Influence of Glass Coating Thickness on Interfacial Heat Transfer Coefficient during Forming of Nickel Based Superalloys

2013 ◽  
Vol 750 ◽  
pp. 104-107
Author(s):  
Markus Busuttil ◽  
Yu Pei Lin ◽  
Jean Christophe Gebelin ◽  
Roger C. Reed
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Numerical Modeling ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Coating Thickness ◽  
Work Piece ◽  
Interfacial Heat Transfer Coefficient ◽  
Glass Coating ◽  
Interfacial Heat Transfer

The influence of glass coating thickness on the interfacial heat transfer coefficient has been examined using numerical modeling. Temperature and heat flux during working of a Inconel 718 work-piece and colder H13 dies have been simulated. The thickness of the glass coating is found to have a significant influence on the forming characteristic.

scholarly journals Mold–Slug Interfacial Heat Transfer Characteristics of Different Coating Thicknesses: Effects on Slug Temperature and Microstructure in Swirled Enthalpy Equilibration Device Process

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1836
Author(s):  
Min Luo ◽  
Daquan Li ◽  
Wenying Qu ◽  
Xiaogang Hu ◽  
Qiang Zhu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Coating Thickness ◽  
Early Stage ◽  
Dendritic Structure ◽  
Mold Surface ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer

Application of a coating on a mold surface is widely used in the foundry industry. Changes in coating change the heat transfer at the mold–melt interface, which influences the microstructure of the casting. In this study, the effect of boron nitride coating thickness on the interfacial heat transfer and slug microstructure in the Swirled Enthalpy Equilibration Device (SEED) process was investigated. The temperatures of the semi-solid slug and mold were measured, and the interfacial heat transfer coefficient and heat flux of the mold–slug interface was estimated based on these data. Microstructures of the quenched slugs were also examined. The results indicated that the interfacial heat transfer coefficient decreased with an increase in coating thickness and was sensitive to a coating thickness of less than 0.1 mm. The interfacial heat flux decreased sharply at the early stage, and then slowed down as the swirling time increased and the coating thickened. The coating thickness affected the temperature evolution of the slug at the early stage of the SEED process. As the coating thickness increased from near zero to 1.0 mm, the grain size of the slug increased by ~20 µm and the globular structure of the slug transformed into a dendritic structure.

A Correlation for Interfacial Heat Transfer Coefficient for Turbulent Flow Over an Array of Square Rods

2005 ◽  
Vol 128 (5) ◽  
pp. 444-452 ◽  
Author(s):  
Marcelo B. Saito ◽  
Marcelo J. S. de Lemos
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Heat Transfer Coefficient ◽  
Turbulent Flow ◽  
Transfer Coefficient ◽  
Energy Equation ◽  
Local Thermal Equilibrium ◽  
Equation Modeling ◽  
Interfacial Heat Transfer Coefficient ◽  
Interfacial Heat Transfer

Interfacial heat transfer coefficients in a porous medium modeled as a staggered array of square rods are numerically determined. High and low Reynolds k-ϵ turbulence models are used in conjunction of a two-energy equation model, which includes distinct transport equations for the fluid and the solid phases. The literature has documented proposals for macroscopic energy equation modeling for porous media considering the local thermal equilibrium hypothesis and laminar flow. In addition, two-energy equation models have been proposed for conduction and laminar convection in packed beds. With the aim of contributing to new developments, this work treats turbulent heat transport modeling in porous media under the local thermal nonequilibrium assumption. Macroscopic time-average equations for continuity, momentum, and energy are presented based on the recently established double decomposition concept (spatial deviations and temporal fluctuations of flow properties). The numerical technique employed for discretizing the governing equations is the control volume method. Turbulent flow results for the macroscopic heat transfer coefficient, between the fluid and solid phase in a periodic cell, are presented.

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