A CFD Investigation of Cutting Fluid Mist Formation Via Atomization
 
 
 

Yeow-Khern Siow | MS | 2000

ABSTRACT:

Cutting fluid mist produced during machining operations is receiving increased attention by industry because of its adverse health effects. Every year, millions of machine shop workers are exposed to cutting fluid mist, and an increasing number of reports on the related workplace illness are filed.
The purpose of this research is to observe the cutting fluid's general behavior when it impinges on a solid surface, in order to achieve a better understanding of the mechanisms that underlie mist formation. This knowledge can, in the later stages of this research, be used as a tool to design machining processes, systems, and control strategies that will help reduce the formation of cutting fluid mist and hence, the health hazard to which workers are exposed.
 

The numerical study is performed using the RIPPLE computer code developed at the Los Alamos National Laboratory (LANL). A high-resolution, two-dimensional, symmetric Total Variation Diminishing (TVD) scheme is incorporated into the code, and it replaces the original van Leer scheme in the momentum advection calculations. The TVD scheme improves the code's capability to capture large distortions on the free surfaces of the fluid, as well as the large velocity gradients and discontinuities that are present in such relatively high-speed two-phase flow.

An experiment was conducted to provide a series of images as a photographic validation for the numerical results. Three machining process variables were considered in this study, namely, the cutting fluid jet speed, the moving plate speed, and the nozzle height measured from the flat plate. The results from the TVD calculations are in better agreement with the images than the van Leer predictions. The TVD scheme is able to resolve free surface deformations that are consistent with the images. The overall results also suggest that nozzle height plays the most significant role in the onset of droplet breakups in the case of slow-moving workpiece surfaces.

If you have any comments or suggestions please e-mail jwsuther@mtu.edu.