26. Simulation of High-Temperature Solid Particle Erosion of HVOF-Sprayed NiCrBSiFe and WC-Co/NiCrBSiFe-Coated Wall Using CFD

The erosion characteristics of HVOF-sprayed NiCrBSiFe and WC-Co/NiCrBSiFe coatings made on SS347 grade steel have been investigated for high-temperature behaviour, especially in the boiler tubes used in thermal power generation. The computational fluid dynamic model has been adopted to study the influence of the impingement angle on the erosion properties of the coatings. The self-fluxing NiCrBSiFe alloys have shown the best erosion resistance of about two times at room temperature and about four times at 700 °C when compared with a composite powered coating of WC-Co/NiCrBSiFe. At 700 °C, The WC-Co/NiCrBSiFe undergoes thermal cracking between nickel rich and WC metallic phases due to low oxidation and thermal expansion mismatch between them leading to degradation of the coating; however, at this temperature, the self-fluxing alloy of NiCrBSiFe performed better when compared to WC-Co/NiCrBSiFe coating. The simulation is done with turbulence model, namely shear stress transport (SST) model with a base on user-defined function predicted from the experimental results. The computational fluid dynamic simulated data obtained from SST model and the experimental results were compared, and they are in good agreement with each other.