Improvement of the design of radial lobe bearing on gas lubrication and development of the corresponding calculation software system

Abstract

BACKGROUND: With the increase in rotation speeds of turbomachinery shafts, particularly for aviation and space applications due to the requirements for compactness and mass reduction, the issue of bearing life becomes relevant. For such devices, it is promising to use gas lubricated petal bearings (GLPB), which do not require additional systems and operate on the gas of the turbomachine working flow with excellent damping characteristics. Despite the attractiveness of GLPB designs, they are difficult to calculate because the direct work is performed by a thin layer of gas instead of balls, as in classical bearings. The efficiency of a GLPB depends directly on its design, especially the shape of the lobes and the amount of clearance between the shaft and the lobe. AIM: To develop a mathematical model of the operation of a gas lubricated lobe bearing to determine the pressure distribution across the lobe surface and the corresponding computer program for calculations. METHODS: Computational modeling of radial GLPB operation is accomplished with the determination of pressure in the lubrication layer. Moreover, its corresponding integral characteristics within the Reynolds model and the equation for the height of the lubrication layer under several assumptions are determined. RESULTS: In this research, a computer program has been developed that allows for automated calculation of the space of change of variables and functions, the layout of a single table and output, construction of a volumetric model for its subsequent use in CAD systems, and generation of pressure graphs. Herein, the calculation of each variant is faster than similar calculations in the MathCAD environment. The same convenience consists of the block structure of the program, the visual setting of interrelations between blocks, and various and understandable outputs, suitable for both the report (construction of graphs) and drawings and visualization. CONCLUSION: A specialized software package for parametric optimization of gas dynamic characteristics of GLPB has been developed. The developed tool permits the calculation of several cases and facilitates the selection of the optimal gap shape based on numerous proposed criteria. Among other things, the calculation allows us to see the variations in a different operating mode of the plant, use of a different substance with different dimensions, and choose the optimum that will suit a particular plant. Moreover, it is possible to expand the limits of applicability of petal bearings, such as at low speeds or large diameters.