Numerical simulation of Oleo-pneumatic Two-phase flow in variable shock absorber

Abstract

In the actual operation of landing gear oil-pneumatic shock absorber, there is a complex gas-liquid two-phase flow problem inside the shock absorber. In this paper, a simplified model of a metering pin variable damping orifice shock absorber is established, and the compression process of the shock absorber is simulated numerically based on CFD method combined with dynamic mesh technology to study the gas-liquid two-phase flow characteristics and the change of oil damping force. The results show that the oil flows out of the damping orifice into the nitrogen cavity in the form of turbulent jet, and the oil and gas phases are mixed and entrained, and the presence of the metering pin significantly affects the flow pattern and flow field structure of the two phases; the damping force increases continuously during the time period of 0-0.02s, and decreases slightly in the late compression period, and the different initial inflation pressures of the nitrogen cavity have little effect on the change of damping force.