均匀磁场中铁磁流体润滑的轴颈轴承
Performance of Ferrofluid Lubricated Journal Bearing
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摘要: 当均匀外加磁场强度从0增加到 0.12 MA/m时, 在高剪切速率下铁磁流体润滑膜的承载能力提高25%,而在低剪切速率下, 承载能力可提高 35%。所以, 从实用的观点来看, 铁磁流体润滑是为了利用外磁场来调节轴承的承载性能, 而不是为了获得高承载力。为了避免轴承承载能力受到限制, 需要将铁磁流体密封与润滑膜分离开来。分析表明均匀磁场和剪切速率对姿态角的影响甚为微小。Abstract: 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.
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Key words:
- ferromagnetic flow lubrication /
- magnetic field /
- bearings /
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