Patent Description:
A distributor, e.g., a header, in refrigeration systems receives single-phase liquid or two-phase refrigerant flow and divides it equally to provide uniform feed to all passages of an evaporator. Thus each passage of an evaporator in a refrigeration system should have an equal fluid mass flow rate of refrigerant in order for the refrigeration system to effectively to use the evaporator. In addition, the distributor is used to reduce flow from a larger area within the distributor to a smaller area in the individual evaporator paths. Under adverse gravity conditions of the type encountered in aerospace applications, characteristics of the flow dynamics into the evaporator passages from the distributor may result in reduced contact between the working fluid and the evaporator. This may reduce effectiveness of the system. <CIT> discloses a swirl generator having a body portion and a center passage formed in the body portion, and a swirl passage extending between the center passage and an outside of the swirl generator.

According to a first aspect, there is provided an evaporator assembly according to claim <NUM>.

Specific embodiments of the evaporator assembly are disclosed by appended dependent claims <NUM>-<NUM>.

According to a further aspect, there is provided a method according to appended independent claim <NUM>.

In addition, optionally, directing the fluid into the center passage of the swirl generator includes directing the fluid into the center passage of respective ones of a plurality of swirl generators from respective ones of a plurality of outlet ports of the header.

The present invention, as defined by appended independent claims, is illustrated by way of example and not limited in the accompanying figures in which like reference numerals indicate similar elements.

Aspects of the disclosed embodiments will now be addressed with reference to the figures. Aspects in any one figure is equally applicable to any other figure unless otherwise indicated. Aspects illustrated in the figures are for purposes of supporting the disclosure and are not in any way intended on limiting the scope of the disclosed embodiments. Any sequence of numbering in the figures is for reference purposes only.

In a thermal management system, the evaporator utilizes the latent heat of the fluid to absorb waste heat from the heat source. After vaporizing, a vapor phase of the working fluid occupies most of the space inside the evaporator. In the case of removing heat from a large footprint area, the evaporator will be designed to have multiple parallel flow passages which allows the working fluid to be vaporized with reasonable pressure drop and temperature uniformity. In a parallel flow passage design, a flow distribution is a factor determining the overall evaporator performance.

<FIG> shows an insert 50a, known in the art, for an evaporator assembly <NUM> (<FIG>). An insert-passage <NUM> is located at the center of the insert 50a. In <FIG>, the evaporator assembly <NUM> includes a header <NUM> that defines a plurality of outlet ports generally referred to as <NUM>, one of which 70a is shown in a cross section. An evaporator body <NUM> includes a plurality of evaporator passages generally referred to as <NUM>, one 80a of which is illustrated in cross section. The evaporator passages <NUM> are generally parallel to one another in the evaporator body <NUM>.

A plurality of inserts generally referred to as <NUM> are disposed in respective ones of the plurality of outlet ports <NUM>. One insert 50a, which is the insert 50a of <FIG>, is illustrated in cross section. Through the plurality of inserts <NUM>, the respective ones of the plurality of outlet ports <NUM> may fluidly connect to respective ones of the plurality of evaporator passages <NUM>. Heat energy <NUM> may be applied to either side or both sides of the evaporator body <NUM>. To achieve uniform flow distribution in the parallel flow passages design, the plurality of inserts <NUM> are commonly used to create desired back pressure at the entrance of the plurality of evaporator passages <NUM>.

The flow lines <NUM> illustrated in <FIG> indicate the fluid flow direction through the insert-passage <NUM> and inside the evaporator passage 80a in a microgravity environment, such as in an aerospace application. Undisturbed fluid may flow mostly in a straight line without contacting a sidewall <NUM> of the evaporator passage 80a. In order to have an efficient operation, the fluid phase of the working fluid should contact the sidewall <NUM> of the evaporator passage 80a along an entire length of the evaporator passage 80a. Otherwise, available heat along the full length of the sidewall <NUM> may remain in the evaporator body <NUM>. This is inefficient and may result in damage to the evaporator body <NUM>.

