Influence of Screw Shaft Inclination on Sealing Performance of Viscoseal

Abstract

The effects of the screw inclination on the sealing performance of a viscoseal, which is a type of noncontact seal, are described. The experimental sealing performance, determined by the seal coefficient, which is based on the Euler number, the clearance Reynolds number and ratio of the radial clearance to the screw length, is generally inferior to the theoretical results when the viscoseals are horizontal. The sealing pressure in the working fluid is closely related to the resultant force, which is based on not only the pressurized force but also gravity and the centrifugal force. The resultant force is simulated under the assumption that these three types of forces are employed and is compared with the experimental results. The simulated circumferential pressure distribution is found to be eccentric and qualitatively similar to the experimental results. Also, the inferiority of the sealing performance seems to be based on the decrease in the pressurized force which is caused by the eccentricity of the pressure distribution. The corrected sealing performance, which is simulated by taking into account the resultant force based on these forces are in good agreement with the experimental results.