HEAT TRANSFER DURING THE SPREADING AND SOLIDIFICATION OF A MOLTEN METAL DROPLET ON A COOLED SUBSTRATE

2000 ◽  
Vol 4 (1) ◽  
pp. 10 ◽  
Author(s):  
T. Loulou ◽  
J.P. Bardon
Keyword(s):  
Heat Transfer ◽  
Molten Metal ◽  
Metal Droplet

A Study on Evolution of Splat Radius and Temperature in Thermal Spray Process

2018 ◽  
Author(s):  
Manpreet Dash ◽  
Sangharsh Kumar ◽  
Partha Pratim Bandyopadhyay ◽  
Anandaroop Bhattacharya
Keyword(s):  
Heat Transfer ◽  
Thermal Spray ◽  
Molten Metal ◽  
Spray Deposition ◽  
Substrate Surface ◽  
Metal Droplet ◽  
Droplet Impingement ◽  
Impact Process ◽  
The Impact ◽  
Maximum Spreading

The impact process of a molten metal droplet impinging on a solid substrate surface is encountered in several technological applications such as ink-jet printing, spray cooling, coating processes, spray deposition of metal alloys, thermal spray coatings, manufacturing processes and fabrication and in industrial applications concerning thermal spray processes. Deposition of a molten material or metal in form of a droplet on a substrate surface by propelling it towards it forms the core of the spraying process. During the impact process, the molten metal droplet spreads radially and simultaneously starts losing heat due to heat transfer to the substrate surface. The associated heat transfer influences impingement behavior. The physics of droplet impingement is not only related to the fluid dynamics, but also to the respective interfacial properties of solid and liquid. For most applications, maximum spreading diameter of the splat is considered to be an important factor for droplet impingement on solid surfaces. In the present study, we have developed a model for droplet impingement based on energy conservation principle to predict the maximum spreading radius and the radius as a function of time. Further, we have used the radius as a function of time in the heat transfer equations and to study the evolution of splat-temperature and predict the spreading factor and the spreading time and mathematically correlate them to the spraying parameters and material properties.

Numerical and Experimental Investigation of Interface Bonding Via Substrate Remelting of an Impinging Molten Metal Droplet

1996 ◽  
Vol 118 (1) ◽  
pp. 164-172 ◽  
Author(s):  
C. H. Amon ◽  
K. S. Schmaltz ◽  
R. Merz ◽  
F. B. Prinz
Keyword(s):  
Heat Transfer ◽  
Numerical Model ◽  
Molten Metal ◽  
Thermal Stresses ◽  
Initial Conditions ◽  
Metal Droplet ◽  
Solid Substrate ◽  
Numerical Results ◽  
Operating Conditions ◽  
Analytical Approaches

A molten metal droplet landing and bonding to a solid substrate is investigated with combined analytical, numerical, and experimental techniques. This research supports a novel, thermal spray shape deposition process, referred to as microcasting, capable of rapidly manufacturing near netshape, steel objects. Metallurgical bonding between the impacting droplet and the previous deposition layer improves the strength and material property continuity between the layers, producing high-quality metal objects. A thorough understanding of the interface heat transfer process is needed to optimize the microcast object properties by minimizing the impacting droplet temperature necessary for superficial substrate remelting, while controlling substrate and deposit material cooling rates, remelt depths, and residual thermal stresses. A mixed Lagrangian–Eulerian numerical model is developed to calculate substrate remelting and temperature histories for investigating the required deposition temperatures and the effect of operating conditions on remelting. Experimental and analytical approaches are used to determine initial conditions for the numerical simulations, to verify the numerical accuracy, and to identify the resultant microstructures. Numerical results indicate that droplet to substrate conduction is the dominant heat transfer mode during remelting and solidification. Furthermore, a highly time-dependent heat transfer coefficient at the droplet/substrate interface necessitates a combined numerical model of the droplet and substrate for accurate predictions of the substrate remelting. The remelting depth and cooling rate numerical results are also verified by optical metallography, and compare well with both the analytical solution for the initial deposition period and the temperature measurements during droplet solidification.

scholarly journals Thermal Stress and Heat Transfer Coefficient for Ceramics Stalk Having Protuberance Dipping into Molten Metal

2010 ◽  
Vol 4 (8) ◽  
pp. 1198-1213 ◽  
Author(s):  
Nao-Aki NODA ◽  
Hendra ◽  
Wenbin LI ◽  
Yasushi TAKASE ◽  
Hiroki OGURA ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Stress ◽  
Transfer Coefficient ◽  
Molten Metal

Fragmentation of a Single Molten Metal Droplet Penetrating Sodium Pool I Copper Droplet and the Relationship with Copper Jet

