Modeling and Experiments of Laser Cladding With Droplet Injection

2005 ◽  
Vol 127 (9) ◽  
pp. 978-986 ◽  
Author(s):  
J. Choi ◽  
L. Han ◽  
Y. Hua
Keyword(s):  
Fluid Flow ◽  
Laser Cladding ◽  
Dynamic Motion ◽  
Cladding Layer ◽  
Melt Pool ◽  
Material Deposition ◽  
Modeling And Experiments ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Impact

Laser aided Directed Material Deposition (DMD) is an additive manufacturing process based on laser cladding. A full understanding of laser cladding is essential in order to achieve a steady state and robust DMD process. A two dimensional mathematical model of laser cladding with droplet injection was developed to understand the influence of fluid flow on the mixing, dilution depth, and deposition dimension, while incorporating melting, solidification, and evaporation phenomena. The fluid flow in the melt pool that is driven by thermal capillary convection and an energy balance at the liquid–vapor and the solid–liquid interface was investigated and the impact of the droplets on the melt pool shape and ripple was also studied. Dynamic motion, development of melt pool and the formation of cladding layer were simulated. The simulated results for average surface roughness were compared with the experimental data and showed a comparable trend.

Two Dimensional Modeling of Laser Cladding With Droplet Injection

2003 ◽  
Author(s):  
L. Han ◽  
J. Choi
Keyword(s):  
Fluid Flow ◽  
Laser Cladding ◽  
Two Dimensional ◽  
Melt Pool ◽  
Dimensional Modeling ◽  
Material Deposition ◽  
Laser Cladding Process ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Impact

Directed Metal/Material Deposition (DMD) process is one of additive manufacturing processes based on laser cladding process. A full understanding of laser cladding process is a must to make the DMD process consistent and robust. A two dimensional mathematical model of laser cladding was developed to understand the influence of fluid flow to the mixing, dilution, and deposition dimension, incorporating melting, solidification, and evaporation phenomena. The fluid flow in the melt pool driven by thermal capillary convection and energy balance at liquid-vapor and solid-liquid interface was investigated and the impact of the droplets on the melt pool shape and ripple was studied. Dynamic motion, development of melt pool and the formation of cladding layer were simulated.

Modeling Coupled Conduction–Convection Ice Formation on Horizontal Axially Finned and Unfinned Tubes

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Hassan M. S. Al-Sarrach ◽  
Ghalib Y. Kahwaji ◽  
Mohamed A. Samaha
Keyword(s):  
Natural Convection ◽  
Liquid Interface ◽  
Ice Formation ◽  
Finite Difference Schemes ◽  
Freezing Process ◽  
Liquid Region ◽  
Water Density ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Impact

The freezing of water around immersed unfinned and finned horizontal tubes is simulated numerically. The impact of natural convection as well as the water density inversion with temperature is considered. The equations governing both fluid flow and heat transfer around the tubes and through the solid–liquid interface are solved using finite difference schemes. To follow the moving solid–liquid boundary, dynamic grid generation is performed using the elliptic partial differential equation method with iterative interpolating smoothing to avoid divergence. For validation, the present results for unfinned tubes are compared with experimental studies reported in the literature. The present numerical simulations are aimed at improving our understanding of the parameters affecting the freezing process around both finned and unfinned tubes. The results showed that the flow patterns are similar in both tube configurations with one main vortex in the liquid region when there is no inversion in the water density. The presence of fins complicates the distribution of local Nusselt number along the solid–liquid interface in comparison with the unfinned tube. The impact of natural convection on the rate of ice formation is limited to the initial period of the freezing process. The results also show the freezing enhancement when utilizing fins. An accumulated ice mass correlation is developed for each tube configuration. This model can be used to optimize the design of both finned and unfinned tubes in energy storage systems, which are viable tools for air conditioning load shifting and leveling.

scholarly journals Application of cellular automata and Lattice Boltzmann methods for modelling of additive layer manufacturing

