EFFECT OF AMBIENT PRESSURE ON VIBRATING-MESH ULTRA-SONIC ATOMIZATION FOR MQL APPLICATIONS

This paper demonstrates the effect of ambient pressure on the ultra-sonic atomization for a minimum quantity lubrication lubricant with kinematic viscosity of 8.9 centistokes. The oil contacted a 113 kHz-actuator using a “fibre liquid delivery column”-configuration. The assembly was installed in a closed-off chamber with gauge pressure incrementally brought up to 0.5 MPa. The influence of pressure was observed for both mist atomization rate and droplet volumetric mean diameter. A five-fold increase of pressure lowered the atomization rate from 20.7 to 10.6 ml/h, also decreasing droplet diameter from 12.5 to 6.42 µm. The significance of airflow was additionally verified by implementing an atmospheric flow rate of 0.5 L/s, maintaining chamber pressure. The atomization rate and droplet diameter at 0.5 MPa went down to 9.00 ml/h and 4.53 µm, respectively, indicating an only minor impact. These measurement results show that ultra-sonic atomization can be effectively employed for minimum quantity lubrication systems with a pressurized oil-mist chamber.