Modeling time-dependent phenomena in plasma spraying of liquid precursors

2008 ◽  
Vol 80 (9) ◽  
pp. 1981-1991 ◽  
Author(s):  
Armelle Vardelle ◽  
Christophe Chazelas ◽  
Cecile Marchand ◽  
Gilles Mariaux
Keyword(s):  
Plasma Spray ◽  
Specific Treatment ◽  
Plasma Jet ◽  
Deposition Efficiency ◽  
Time Dependent ◽  
Spray Process ◽  
Liquid Precursors ◽  
Liquid Injection ◽  
Liquid Material ◽  
And Control

The recently developed plasma spray processes using liquid precursors make it possible to produce finely structured coatings with a broad range of microstructures and, thus, properties. However, coating reproducibility and control of the deposition efficiency are critical to industrial acceptance of these processes. Both depend on time-dependent interactions between the plasma jet and liquid material. Transient and realistic modeling of the liquid spray process may help to increase the understanding of the process. A comprehensive model should involve the formation of the plasma jet inside the torch and the transient specific treatment (break-up, droplet collision, coalescence, evaporation, chemistry) of the liquid material in the plasma jet. If much progress has been recently made on the modeling of the interaction of arc and transverse flow in the plasma torch, further theoretical and experimental research is needed, especially in respect of liquid injection and fragmentation under plasma spray conditions.

Three-Dimensional Simulation of Plasma Spray Jet

2003 ◽  
Author(s):  
H. Xiong ◽  
L. L. Zheng ◽  
S. Sampath ◽  
Jim Fincke ◽  
Richard Williamson
Keyword(s):  
Plasma Spray ◽  
Gas Flow ◽  
Probability Distributions ◽  
Three Dimensional ◽  
Plasma Jet ◽  
Carrier Gas ◽  
Spray Process ◽  
Lagrangian Coordinate ◽  
Dimensional Simulation ◽  
Physical Phenomena

A three-dimensional computational model has been developed to describe the compressible, multi-component, turbulent, reacting plasma jet coupled with the orthogonal injection of carrier gas and particles. This model has been applied to plasma spray process that includes physical phenomena such as heating, melting, accelerating, and evaporation of in-flight particles. The entrained particles, NiCrAlY and ZrO2, are discretely treated in a Lagrangian coordinate and stochastically generated by sampling from the probability distributions of the particle size and its velocity at the injection nozzle. In this study, special attention has been directed to the effects of carrier gas injection on the characteristics of plasma jet. The computational results show that the injection of carrier gas from the orthogonal injector above the plasma jet introduce the 3-D phenomena of plasma gas flow. The plasma jet is defected and the thermo-fluid flow near the injector is locally deformed.

Intelligent system for prediction and control: Application in plasma spray process

2011 ◽  
Vol 38 (1) ◽  
pp. 260-271 ◽  
Author(s):  
A.-F. Kanta ◽  
G. Montavon ◽  
C.C. Berndt ◽  
M.-P. Planche ◽  
C. Coddet
Keyword(s):  
Plasma Spray ◽  
Intelligent System ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Prediction And Control ◽  
Control Application ◽  
And Control

On the Reproducibility of Air Plasma Spray Process and Control of Particle State

2006 ◽  
Vol 15 (4) ◽  
pp. 739-743 ◽  
Author(s):  
V. Srinivasan ◽  
A. Vaidya ◽  
T. Streibl ◽  
M. Friis ◽  
S. Sampath
Keyword(s):  
Plasma Spray ◽  
Particle State ◽  
Air Plasma Spray ◽  
Air Plasma ◽  
Spray Process ◽  
Plasma Spray Process ◽  
And Control

The Solution Precursor Plasma Spray Process for Making Durable Thermal Barrier Coatings

2005 ◽  
Author(s):  
Maurice Gell ◽  
Fang Wu ◽  
Eric H. Jordan ◽  
Nitin P. Padture ◽  
Baki M. Cetegen ◽  
...  
Keyword(s):  
Plasma Spray ◽  
Plasma Plume ◽  
Thermal Barrier ◽  
Solution Precursor Plasma Spray ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Barrier Coating ◽  
Solution Precursor ◽  
And Control ◽  
Thick Coatings

The Solution Precursor Plasma Spray (SPPS) process involves the injection of atomized droplets of precursor into the plasma plume, instead of powder that is used in conventional plasma spray. The resultant thermal barrier coating (TBC) microstructure consists of (1) through-coating-thickness cracks, (2) ultra-fine splats, and (3) nanometer and micrometer-sized dispersed pores. These unique SPPS microstructural features provide highly durable TBCs. The SPPS TBCs in 1121°C /1 hour cyclic furnace tests exhibit a significantly improved spallation life compared to APS, DVC, and EB-PVD/Pt-Al TBCs. Extensive process diagnostic and modeling studies have been conducted to provide a foundation for understanding and control of the process. Process/microstructure/property relationships have been defined. Extension of the process for making thick coatings (> 3mm) and low thermal conductivity coatings are described.

scholarly journals High-Speed Video Analysis of the Process Stability in Plasma Spraying

2021 ◽  
Author(s):  
K. Bobzin ◽  
M. Öte ◽  
M. A. Knoch ◽  
I. Alkhasli ◽  
H. Heinemann
Keyword(s):  
Plasma Spraying ◽  
High Speed ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Time Dependent ◽  
Acquisition Time ◽  
Fast Fourier Transformation ◽  
Frequency Spectra ◽  
Dependent Signal ◽  
The Stability

AbstractIn plasma spraying, instabilities and fluctuations of the plasma jet have a significant influence on the particle in-flight temperatures and velocities, thus affecting the coating properties. This work introduces a new method to analyze the stability of plasma jets using high-speed videography. An approach is presented, which digitally examines the images to determine the size of the plasma jet core. By correlating this jet size with the acquisition time, a time-dependent signal of the plasma jet size is generated. In order to evaluate the stability of the plasma jet, this signal is analyzed by calculating its coefficient of variation cv. The method is validated by measuring the known difference in stability between a single-cathode and a cascaded multi-cathode plasma generator. For this purpose, a design of experiment, covering a variety of parameters, is conducted. To identify the cause of the plasma jet fluctuations, the frequency spectra are obtained and subsequently interpreted by means of the fast Fourier transformation. To quantify the significance of the fluctuations on the particle in-flight properties, a new single numerical parameter is introduced. This parameter is based on the fraction of the time-dependent signal of the plasma jet in the relevant frequency range.

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