tailieunhanh - Engineering Tribology 2E Episode 6

Tham khảo tài liệu 'engineering tribology 2e episode 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 5 COMPUTATIONAL HYDRODYNAMICS INTRODUCTION The differential equations which arose from the theories of Reynolds and later workers rapidly exceeded the capacity of analytical solution. For many years some heroic attempts were made to solve these equations using specialized and obscure mathematical functions but this process was tedious and the range of solutions was limited. A gap or discrepancy always existed between what was required in the engineering solutions to hydrodynamic problems and the solutions available. Before numerical methods were developed analogue methods such as electrically conductive paper were experimented with as a means of determining hydrodynamic pressure fields. These methods became largely obsolete with the advancement of numerical methods to solve differential equations. This change radically affected the general understanding and approach to hydrodynamic lubrication and other subjects . heat transfer. It is now possible to incorporate in the numerical analysis of the bearing common features such as heat transfer from a bearing to its housing. The application of traditional analytical methods would require to assume that the bearing is either isothermal or adiabatic. Numerical solutions to hydrodynamic lubrication problems can now satisfy most engineering requirements for prediction of bearing characteristics and improvements in the quality of prediction continue to be found. In engineering practice problems like what is the maximum size of the groove to reduce friction before lubricant leakage becomes excessive or how does bending of the pad affect the load capacity of a bearing need to be solved. In this chapter the application of numerical analysis to problems encountered in hydrodynamic lubrication is described. A popular numerical technique the finite difference method is introduced and its application to the analysis of hydrodynamic lubrication is demonstrated. The steps necessary to obtain solutions for different bearing .