A 3-D Navier-Stokes computer model, which was previously experimentally verified, was used to explore eccentricity effects on the minimum required coolant flow to prevent ingress (Cw,min) and blade root/retainer temperature. A recently developed three-scale k-ϵ turbulence model was experimentally verified and utilized in the computations. The temperature, pressure, Mach number and Reynolds number of a typical commercial gas turbine engine were specified for the mainstream, coolant stream and turbine wheel. It was found that Cw,min increases markedly with rotor eccentricity, even for small eccentricity values, in an almost linear fashion. The computations were used to establish a correlation for the dependence of Cw,min on eccentricity. It was found, for example, that an eccentricity increase from 5% to only 12.5% of the rim seal clearance increases Cw,min from approximately 8000 to 11000. In addition, for 25% eccentricity, the highest blade root/retainer temperature for Cw = 3600 is 49% higher than that for Cw = 7200, whereas for 12.5% eccentricity, it is only 20% higher.

This content is only available via PDF.