Patent Description:
Phase separation is required in a variety of multi-phase systems. For example, in certain environments (e.g., space vehicle or habitat), a heat exchanger may be used to revitalize air through condensing, cooling, filtering, and humidifying. This can result in a multi-phase product, specifically a mix of water and air. In a zero-gravity environment such as the space environment, condensation of water and its separation from the remaining gaseous phase presents a technical challenge. Any water droplets remaining in the gas (e.g., cabin air) may impede the function of various equipment (e.g., soak the filter) or coalesce to form a potential hazard (e.g., within a space vehicle, life support suit, space station, habitat). <CIT> discloses an air pillow liquid separation system including housing with a plurality of air pillow pockets arranged within. An airflow stream enters the housing and is redirected, separating entrained liquids from the airflow stream by inertia effects. The separated liquids are directed of the air pillow pockets where the liquids collect on the air pillow pocket ribs forming droplets flowing to a drain opening in the housing. <CIT>, <CIT>, <CIT> and <CIT> are other relevant prior art documents.

According to a first aspect of the invention, there is provided a passive phase separator as claimed in claim <NUM>.

In addition to one or more of the features described herein, the input conduit includes a liquid inlet that forms an opening of the liquid removal chamber on a side of the input conduit opposite the side of the inlet.

In addition to one or more of the features described herein, the liquid water that passes through the hydrophilic material enters a volume of the liquid conduit.

In addition to one or more of the features described herein, the liquid removal chamber and the liquid conduit form a liquid capture portion. The liquid conduit surrounds the liquid removal chamber with a volume therebetween.

In addition to one or more of the features described herein, the liquid capture portion is modular and replaceable.

In addition to one or more of the features described herein, the angle is <NUM> degrees.

In addition to one or more of the features described herein, the angle is less than <NUM> degrees.

In addition to one or more of the features described herein, some or all of the input conduit or the gas conduit is formed from or coated with a hydrophobic material.

According to a further embodiment of the invention, there is provided a method of assembling a passive phase separator as claimed in claim <NUM>.

In addition to one or more of the features described herein, the method also includes forming an opening of the liquid removal chamber on a side of the input conduit opposite the side of the inlet as a liquid inlet.

In addition to one or more of the features described herein, the liquid water that passes through the hydrophilic material enters a volume of the liquid conduit. The liquid conduit surrounds the liquid removal chamber with a volume therebetween.

In addition to one or more of the features described herein, the method also includes forming a liquid capture portion with the liquid removal chamber and the liquid conduit.

In addition to one or more of the features described herein, the forming the liquid capture portion includes the liquid capture portion being modular and replaceable.

In addition to one or more of the features described herein, the forming the gas conduit includes arranging the gas conduit at a <NUM> degree angle from the input conduit.

In addition to one or more of the features described herein, the forming the gas conduit includes arranging the gas conduit at the angle less than <NUM> degrees from the input conduit.

In addition to one or more of the features described herein, the method also includes forming some or all of the input conduit or the gas conduit with a hydrophobic material or coating some or all of the input conduit or the gas conduit with the hydrophobic material.

As previously noted, multi-phase flow may have to be separated by a phase separator in a variety of applications. For example, a heat exchanger may be used to revitalize breathable air in space applications and may produce two-phase flow of water and air. As also noted, removing all the water droplets from the heat exchanger before redirecting the air for use in life support may avoid various issues, especially in a zero gravity space environment. Embodiments of the systems and methods detailed herein relate to a passive phase separator with a liquid removal chamber. The multi-phase flow may include two phases (i.e., water and air) that flow from a condensing heat exchanger to the passive phase separator. As a result of the phase separation, air is allowed to flow to a life support environment (e.g., space suit, space vehicle, habitat) while water is separated and retained for reuse. The passive phase separator according to one or more embodiments includes a liquid removal chamber. In addition to being passive (i.e., requiring no external power), the phase separator facilitates phase separation even for slug flow (i.e., multi-phase flow in which the liquid concentration is higher in some portions that include a "slug of liquid"). The phase separator operates in a zero gravity/microgravity environment with a low pressure drop.

