Experimental Study of Converging Ferrofluid Seal With Small Clearance and Double Magnetic Sources

To improve the pressure capability of ferrofluid seals with small clearance, a converging ferrofluid seal with double magnetic sources was designed. The magnetic field distribution in the clearances of the converging ferrofluid seal was studied by employing the finite-element method, and the theoretical pressure capability of the seal is calculated. The effects of ferrofluid injection volume, radial clearance, axial clearance, and the numbers of radial pole teeth and axial pole teeth on the pressure capabilities of converging ferrofluid seal device were investigated by experimental methods and compared with the experimental pressure capability of the stepless ferrofluid seal. The results show that the experimental and theoretical pressure capabilities of the converging ferrofluid seal are in good agreement. The saturated ferrofluid injection volume of the converging ferrofluid seal device is 1 mL. The experimental pressure capability of the converging ferrofluid seal does not decrease with increasing clearance or decreasing number of pole teeth. The pressure capability of the converging ferrofluid seal is related not only to the size of the clearance but also to the number of pole teeth. The pressure capability of the converging ferrofluid seal is better than that of the stepless ferrofluid seal.