Fanghui Shi

Bio: Fanghui Shi is an academic researcher from Florida International University. The author has contributed to research in topics: Bearing (mechanical) & Lubrication. The author has an hindex of 7, co-authored 7 publications receiving 343 citations.

A Mixed-TEHD Model for Journal-Bearing Conformal Contacts—Part I: Model Formulation and Approximation of Heat Transfer Considering Asperity Contact

Abstract: A mixed- TEHD (thermal elastohydrodynamic) model was developed for journal bearings working at large eccentricity ratios in order to facilitate a better understanding of mixed-lubrication phenomena for conformal-contact elements. The model consists of a mixed-lubrication process that considers the roughness effect and asperity contact, a thermal process for temperature analyses, and a thermal-elastic process for deformation calculations. In this model, the interactive journal, lubricant, and bearing were treated as an integrated system. Finite-element, finite-difference, and influence-function methods were utilized in the numerical process. The overall solution was achieved by the iteration method. Analyses of a simulated bearing-lubricant-journal system working under mixed-lubrication conditions were conducted, and the influence of the changes of lubricant flows as a result of the asperity contact on the system heat transfer and temperature distributions was numerically investigated.

A Mixed-TEHD Model for Journal-Bearing Conformal Contact—Part II: Contact, Film Thickness, and Performance Analyses

Abstract: Investigation of the mixed lubrication of journal-bearing conformal contacts is very important for failure prevention and design improvement. This paper studies the asperity contact in heavily loaded journal bearings with Lee and Ren's asperity contact theory in a newly developed mixed-TEHD (Thermal Elasto-Hydro-Dynamic) model and analyzes the performance of simulated journal bearings under high eccentricity ratios. The effects of operating conditions, bearing structures, and thermal conditions on the contact severity were numerically investigated. The results indicate that the asperity contact pressure and the performance of journal bearings in the mixed lubrication are strongly affected by the geometric design and the thermal-elastic deformations. The heat transfer of the bearing-lubricant-journal system was also shown to play a role.

A Mixed-Lubrication Study of Journal Bearing Conformal Contacts

Abstract: Numerical analyses of finite journal bearings operating with large eccentricity ratios were conducted to better understand the mixed lubrication phenomena in conformal contacts. The average Reynolds equation derived by Patir and Cheng was utilized in the lubrication analysis. The influence function, calculated numerically using the finite element method, was employed to compute the bearing deformation. The effects of bearing surface roughness were incorporated in the present analysis for the calculations of the asperity contact pressure and the asperity contact area. The numerical solutions of the hydrodynamic and asperity contact pressures, lubricant film thickness, and asperity contact area were evaluated based on a simulated bearing-journal geometry. The calculations revealed that the asperity contact pressure may vary significantly along both the width and the circumferential directions. It was also shown that the asperity contacts and the lubricant film thickness were strongly dependent on the bearing width, asperity orientation, and operating conditions.

The Stribeck Curve: Experimental Results and Theoretical Prediction

Abstract: The Stribeck curve plays an important role in identifying boundary, mixed, elastohydrodynamic, and hydrodynamic lubrication regimes. Recent advances in elastohydrodynamic lubrication together with rough surface interaction have made it possible to develop a methodology for predicting the trend of the Stribeck curve. In this paper; we report the results of a series of experiments performed on a journal bearing together with a theoretical prediction of the Stribeck-type behavior. Various loads and oil temperatures are considered. The comparison between the experimental results with a mixed elastohydrodynamic lubrication model for line contacts is indicative of good agreement.

A Mixed-TEHD Model for Journal-Bearing Conformal Contacts—Part I: Model Formulation and Approximation of Heat Transfer Considering Asperity Contact

Abstract: A mixed- TEHD (thermal elastohydrodynamic) model was developed for journal bearings working at large eccentricity ratios in order to facilitate a better understanding of mixed-lubrication phenomena for conformal-contact elements. The model consists of a mixed-lubrication process that considers the roughness effect and asperity contact, a thermal process for temperature analyses, and a thermal-elastic process for deformation calculations. In this model, the interactive journal, lubricant, and bearing were treated as an integrated system. Finite-element, finite-difference, and influence-function methods were utilized in the numerical process. The overall solution was achieved by the iteration method. Analyses of a simulated bearing-lubricant-journal system working under mixed-lubrication conditions were conducted, and the influence of the changes of lubricant flows as a result of the asperity contact on the system heat transfer and temperature distributions was numerically investigated.