A full inertia effect model for open-ends squeeze film damper including free air entrainment and validation with experiments

This work further extends the compressible Reynolds equation by including the advection inertia effect, refining the theoretical model of the open-ends squeeze film damper (SFD) with free air entrainment. A comprehensive numerical analysis method addresses the feed-port and groove, using a bubble mixture model to estimate the reference gas volume fraction iteratively. A comparison with the force coefficients experimental results of an open-ends SFD in literature verifies the model and method in this paper. Finally, an SFD with a journal diameter of 235 mm and a film land length of 25 mm is subjected to dynamic load tests with unilateral excitation amplitudes ranging from 15 μm to 30 μm (with clearance of 220 μm) at a frequency of 100 Hz. Numerical predictions are presented using the proposed model and methodology, considering the full inertia effect (temporal and advection inertia) and free air entrainment. Based on the orbital analysis method, the tested displacement response signals are filtered and reshaped to accurately reproduce the experimental journal orbital path and improve the accuracy of the numerical prediction. The results show that, within the range of small to moderate excitation amplitudes, the inertia and damping coefficients slightly decrease as the excitation amplitude increases. The estimated gas volume fraction gradually rises with the excitation amplitude, indicating increased free air ingestion, likely contributing to the decrease in force coefficients. The numerical predictions agree well with the experimental results, inspiring further research on SFDs.