Patent Description:
Certain types of machines, such as high-power-density aviation-class electric motor and drives, generally may be thermally limited at high power ratings due to the generation of heat, which may limit their available performance. Thus, such machinery may utilize various types of cooling technologies to control the generation of heat. Two-phase cooling technologies may be an efficient approach for controlling heat generation. <CIT> or <CIT> disclose heat exchangers according to the preamble of claim <NUM>.

Disclosed is a heat exchanger including: an inlet manifold configured to receive a cooling fluid; a reservoir; first and second condenser arms connected between and that respectively fluidly couple the inlet manifold to the reservoir, so that fluid received at the inlet manifold travels from the inlet manifold into the reservoir; and an outlet pump having a pump inlet port coupled to the reservoir and having a pump outlet port, wherein the inlet manifold, the reservoir, the first and second condensers, in combination, form a continuous shape.

In embodiments, gravity, suction created by the pump or a combination of both draws the cooling fluid from the inlet manifold, through the condenser arms and into the reservoir.

In embodiments, the inlet manifold includes a manifold inlet port and first and second manifold outlet ports; the first and second condenser arms respectively extend from first and second condenser inlets to first and second condenser outlets; and wherein the first and second condenser inlets are fluidly coupled to respective ones of the first and second manifold inlet ports.

In embodiments, the reservoir extends from first and second reservoir inlets to a reservoir outlet; and the first and second reservoir inlets are fluidly coupled to respective ones of the first and second condenser outlets.

In embodiments, the pump inlet port is fluidly coupled to the reservoir outlet.

In embodiments, the first and second condenser arms includes one or more fluid conduction passageways that respectively extend between the first and second condenser inlets and the first and second condenser outlets.

In embodiments, the fluid conduction passageways includes fins.

In embodiments, the fins are formed from plates that define the first and second passageways or wherein the passageways are tubes and the fins contact and extend outwardly from the tubes.

In embodiments, one or more of the inlet manifold, the condenser arms and the reservoir are formed by an additive manufacturing process.

In embodiments, the heat exchanger is symmetric about an axis extending between the inlet manifold and the outlet pump.

In embodiments, the continuous shape of the heat exchanger is a ring shape.

In embodiments, the outlet pump is a variable speed pump.

In embodiments, the outlet pump is configured to disengage when a temperature of the cooling fluid at the pump inlet port is above a threshold or when a pressure of the cooling fluid is below a threshold.

In embodiments, the heat exchanger further includes a valve in fluid communication with the outlet pump, wherein the valve is configured to control the cooling fluid through it when a characteristic of the cooling fluid crosses a threshold.

In embodiments, the reservoir defines first and second reservoirs that respectively have first and second reservoir outlets, and the pump is circumferentially disposed between the first and second reservoirs and fluidly coupled to the first and second reservoir outlets.

Further disclosed is an aircraft including: a motor; a motor cooling circuit extending through the motor; and a heat exchanger including: an inlet manifold configured to receive a cooling fluid; a reservoir; first and second condenser arms connected between and that respectively fluidly couple the inlet manifold to the reservoir, so that fluid received at the inlet manifold travels from the inlet manifold into the reservoir; and an outlet pump having a pump inlet port coupled to the reservoir and having a pump outlet port, wherein the inlet manifold, the reservoir, the first and second condensers, in combination, form a continuous shape.

Further disclosed is a method of directing fluid in a heat exchanger, including: directing a cooling fluid from an inlet manifold into first and second condenser arms; directing the cooling fluid out of the first and second condenser arms and into respective ones of first and second reservoirs; and directing the cooling fluid out of the first and second reservoirs and into an inlet port of an outlet pump having a pump outlet port, wherein the inlet manifold, the first and second reservoirs, the first and second condenser arms, in combination, form a continuous shape.

In embodiments, directing the cooling fluid from the inlet manifold into the first and second condenser arms includes: directing the cooling fluid out of first and second manifold outlet ports of the inlet manifold and into respective ones of first and second condenser inlets of the first and second condenser arms.

In embodiments, directing the cooling fluid out of the first and second condenser arms and into the reservoir includes: directing the cooling fluid out of first and second condenser outlets of the first and second condenser arms and into first and second reservoir inlets of the reservoir.

In embodiments, the method further includes: controlling the cooling fluid through the outlet pump based on one or more of a temperature and a pressure of the cooling fluid at the outlet pump.

