JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

Pre-requisites

Fluid mechanics, Design of machine members-II

Course Objectives:

• To expose the student to different types of bearings, bearing materials,
• To understand friction characteristics and power losses in journal bearings.
• To learn theory and concepts about different types of lubrication.

Course Outcomes:

• Understanding friction characteristics in journal bearings.
• Knowledge about different theories of lubrication to reduce friction and wear.

UNIT - I

Study of various parameters: Viscosity, flow of fluids, viscosity and its variation, absolute and kinematic viscosity, temperature dependent variation, viscosity index, determination of viscosity, different viscometers used. Hydrostatic lubrication: Hydrostatic step bearing, application to pivoted pad thrust bearing and other applications, hydrostatic lifts, hydrostatic squeeze films and its application to journal bearing.

UNIT - II

Hydrodynamic theory of lubrication: Various theories of lubrication, petroffs equation, Reynold’s equation in two dimensions -Effects of side leakage - Reynolds equation in three dimensions, Friction in sliding bearing, hydro-dynamic theory applied to journal bearing, minimum oil film thickness, oil whip and whirl anti -friction bearing.

UNIT - III

Friction and power losses in journal bearings: Calibration of friction loss, friction in concentric bearings, bearing moduIus, Sommer-field number, heat balance, practical considerations of journal bearing design

UNIT - IV

Air lubricated bearing: Advantages and disadvantages, application to Hydrodynamic journal bearings, hydrodynamic thrust bearings. Hydrostatic thrust bearings. Hydrostatic bearing Analysis including compressibility effect. Study of current concepts of boundary friction and dry friction.

UNIT - V

Types of bearing oil pads: Hydrostatic bearing wick oiled bearings, oil rings, pressure feed bearing, partial bearings -externally pressurized bearings. Bearing materials: General requirements of bearing materials, types of bearing materials.

TEXT BOOK:

• 1. Engineering Tribology/ Gwidon W. Stachowiak & Andrew W. Batchelor/ Elesevier
• 2. Engineering Tribology/ Prasanta Sahoo / PHI

REFERENCE BOOKS:

• 1. Tribology – B.C. Majumdar
• 2. Fundamentals of Tribology, Basu, Sen Gupta and Ahuja/PHI
• 3. Tribology in Industry: Sushil Kumar Srivatsava, S. Chand &Co.