Robot Trajectory Generation and Coating Temperature Prediction of Plasma Sprayed Coatings

1997 ◽  
Author(s):  
P. Nylén ◽  
M. Edberg
Keyword(s):  
Coating Thickness ◽  
Simulation Method ◽  
Ideal Gas ◽  
Particle Model ◽  
Transfer Model ◽  
System A ◽  
Robot Trajectory ◽  
Offline Programming ◽  
Discrete Particle Model ◽  
Plasma Sprayed

Abstract This paper presents a simulation method in which robot trajectories can be optimised to produce an even coating thickness and how they can be used to predict transient coating temperatures on complex geometries. The coating thickness was simulated by the use of a commercial Offline programming (OLP) system. A robot trajectory was calculated, maintaining a constant spraying distance and normal orientation to the surface. The trajectory was optimised to give a uniform coating thickness while also handling non collision requirements. The plasma was represented as an ideal gas with temperature dependent thermodynamic and transport properties. The governing equations were solved by a developed finite difference elliptic code using a simplified turbulence model. The particles were modelled by a stochastic discrete particle model. The robot trajectory together with the heat transfer model were then used to calculate transient coating and substrate temperatures by the use of the finite element method (FEM). The model predictions were tentatively compared with experimental measurements and reasonable correlations were obtained.

Modelling of Coating Thickness, Heat Transfer and Fluid Flow and It's Correlation with the TBC Microstructure for a Plasma Sprayed Gas Turbine Application

1998 ◽  
Author(s):  
P. Nylen ◽  
J. Wigren ◽  
L. Pejryd ◽  
M.-O. Hansson
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Gas Turbine ◽  
Coating Thickness ◽  
Spray Deposition ◽  
Temperature History ◽  
Particle Model ◽  
Barrier Coating ◽  
Discrete Particle Model ◽  
Turbine Component

Abstract The plasma spray deposition of a zirconia thermal barrier coating (TBC) on a gas turbine component has been examined using analytical and experimental techniques. The coating thickness was simulated by the use of commercial off-line programming software. The impinging jet was modelled by means of a finite difference elliptic code using a simplified turbulence model. Powder particle velocity, temperature history and trajectory were calculated using a stochastic discrete particle model. The heat transfer and fluid flow model were then used to calculate transient coating and substrate temperatures using the finite element method. The predicted thickness, temperature and velocity of the particles and the coating temperatures were compared with these measurements and good correlations were obtained. The coating microstructure was evaluated by optical and scanning microscopy techniques. Special attention was paid to the crack structures within the top coating. Finally, the correlation between the modelled parameters and the deposit microstructure was studied.

Coating Thickness Prediction and Robot Trajectory Generation of Thermal Sprayed Coatings

1996 ◽  
Author(s):  
P. Nylén ◽  
I. Fransson ◽  
A. Wretland ◽  
N. Mårtensson
Keyword(s):  
Coating Thickness ◽  
Control Process ◽  
Simulation Method ◽  
Rate Function ◽  
Free Form ◽  
Spray Cone ◽  
Robot Controller ◽  
Robot Trajectory ◽  
Thickness Prediction ◽  
Sprayed Coatings

Abstract Off-line programming (OLP) techniques can be used to reduce programming time and to be able to better control process parameters, such as spray distance and nozzle orientation. This paper presents a simulation method to predict coating thickness build-up on complex geometries. Discretization in time and space is done by using a finite difference model. The model starts with an empirical deposit rate function, which calculates the thickness on a flat surface normal to the spray cone. This model is integrated into a commercial robot simulation program (IGRIP) where discretization of a free form surface into planar polygons is carried out. The thickness is then calculated by stepping the process in increments of time. A robot trajectory is calculated, maintaining spraying distance and normal orientation to the surface. This trajectory is optimized numerically giving a collision free path and a uniform coating thickness. Devices are then programmed, the programs are translated and finally downloaded to the robot controller.