2009 ◽  
Vol 46 (5) ◽  
pp. 453-459 ◽  
Author(s):  
Zhi-gang ZHANG ◽  
Ken-ichiro SUGIYAMA ◽  
Wataru ITAGAKI ◽  
Satoshi NISHIMURA ◽  
Izumi KINOSITA ◽  
...  
Keyword(s):  
Molten Metal ◽  
Metal Droplet ◽  
The Relationship

Charged Molten Metal Droplet Deposition as a Direct Write Technology

2000 ◽  
Vol 624 ◽  
Author(s):  
M. Orme ◽  
J. Courter ◽  
Q. Liu ◽  
J. Zhu ◽  
R. Smith
Keyword(s):  
Molten Metal ◽  
High Speed ◽  
Droplet Diameter ◽  
Metal Droplet ◽  
Circuit Board ◽  
Charged Droplet ◽  
Direct Write ◽  
Direct Writing ◽  
Drop On Demand ◽  
Metal Droplets

ABSTRACTThe formation of highly uniform charged molten metal droplets from capillary stream breakup has recently attracted significant industrial and academic interest for applications requiring high-speed and high-precision deposition of molten metal droplets such as direct write technologies. Exploitation of the high droplet production rates intrinsic to the phenomenon of capillary stream break-up and the unparalleled uniformity of droplet sizes and speeds attained with proper applied forcing to the capillary stream make many new applications related to the manufacture of electronic packages, circuit board printing and rapid prototyping of structural components feasible. Recent research results have increased the stream stability with novel acoustic excitation methods and enable ultra-precise charged droplet deflection. Unlike other modes of droplet generation such as Drop-on-Demand, droplets can be generated at rates typically on the order of 10,000 to 20,000 droplets per second (depending on droplet diameter and stream speed) and can be electrostatically charged and deflected onto a substrate with a measured accuracy of ±12.5 µm. Droplets are charged on a drop-to-drop basis, enabling the direct writing of fine details at high speed. New results are presented in which fine detailed patterns are “printed” with individual molten metal solder balls, and issues relevant to the attainment of high quality printed artifacts are investigated.

Heat Transfer and Fragmentation During Molten-Metal/Water Interactions

1973 ◽  
Vol 95 (4) ◽  
pp. 521-527 ◽  
Author(s):  
L. C. Witte ◽  
T. J. Vyas ◽  
A. A. Gelabert
Keyword(s):  
Heat Transfer ◽  
Surface Area ◽  
Liquid Nitrogen ◽  
Molten Metal ◽  
High Speed ◽  
Vapor Film ◽  
Molten Metals ◽  
Lead Zinc ◽  
Insight Into ◽  
Rapid Transfer

Molten metals, (mercury, lead, zinc, bismuth, tin, and aluminum) were quenched in water and liquid nitrogen. High-speed photographs provide insight into the fragmentation phenomenon. The key to the vapor explosion is the very rapid transfer of heat which requires substantial surface area: fragmentation provides this necessary surface area. Prior fragmentation theories are examined in light of these experiments and are found to be inadequate. This study indicates strongly that fragmentation occurs when a sample is molten and fragmentation is a response to an external stimulus. Alternate causes of fragmentation are proposed and are predicated upon the initial collapse of a vapor film around the molten metal. The data also show that energy required to form new surface area and to displace water during the fragmentation phenomenon is not significant when compared to the energy available in a molten sample.

Numerical simulation of heat transfer and fluid flow of molten metal in MMA–St copolymer lost foam casting process

2010 ◽  
Vol 210 (14) ◽  
pp. 2071-2080 ◽  
Author(s):  
Ali Charchi ◽  
Mostafa Rezaei ◽  
Siyamak Hossainpour ◽  
Jamal Shayegh ◽  
Sohrab Falak
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluid Flow ◽  
Molten Metal ◽  
Casting Process ◽  
Lost Foam Casting ◽  
Lost Foam

In-flight thermal control of molten metal droplet streams

2007 ◽  
Vol 50 (23-24) ◽  
pp. 4554-4558 ◽  
Author(s):  
B. Matthew Michaelis ◽  
Derek Dunn-Rankin ◽  
Robert F. Smith ◽  
James E. Bobrow
Keyword(s):  
Molten Metal ◽  
Metal Droplet ◽  
Thermal Control

scholarly journals Flattening Behavior of Freely Fallen Molten Metal Droplet on Flat Substrate.

1998 ◽  
Vol 16 (4) ◽  
pp. 437-444 ◽  
Author(s):  
Eiji NISHIOKA ◽  
Masahiro FUKUMOTO
Keyword(s):  
Molten Metal ◽  
Metal Droplet ◽  
Flat Substrate
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