Both foil structure and surface texturing have been widely used to improve bearing performance. However, there is little research on their combination, namely, textured gas foil bearing. This paper adopts the Reynolds equation as the pressure governing equation of bump-type foil journal bearing to study the influence of textures located on the top foil. The Newton-Raphson iterative method and the perturbation method are employed to obtain static and dynamic characteristics, respectively. Thereafter, based on three texture distribution types, further analysis about the effect of the relative texture depth and the textured portion is carried out. The results indicate that an appropriate arrangement of textures could improve the performance of gas foil bearing. For #1 texture distribution, the maximum increment of load capacity could exceed 10% when ω  =  1.4 × 105 r/min, ε  =  0.2.

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This paper focuses on the flow and thermal characteristics of the lubricant film in the micro clearance of a hydrodynamic journal bearing (HJB) at high rotating speed. A thermohydrodynamic (THD) method consists of the Reynolds equation coupled with energy and viscosity-temperature equation with considering the cavitation is put forward. The 3D surface diagrams of the lubricant film thickness, pressure, temperature, liquid mass fraction, flow rate and heat dissipation distributions under different geometric, operating, slip and no-slip boundary conditions are systemically exhibited and analyzed. The results show that with the rise of eccentricity or length diameter ratio, the maximum peaks of pressure, temperature and heat dissipation are rapidly increased, the cavitation is aggravated, and the flow rate is accelerated in different extent. As the bearing speed accelerating, the maximum peak of temperature is strongly increased, whereas, the distinction between peaks of flow rate and heat dissipation is magnified and reduced, respectively. It provides a fruitful inside view of the inner flow and thermal characterizations of HJB for further understanding its flow-thermal interaction mechanisms and offers theoretical support for improving its working performance.

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For such a specific object as asphalt pavement with inconspicuous feature points, the traditional image vision algorithm has limited effect on its texture measurement. In order to realize the high-resolution, high-precision, and convenient detection of three-dimensional (3D) pavement texture while better serving traffic safety, the traditional binocular reconstruction technology was improved in this study threefold. First, the improved binocular reconstruction test system and the measurement accuracy evaluation device were manufactured to realize the reconstruction of the 3D texture and the true point-to-point evaluation of measurement accuracy. Second, the global scanning constraint posed by a moving laser line was introduced to shoot video images, which formed numerous mandatory constraints and improved the matching accuracy. Last, the centroid enhanced subregion segmentation algorithm was proposed to complete stereo matching under global scanning constraint. Results show that the binocular reconstruction algorithm improved by moving a laser line constraint under a centroid enhanced subregion segmentation matching mode can significantly improve the accuracy in the measurement of asphalt pavement 3D texture. Ultimately, the test results can meet the precision requirement of micro-texture.