Passive cooling device and method for cooling an auxiliary power unit on an airoplane

摘要

A passive cooling system for aircraft auxiliary power units having an intake duct (30) extending between an inlet opening (32) and the compartment in which the auxiliary power unit (10) is positioned. An inlet scoop (60) is positioned in the intake duct for diverting a portion of the airflow in the intake duct through an outlet in a wall of the intake duct. A vacuum duct (30) is positioned near an oil cooler (27) for the auxiliary power unit, and an aspirator is operatively positioned between the vacuum duct and an exhaust passage of the auxiliary power unit. The aspirator creates a low-pressure region in the vacuum duct that draws the diverted air out of the outlet and through the oil cooler.