Numerical Analyses of Static Characteristics of Liquid Annular Seals Based on 2D LBM-LES Model

Static characteristics and leakage flow rates of liquid annular seals have great influences on the hydraulic efficiency of turbomachinery. In this paper, a two-dimensional (2D) mathematical model for predicting the leakage flow rates and static characteristics of liquid seal is established, based on the lattice Boltzmann method (LBM) combined with the D2G9 velocity model for incompressible fluid and large eddy simulation (LES) turbulence model, in which the transformation equation of reference pressure is developed with the Bernoulli equation. Moreover, the proposed model is validated by comparing with the experimental results, calculation results based on the finite volume method (FVM), and the results based on the empirical method of three seals under different operating conditions. The comparisons show that the maximum deviation in leakage prediction of the calculating model based on 2D LBM is 4%, and this calculating model will effectively improve the leakage prediction accuracy of the seals compared with the FVM and theoretical method.

Investment Payback Period Calculating Model for Airport Bridge Facility

Due to the uncertainty and difficulty of estimating the investment payback period of the airport bridge facility, a model for calculating the investment payback period of bridge facility is proposed in this paper from the perspective of airport routine operation. Based on the actual operational data of Kunming Changshui Airport, Wuhan Tianhe Airport, and Lijiang Sanyi Airport in 2018, the factors influencing the payback period of bridge facility are the number of bridge facilities and service time, which have been discussed in this paper. According to the simulation, it is concluded that the number of bridge facilities and service time are the key points to the length of the investment payback period, and the annual operating cost of the airline can be saved quite a lot. The research results can be used to assist the leaders’ decision-making of airports and airlines for the promotion of the service of bridge facilities.