Experimental and Numerical Analysis of the Nickel Deposition and Diffusion Using Plasma in a Confined Anode-Cathode Configuration

2009 ◽  
Vol 283-286 ◽  
pp. 183-189 ◽  
Author(s):  
Rodrigo Perito Cardoso ◽  
A.M. Maliska ◽  
C.R. Maliska
Keyword(s):  
Deposition Process ◽  
Interstitial Free ◽  
Cathode Voltage ◽  
Nickel Deposition ◽  
Plasma Sintering ◽  
Pulsed Dc ◽  
Proposed Model ◽  
Constant Rate ◽  
Experimental Values ◽  
Volume Method

This work presents a theoretical and experimental study of nickel deposition on iron samples at relatively high pressure using a pulsed DC glow discharge. The deposition process was conducted in conditions similar to that used for plasma sintering, using the confined anode-cathode configuration. The cathode was made from nickel commercially pure and the samples were made from interstitial free steel and sintered pure iron. The samples were characterized by mass weight gain, scanning electron microscopy and energy-dispersive X-ray microanalysis. The deposition process was mathematically modeled and the model was numerically solved using a conservative finite-volume method. The experiments demonstrated that the deposition occurs at a constant rate, with the mass flux changing linearly with the cathode voltage in the range of parameters considered. The results obtained from the diffusion model applied to the sample presented good agreement with the experimental values. Concerning the gas phase, the proposed model helped us to clarify some phenomenological aspects of the process. However, further studies, principally in the area of electrical discharges, are needed to permit a complete comprehension of this process.

Ignition and flame quenching of quiescent fuel mists

1978 ◽  
Vol 364 (1717) ◽  
pp. 277-294 ◽  
Keyword(s):  
Reaction Rates ◽  
Ignition Energy ◽  
Minimum Ignition Energy ◽  
Proposed Model ◽  
Theoretical Predictions ◽  
Quenching Distance ◽  
Experimental Values ◽  
Sole Criterion ◽  
Fuel Vapour ◽  
Level Of Agreement

A model is proposed for the ignition of quiescent multidroplet fuel mists which assumes that chemical reaction rates are infinitely fast, and that the sole criterion for successful ignition is the generation, by the spark, of an adequate concentration of fuel vapour in the ignition zone. From analysis of the relevant heat transfer and evaporation processes involved, ex­pressions are derived for the prediction of quenching distance and minimum ignition energy. Support for the model is demonstrated by a close level of agreement between theoretical predictions of minimum ignition energy and the corresponding experimental values obtained using a specially designed ignition apparatus in which ignition energies are measured for several different fuels, over wide ranges of pressure, mixture composition and mean drop size. The results show that both quenching distance and mini­mum ignition energy are strongly dependent on droplet size, and are also dependent, but to a lesser extent, on air density, equivalence ratio and fuel volatility. An expression is derived to indicate the range of drop sizes over which the proposed model is valid.

Effect of recess depth on lubrication performance of annular recess hydrostatic thrust bearing by constant rate flow

2018 ◽  
Vol 70 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Jun-peng Shao ◽  
Guang-dong Liu ◽  
Xiao-dong Yu ◽  
Yan-qin Zhang ◽  
Xiu-li Meng ◽  
...  
Keyword(s):  
Thrust Bearing ◽  
Simulation Method ◽  
Content Type ◽  
Oil Film ◽  
Constant Rate ◽  
Lubrication Performance ◽  
Optimal Value ◽  
Improved Performance ◽  
Lubrication Characteristics ◽  
Volume Method

Purpose The purpose of this paper is to describe a simulation and experimental research concerning the effect of recess depth on the lubrication performance of a hydrostatic thrust bearing by constant rate flow. Design/methodology/approach The computational fluid dynamics and finite volume method have been used to compute the lubrication characteristics of an annular recess hydrostatic thrust bearing with different recess depths. The performances are oil recess pressure, oil recess temperature and oil film velocity. The recess depth has been optimized. A test rig is established for testing the pressure field of the structure of hydrostatic thrust bearing after recess depth optimization, and experimental results show that experimental data are basically identical with the simulation results, which demonstrates the validity of the proposed numerical simulation method. Findings The results demonstrate that the oil film temperature decreases and the oil film pressure first increases and then decreases with an increase in the recess depth, but oil film velocity is constant. To sum up comprehensive lubrication performance, the recess depth of 3.5 mm is its optimal value for the annular recess hydrostatic thrust bearing. Originality/value The computed results indicate that to get an improved performance from a constant flow hydrostatic thrust bearing, a proper selection of the recess depth is essential.

