Effect and correction of turbulence coefficient on performance calculation of aerostatic thrust bearing lubricated by supercritical CO2

In this article, the flow field and bearing performance of aerostatic thrust bearing (ATB) lubricated by supercritical CO2 (ATB-SCO2) are analyzed by solving the Reynolds equation with the laminar model and four turbulence models (Hirs model, Ng–Pan model, Constantinescu model, and Elrod–Ng model) through the finite difference method. The calculation accuracy and efficiency of ATB-SCO2 performance under different flow and CO2 models are discussed. Furthermore, the turbulence coefficient is corrected by analyzing the influences of empirical coefficient and empirical exponent on the calculation results of ATB-SCO2 performance. The turbulence models with turbulence coefficients increase the pressure and Reynolds number but decrease the velocity in the lubricating film. The ideal gas assumption shows the same effect (i.e., an increase) on pressure but opposite effects (i.e., an increase) on Reynolds number and velocity. Moreover, both turbulence models with turbulence coefficients and ideal gas assumption increase the bearing load capacity and stiffness but reduce the mass flow rate. Compared to Elrod–Ng model, the calculation adopting laminar model, Hirs model, Ng–Pan model, and Constantinescu model are less accurate but more efficient. The accuracy using the model with corrected turbulence coefficient improves by 86.02%, 82.03%, and 79.56% compared to Hirs model, Ng–Pan model, and Constantinescu model, respectively, and the calculation time reduces by 92.56% compared to Elrod–Ng model. The corrected turbulence coefficient is further verified by the performance calculation of ATB-SCO2 at eight working conditions.