Abstract:In order to further understand the stiffness characteristics of the aerostatic gas lubricating mechanical seal, an analytical expression of the gas film stiffness was deduced based on analytical method. The calculated results by the analytical expression are very close to the results obtained by differentiating the opening force curve-fitting equation. The gas film stiffness characteristics influenced by the orifice diameter, supplying gas pressure and process gas pressure had been analyzed by the analy-tical expression, and the 3D surface charts of the gas film stiffness influenced by gas film thickness and the supplying gas pressure or the process gas pressure had been obtained. The results show that the effect of orifice diameter on the stiffness is obvious and larger stiffness can be got when the orifice dia-meter is about 0.2 mm as to the seal investigated. The gas film stiffness increases with increasing of supplying gas pressure or boundary pressure ratio of the supplying gas pressure over the process gas pressure. Raising the supplying gas pressure or boundary pressure ratio can obviously increase the gas film stiffness. The gas film stiffness is increasing firstly and then reducing with the increasing of gas film thickness at the specific pressure or pressure ratio. There is maximum gas film stiffness as the gas film thickness reaches a certain value. The gas film stiffness will be larger when the gas film thickness is 3-6 μm as to the dry gas seal investigated.
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