A system includes a gas turbine enclosure. The system also includes a gas turbine engine disposed in the gas turbine enclosure, wherein the gas turbine engine is configured to output an exhaust flow. The system further includes an exhaust driven eductor configured to draw an air flow through and out of the gas turbine engine enclosure using the exhaust flow. The system yet further includes an exhaust stack coupled to the gas turbine enclosure, wherein the exhaust stack is configured to output a mixed flow of the exhaust flow and the air flow. The system still further includes a diffuser plate disposed within the exhaust stack, wherein the diffuser plate is configured to provide a homogenous flow distribution for the mixed flow downstream of the diffuser plate.