Jet impingement onto a laser produced kerf: Influence of kerf thickness on heat transfer and skin friction

Purpose - The purpose of this paper is to investigate the heat transfer rates from the kerf surfaces and skin friction at the kerf wall due to the jet impingement in relation to laser cutting process. Design/methodology/approach - Three-dimensional modeling for the flow and heat transfer analysis is considered. The numerical scheme using the control volume approach is introduced to solve the governing equations of flow and heat transfer. The k-w turbulence model is incorporated to account for the turbulence. Findings - It is found that the Nusselt number and the skin friction remains high in the region next to the kerf inlet and it decreases towards the kerf exit for all kerf thicknesses considered. The flow acceleration in the kerf also results in the second peak of the Nusselt number and the skin friction. Research limitations/implications - The melting at the kerf surface was omitted and the constant temperature boundary representing the melt surface is incorporated in the analysis. However, care was taken during the mesh generation to avoid grid dependent solutions. Practical implications - The findings and discussions provide the useful information on the practical laser cutting process, in particular, physical insight into the effect of the kerf thickness on the heat transfer and skin friction. Originality/value - No previous work has been carried out in three-dimensional space to predict the heat transfer and skin friction, which are important for practical laser cutting applications. Therefore, the work reported is original.