Ejecting performance simulation of an innovative piezoelectric actuated lubrication generator for space mechanisms

A novel lubrication generator combing piezoelectric drop-on-demand (DOD) oil-jet technology is proposed for space mechanisms. A finite difference numerical model was established to analyze the design parameters of droplet ejection. The volume-of-fluid piecewise linear-interface construction (VOF-PLIC) interface-capturing method was adopted to represent the fluid domain and to track the evolution of its free boundaries whereas the continuous surface force (CSF) mode was chosen to model the interfacial physics. To explore the practicability of the proposed new lubrication generator, the flow behavior during the stages of fluid ejection and droplet formation are examined with Krytox 143AB lubricant as the baseline test fluid for a ejection cycle of 100 μs. To improve the droplet ejecting performance of lubricant, the characters of inject flow part have been investigated with the variation of the pulse voltage for different spatial temperature. Injection process in the extra-low pressure is also investigated. The developed model helps to understand the drop formation process and this approach can be applied in various inject head designs.