Hydrodynamic film lubrication

11062016, 12:04 PM
(This post was last modified: 11062016 04:28 PM by Ángel Martin.)
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Hydrodynamic film lubrication
Hydraulic Film lubrication. [ PMICHEL ]
From the author’s Engineering Collection, included in the ETSII4 module (ETI4 on the CL Library) This program calculates the required flow Q and front edge thickness (b1) on a film lubrication inclined pad with a perpendicular load F and moving at a uniform speed U0. The geometric data required may be either the slope angle (beta) or the thickness of the oil film at the lower end (b2). tan(beta) = (b1b2)/L The formula for the radial force is a nonexplicit equation on b1, the thickness of the front edge of the fluid film. This can be resolved with a rootfinder routine like SLV, also included in the module. The expression is given below, where mu is the fluid viscosity: Fr = [2 mu U0 L / (b1b2)] [ 2 Ln (b1/b2) – 3 (b1b2)/(b1+b2) ] And the flow required: Q = U0 b1b2 / (b1+b2) Examples. Calculate Q and b1 for a Michell pad moving at 15 m/s and bearing a perpendicular load of 200,000. The geometric parameters of the pad are 0.2 m deep x 0.4 m long, and the tapper slop is 0.0573 deg. The fluid viscosity is mu = 0.01 N/s m^2 The solutions are shown below: GEOMETRY: b1=99,327E6 m b2=59,327E6 m L=0,4000 m SLOPE<)=0,0001 rad WORK DATA: mu=0,0100 N/s m^2 U0=15,0000 m/s F=1.000.000,000 N FR=823,0323 N Q=0,0006 m^3/s 

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