Deaerator and conduit assembly

An example deaerator assembly includes a housing having a housing inlet and a housing outlet. A conduit configured to communicate a deaerated coolant is located within the housing. A mixture of coolant and air is deaerated as the mixture is communicated from the housing inlet to the housing outlet within the housing and outside the conduit.

BACKGROUND

This disclosure relates generally to a deaerator and, more particularly, to a deaerator and conduit assembly.

Generators provide electric power as is known. Aircraft auxiliary power units, for example, typically include a generator that is driven by a turbine of a turbine engine. The turbine is rotatably coupled to the generator through a gearbox. Coolant, such as oil, is circulated through the gearbox and the generator. The coolant removes thermal energy and lubricates various components.

Coolant mixes with air as the coolant circulates through the generator. As known, at least some of the air must be separated from the coolant before the coolant can be reintroduced to the gearbox and the generator. Deaerators are used to separate air from the coolant. The coolant is collected within a sump after the deaerator removes the air. The coolant is recirculated through the gearbox and the generator from the sump. The coolant is communicated to the gearbox and the generator through an inlet tube that is separate from the deaerator.

SUMMARY

An example deaerator assembly includes a housing having a housing inlet and a housing outlet. A conduit configured to communicate a deaerated coolant is located within the housing. A mixture of coolant and air is deaerated as the mixture is communicated from the housing inlet to the housing outlet within the housing and outside the conduit.

An example aircraft auxiliary power unit assembly includes a gearbox configured to rotatably couple a turbomachine to a generator, and a coolant path that communicates a coolant through the gearbox and the generator. A deaerator assembly has a deaerating member. A mixture of air and the coolant is communicated about the deaerating member to separate air from the coolant. The deaerating member communicates the coolant along a portion of the coolant path.

An example method of communicating deaerated coolant includes communicating a mixture of air and coolant relative to a deaerating member into a sump. The method also includes communicating deaerated coolant from the sump using the deaerating member.

DETAILED DESCRIPTION

Referring toFIG. 1, an example auxiliary power unit arrangement10includes a turbine12of a turbomachine. The turbine12is rotatably coupled to a generator14through a gearbox16. A pump18circulates a coolant, such as a lubricating and cooling oil, along a coolant path20. The coolant cools and lubricates portions of the generator14and the gearbox16.

The coolant mixes with air when circulating through the generator14and the gearbox16. Coolant mixed with a substantial amount of air is considered Cmin this example. The coolant Cm, is not suitable for direct recirculation back to the gearbox16and the generator14because the coolant Cmcontains the substantial amount of air.

The example arrangement10includes a deaerator assembly22. The coolant Cmis communicated through the deaerator22to remove at least some of the air. A sump24collects the deaerated coolant Cdexiting the deaerator22. The deaerated coolant Cdis suitable for direct recirculation back to the gearbox16and the generator14because the deaerated coolant Cddoes not contain a substantial amount of air. Notably, the deaerated coolant Cdcommunicates back through the deaerator22when leaving the sump24. Thus, no conduit separate from the deaerator22is needed to move deaerated coolant Cdfrom the sump24.

The deaerated coolant Cdmay move through a chiller26along some portion of the coolant path20. Although the pump18, the deaerator22, the sump24, and the chiller26are schematically shown as separate from the gearbox16, some or all of these components may be disposed within the gearbox16.

Referring toFIGS. 2-5with continuing reference toFIG. 1, the example deaerator22includes a deaerator housing32that is generally cylindrical and extends along an axis X. The example deaerator housing32establishes an inlet34and a plurality of outlets36. The coolant Cmcommunicates into the deaerator22through the inlet34. Air is removed from the coolant Cmwithin the deaerator22. The outlets36then communicate the deaerated coolant Cdfrom the deaerator22into the sump24. The outlets36are positioned vertically below the inlet34in this example. The inlet34and the outlets36are radially facing. Other numbers of the inlet34and the outlets36could be used in other examples.

The deaerator22includes a deaerating member40. The deaerating member has a pedestal42. The deaerating member40is disposed within an interior of the deaerator housing32and aligned coaxially with the axis X. The example deaerator22and deaerating member40are aluminum, but may be other materials in other examples.

