Multiphase modelling of cutting fluid and its aerosols in cutting simulations using the Finite Pointset Method (FPM) for analysing the mechanisms of action (MultiCuttingFluid)

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The mechanisms of action of cutting fluids and its aerosols are not fully understood today. There are different unproved theories for these mechanisms of action for various factors like process parameters, cutting fluid strategy or properties of cutting fluids. For example, the flush out of an insulating vapour layer which is formed due to high chip and tool surface temperatures, is assumed to be the cause of an increased cooling effect above a certain cutting fluid pressure. The positive influence of atomized cutting fluids in the form of sprays, which is used for minimum quantity lubrication (MQL) machining, is partly attributed to the drop evaporation. Even the elementary processes, such as drop transport, drop-drop collisions, drop hot wall collisions and drop evaporation within a spray, are influenced by the cutting fluid properties which change the mechanisms of action.These scientific issues will be numerically answered by using the meshfree Finite Pointset-Method (FPM) during this research project. The advantage of the FPM is the ability for completely modelling rigid and deformable structures and fluid, as well as fluid-structure-interactions during large deformations using this method. Therefore, it is currently possible to simulate chip forming for a wet cylindrical turning process by considering a single-phase fluid. During this research project the existing models are extended by vapour phase and spray as well as their physical mechanisms of action. The vapour phase is implemented in the FPM as a monolithic numerical entity by using an extended equation of state. Elementary processes within a spray are considered by semi-empirical models of droplet interactions implemented in a Lagrange way. The model development will be based on detailed laboratory experiments. The resulting multiphase model of the cutting fluid and its aerosols is used to numerically investigate the mechanisms of action in the machining process.In order to achieve this aim, models of the cutting fluid and its mechanisms of action are developed with regard to evaporation within project period 1. In the following project period 2 these models are integrated into cutting simulations to analyse evaporation mechanisms during cutting. Furthermore, the models of the cutting fluid are extended by a spray phase for the purpose of MQL applications in project period 3. The developments are used to increase the general understanding of cutting considering a cutting fluid as well as for ecological and economical optimisations of the cooling strategies flood cooling, high pressure cooling and MQL.