Meshless analysis of the substrate temperature in plasma spraying process

The substrate temperature plays a very important role in coating formation and its quality during the thermal spraying. Heating effect of the plasma and particle flux on the substrate is explored in detail in terms of different spraying distances using the meshless local Petrov–Galerkin method (MLPG). Based on this approach, a 3D transient heat transfer model is derived rigorously, in which the moving least-squares (MLS) method is introduced to construct the shape functions. A quartic spline function is selected as the weight function of the MLS scheme and also the test function for the discretized weak form, in which the penalty technique is used to treat the essential boundary conditions. For comparison, the finite element method (FEM) is also adopted to solve the same problem. It is found that the computed temperature is in very good agreement with the empirical data and better than that obtained using FEM, which validates the meshless formulation. Both numerical and experimental results indicate that the spraying distance has a crucial influence on heating effect of the plasma jet and particle flux onto the substrate.