The inlet34of the deaerator22has a generally oval profile and is established within the deaerator housing32such that the coolant Cmis communicated into the deaerator housing32in a manner that encourages a spiraling movement of the coolant Cmabout the deaerating member40. That is, the coolant Cmis not communicated through the inlet34directly toward the axis X.

After the coolant Cmmoves through the inlet34into the interior of the deaerator housing32, the mixture spirals around the deaerating member40toward the pedestal42. As the coolant Cmspirals, centrifugal force tends to separate the coolant from the air. The coolant tends to move away from the axis X, and the air tends to move toward the axis X. The air that has been separated from the coolant Cmexits the deaerator housing32through a vent44established in the deaerator housing32. The coolant Cmgradually includes less of the air as the coolant Cmspirals vertically downward toward the pedestal42.

After moving vertically downward a sufficient amount, the coolant Cmis forced through a gap G established between the pedestal42and an inner wall46of the deaerator housing32. Moving the coolant Cmthrough the gap G separates some of the remaining air from the coolant Cm. The air that has been separated from the coolant Cmdue to movement through the gap G also exits the deaerator housing32through the vent44established in the deaerator housing32.

After moving through the gap G, the coolant Cm, which now includes considerably less of the air A than when the coolant Cmwas moved into the deaerator22, is considered deaerated coolant Cdand suitable for recirculation through the gearbox16and the generator14. The deaerator22may not remove all of the air A from the coolant Cm, but the deaerator22removes enough of the air A from the coolant Cmso that the coolant is suitable for recirculation as deaerated coolant Cd. A person having skill in this art and the benefit of this disclosure would understand how much of the air A must be removed from the coolant Cmbefore the coolant Cmcan be considered deaerated coolant Cdthat is suitable for recirculation.

The example deaerating member40is a conduit that extends between an inlet48and an outlet50. The inlet48is positioned vertically below the outlets36. The inlet48is configured to be submerged within the coolant Cdthat is collected within the sump24. During operation of the deaerator22, the coolant Cdis pulled into the inlet48. The level of deaerated coolant Cdwithin the sump24is typically kept at a level that is vertically above both the inlet48and the outlets36.

The deaerating member40communicates the coolant Cdfrom the inlet48to the outlet50. The deaerating member40delivers the deaerated coolant Cdfrom sump24. Since the deaerating member40forms a portion of the coolant path20, no separate conduit is required to deliver the deaerated coolant Cdfrom the sump24.

Generally, air is removed from the coolant Cmas the coolant Cmcommunicates downward through an annular chamber established between the deaerator housing32and the deaerating member40. The coolant Cmmoves along a first flow path.

The deaerated coolant Cdcommunicates upward through the deaerating member40inside the annular chamber and along a second, different flow path. In this example, the coolant Cmcommunicates downward at the same time as the deaerated coolant Cdcommunicates upward. In another example, the coolant Cmcommunicates downward and the deaerated coolant Cdcommunicates upward at different times.

In this example, the inlet48is established in the bottom axially-facing surface of the deaerator22. A screen52may cover the inlet48to block contaminates and debris from moving through the deaerating member40and into the pump18. The example screen52has a wavy cross-section.

The outlet50of the example deaerating member40is established in a sidewall of the deaerator housing32. The outlet50faces radially outward away from the axis X. Positioning the outlet50in the sidewall of the deaerator housing32provides room for the vent44.

The example outlet50is also positioned vertically above the inlet34. Accordingly, the radially oriented portion of the deaerating member40does not significantly interfere with the spiraling movement of the coolant Cm.

Referring toFIG. 5with continuing reference toFIG. 1, another example deaerator22amay include radially facing inlets48ato a deaerating member40athat communicate the deaerated coolant Cdfrom the sump24through an outlet50a. At least one screen52acovers these inlets48a. The screen52ais relatively planar and does not have a wavy cross-section.

Air communicates from the example deaerating member40athrough a vent44a, and deaerated coolant Cdis communicated to the sump24through a plurality of outlets36a.

Features of the disclosed examples include a deaerator that is able to deliver deaerated coolant from the sump. Accordingly, no separate conduit from the sump is needed.