<FIG> illustrates an example of an aircraft <NUM> having aircraft engines surrounded by (or otherwise carried in) nacelles <NUM>. The aircraft <NUM> includes two wings <NUM> that can each include one or more slats <NUM> and one or more flaps <NUM>. The aircraft may further include ailerons <NUM>, spoilers <NUM>, horizontal stabilizer trim tabs <NUM>, horizontal stabilizer <NUM> and rudder <NUM>, and vertical stabilizer <NUM> (the tail structure being collectively referred to as an and empennage) each of which may be typically referred to as "control surfaces" as they are movable via one or more motors, including e.g., motor <NUM>, under aircraft power systems.

As indicated, certain types of machines, including aviation-class electric motor and drives (such as the motor <NUM>), may utilize various types of cooling technologies, including two-phase cooling technologies, to control the generation of heat in the motor <NUM>. However, the availability of storage space around or adjacent to the motor <NUM> may limit the size of the cooling technologies.

In view of the above concerns, as shown in <FIG>, a heat exchanger <NUM> is connected an external cooling circuit <NUM> (<FIG>) and is configured to circulate a cooling fluid <NUM> to the external cooling circuit <NUM>. In one embodiment, the cooling fluid <NUM> is a coolant, which may be a refrigerant such as but not limited to any of hydrofluoroolefins (HFOs), hydrofluorocarbons (HFCs), hydrofluoroethers (HFEs), chlorofluorocarbons (CFCs) or other phase-change fluids. In one embodiment the external cooling circuit <NUM> may be a motor cooling circuit of a motor <NUM> (<FIG>).

The heat exchanger <NUM> may include an inlet manifold <NUM> configured to receive the cooling fluid <NUM>. The inlet manifold <NUM> may define a manifold inlet <NUM> that is configured to receive the cooling fluid <NUM> from the external cooling circuit <NUM>. First and second manifold outlets <NUM>, <NUM> (<FIG>), may be respectively configured to direct first and second flow portions <NUM>, <NUM> (<FIG>, shown schematically) downstream into the heat exchanger <NUM> as indicated below.

First and second condenser arms <NUM>, <NUM> (<FIG>) may be respectively connected to the first and second manifold outlets <NUM>, <NUM>. Specifically, the first and second condenser arms <NUM>, <NUM> may respectively extend from first and second condenser inlets <NUM>, <NUM> to first and second condenser outlets <NUM>, <NUM>.

The first and second condenser arms <NUM>, <NUM> may include one or more fluid conduction passageways <NUM> that extend between first and second condenser inlets and outlets. The fluid conduction passageways <NUM> may include exterior heat fins <NUM> the formed from plates <NUM> that define the first and second passageways <NUM>. Alternatively, the passageways <NUM> are tubes <NUM> (<FIG>, shown schematically in the first condenser <NUM> for simplicity) that form coolant channels and the fins contact and extend outwardly from the tubes <NUM>. In one embodiment, the tubes <NUM> may form a single pass channel (shown schematically in <FIG>). In one embodiment, the tubes <NUM> may form a multi-pass channel <NUM> (shown schematically in <FIG>). A configuration of the tubes <NUM> may depend on the amount of cooling required to change the cooling fluid <NUM> from vapor to liquid in the first condenser <NUM>. While a single channel is shown, it should be understood that the tubes could be formed of multiple separated paths (e.g., multiple tubes or passageways). In one embodiment, the heat exchanger <NUM> is a tube-fin heat exchanger. In another embodiment, the heat exchanger <NUM> may be a plate-fin heat exchanger. The heat exchanger <NUM> may be formed from an additive manufacturing process.

First and second reservoirs <NUM>, <NUM> may be respectively connected to the first and second condenser arms <NUM>, <NUM>. Specifically, the first and second reservoirs <NUM>, <NUM> may respectively extend from first and second reservoir inlets <NUM>, <NUM> to first and second reservoir outlets <NUM>, <NUM>. From this configuration, fluid received at the inlet manifold <NUM> travels from the inlet manifold <NUM> into the first and second reservoirs <NUM>, <NUM> via the first and second condenser arms <NUM>, <NUM>.

An outlet pump <NUM> is located circumferentially between the first and second reservoirs <NUM>, <NUM>, i.e., between the first and second reservoirs <NUM>, <NUM> relative to an outer boundary <NUM> that defines a perimeter of the heat exchanger <NUM>. The outlet pump <NUM> may include first and second pump inlets <NUM>, <NUM> (<FIG>) respectively connected to the first and second reservoir outlets <NUM>, <NUM>. A pump outlet port <NUM> of the outlet pump <NUM> may be configured to direct the cooling fluid <NUM> towards the external cooling circuit <NUM>. In the disclosed embodiments, the external cooling circuit <NUM> (<FIG>) may extend from the pump outlet port <NUM>, though the motor <NUM>, and into the manifold inlet <NUM>. In one embodiment, the outlet pump <NUM> alone provides sufficient pressure to drive (e.g. from negative pressure, or suction, created on the inlet side of the pump) the coolant through the heat exchanger <NUM>. In one embodiment, flow is gravity assisted, or gravity driven, with the inlet manifold <NUM> located above the outlet pump <NUM> relative to a direction of gravity.