2018 ◽  
Vol 28 (1) ◽  
pp. 31-46 ◽  
Author(s):  
Dmytro Svyetlichnyy ◽  
Michal Krzyzanowski ◽  
Robert Straka ◽  
Lukasz Lach ◽  
W. Mark Rainforth
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Cellular Automata ◽  
Integrated Modelling ◽  
Holistic Model ◽  
Content Type ◽  
Powder Bed ◽  
Physical Mechanisms ◽  
Solid Liquid Interface ◽  
Solid Liquid

Purpose The holistic numerical model based on cellular automata (CA) and lattice Boltzmann method (LBM) are being developed as part of an integrated modelling approach applied to study the interaction of different physical mechanisms in laser-assisted additive layer manufacturing (ALM) of orthopaedic implants. Several physical events occurring in sequence or simultaneously are considered in the holistic model. They include a powder bed deposition, laser energy absorption and heating of the powder bed by the moving laser beam, leading to powder melting or sintering, fluid flow in the melted pool and flow through partly or not melted material, and solidification. The purpose of this study is to develop a structure of the holistic numerical model based on CA and LBM applicable for studying the interaction of the different physical mechanisms in ALM of orthopaedic implants. The model supposed to be compatible with the earlier developed CA-based model for the generation of the powder bed. Design/methodology/approach The mentioned physical events are accompanied by heat transfer in solid and liquid phases including interface heat transfer at the boundaries. The sintering/melting model is being developed using LBM as an independent numerical method for hydrodynamic simulations originated from lattice gas cellular automata. It is going to be coupled with the CA-based model of powder bed generation. Findings The entire laser-assisted ALM process has been analysed and divided on several stages considering the relevant physical phenomena. The entire holistic model consisting of four interrelated submodels has currently been developed to a different extent. The submodels include the CA-based model of powder bed generation, the LBM-CA-based model of heat exchange and transfer, the thermal solid-liquid interface model and the mechanical solid-liquid interface model for continuous liquid flow. Practical implications The results obtained can be used to explain the interaction of the different physical mechanisms in ALM, which is an intensively developing field of advanced manufacturing of metal, non-metal and composite structural parts, for instance, in bio-engineering. The proposed holistic model is considered to be a part of the integrated modelling approach being developed as a numerical tool for investigation of the co-operative relationships between multiphysical phenomena occurring in sequence or simultaneously during heating of the powder bed by the moving high energy heat source, leading to selective powder sintering or melting, fluid flow in the melted pool and through partly (or not) melted material, as well as solidification. The model is compatible with the earlier developed CA-based model for the generation of the powder bed, allowing for decrease in the numerical noise. Originality/value The present results are original and new for the study of the complex relationships between multiphysical phenomena occurring during ALM process based on selective laser sintering or melting, including fluid flow and heat transfer, identified as crucial for obtaining the desirable properties.

scholarly journals The impact of non-ideal surfaces on the solid-water interaction: a time-resolved adsorption study

2019 ◽  
Vol 6 (5) ◽  
Author(s):  
Matthias May ◽  
Helena Stange ◽  
Jonas Weinrich ◽  
Thomas Hannappel ◽  
Oliver Supplie
Keyword(s):  
Electronic Structure ◽  
Gallium Phosphide ◽  
Exact Nature ◽  
Time Resolved ◽  
Surface Steps ◽  
Qualitative Nature ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Impact

The initial interaction of water with semiconductors determines the electronic structure of the solid–liquid interface. The exact nature of this interaction is, however, often unknown. Here, we study gallium phosphide-based surfaces exposed to H_22O by means of in situ reflection anisotropy spectroscopy. We show that the introduction of typical imperfections in the form of surface steps or trace contaminants not only changes the dynamics of the interaction, but also its qualitative nature. This emphasises the challenges for the comparability of experiments with (idealised) electronic structure models for electrochemistry.

scholarly journals Effect of Eccentric Distance on Successive Dual-droplet Impacting a Super-hydrophobic Tube

2021 ◽  
Vol 299 ◽  
pp. 01002
Author(s):  
Kaimin Wang ◽  
Han Chen ◽  
Jiawei Liu ◽  
Hongyu Ge ◽  
Hongsheng Liu ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Initial Period ◽  
Volume Of Fluid Method ◽  
Significant Phenomenon ◽  
Break Up ◽  
High Pressure Zone ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Impact ◽  
Eccentric Distance