Robust probabilistic calibration of a stochastic lattice discrete particle model for concrete

2021 ◽  
Vol 236 ◽  
pp. 112000
Author(s):  
Eliška Janouchová ◽  
Anna Kučerová ◽  
Jan Sýkora ◽  
Jan Vorel ◽  
Roman Wan-Wendner
Keyword(s):  
Particle Model ◽  
Discrete Particle ◽  
Discrete Particle Model ◽  
Lattice Discrete Particle Model

Thermo-mechanical coupling particle simulation of three-dimensional large-scale non-isothermal problems

2017 ◽  
Vol 34 (5) ◽  
pp. 1551-1571 ◽  
Author(s):  
Ming Xia
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Simulation Method ◽  
Particle Simulation ◽  
Similarity Criteria ◽  
Particle Model ◽  
Length Scale ◽  
Content Type ◽  
Mechanical Coupling ◽  
Particle Simulation Method

Purpose The main purpose of this paper is to present a comprehensive upscale theory of the thermo-mechanical coupling particle simulation for three-dimensional (3D) large-scale non-isothermal problems, so that a small 3D length-scale particle model can exactly reproduce the same mechanical and thermal results with that of a large 3D length-scale one. Design/methodology/approach The objective is achieved by following the scaling methodology proposed by Feng and Owen (2014). Findings After four basic physical quantities and their similarity-ratios are chosen, the derived quantities and its similarity-ratios can be derived from its dimensions. As the proposed comprehensive 3D upscale theory contains five similarity criteria, it reveals the intrinsic relationship between the particle-simulation solution obtained from a small 3D length-scale (e.g. a laboratory length-scale) model and that obtained from a large 3D length-scale (e.g. a geological length-scale) one. The scale invariance of the 3D interaction law in the thermo-mechanical coupled particle model is examined. The proposed 3D upscale theory is tested through two typical examples. Finally, a practical application example of 3D transient heat flow in a solid with constant heat flux is given to illustrate the performance of the proposed 3D upscale theory in the thermo-mechanical coupling particle simulation of 3D large-scale non-isothermal problems. Both the benchmark tests and application example are provided to demonstrate the correctness and usefulness of the proposed 3D upscale theory for simulating 3D non-isothermal problems using the particle simulation method. Originality/value The paper provides some important theoretical guidance to modeling 3D large-scale non-isothermal problems at both the engineering length-scale (i.e. the meter-scale) and the geological length-scale (i.e. the kilometer-scale) using the particle simulation method directly.

Simulation of Thermal Spray Process Based on Particle Tracing Method

2000 ◽  
Author(s):  
K. Wada ◽  
M. Ito ◽  
M. Takahashi ◽  
K. Takaishi
Keyword(s):  
Thermal Spray ◽  
Coating Thickness ◽  
Computer Aided Design ◽  
Simulation Method ◽  
Work Piece ◽  
Stainless Steel 316L ◽  
Particle Tracing ◽  
Computer Aided ◽  
Thermal Spray Processes ◽  
Tracing Method

Abstract As applications of thermal spray processes are expanding, the importance of computer-aided design systems and computer-aided engineering systems for these processes has been growing. The principal objective of this study is to propose a new analytic method for the prediction of coating thickness and deposition efficiency. This method is called the particle tracing method and is based on the Monte Carlo simulation method. In order to evaluate the validity of this model, several tests were carried out. The same stainless steel 316L layers coated by the HP/HVOF process (TAFA JP-5000) were used throughout each test. First, spray patterns were observed which had formed on flat-plate specimens from various spray gun angles. Coating thickness distributions on several curved planes were consequently investigated. Finally, the coating process for a blade of a compressor in a gas turbine was simulated. In the right of the results of these experiments, it is summarized that the calculated values of the coating thickness obtained by our method are in good agreement with experimental values. The accuracy is within 10% of the maximum thickness value in each specimen, except for at the edge of the work-piece. In conclusion, the particle-tracing method can be applied to the fundamental analytic model in the CAD or CAE system for thermal spray processes.