The heat exchanger <NUM> may be an air-cooled heat exchanger, e.g., cooled by an airflow <NUM> (<FIG>), e.g., impinging against a front side <NUM> of the heat exchanger <NUM> (<FIG>). In an aircraft <NUM> (<FIG>), such airflow <NUM> may be provided by RAM air, or may be provided by an onboard fan, for example. The heat exchanger <NUM> also may be utilized in non-flight commercial or residential systems to cool a variety of types of equipment, such as a heating, ventilation, air-conditioning (HVAC) system. The cooling fluid <NUM> as more fully shown below may be a two-phase cooling fluid.

With the heat exchanger <NUM>, the cooling fluid <NUM> enters the heat exchanger as a vapor or a combination of vapor and liquid at the inlet manifold <NUM>. As the cooling fluid is drawn through the condenser arms, heat is removed from it. This removal of heat causes the cooling fluid <NUM> to condense to a liquid phase through the first and second condenser arms <NUM>, <NUM> and collects as liquid in the first and second reservoirs <NUM>, <NUM>. The first and second reservoirs <NUM>, <NUM> feed the outlet pump <NUM>, and the pump outlet port <NUM> feeds the external cooling circuit <NUM>, which is directed to the motor <NUM> or other components to be cooled. The arrangement provides for a compact packaging and ensures the outlet pump <NUM> has available pressure to pump the near-saturated liquid, for example, without cavitating.

To prevent the outlet pump <NUM> from running dry, which may damage the outlet pump <NUM>, the first reservoir <NUM> may be sized to capture a predetermined volume of condensed fluid from the cooling fluid <NUM>. In one embodiment, the outlet pump <NUM>, to prevent the outlet pump <NUM> from running dry, the outlet pump <NUM> may be configured to disengage when a characteristic of the cooling fluid <NUM> crosses a threshold. For example, the outlet pump <NUM> may be configured to disengage when a temperature of the cooling fluid <NUM> is above a threshold. In another embodiment, the outlet pump <NUM> may be configured to disengage when a pressure of the cooling fluid <NUM> drops below a threshold. Either of these characteristics may be indicative of an availability of a lower than a minimal amount of a liquid phase of the cooling fluid <NUM> between the reservoirs to run the outlet pump <NUM> without causing damage.

In addition, in one embodiment, the outlet pump <NUM> may be a variable speed pump, enabling the outlet pump <NUM> to provide a constant pressure through the external cooling circuit <NUM>. In one embodiment, a valve <NUM> (<FIG>) may be in fluid communication with the outlet pump <NUM>, e.g., with the pump outlet port <NUM>. The valve <NUM> may be configured to control the cooling fluid <NUM> through it when a characteristic of the cooling fluid <NUM> crosses a threshold; for example, when the temperature of the coolant in reservoir exceeds a certain value or a level of subcooling (e.g., formation of liquid) at the pump inlet drops below a certain threshold.

As shown in <FIG>, the heat exchanger <NUM> may be surround and be radially outward from the motor <NUM> and may be configured with a compact size relative to the motor <NUM>. The heat exchanger <NUM> can contact the motor or be spaced from it.

As shown in <FIG>, the heat exchanger <NUM>, via the inlet manifold <NUM>, the first and second reservoirs <NUM>, <NUM>, the first and second condenser arms <NUM>, <NUM>, in combination, may form a continuous shape. The continuous shape may be defined by the outer boundary <NUM> that is symmetrical about an axis <NUM> (<FIG>) extending between the inlet manifold <NUM> to the outlet pump <NUM>. As shown in <FIG>, the heat exchanger <NUM> may be shaped as a ring or annulus. Thus, each condenser-reservoir pair may be formed as continuous arcs, e.g., with a semi-annular shape. It is to be appreciated that a ring shape is one of many available shape options. For example, each of the first and second condenser arms <NUM>, <NUM> may be divided into segments <NUM>, <NUM> disposed at segmentation angles <NUM>, <NUM> as shown schematically with the first condenser <NUM> in <FIG>. The formation and distribution of the segments <NUM>, <NUM> may be such that the resulting configuration is similar to the ring shape or other desired shape. The compact sizing of the heat exchanger <NUM> may enable a packaging of it that is convenient for residential or commercial applications where a storage area may be limited.

