Experimental characterization of heat transfer coefficients for hot stamping AA7075 sheets with an air gap

2020 ◽  
Vol 20 (3) ◽  
Author(s):  
Wenchao Xiao ◽  
Kailun Zheng ◽  
Baoyu Wang ◽  
Xiaoming Yang
Keyword(s):  
Heat Transfer ◽  
Hot Stamping ◽  
Air Gap ◽  
Experimental Characterization ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

scholarly journals Heat Transfer Coefficient Determination in a Gravity Die Casting Process with Local Air Gap Formation and Contact Pressure Using Experimental Evaluation and Numerical Simulation

2021 ◽  
Author(s):  
T. Vossel ◽  
N. Wolff ◽  
B. Pustal ◽  
A. Bührig-Polaczek ◽  
M. Ahmadein
Keyword(s):  
Heat Transfer ◽  
Contact Pressure ◽  
Local Heat Transfer ◽  
Casting Process ◽  
Local Heat ◽  
Air Gap ◽  
Gap Formation ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Die Casting Process

AbstractAnticipating the processes and parameters involved for accomplishing a sound metal casting requires an in-depth understanding of the underlying behaviors characterizing a liquid melt solidifying inside its mold. Heat balance represents a major factor in describing the thermal conditions in a casting process and one of its main influences is the heat transfer between the casting and its surroundings. Local heat transfer coefficients describe how well heat can be transferred from one body or material to another. This paper will discuss the estimation of these coefficients in a gravity die casting process with local air gap formation and heat shrinkage induced contact pressure. Both an experimental evaluation and a numerical modeling for a solidification simulation will be performed as two means of investigating the local heat transfer coefficients and their local differences for regions with air gap formation or contact pressure when casting A356 (AlSi7Mg0.3).

Experimental Platforms and Finite Element Analysis on Hot Stamping Processes

2014 ◽  
Vol 1063 ◽  
pp. 334-338 ◽  
Author(s):  
Tzu Hao Hung ◽  
Heng Kuang Tsai ◽  
Fuh Kuo Chen ◽  
Ping Kun Lee
Keyword(s):  
Heat Transfer ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Process Design ◽  
Hot Stamping ◽  
Boron Steel ◽  
Transfer Coefficients ◽  
Element Analysis ◽  
Heat Transfer Coefficients ◽  
The Finite Element Analysis

Due to the complexity of hot stamping mechanism, including the coupling of material formability, thermal interaction and metallurgical microstructure, it makes the process design more difficult even with the aid of the finite element analysis. In the present study, the experimental platforms were developed to measure and derive the friction and heat transfer coefficients, respectively. The experiments at various elevated temperatures and contact pressures were conducted and the friction coefficients and heat transfer coefficients were obtained. A finite element model was also established with the experimental data and the material properties of the boron steel calculated from the JMatPro software. The finite element simulations for the hot stamping forming of an automotive door beam, including transportation analysis, hot forming analysis and die quenching analysis were then performed to examine the forming properties of the door beam. The validation of the finite element results by the production part confirms the efficiency and accuracy of the developed experimental platforms and the finite element analysis for the process design of hot stamping.

Experimental and Numerical Characterization of an Electrically Propelled Vehicles Battery Casing Including Battery Module

2014 ◽  
Vol 6 (4) ◽  
Author(s):  
Johan Anderson ◽  
Johan Sjöström ◽  
Petra Andersson ◽  
Francine Amon ◽  
Joakim Albrektsson
Keyword(s):  
Heat Transfer ◽  
Transfer Coefficients ◽  
Power Train ◽  
Fire Model ◽  
Heat Transfer Coefficients ◽  
Fire Resistance Test ◽  
Numerical Characterization ◽  
Computational Fluid Dynamics Cfd ◽  
Battery Module

This paper demonstrates the possibility to predict a battery system's performance in a fire resistance test according to the new amendment of United Nations Regulation No. 100 “Uniform Provisions Concerning the Approval of Vehicles with Regard to Specific Requirements for the Electric Power Train” (R100) based on careful measurements of the physical properties of the casing material, as well as modeling of the battery modules and computer simulations. The methodology of the work consists of estimating the heat transfer coefficients by using a gasoline pool fire model in the computational fluid dynamics (CFD) software FireDynamicsSimulator (FDS), followed by finite-element (FE) calculations of the temperatures in the battery

Characterization of Cryogenic Spray Nozzles With Application to Skin Cooling

2000 ◽  
Author(s):  
Guillermo Aguilar ◽  
Boris Majaron ◽  
Wim Verkruysse ◽  
J. Stuart Nelson ◽  
Enrique J. Lavernia
Keyword(s):  
Heat Transfer ◽  
Droplet Diameter ◽  
Straight Tube ◽  
Port Wine Stain ◽  
Port Wine ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Skin Cooling ◽  
Laser Treatments

Abstract Cryogenic sprays are used for cooling of human skin during laser treatments of hypervascular lesions, such as Port Wine Stain birthmarks. In this work, six straight-tube nozzles, including two commercial nozzles, are characterized by obtaining photographs of cryogenic spray shapes, as well as measurements of the average droplet diameter, velocity and temperature. An evaporation model is used to predict the evolutions of average droplet diameter and temperature. The results show two distinct spray patterns—jet-like sprays for wide nozzle diameters, and cone-like sprays for narrow nozzle diameters. The wide nozzles show significantly larger droplet diameters, larger velocities and higher temperatures, as all these variables are measured as a function of distance from the nozzle. These results complement and support previously reported results, where it was shown that wide nozzles are capable of producing larger heat transfer coefficients than those obtained with narrow nozzles.

Thermal Performance of Micro-Structured Evaporation Surfaces: Application to Cooling of High Flux Microelectronics

2005 ◽  
Author(s):  
E. Al-Hajri ◽  
M. Ohadi ◽  
S. V. Dessiatoun ◽  
J. Qi
Keyword(s):  
Heat Transfer ◽  
Smooth Surface ◽  
Pool Boiling ◽  
High Flux ◽  
Transfer Coefficients ◽  
Experimental Conditions ◽  
Heat Transfer Coefficients ◽  
Evaporation Heat ◽  
Order Of Magnitude

An experimental investigation on characterization of copper-finned micro-grooved surfaces for effective evaporation heat transfer with applications to cooling of high flux electronics was conducted in the present study. Performance of the copper-finned microstructures were studied as a function of operating parametric values of fin density, fin height, fin length, and channel width over a surface which was rosin soldered to a 10 mm × 10 mm heating block (typical size of an electronic chip). The performance of the copper-finned microstructures versus a flat/smooth nichrome plate in HFE-7100 was significantly higher. Two experimental conditions were investigated. In the first set of experiments pool boiling over the groves was examined, where as in the second set of experiments the fluid was forced-fed into the grooves in a forced convection mode. It is shown that the forced fed mode yields higher heat transfer coefficients than the submerged/pool boiling mode. In general the micro-grooved surfaces performed at least three times better than the flat/smooth surface and preliminary results with the forced-fed evaporation experiments suggest that an order of magnitude heat transfer coefficients are possible when compared with a smooth surface.

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