Influence of combined radial location and growth on the leakage performance of a rotating labyrinth gas turbine seal

Leakage characteristics, influenced by centrifugal and thermal radial growth are determined computationally for a generic rotating labyrinth seal used in the gas turbine secondary air system. Three seal locations, namely, R25, R50 and R75 are represented by means of varying the rotor radius mimicking different radial positions of the seal from the shaft axis. The combined influence of seal location and its radial (Centrifugal and thermal) growth on the leakage performance is investigated for a wide-ranging speeds from 1000 to 3000 rad/s, temperatures ranging from 200 to 450 A degrees C and pressure ratios varying from 1.1 to 2.5, for a chosen initial clearance of 500 micron. A comparison of the effect of rotation and temperature gradient among different rotors shows that the radial growth and leakage flow rates significantly vary with the increasing radius.