<FIG> is a cross-sectional view of relevant aspects of a passive phase separator <NUM> with a liquid removal chamber <NUM> according to one or more embodiments. As shown, a two-phase flow of liquid and gas enters the passive phase separator <NUM> through an inlet <NUM> of an input conduit <NUM>. This two-phase flow is split between a gas conduit <NUM> and a liquid removal chamber <NUM>. The gas (e.g., air) in the two-phase flow in the input conduit <NUM> has lower density than the liquid (e.g., water) in the two-phase flow and follows the turn into the gas conduit <NUM>. Meanwhile, the higher density liquid (e.g., water) in the two-phase flow in the input conduit <NUM> continues straight through the liquid inlet <NUM> to the liquid removal chamber <NUM> based on inertia. The inertial separation is similar to that in an elbow wick, for example. However, the liquid removal chamber <NUM> facilitates the inertial separation even when the concentration of liquid in the two-phase flow increases (i.e., slug flow occurs).

A hydrophobic material <NUM> is shown on the inside of the input conduit <NUM> and at a corner with the gas conduit <NUM>. In the input conduit <NUM>, the hydrophobic material <NUM> may prevent water or a water-based liquid in the two-phase flow from separating and clinging to the walls of the input conduit <NUM>. At the corner, the hydrophobic material <NUM> may discourage collection of liquid at the corner and encourage flow into the liquid removal chamber <NUM>. The hydrophobic material <NUM> may also be included in the gas conduit <NUM> where it would maintain the effectiveness of the inertial separation while changing the flow that downstream components see, which may alter their performance. The hydrophobic material <NUM> may be included as a coating or, in alternate embodiments, may be fabricated as the tubing.

The gas conduit <NUM>, which forms an angle θ with the input conduit <NUM>, may vent the gas (e.g., air) as part of a life support system, for example. The angle θ is shown to be <NUM> degrees (i.e., gas conduit <NUM> is perpendicular to the input conduit <NUM>) in <FIG>, but this exemplary illustration is not intended to be limiting. In alternate embodiments, the angle θ may be based on the expected flow rate and the expected amount of water (e.g., slug concentration) to ensure that inertial separation occurs completely. Lower values of the angle θ may result in relatively better separation of the gas from the liquid but also a relatively higher pressure drop for the gas exiting the gas conduit <NUM> as compared with gas in the two-phase flow at the inlet <NUM>. Higher pressure drop may mean that more power is needed to move the gas through the passive phase separator <NUM>.

On the other hand, higher values of the angle θ may result in a relatively lower pressure drop but also relatively less separation of the gas from the liquid. For example, if the angle θ were <NUM> degrees (e.g., almost parallel with the portion of the input conduit <NUM> that continues through the liquid inlet <NUM>), liquid may flow into the gas conduit <NUM> as easily as it does into the liquid removal chamber <NUM>. That is, the inertia associated with the liquid, which is more dense than the gas, making the turn into the gas conduit <NUM> may be too easily overcome if the angle θ were too close to <NUM> degrees. At the same time, gas moving from the input conduit <NUM> to the gas conduit <NUM> may not experience much of a decrease in pressure. The lower the expected concentration and flow rate, the higher the angle θ may be.

In the exemplary embodiment shown in <FIG>, the liquid removal chamber <NUM> perimeter is defined by hydrophilic material <NUM> while its opening is defined by the liquid inlet <NUM>. The hydrophilic material <NUM> may be in the form of a membrane or metal plate produced from sintered powder, calendared screen, or porous carbon, for example. The hydrophilic material <NUM> attracts and passes through water or water-based liquid in the liquid removal chamber <NUM> into a liquid conduit <NUM> that is coupled to the liquid removal chamber <NUM>. As shown in the exemplary illustration of <FIG>, the liquid conduit <NUM> surrounds the liquid removal chamber <NUM> with a volume therebetween such that liquid flows from the liquid removal chamber <NUM> through the hydrophilic material <NUM> into that volume of the liquid conduit <NUM> (shown with captured liquid in <FIG>). The liquid conduit <NUM> may have lower pressure as compared with pressure in the liquid removal chamber <NUM> to urge the liquid through the hydrophilic material <NUM> into the liquid conduit <NUM>. At the same time, pressure in the liquid conduit <NUM> may be sufficiently high as to prevent gas from entering the liquid conduit <NUM>. Use of the liquid conduit <NUM> allows capture of the separated liquid and may facilitate reuse of the liquid. The liquid in the liquid conduit <NUM> includes water, that is directed to a system that processes the liquid to produce drinking water. Together, the liquid removal chamber <NUM> defined by the hydrophilic material <NUM> and the liquid conduit <NUM> form a liquid capture portion <NUM> of the passive phase separator <NUM> and may be modular according to exemplary embodiments.

