoost process. Lignin was removed from a softwood kraft black liquor and four different black liquors were studied: one reference black liquor (with no lignin extracted); two ligninlean black liquors with a lignin removal rate of 5.5% and 21%, respectively; and one liquor with maximum lignin removal of 60%. Evaporation tests were carried out at the research evaporator in Chalmers University of Technology. Studied parameters were liquor viscosity, boiling point rise, heat transfer coefficient, scaling propensity, changes in liquor chemical composition, and tube incrustation. It was found that the solubility limit for incrustation changed towards lower dry solids for the lignin-lean black liquors due to an increased salt content. The scaling obtained on the tubes was easily cleaned with thin liquor at 105°C. It was also shown that the liquor viscosity decreased exponentially with increased lignin outtake and hence, the heat transfer coefficient increased with increased lignin outtake. Long term tests, operated about 6 percentage dry solids units above the solubility limit for incrustation for all liquors, showed that the heat transfer coefficient increased from 650 W/m2K for the reference liquor to 1500 W/m2K for the liquor with highest lignin separation degree, 60%.

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