<FIG> shows another embodiment of the heat exchanger 120a. Elements of the heat exchanger 120a that are not labeled in <FIG> are the same as those in the heat exchanger <NUM> of <FIG>. For example, the condenser arms <NUM>, <NUM>, cooled by air <NUM>, and manifold <NUM> are the same as those components discussed with FIGS. In addition, the heat exchanger 120a of <FIG> connects with the motor 50a in the same way as the heat exchanger <NUM> of <FIG>. In the embodiment of <FIG>, a continuous reservoir 380a is provided rather than the two reservoirs <NUM>, <NUM> (<FIG>). The continuous reservoir 380a may be arc shaped to form a semicircular c-shape (or U-shape) along its front or rear profile. The reservoir 380a may have a single outlet port 386a (shown schematically) that feeds a single pump inlet port 300a (shown schematically) of the pump 280a for this embodiment. As shown, the pump 280a may be located axially ahead or aft of the reservoir 380a (shown in the aft location in <FIG>). The pump 280a has the single outlet <NUM> and functions the same as the pump <NUM> discussed in <FIG> through4.

Turning to <FIG>, a flowchart shows a method of directing a cooling fluid <NUM> (e.g. a fluid) through the heat exchanger <NUM> shown in <FIG>. As shown in block <NUM>, the method includes directing the cooling fluid <NUM> from the inlet manifold <NUM> into first and second condenser arms <NUM>, <NUM>. As indicated above, this includes directing the cooling fluid <NUM> out of the first and second manifold outlet ports <NUM>, <NUM> of the inlet manifold <NUM> and into respective ones of the first and second condenser inlets <NUM>, <NUM> of the first and second condenser arms <NUM>, <NUM>.

As shown in block <NUM>, the method includes directing the cooling fluid <NUM> out of the first and second condenser arms <NUM>, <NUM> and into respective ones of the first and second reservoirs <NUM>, <NUM>. As indicated above, this includes directing the cooling fluid <NUM> out of first and second condenser outlets <NUM>, <NUM> of the first and second condenser arms <NUM>, <NUM> and into respective ones of the first and second reservoir inlets <NUM>, <NUM> of the first and second reservoirs <NUM>, <NUM>.

As shown in block <NUM>, the method includes directing the cooling fluid <NUM> out of the first and second reservoirs <NUM>, <NUM> and into the first and second pump inlet ports <NUM>, <NUM> of the outlet pump <NUM> having the pump outlet port <NUM>. As shown in block <NUM>, the method may also optionally include controlling the flow of the cooling fluid <NUM> through the outlet pump <NUM> based on one or more of a temperature and a pressure of the cooling fluid <NUM> or a combination of the two indicative of the level of subcooling at pump <NUM> inlet or superheating at the condenser inlets.

Turning to <FIG>, a flowchart shows a method of directing a cooling fluid <NUM> (e.g. a fluid) through the heat exchanger 120a shown in <FIG>. Aspects not expressly identified with respect to <FIG> are the same as those in <FIG>. As shown in block <NUM>, the method includes directing the cooling fluid <NUM> from the inlet manifold <NUM> into first and second condenser arms <NUM>, <NUM>. As shown in block <NUM>, the method includes directing the cooling fluid <NUM> out of the first and second condenser arms <NUM>, <NUM> and into the reservoir 380a. As shown in block <NUM>, the method includes directing the cooling fluid <NUM> out of the reservoir 380a and into the pump inlet port 300a of the outlet pump 280a having the pump outlet port <NUM>. As shown in block <NUM>, the method may also optionally include controlling the flow of the cooling fluid <NUM> through the outlet pump 280a based on one or more of a temperature and a pressure of the cooling fluid <NUM> or a combination of the two indicative of the level of subcooling at pump 280a inlet or superheating at the condenser inlets.

The above disclosed embodiments provide machines, including aviation-class electric motor and drives, with a two-phase heat exchanger <NUM> that may be configured to fit within a relatively small storage space around or adjacent to the machinery. It is to be appreciated that the heat exchanger may be implemented with an environmental control system (ECS) of an aircraft, or other implantation in which the apparatus/structure to be cooled is not configured with moving parts.

Claim 1:
A heat exchanger comprising:
an inlet manifold (<NUM>) configured to receive a cooling fluid;
a reservoir (<NUM>);
first and second condenser arms (<NUM>, <NUM>) connected between, and respectively fluidly coupling, the inlet manifold and the reservoir, so that fluid received at the inlet manifold travels from the inlet manifold into the reservoir; and
an outlet pump (<NUM>) having a pump inlet port (<NUM>) coupled to the reservoir and having a pump outlet port,
characterized in that
the inlet manifold, the reservoir, the first and second condensers, in combination, form a continuous shape.