scholarly journals Numerical Simulation of Water Absorption and Swelling in Dehulled Barley Grains during Canned Porridge Cooking

Processes ◽  
2018 ◽  
Vol 6 (11) ◽  
pp. 230 ◽  
Author(s):  
Lei Wang ◽  
Mengting Wang ◽  
Mingming Guo ◽  
Xingqian Ye ◽  
Tian Ding ◽  
...  
Keyword(s):  
Moisture Absorption ◽  
Three Dimensional ◽  
Processing Conditions ◽  
Relative Deviation ◽  
Cooking Process ◽  
Proposed Model ◽  
Hygroscopic Swelling ◽  
3D Numerical Model ◽  
Barley Grains ◽  
Experimental Values

Understanding the hydration behavior of cereals during cooking is industrially important in order to optimize processing conditions. In this study, barley porridge was cooked in a sealed tin can at 100, 115, and 121 °C, respectively, and changes in water uptake and hygroscopic swelling in dehulled barley grains were measured during the cooking of canned porridge. In order to describe and better understand the hydration behaviors of barley grains during the cooking process, a three-dimensional (3D) numerical model was developed and validated. The proposed model was found to be adequate for representing the moisture absorption characteristics with a mean relative deviation modulus (P) ranging from 4.325% to 5.058%. The analysis of the 3D simulation of hygroscopic swelling was satisfactory for describing the expansion in the geometry of barley. Given that the model represented the experimental values adequately, it can be applied to the simulation and design of cooking processes of cereals grains, allowing for saving in both time and costs.

Determination of Recrystallization Kinetics Model of 30Cr2Ni4MoV Steel Based on Dislocation Density

2017 ◽  
Vol 263 ◽  
pp. 59-66
Author(s):  
Peng Zhou ◽  
Qing Xian Ma
Keyword(s):  
Dislocation Density ◽  
Model Comparison ◽  
Kinetics Model ◽  
Structure Evolution ◽  
Metallographic Analysis ◽  
Recrystallization Kinetics ◽  
Proposed Model ◽  
Different Temperatures ◽  
Predicted Values ◽  
Experimental Values

A new model to predict the structure evolution of 30Cr2Ni4MoV steel is proposed based on the dislocation density in this research. Hot compression of 30Cr2Ni4MoV steel is carried out on Gleeble 1500 at different temperatures from 1233 K to 1473 K with a strain rate of 0.01 s-1 and the deformed samples are immediately quenched by water to frozen the austenite structure. The recrystallization kinetics model of 30Cr2Ni4MoV steel is successfully established by inverse analysis of the flow curve based on the relation between flow stress and dislocation density. In order to validate the proposed model, comparison between the predicted values and experimental values obtained by metallographic analysis is implemented. It is shown that the predicted results agree with the experimental results well.

Experimental and Numerical Analysis of the Powder Flow in a Multi-Channel Coaxial Nozzle of a Direct Metal Deposition System

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Piyush Pant ◽  
Dipankar Chatterjee ◽  
Sudip Kumar Samanta ◽  
Aditya Kumar Lohar
Keyword(s):  
Gas Flow ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Deposition Process ◽  
Metal Deposition ◽  
Direct Metal Deposition ◽  
Powder Flow ◽  
Coaxial Nozzle ◽  
Proposed Model ◽  
Blown Powder

Abstract The work explores the powder transport process, using numerical simulation to address the dynamics of the powder flow in an in-house built multi-channel coaxial nozzle of a direct metal deposition (DMD) system. The fluid turbulence is handled by the standard k–ɛ and k–ω turbulence models, and the results are compared in order to predict their suitability. An image-based technique using CMOS camera is adopted to determine the powder flow characteristics. The model is validated with the in-house experimental results and verified available results in the literature. The findings of this work confirms the application of the k–ω model for powder gas flow investigations in blown powder additive manufacturing (AM) processes due to its better predictive capability. The proposed model will assist in simulating the direct metal deposition process.

