Abstract
Experimental and theoretical investigations concerning a long staggered labyrinth gas seal are presented. Accurate static measurements help to assess the influence of the entry swirl, the rotational speed and the pressure difference on the conservative and the nonconservative force. For a better understanding of the phenomena the forces in each cavity are investigated. A coupling between the circumferencial flow and the axial flow in the cavity is revealed. The theoretical results are obtained by a one-volume bulk-flow theory which is essentially based on the momentum equation in circumferencial direction and therefore neglects some effects caused by the axial flow. The experimental results are compared to calculated results.