An assembly for a gas turbine engine comprising: a housing having a housing cavity, an inlet, and an outlet; a rotatable shaft positioned proximate the outlet; a seal positioned at an interface of the rotatable shaft and the housing, wherein the seal comprises: porous material adjacent the shaft and the housing; and a shell substantially separating the porous material from the housing cavity, the shell comprising: an inlet that allows fluid flow from the housing cavity to the porous material; and an outlet that allows fluid flow from the porous material to the housing interior, and characterized in that the inlet is positioned radially inward of the outlet, and wherein the shell is substantially annular, having a radially inner edge abutting the shaft, and wherein the shell further comprises: a first radial surface extending substantially radially outward from the radially inner edge with respect to a centerline axis of the shaft, wherein the inlet is one of a plurality of holes extending through the first radial surface. a housing having a housing cavity, an inlet, and an outlet; a rotatable shaft positioned proximate the outlet; a seal positioned at an interface of the rotatable shaft and the housing, wherein the seal comprises: porous material adjacent the shaft and the housing; and a shell substantially separating the porous material from the housing cavity, the shell comprising: an inlet that allows fluid flow from the housing cavity to the porous material; and an outlet that allows fluid flow from the porous material to the housing interior, and characterized in that the inlet is positioned radially inward of the outlet, and wherein the shell is substantially annular, having a radially inner edge abutting the shaft, and wherein the shell further comprises: a first radial surface extending substantially radially outward from the radially inner edge with respect to a centerline axis of the shaft, wherein the inlet is one of a plurality of holes extending through the first radial surface. porous material adjacent the shaft and the housing; and a shell substantially separating the porous material from the housing cavity, the shell comprising: an inlet that allows fluid flow from the housing cavity to the porous material; and an outlet that allows fluid flow from the porous material to the housing interior, and characterized in that the inlet is positioned radially inward of the outlet, and wherein the shell is substantially annular, having a radially inner edge abutting the shaft, and wherein the shell further comprises: a first radial surface extending substantially radially outward from the radially inner edge with respect to a centerline axis of the shaft, wherein the inlet is one of a plurality of holes extending through the first radial surface. an inlet that allows fluid flow from the housing cavity to the porous material; and an outlet that allows fluid flow from the porous material to the housing interior, and characterized in that the inlet is positioned radially inward of the outlet, and wherein the shell is substantially annular, having a radially inner edge abutting the shaft, and wherein the shell further comprises: a first radial surface extending substantially radially outward from the radially inner edge with respect to a centerline axis of the shaft, wherein the inlet is one of a plurality of holes extending through the first radial surface.