Drainage mast of the compartment of the auxiliary power unit of an aircraft

摘要

A drainage mast for draining liquids from an APU compartment of an aircraft with a first end connected to the APU compartment and a second end for discharging the liquids to the atmosphere. The drainage mast is configured with at least a sector having decreasing cross section areas towards the second end. The area of the initial cross section of the sector is lesser than the area of any cross section of the drainage mast closer to the first end. The invention also refers to an aircraft comprising the drainage mast.

主权项

1. A drainage mast for draining liquids from an Auxiliary Power Unit (APU) compartment of an aircraft, the drainage mast comprising:
a first end connected to the APU compartment, and a second end that discharges the liquids to atmosphere, the drainage mast being a tube extending from the first end to the second end, the liquids flowing in an interior portion of the drainage mast, the drainage mast including an outlet sector having decreasing cross section areas towards the second end and an area of the interior portion at an initial cross section of the outlet sector being less than an area of the interior portion at any cross section of the drainage mast closer to the first end, the drainage mast being configured to drain the liquids from the APU compartment where the APU has a pressure that is less than an atmospheric pressure outside the APU compartment and outside the drainage mast, wherein a ratio between an effective diameter of the interior portion at a final cross section and a diameter of the interior portion at the initial cross section of the outlet sector is between 0.8-0.9, and wherein the outlet sector is further comprised of a nozzle with a streamline shape so that streamlines of the liquid in the second end are very closely parallel to an axis of the drainage mast.