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Unformatted text preview: Chapter 6 Fundamentals of Convection 640 The oil in a journal bearing is considered. The velocity and temperature distributions, the maximum temperature, the rate of heat transfer, and the mechanical power wasted in oil are to be determined. Assumptions 1 Steady operating conditions exist. 2 Oil is an incompressible substance with constant properties. 3 Body forces such as gravity are negligible. Properties The properties of oil at 50 ° C are given to be k = 0.17 W/mK and μ = 0.05 Ns/m 2 Analysis ( a ) Oil flow in journal bearing can be approximated as parallel flow between two large plates with one plate moving and the other stationary. We take the xaxis to be the flow direction, and y to be the normal direction. This is parallel flow between two plates, and thus v = 0. Then the continuity equation reduces to Continuity : = ∂ ∂ + ∂ ∂ y v x u ⎯→ = ∂ ∂ x u ⎯→ u = u ( y ) Therefore, the x component of velocity does not change in the flow direction (i.e., the velocity profile remains in the flow direction (i....
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This note was uploaded on 01/22/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.
 Fall '10
 Dr.DanielArenas
 Thermodynamics, Convection, Mass, Power, Heat

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