Viscosity monitoring and control on oil-film bearing lubrication with ferrofluids

Ferrofluid application in the oil-film bearing can improve the viscosity and the load-carrying capacity in a magnetic field. A solenoid was developed to provide magnetic field for ferrofluid, using which the distribution of magnetic induction intensity was calculated. The viscosity equation of ferrofluid was derived. The effects of oil-film temperature T, oil-film pressure P and magnetic intensity H on ferrofluid viscosity [eta] sub()fwas analyzed and tested by an unifactor experiment method. The control equations and transfer functions of each variable were given based on a large-scale oil-film bearing test rig. The variations of P, T, H and [eta] sub()fwere simulated and monitored by a reasonable control strategy. The results suggest that the viscosity increment by magnetic intensity could compensate the viscosity decrement by temperature rise.