To obtain a longer longevity of control momentum gyroscopes in spacecraft

a positive-feed on-demand lubricating system was proposed.The system consists of an oil container and a piezoelectric lubricating device based on drop on demand technology.To solve the interface movements with continuing topology changes during the ejection process

volume-of-fluid method along with the piecewise linear interface construction technique was implemented to describe the interfacial movements.A computational approach based on VOF(volume of fluid) method was applied to analyze the ejection process of lubricating oil droplet.In simulations

the ejection process of lubricating oil was examined by varying diameter of nozzle and temperature in the aerospace.The experimental results show that it is difficult to form droplet with larger nozzle

and the variety of space temperature has impact on the lubricating oil droplet velocity

but little effect on the formation time.