Coordinated improvement effects of the wing-shaped texture on the bearing load-carrying capacity and stability performance of rotor-bearing systems

As critical components of modern rotating machinery, journal bearings face two major challenges: oil-film whirl/whip under light loads and insufficient load-carrying capacity (LCC) under heavy loads. To achieve coordinated improvements in both metrics under general operating conditions, this study designs a wing-shaped textured journal bearing based on our previous work and establishes an evaluation framework that integrates LCC and stability. A three-dimensional multiphase computational fluid dynamics model with the structured dynamic mesh is constructed to resolve the flow field, and dynamic characteristic coefficients are identified via the multi-frequency perturbation method. The influence of the wing-shaped texture on LCC and stability is systematically assessed across operating conditions. Results show that the leading edge geometry enlarges the contact area exposed to the incoming flow, while the trailing edge promotes downstream lubricant convergence. Under heavy loads, the resulting micro-hydrodynamic pressure enhances LCC more effectively than circle and triangle textures. Under light loads, vortices induced from the wingtips and tail substantially increase oil-film damping. Texture depth and placement are also two decisive factors. Positioning the texture in the converging wedge with the dimensionless depth h* = 1.0 yields the optimal synergistic improvements: an 18.5% increase in LCC and a 21.9% increase in stability threshold speed. A finite-element case study on a 1000 MW low-pressure steam turbine corroborates these findings: the wing-shaped textured bearing raises the system's stability threshold by 500 rpm, increases the logarithmic decrement by up to 4.62 times when the rotational speed n = 4000 rpm. It yields a maximum increase in oil-film thickness of 64.2 µm, while LCC gains diminish with increasing speed. Campbell diagram and unbalance response analyses further corroborate the gains in critical speed margin and vibration attenuation.