A flow combiner is provided for a gas turbine engine. The flow combiner includes an outlet duct, a compressor bleed inlet duct coupled to the outlet duct, and a ventilation inlet duct coupled to the outlet duct. The compressor bleed inlet duct is configured to receive a bleed flow from a compressor of the gas turbine engine. The ventilation inlet duct is configured to receive a ventilation flow from an enclosure surrounding the gas turbine engine. The bleed flow and the ventilation flow are combined as an outlet flow through the outlet duct.