This study utilizes a dynamic mesh technology to investigate the dynamic performance of aerostatic thrust bearings with orifice restrictor, multiple restrictors, and porous restrictor. An experiment, which investigates the bearing static load capacity, was carried out to verify the calculation accuracy of dynamic mesh technology. Further, the impact of incentive amplitude, incentive frequency, axial eccentricity ratio, and non-flatness on the bearing dynamic performance was also studied. The results show incentive amplitude effect can be ignored at the condition of amplitude less than 5% film thickness, while the relationship between dynamic characteristics and incentive frequency presented a strong nonlinear relationship in the whole frequency range. The change law of dynamic stiffness and damping coefficient for porous restrictor was quite different from orifice restrictor and multiple restrictors. The bearing dynamic performance increased significantly with the growth of axial eccentricity ratio, and the surface non-flatness enhanced dynamic performance of aerostatic thrust bearings.

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For the aerostatic journal bearing with orifice-type restrictor, it is difficult to analyse the bearing performances because of the complex air film geometry. In the present work, based on the traditional engineering simplification algorithm (ESA) for bearing performances calculation, an ESA-CFD combined method is proposed by integrating ESA method with modern computational fluid dynamics (CFD) simulation technique, where both advantages of the ESA and CFD methods are retained. With this approach, both static and dynamic performances of the journal bearing can be analyzed with a high level of accuracy and low computational cost. As an example, an engineering journal bearing is considered and its performances are analyzed. The influences of bearing parameters on dynamic performances are particularly discussed, and meanwhile, the calculation accuracy is verified by conducting experiments. The proposed ESA-CFD combined method can provide an efficient way for engineering application in design of aerostatic journal bearing, especially for the design optimization.

This paper puts forward a simplified FEM based on MATLAB PDE tool to investigate the static performance of aerostatic journal bearings. The pressure distribution equation is transformed into a standard elliptic equation, the boundary conditions and coefficients of the transformed equation are also confirmed by contrasting it with the standard elliptic equation. Then the effects of bearings structural parameters and external supply pressure on the film pressure distribution, load capacity and static stiffness are studied. The film pressure distribution changes significantly with the eccentricity ratio, and an eccentricity range corresponding to the optimal stiffness is also confirmed. Finally, an experimental platform with reversal structure is applied to reduce the measurement error, the maximum relative error between the results of simulation and experimental result is 11.54%.

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