Performance of Ferrofluid Lubricated Journal Bearing

The load carrying capacity of the ferrofluid lubricating films can be increased directly by means of the applied magnetic field.The ferrofluid behaves simultaneously as a Binghamoplastic and as a pseudoplastic.The constitutive equations of the ferrofluid can be expressed as τ(H,D)=τ s(H)+η 1(H)D+η 2(H)D 2 .When the uniform applied magnetic field intensity increases from zero to 0.12 MA/m,the load carrying capacity of ferrofluid lubricating film is enhanced by 25 per cent under the condition of high shear rate and by 35 per cent under the condition of low shear rate.So for practical purpose,the ferrofluid lubrication is used to control load carrying capacity by applied magnetic field,but not to obtain high load carrying capacity.It is necessary to make the ferrofluid seal separate from lubricating film in order to avoid restrictions on the load carrying capacity of journal bearing.The calculated results show that the uniform applied magnetic field intensity and the shear rate have little effect on the attitude angle.