Manufacturing Technology Today

M. L. N. Sarma ¹, G. Jaya Chandra Reddy ², K. Rama Krishna Prasad ¹

Affiliations
1 Dept. of Mathematics, S. V. University, Tirupati, IN
2 Y. S. R. Engg. College of Yogi Vemana University, Proddatur, IN

Abstract

Hydrodynamic journal bearing with circular cross section when used in high speed rotating machinery such as Turbines, Compressors, Pumps, Engine cranks and Large Milling systems, etc., often face the problem of instability. In such high speed machinery non-circular bearings are widely used to support the oil whirl. The present paper focuses on one of the non-circular bearings called Spiral Bearing. It is also well known that additives are added to the base lubricant to improve its lubricating properties. If additives are in the form of particles at low concentration a micro polar fluid may characterized the resulting fluid. Based on the micro polar theory a theoretical analysis on the load carrying capacity of finite spiral bearing operating with micro polar fluid is presented. The modified Reynolds Equation is obtained based on the theory of micro polar fluids. The film pressure distribution equation is numerically solved by using Finite Difference Technique. According to the results the micro polar effects exhibit increase in load carrying capacity. The spiral bearing is having more load carrying capacity than circular bearing.

Keywords

Hydrodynamic Journal Bearing, Spiral Bearing, Micro Polar Fluid and Static Characteristic.

Full Text

     

G. Jaya Chandra Reddy ¹, C. Eswara Reddy ², K. Rama Krishna Prasad ²

Affiliations
1 K. S. R. M. College of Engg., Kadapa, IN
2 S. V. U. College of Engg., Tirupati, IN

Abstract

Porous bearings have an advantage over conventional sleeve bearings, in which no external supply of lubricant is necessary for their satisfactory operation for long periods. These can operate as self-acting bearings; squeeze film bearings or externally pressurized bearings. Squeeze film is a phenomenon of two lubricated surfaces approaching each other with a normal velocity. The thin film of lubricant between the two surfaces acts as a cushion and prevents the surfaces making instantaneous contact. Generally, the pressure distribution in this fluid film is determined by using numerical methods. In the present analysis, a modified Reynolds equation has been developed by combining the Reynolds equation and the Laplace equation for the finite porous squeeze film bearing. The load carrying capacity is studied by solving this modified Reynolds equation using Rapid Technique. The results are shown graphically for selected parameter values. The results indicate, as the L/D ratio, and or eccentricity ratio increases, load carrying capacity increases but as the permeability parameter increases load carrying capacity decreases. For highly porous bearings, the squeezing effects are not significant. The obtained results are compared with the short bearing and solid bearing analysis.

Full Text