Determining Local Distribution of Convective Heat Transfer Coefficients on the Tool during Orthogonal Cutting - Supplementary Dataset

Particularly during machining, large heat sources and thus high temperature gradients and mechanical stress occur in the cutting zone. By using cutting fluids, part of the heat generated can be dissipated, thereby reducing local temperatures. In order to quantify the cooling efficiency of the cutting fluid, the flow behavior of the cutting fluid in vicinity of the cutting zone must be determined to derive the resulting convective heat transfer coefficients at the tool. The geometries, temperature fields as well as the heat sources resulting during the machining process are extracted from a chip formation simulation using FEM and used to set up a three-dimensional CFD flow simulation. This work investigates the local distribution of the convective heat transfer coefficient as a function of the flow boundary conditions, specifically evaluating the effects of Reynolds number, injection angle, and nozzle radius. Simulation results reveal that the distribution of the convective heat transfer coefficient on the tool rake face can be divided into three distinct regions: The impingement zone where the impinging jet first strikes, the deflection zone near the chip where the flow sharply redirects, and the boundary layer zone covering the remaining surface. A geometric function is derived to describe the position and extent of each of these areas. In addition, the mean convective heat transfer coefficient can be determined for each of the regions using a Nusselt correlation based on the flow parameters. These correlations allow for simplified determination of the local convective heat transfer coefficient on the tool.

尤其在机械加工过程中，切削区域会产生大量热源，进而形成高温度梯度与机械应力。通过使用切削液，可消散部分产生的热量，从而降低局部温度。为量化切削液的冷却效率，需确定切削区域附近切削液的流动行为，以推导刀具处的对流换热系数（convective heat transfer coefficient）。加工过程中产生的几何形状、温度场及热源，均从基于有限元法（FEM）的切屑形成模拟中提取，并用于建立三维计算流体动力学（CFD）流动模拟。本研究探讨对流换热系数的局部分布随流动边界条件的变化规律，具体评估雷诺数（Reynolds number）、喷射角度及喷嘴半径的影响。模拟结果表明，刀具前刀面上的对流换热系数分布可划分为三个明显区域：冲击射流首次撞击的冲击区、切屑附近流动急剧转向的偏转区，以及覆盖剩余表面的边界层区。推导得到一个几何函数，用于描述各区域的位置与范围。此外，基于流动参数的努塞尔特关联式（Nusselt correlation）可用于确定各区域的平均对流换热系数。这些关联式可简化刀具局部对流换热系数的确定过程。