Efficient Simulation of Nonlinear Heat Transfer during Thermal Spraying of Complex Workpieces

Rolf Berthelsen,Ralf Denzer,Heinrich Müller,Thomas Wiederkehr,Andreas Menzel

doi:10.4236/wjm.2014.49029

Abstract

The quality of coatings, produced by thermal spraying processes, considerably decreases with the occurrence of higher residual stresses, which are especially pronounced for complex workpiece geometries. To understand the occurring effects and to aid in the planning of coating processes, simulations of the highly transient energy flux of the HVOF spray gun into the substrate are of great value. In this article, a software framework for the simulation of nonlinear heat transfer during (HVOF) thermal spraying is presented. One part of this framework employs an efficient GPU-based simulation algorithm to compute the time-dependent input boundary conditions for a spray gun that moves along a complex workpiece of arbitrary shape. The other part employs a finite-element model for a rigid heat conductor adhering to the computed boundary conditions. The model is derived from the fundamental equations of continuum thermodynamics where nonlinear temperature-depending heat conduction is assumed.<

Highlights

IntroductionHow to cite this paper: Berthelsen, R., Wiederkehr, T., Denzer, R., Menzel, A. and Müller, H. (2014) Efficient Simulation of Nonlinear Heat Transfer during Thermal Spraying of Complex Workpieces
Thermal spraying is a cost-efficient coating technique for the production of wear-resistant surfaces consisting ofHow to cite this paper: Berthelsen, R., Wiederkehr, T., Denzer, R., Menzel, A. and Müller, H. (2014) Efficient Simulation of Nonlinear Heat Transfer during Thermal Spraying of Complex Workpieces
While thermal-spraying of planar work pieces delivers coatings of quite satisfying quality, the quality considerably decreases with the rising degree of complexity of the work pieces’ geometry, for instance due to radii or curvatures

Summary

Introduction

How to cite this paper: Berthelsen, R., Wiederkehr, T., Denzer, R., Menzel, A. and Müller, H. (2014) Efficient Simulation of Nonlinear Heat Transfer during Thermal Spraying of Complex Workpieces. A novel approach is presented, which makes use of an elegant GPU-acceleration technique and is an adaption of a method developed earlier in the context of mass deposition simulation [6] This two-level simulation approach enables the highly detailed thermodynamic model, which is adjusted to the HVOF spraying process, to be efficiently applied even to larger workpieces such as forming tools in the automotive industry or complex geometries like turbine blades. Another contribution of this work is the “inner” finite element simulation module including a multi-threaded C++ based implementation which uses the solver library Eigen. The material parameters of the underlying constitutive relations—the heat capacity c as well as the heat conduction coefficient λ —are represented by suitable functions which are fitted to experimental data

Continuum Thermodynamics

Finite Element Discretisation

Implementation

Examples

Summary