A labyrinth seal test setup with a data acquisition system was designed and established to investigate the leakage characteristics of a typical straight-through labyrinth seal with engineering size. The effects of sealing clearance

tooth number

cavity depth and cavity width on the leakage rate and chamber pressure distribution were measured at the pressure ratios with range of 1.1-2.0. Result shows that

the leakage coefficient increased with increasing pressure ratio and sealing clearance

but the increasing trend gradually slowed down when the pressure ratio reached 1.6. The leakage rate decreased rapidly as the tooth number increased. But the tooth number's effects on leakage rate decreased gradually with growing tooth number. The shallow and broad cavity was help to decrease the leakage rate. The decrease of the pressure coefficient became slower in the flow direction. The pressure ratio

sealing clearance and cavity depth had little effect on the cavity pressure coefficient distribution. The upstream cavities mode more contributions to reducing the leakage loss and had key effects on the labyrinth seal performance.