Dimensional analysis on resistance characteristics of labyrinth seals

Experimental investigation of stepped and straight-through labyrinth seals was designed to study the sealing performance of two different typical labyrinth seals. In order to facilitate dimensional analysis on the flow resistance characteristics of labyrinth seals, the variable cross-section of the flow channels are considered as constant cross-section flow. The mechanical energy loss of flow caused by throttle turbulence intensity is considered as caused by friction along the way. The friction coefficient of stepped labyrinth seals is bigger than that of straight-through labyrinth seals by more than 40% for the same Reynolds number and the ratio of equivalent diameter and the seal length. The expression of friction coefficient f and fRe are obtained from experimental data. The verifications indicate that the expressions are highly accurate. The contribution to the total pressure drop of each tooth cavity gradually becomes less along the flow direction.