Computed Eccentricity Effects on Turbine Rim Seals at Engine Conditions With a Mainstream

Abstract

A previously verified axisymmetric Navier–Stokes computer code was extended for three-dimensional computation of eccentric rim seals of almost any configuration. All compressibility and thermal/momentum interaction effects are completely included, and the temperature, pressure, and Reynolds number of the mainstream, coolant stream, and turbine wheel are fixed at actual engine conditions. Regardless of the seal eccentricity, both ingress and egress are found between θ = −30 and 100 deg, which encompasses the location of maximum radial clearance at θ = 0 deg. All other θ locations within the rim seal show only egress, as does the concentric base case for all circumferential locations. Further, the maximum ingress occurs near θ = 30 deg for all eccentricities. This is found to produce a blade root/retainer temperature rise from the concentric case of 390 percent at 50 percent eccentricity and a 77 percent rise at 7.5 percent eccentricity. In addition, the nature of an increased eccentricity causing a decreased seal effectiveness is examined, along with the corresponding increase of cavity-averaged temperature.