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1、RESEARCH ARTICLES CURRENT SCIENCE, VOL. 90, NO. 11, 10 JUNE 2006 1480 *For correspondence. (e-mail: aozalpuludag.edu.tr) Optimum surface profile design and performance evaluation of inclined slider bearings A. A. Ozalp* and H. Umur Uludag University, Mechanical Engineering Department, 16059, Gorukle
2、 Bursa, Turkey The aim of the present optimization study is to propose an innovative surface profile design by implementing a wavy form on the upper surface, without varying the physical limits of the complete slider-bearing struc- ture. Differential equations governing the fluid-film mass, Reynolds
3、 and energy equations, are solved simul- taneously by the iterative transfer matrix approach, which also takes into account the streamwise decrease of lubricant viscosity. Computations indicated that friction coefficient values decrease with wave amplitude in pad inclination ranges of 03.77 , 3.34.1
4、7 and 3.94.22 for inlet/exit pressure ratios of 1.01, 3.01 and 5.01 respectively. Wave number is determined to augment the complete pressure distribution inside the bearing and optimum wave number is evaluated as 25 for pressure management. Keywords: Performance optimization, slider-bearing, wavines
5、s. WITH extensive applications of slider-bearings in mechani- cal devices, investigations associated with their design and performance optimization have been given privilege. The present industrial needs cover increased load capacity, lowered friction and power consumption and creative de- signs, wh
6、ich in return contribute to considerable progress in computer-aided modelling1 of slider-bearing lubrica- tion. Analysis on sliding surface definitions is important in predicting the system responses, where application of a wavy pattern to the flow surfaces is a new approach and complicates the nume
7、rical-lubrication simulations, as the waviness is defined by two independent variables: ampli- tude and wavelength. A few studies have concentrated on the effects of surface waviness on the lubrication process numerically. A numerical model that takes the sources of nonlinearities, such as surface w
8、aviness into account for ball-bearing applications, was developed by Harsha et al.2. Rasheed3 considered the influence of waviness on cylindrical sliding element and proposed a critical wave number range of 19 for improved operating conditions. Sottomayor et al.4 studied roller bearings for various
9、waviness amplitude values and recorded augmented friction coefficients in higher amplitude cases. van Ostayen et al.5 investigated the performance of a hydro-support with random waviness and Honchi et al.6 applied a micro-waviness model to an air slider-bearing. Kwan and Post7 evaluated augmented lo
10、ad values of aerostatic bearings with higher wave amplitudes, whereas Ai et al.8 showed that the lubricant film thick- ness decreased with waviness in journal-bearings. Journal bearings were also studied by Mehenny and Taylor9, who found that the maximum pressure increased with wave num- ber, wherea
11、s the numerical model for journal-bearing sys- tems of Liu et al.10 did not converge efficiently for waviness amplitudes above 6 m. Performance predictions of the lubrication process under various boundary and geometric conditions have also been considered. Naduvinamani et al.11 investigated sur- fa
12、ce roughness effects on the load carrying capacity. Lin12, and Karkoub and Elkamel13 inspected the geometric in- fluences on the load values. Effects of input pressure on the work and friction characteristics have been numerically evaluated14,15. Kumar et al.16 performed a numerical study on the sur
13、face roughness effects on elastohydrodynamic lubrication of rolling line contacts. Watanabe et al.17 pre- dicted the influence of structural design features on the frictional characteristics of microgrooved bearings. Lu- bricant flow rate is a major design consideration studied by Luong et al.18, bo
14、th numerically and experimentally for thrust-bearing applications, and by Tian19, numerically for porous bearings. Hargreaves and Elgezawy20 worked on the upper surface discontinuities and so occurring pressure variations in slider-bearings. Non-Newtonian character of the lubricant has a considerabl
15、e contribution in the lubrication systems; and specifically concentric and eccentric cases have been experimentally investigated21,22. Optimization of slider-bearing lubrication is also included in the scope of numerical studies. Stokes and Symmons23 performed a multi-dimensional optimization on the
16、 plasto- hydrodynamic drawing of wires. Lin24 tried to get an optimum flow cavity for one-dimensional porous curved slider- bearing. Stability is a chief concern for system durability and safety. Instabilities based on pressure perturbations and geometric definitions have been investigated2527. Lubricant viscosity is known to vary significantly with temperature. However, numerical studies on waviness and performance
