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

切削液及其气溶胶的作用机制目前尚未完全了解。对于这些作用机理，如工艺参数、切削液策略或切削液的性质，存在不同的未经证实的理论。例如，由于高切屑和刀具表面温度而形成的绝缘蒸汽层的冲出被认为是在一定切削液压力以上增加冷却效果的原因。用于最小量润滑（MQL）加工的喷雾形式的雾化切削液的积极影响部分归因于液滴蒸发。切削液的性质改变了液滴在喷雾中的作用机理，甚至液滴的输运、液滴-液滴碰撞、液滴热壁碰撞和液滴蒸发等基本过程都受到了影响，这些科学问题将在本研究项目中通过无网格有限点集方法（FPM）得到数值解答。FPM的优点是能够完全建模刚性和可变形的结构和流体，以及使用该方法在大变形期间的流体-结构-相互作用。因此，目前可以通过考虑单相流体来模拟湿式圆柱形车削工艺的切屑形成。 在这个研究项目中，现有的模型扩展了气相和喷雾以及它们的物理作用机制。通过使用扩展的状态方程，气相在FPM中被实现为单片数值实体。喷雾内的基本过程被认为是在拉格朗日方式实现的液滴相互作用的半经验模型。模型开发将基于详细的实验室实验。切削液及其气溶胶的多相模型用于数值研究加工过程中的作用机制。为了实现这一目标，在项目周期1内开发了切削液及其作用机制的蒸发模型。在下一个项目周期2中，这些模型被集成到切割模拟中，以分析切割过程中的蒸发机制。此外，切削液的模型通过喷雾阶段进行了扩展，以用于项目周期3中的MQL应用。这些发展用于提高对切削液的普遍理解，以及冷却策略洪水冷却，高压冷却和MQL的生态和经济优化。

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.