Numerical modeling for the effects of gravel permeability coefficient based on DEM and CFD method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Anan Zhang ◽  
Jie Yang ◽  
Chuihui Ma ◽  
Lin Cheng ◽  
Liangcai Hu
Keyword(s):  
Permeability Coefficient ◽  
Fine Particles ◽  
Simulation Method ◽  
Test Sample ◽  
Treatment Method ◽  
Particle Model ◽  
Equal Weight ◽  
Content Type ◽  
Seepage Characteristics ◽  
Element Method

Purpose The purpose of this paper is to form a numerical simulation method for permeability coefficient that can consider the characteristics of gravel gradation and further explore the effects of indoor test factors and gradation characteristics on the permeability coefficient of gravel. Design/methodology/approach The random point method is used to establish the polyhedral gravel particle model, the discrete element method (DEM) is used to construct the gravel permeability test sample with gradation characteristics and the finite element method is used to calculate the permeability coefficient to form a DEM-computational fluid dynamics combined method to simulate the gravel seepage characteristics. Then, verified by the indoor test results. Based on this method, the influence of sample size, treatment method of oversize particles and the content of fine particles on the permeability coefficient of gravel is studied. Findings For the gravel containing large particles, the larger size permeameter should be used as far as possible. When the permeameter size is limited, the equal weight substitution method is recommended for the treatment method of oversized particles. Compared with the porosity, the pore connectivity has a higher correlation with the permeability coefficient of the sample. Research limitations/implications Insufficient consideration of the movement of gravel particles in the seepage process is also an issue for further study. Originality/value The simulation method described in this paper is helpful for qualitative analysis, quantitative expression of pore size and makes up for the defect that the seepage characteristics in pores cannot be observed in laboratory tests.

The analyses of frictional losses and thermal stresses in a diesel engine piston coated with different thicknesses of thermal barrier films using co-simulation method

2021 ◽  
pp. 146808742110656
Author(s):  
Fatma Bayata ◽  
Cengiz Yildiz
Keyword(s):  
Diesel Engine ◽  
Coating Thickness ◽  
Thermal Stresses ◽  
Equivalent Stress ◽  
Simulation Method ◽  
Thermal Barrier ◽  
Barrier Films ◽  
Engine Piston ◽  
Frictional Performance ◽  
Artificial Neural Network Ann

This study comparatively presents the thermal and mechanical effects of different Thermal Barrier Coatings (TBCs) and their thicknesses on the performance of aluminum diesel engine piston by combining Finite Element Analyses (FEA) and Artificial Neural Network (ANN) methods. The piston structure of MWM TbRHS 518S indirect injection six-cylinder diesel engine was modeled. The clustered TBCs (NiCrAlY–Gd2Zr2O7, NiCrAlY–MgO-ZrO2, NiCrAl–Yttria Partially Stabilized Zirconia (YPSZ), and NiCrAlY–La2Zr2O7) were implemented to the related surface of aluminum alloy piston and then static, thermal, and transient structural FEA were conducted for each model. Based on both of the temperature and equivalent stress distributions, NiCrAlY–Gd2Zr2O7 coated model displayed the best performance. Additionally, the effects of top coating thicknesses of TBCs were investigated in the range of 0.1–1.0 mm with 0.1 mm increments in FEAs. The thermally effective top coating thickness was predicted as 0.95 mm for the selected TBC using ANN method. Then the effects of coating thickness on frictional performance were revealed by generating transient structural FE models and utilizing stribeck diagram. The uncoated and 0.95 mm NiCrAlY–Gd2Zr2O7 coated models were adjusted as transient and the related crank angle – dependent in-cylinder combustion pressure data was implemented. The friction force was reduced by at least 15% in NiCrAlY–Gd2Zr2O7 coated model.

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