Droplet impact is a common but significant phenomenon in industry. The CLSVOF (coupled level set and volume-of-fluid) method is used to numerically study the successive dual-droplet impacting a super-hydrophobic tube. For the impact velocity of 1.0 m/s, the effect of the eccentric distance on dynamic characteristics is analysed, the corresponding eccentric distances are 0.5, 1.0 and 2.0, respectively. In addition, the break-up during rebound is analysed with velocity field and pressure nephogram. Results show that, the eccentric distance hinders the spread during the initial period of spreading. With the increase in eccentric distance, more liquid gathers at the eccentric side and the liquid film might rebound easily without break-up under the same impact velocity. The break-up during rebound mainly depends on the local airflow and pressure difference. The high-pressure zone near the solid-liquid interface moves towards the eccentric side with the increase in eccentric distance.

The Role of Slip and No Slip Behavior On Droplet Impingement

2021 ◽  
Author(s):  
A. R. Pati ◽  
Biswajit Swain ◽  
Soumya Sanjeeb Mohapatra
Keyword(s):  
Hydrophobic Surface ◽  
Slip Condition ◽  
Dimensionless Time ◽  
Droplet Impingement ◽  
Slip Conditions ◽  
Superhydrophilic Surface ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Impact

Abstract For the identification of role of slip and no slip conditions at the solid-liquid interface in case of hydrophobic, superhydrophilic and superhydrophobic surfaces, the experimentally determined velocity profiles are analysed. Before experimentation, each surface was characterized by using SEM, 2D and 3D Surface profilometer. The impact mapping results reveal that in case of hydrophobic surface, first no slip condition is achieved and then slip condition is noticed. Conversely, for superhydrophilic surface, initially slip and then no slip conditions are observed. Furthermore, in case of superhydrophobic surface, slip behaviour is observed throughout the process for the dimensionless time ranges 0.06-0.94 and this behaviour of the process promotes local enhancement of viscous and capillary forces. The experimentally obtained results are further tried to validate with the help of theoretical and visual observations.

scholarly journals The impact of grafted surface defects on the on-surface Schiff-base chemistry at the solid–liquid interface

2018 ◽  
Vol 54 (71) ◽  
pp. 9905-9908 ◽  
Author(s):  
Nerea Bilbao ◽  
Yanxia Yu ◽  
Lander Verstraete ◽  
Jianbin Lin ◽  
Shengbin Lei ◽  
...  
Keyword(s):  
Schiff Base ◽  
Surface Defects ◽  
Single Layer ◽  
Liquid Interface ◽  
Covalent Organic Frameworks ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
The Impact

We investigate the effect of covalently modified graphitic surfaces on the formation of single-layer covalent organic frameworks (sCOFs) at the solid–liquid interface.

Numerical Study on Laser Cladding of BT20 Alloy

2012 ◽  
Vol 479-481 ◽  
pp. 850-853
Author(s):  
Qing Ming Chang ◽  
Jing Yuan ◽  
Yin Kai Yang ◽  
Xia Chen ◽  
Chang Jun Chen ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Laser Cladding ◽  
Molten Pool ◽  
Numerical Study ◽  
Scanning Speed ◽  
Work Piece ◽  
Numerical Resolution ◽  
Incident Laser Power ◽  
Melt Pool ◽  
Thermal Phenomena

A 3-D modeling based on the numerical resolution of fluid flow and heat transfer are utilized to investigate the thermal phenomena during laser laser-cladding processes of BT20 alloy. From this model, it has been found that the shape and size of the molten pool in the work piece are affected by laser cladding parameters such as scanning speed and the incident laser power. The effects of process parameters on the melt pool are quantitatively discussed by numerical analysis. Furthermore, it has been observed that the surface tension temperature coefficient, Marangoni convection, which is sensitive to the active elements in the titanium alloy composition, also affect the pattern of the fluid flow in the molten pool.

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