抄録
Hydraulic systems have high-power density because its oil transmitting power has high rigidity. However, when air bubbles are mixed into oil, they reduce oil stiffness and decrease system efficiency. This study mitigates this problem by removing air bubbles from the oil using an active bubble elimination device that uses a swirl flow to eliminate air bubbles from a hydraulic fluid. We focus on the relationship between the change in the density and elimination of air bubbles from the hydraulic fluid and experimentally measure the density of the hydraulic oil with and without air bubbles. A Coriolis flowmeter can directly measure mass flow and density of fluid regardless of its temperature and pressure. Therefore, it is possible to calculate simultaneously the density the fluid, from which the volume of air bubbles content in the oil can be derived. The experimental results using the Coriolis meter indicate that the oil stiffness and the system efficiency increases by eliminating the air bubbles in oil.