As such, a different liquid capture portion <NUM> may be affixed (e.g., screwed, adhered) into the passive phase separator <NUM> as needed. The size and shape of the liquid removal chamber <NUM>, as well as characteristics (e.g., material) of the hydrophilic material <NUM> and the sizing of the liquid conduit <NUM> may be selected based on an expected flow rate and amount of liquid (e.g., slug concentration). For example, if high liquid concentrations (i.e., slugs) are expected frequently at a high flow rate, this may suggest a relatively larger liquid removal chamber <NUM> to store the liquid, a hydrophilic material <NUM> with a higher permeability, and a larger liquid conduit <NUM> to hold and channel that liquid.

<FIG> are cross-sectional views of a liquid capture portion <NUM> of a passive phase separator <NUM> according to two exemplary embodiments. The figures illustrate some of the aspects that may be modified in the modular liquid capture portion <NUM> according to different embodiments. The liquid removal chamber <NUM> is shaped differently in the exemplary embodiment of <FIG> than in the exemplary embodiment of <FIG>. The exemplary shapes are not intended to limit alternate shapes that may be used for the liquid removal chamber <NUM>.

<FIG> illustrates that only a portion of the perimeter of the liquid removal chamber <NUM> may be hydrophilic (e.g., be coated with or formed from hydrophilic material <NUM>). In the exemplary illustration of <FIG>, one of the perimeter walls is hydrophilic. <FIG> also illustrates that the liquid conduit <NUM> may be shaped and sized based on which of the perimeter walls of the liquid removal chamber <NUM> are hydrophilic. For example, the liquid conduit <NUM> has a larger volume in the exemplary embodiment of <FIG> as compared with the exemplary embodiment of <FIG>. This is, at least in part, because the liquid conduit <NUM> in <FIG> only obtains an inflow of liquid from one of the perimeter walls of the liquid removal chamber <NUM>, while the liquid conduit <NUM> in <FIG> experiences an inflow of liquid from all around the liquid removal chamber <NUM>. The different volumes of the liquid conduit <NUM> may additionally be because the flow rate or amount of liquid is expected to be higher when the modular liquid capture portion <NUM> shown in <FIG> is used, for example.

<FIG> is a process flow of a method <NUM> of fabricating a passive phase separator <NUM> with a liquid removal chamber <NUM> according to one or more embodiments. At block <NUM>, arranging an input conduit <NUM> may include disposing the inlet <NUM> of the input conduit <NUM> to receive a multi-phase flow such as a two-phase flow of liquid and gas. The input conduit <NUM> may be fabricated from or coated with hydrophobic material <NUM>. At block <NUM>, forming a gas conduit <NUM> at an angle θ from the input conduit <NUM> may refer to forming the gas conduit <NUM> perpendicular to the input conduit <NUM>, as shown in <FIG>. As previously noted, other angles θ may be formed based on characteristics expected for the incoming flow. At block <NUM>, extending the input conduit <NUM> to meet a liquid removal chamber <NUM> refers to extending the input conduit to an inlet <NUM> of the liquid removal chamber <NUM>. As shown in <FIG>, <FIG>, the liquid removal chamber <NUM> is in line with the input conduit <NUM>, unlike the gas conduit <NUM>, which is at an angle with the input conduit <NUM>.

Claim 1:
A passive phase separator (<NUM>) comprising:
an input conduit (<NUM>) including an inlet (<NUM>) through which multi-phase flow enters the input conduit;
a gas conduit (<NUM>) formed at an angle from the input conduit; and
a liquid removal chamber (<NUM>) formed in line with the input conduit and configured to hold liquid water from the multi-phase flow,
wherein the gas conduit is configured to carry gas from the multi-phase flow to a life support environment,
the multi-phase flow flows from a condensing heat exchanger to the passive phase separator,
a liquid conduit (<NUM>) surrounds the liquid removal chamber, wherein the liquid conduit is configured to direct the liquid water to a system that processes the liquid water to produce drinking water, and
hydrophilic material (<NUM>) defining some or all of a perimeter of the liquid removal chamber (<NUM>), wherein the hydrophilic material is configured to attract and pass through the liquid water.