THE SEALING CAPACITY AND HEAT TRANSFER CHARACTERISTICS OF A STRAIGHT-THROUGH LABYRINTH SEAL WITH DIFFERENT GEOMETRIC PARAMETERS

Abstract

The sealing capacity and heat transfer characteristics of the straight-through labyrinth seal with different geometric parameters are analyzed in this paper through numerical investigation. The geometric parameters studied include the gap width varying from 2 mm to 6 mm, the tooth tip thickness varying from 1 mm to 3 mm, and the front inclination angle varying from 75° to 100°. For each case, the Reynolds number is varied from 10,000 to 40,000. According to the results, the sealing performance is mainly influenced by the gap width, and less affected by the tooth tip thickness and the front inclination angle. As the gap width is increased, the discharge coefficient is increased by about 40%. With the tip thickness or the front inclination angle increased, the discharge coefficient is increased by less than 5%. For the heat transfer of the end wall, the gap width has significant effects, while the effects of the other two parameters are mainly in the first tooth cavity. For the stator, the increased flow rate at the tooth tip results in enhanced local heat transfer. For the rotor, the heat transfer is determined by the vortex intensity in the tooth cavity. The presence of small secondary vortices weakens the local heat transfer.