Creep Prediction Model for Concrete Made of Crushed Clay Bricks as Coarse Aggregate

2012 ◽  
Vol 166-169 ◽  
pp. 994-997 ◽  
Author(s):  
Syed Ishtiaq Ahmad ◽  
Sushanta Roy
Keyword(s):  
Coarse Aggregate ◽  
Generalized Equation ◽  
Time Behavior ◽  
Simple Design ◽  
Clay Bricks ◽  
Design Office ◽  
Proposed Model ◽  
Creep Time ◽  
Experimental Values ◽  
Two Parameters

A simple design office oriented empirical model containing only two parameters has been developed to predict creep behavior of concrete made of crushed clay bricks as coarse aggregate. For this, concrete samples having three different normal compressive strengths in the range of 18.9 up to 24.0 N/mm2 are first prepared and then tested for their creep deformation. For each of the samples, a hyperbolic equation is developed from their creep-time behavior. These equations are then combined and modified according to statistical norms to finally obtain a generalized equation. Comparison of creep strain obtained from this equation with that of experimental values show that the proposed model can closely predict creep in brick aggregate made concrete.

Spark Plasma Synthesis/Sintering of Dense Ceramic, Intermetallic and Composite Materials

2006 ◽  
Vol 45 ◽  
pp. 1411-1416
Author(s):  
Antonio Mario Locci ◽  
Roberta Licheri ◽  
Roberto Orrù ◽  
A. Cincotti ◽  
Giacomo Cao
Keyword(s):  
Mechanical Load ◽  
Plasma Synthesis ◽  
Simultaneous Application ◽  
Plasma Sintering ◽  
Pulsed Dc ◽  
Spark Plasma ◽  
One Step ◽  
Powder Particles ◽  
Dc Current ◽  
Spark Plasma Synthesis

Spark Plasma Sintering (SPS) represents a very attractive technique for the obtainment of dense materials including nanostructured ones. SPS basically consists in the simultaneous application of a pulsed DC current and an uniaxial mechanical load through a powder compact. Other than providing rapid Joule heating and likely enhancing mass transport through electromigration, the imposed pulsed high current is also reported to generate a plasma within the voids surrounding the powder particles, thus facilitating the removal of oxides surface layers that may hinder the sintering process. Selected results obtained through SPS in our laboratory for the preparation of a wide variety of materials, i.e. TiC-TiB2, MgB2, and NbAl3, will be presented in this work. Specifically, all the chosen examples are related to the use of the SPS technique for obtaining the desired material by simultaneously performing synthesis and consolidation stages in one-step.

Room temperature pulsed-DC sputtering deposition process for CIGS absorber layer: Material and device characterizations

2018 ◽  
Vol 660 ◽  
pp. 175-179 ◽  
Author(s):  
Boubakeur Ayachi ◽  
Thomas Aviles ◽  
Jean-Pierre Vilcot ◽  
Cathy Sion ◽  
Patrice Miska
Keyword(s):  
Room Temperature ◽  
Deposition Process ◽  
Absorber Layer ◽  
Sputtering Deposition ◽  
Layer Material ◽  
Dc Sputtering ◽  
Pulsed Dc

scholarly journals Effect of Cr Atom Plasma Emission Intensity on the Characteristics of Cr-DLC Films Deposited by Pulsed-DC Magnetron Sputtering

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 608
Author(s):  
Guang Li ◽  
Yi Xu ◽  
Yuan Xia
Keyword(s):  
Magnetron Sputtering ◽  
Emission Intensity ◽  
Gas Flow ◽  
Optical Emission ◽  
Scratch Test ◽  
Deposition Process ◽  
Plasma Emission ◽  
Cross Sectional ◽  
Pulsed Dc ◽  
Plasma Emission Intensity

A pulsed-dc (direct current) magnetron sputtering with a plasma emission monitor (PEM) system was applied to synthesize Cr-containing hydrogenated amorphous diamond-like carbon (Cr-DLC) films using a large-size industrial Cr target. The plasma emission intensity of a Cr atom at 358 nm wavelength was characterized by optical emission spectrometer (OES). C2H2 gas flow rate was precisely adjusted to obtain a stable plasma emission intensity. The relationships between Cr atom plasma emission intensity and the element concentration, cross-sectional morphology, deposition rate, microstructure, mechanical properties, and tribological properties of Cr-DLC films were investigated. Scanning electron microscope and Raman spectra were employed to analyze the chemical composition and microstructure, respectively. The mechanical and tribological behaviors were characterized and analyzed by using the nano-indentation, scratch test instrument, and ball-on-disk reciprocating friction/wear tester. The results indicate that the PEM system was successfully used in magnetron sputtering for a more stable Cr-DLC deposition process.

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