A study on building and testing fractal model for predicting end face wear of Aeroengine's floating ring seal

The graphite floating ring is a key sealing element of the turbopump of aeroengines. Its wear induced by frequent flotation during its operation can result in stress concentration and microscopic cracks in its seal end face, more leakage from its sealing surface, a lower engine efficiency, and even serious safety concerns. However, there are currently no published studies regarding the modeling of the end face wear of the floating ring seal. This work presents a new fractal model for predicting the wear rate and wear evolution of the end face of the floating ring seal. Firstly, a new normal fractal contact model was implemented by microscopically considering the defor-mation mechanism, interaction forces, and flash points of the asperities on the end face of the floating ring. On this basis, a fractal model was built to predict the wear of the end face of the floating ring according to its wear mechanism and the corrected Archard theory. The wear rates predicted according to this model are in good agreement with the test results. The simulation results show that (i) the depth wear rate of the end face of the floating ring first decreases and then increases as the fractal dimension D increases (the minimum is reached when the fractal dimension ranges from 1.60 to 1.725); (ii) the depth wear rate of the end face of the floating ring increases as the characteristic scale G, friction factor f, floatation speed of the floating ring v, and end face pressure P increase; (iii) the impact of the end face pressure on the depth wear rate is minimum when the fractal dimension ranges from 1.60 to 1.65; (iv) the flotation displacement of the floating ring cannot exceed 12 & mu;m when the engine speed is higher than 30,000 r/min.