Effects of blade tip clearance on the aerodynamic characteristics and condensation mechanism of internal non-equilibrium condensing flow in vapor centrifugal compressor

In this paper, the effect of blade tip clearance (BTC) variation on the non-equilibrium condensation mechanism of vapor in a centrifugal compressor is numerically investigated. The Kantrowitz non-isothermal modified nucleation model is proposed. The predictions of aerodynamic characteristics and condensation mechanisms are systematically performed using a modified homogeneous nucleation theory. The modified condensation prediction model is further validated within the nozzle, and the results are shown to be in good agreement with previously published experimental data. Additionally, aerodynamic characteristics and condensation mechanisms are comprehensively compared across centrifugal compressors with different BTCs. It is observed that fluid structure disturbance is progressively exacerbated and energy losses are significantly intensified with increasing BTC. Meanwhile, the quantitative relationship is also established between average particle diameter and mass flow rate. It is obtained that the average droplet number gradually increases with the increase in BTC, while the growth rate is slow. Surprisingly, it is found that with the increase in mass flow rate, the growth rate of average droplet number is significantly accelerated with the increase in the width of BTC.