Improving a rotating steel milling tool cooling by an air jet impingement flow

Turbulent jets impacting flat or curved surfaces have been the subject of several research reports in the literature over the past decades, and it is all about the improvement of localized heat and/or mass transfer in part of a system, to achieve this goal, it is necessary to understand the dynamic behavior of the fluid and its effect on local heat and/or mass transfer. The aim of our work is the numerical investigation of a steel milling tool cooling driven in rotation, emitting a heat flux caused by machining a surface, using an impacting cold air jet; Although the technology of cooling the machining tools exists by using liquid jets, it signaled that it is less economical and efficient then using the impinging air jet. The milling tool is cooled using forced convection produced by the air jet at different Reynolds numbers, this phenomenon is governed by the equations of conservation of mass, momentum, and energy. We adopted a mathematical model based on the finite volume method; the calculation code was validated using experimental results available in the literature. We obtained our results by varying the Reynolds number between 12,000 and 26,000 values for an impact distance ratio h/D = 4, and two configurations: one nozzle and two nozzles. Our results showed that when using two cold air jet inlets to cool the milling tool, the distribution of the Nusselt number on the surface is enhanced compared to the one nozzle case, mainly because of the two impact points of the jet on the surface. We also note that increasing the Reynolds number has a significant influence on the distribution of the averaged Nusselt number.