In view of the above identified concerns, turning to <FIG> a swirl generator 200a is disclosed herein. The swirl generator 200a includes a swirl generator body <NUM> that extends along a body-center axis <NUM> between opposing ends (inlet and outlet ends) generally referred to as <NUM>. The swirl generator body <NUM> is illustrated as being cylindrical though other shapes are within the scope of the disclosure. A curved outer boundary <NUM> is defined by an outer surface <NUM> of the swirl generator body <NUM> at the outlet end 218a of the swirl generator body <NUM>.

The curved outer boundary <NUM> is illustrated as a rounded edge, such as a fillet. A center passage <NUM> having opposing ends (inlet and outlet ends) generally referred to as <NUM> is defined by the swirl generator body <NUM>, and which extends along the body-center axis <NUM>. The outlet end 260a of the center passage <NUM> is intermediate the opposing ends <NUM> of the swirl generator body <NUM>. The inlet end 260b of the center passage <NUM> is disposed on the body-center axis <NUM>. The center passage <NUM> identified herein may be formed at least initially, that is before additional passages (identified below) are fabricated in the swirl generator 200a, as blind hole. As would be understood by one of ordinary skill, a blind hole refers to a hole that is reamed, drilled, or milled to a specified depth without breaking through to the other side of a workpiece.

A swirl passage 270a is defined by the swirl generator body <NUM>. The swirl passage 270a extends between the outlet end 260a of the center passage <NUM> and the curved outer boundary <NUM>. The swirl passage 270a defines a swirl-passage axis <NUM> extending between a swirl passage inlet 290a and a swirl passage outlet 300a. The swirl passage inlet 290a is defined at the outlet end 260a of the center passage <NUM> and the swirl passage outlet 300a is defined on the curved outer boundary <NUM>.

The body-center axis <NUM> and the swirl-passage axis <NUM> are oriented at an angle <NUM>, which may be an acute angle with respect to the body-center axis <NUM>. Thus, as will be explained below, the swirl passage 270a is designed to tangentially face the sidewall <NUM> of the evaporator passage 80a (<FIG>). A center passage diameter D1 is larger than a swirl passage diameter D2. This way, fluid is throttled through the swirl passage 270a from the center passage <NUM>.

The outer surface <NUM> of the swirl generator body <NUM> defines a flange <NUM> between the opposing ends <NUM> of the swirl generator body <NUM>. The flange <NUM> partitions the swirl generator 200a into opposing sides generally referred to as <NUM>. One side 340a of the swirl generator body <NUM> is between the flange <NUM> and the outlet end 218a of the swirl generator body <NUM>. Another side 340b of the swirl generator body <NUM> is between the flange <NUM> and the inlet end 218b of the swirl generator body <NUM>. The flange <NUM> is used, as indicated below, for seating of the swirl generator 200a between the header <NUM> and the evaporator body <NUM> in the outlet port 70a. An outer diameter DS1 of the swirl generator body <NUM> is larger on the one side 340a of the swirl generator body <NUM> than the diameter DS2 of the other side 340b of the swirl generator body <NUM>. The configuration of the outer surface <NUM> of the swirl generator body <NUM>, as indicated below, enables a proper fitting between the header <NUM>, the swirl generator 200a and the evaporator body <NUM>. However this configuration is not intended on limiting the relative sizing of the opposing sides <NUM> of the swirl generator body <NUM> relative to each other and the flange <NUM>. In addition, in certain embodiments a flange <NUM> is not provided.

As illustrated, the swirl generator 200a includes a plurality of swirl passages generally referred to as <NUM>. The outlet end 260a of the center passage <NUM> defines a plurality of swirl passage inlets generally referred to as <NUM>. The curved outer boundary <NUM> defines a plurality of swirl passage outlets generally referred to as <NUM>. As illustrated, the outlet end 260a of the center passage <NUM> and the curved outer boundary <NUM> are each annular. With the illustrated configuration, the plurality of swirl passages <NUM> are circumferentially offset from one another and axially aligned with one another along the body-center axis <NUM>.

<FIG> shows an evaporator assembly <NUM> which is similar to the evaporator assembly 55a of <FIG> except as identified. The evaporator assembly <NUM> includes the header <NUM> that defines the plurality of outlet ports <NUM>, one 70a of which is illustrated in cross section. The evaporator body <NUM> defines the plurality of evaporator passages <NUM>, one of which 80a is illustrated in cross section. The plurality of outlet ports <NUM> are in fluid communication with respective ones of the plurality of evaporator passages <NUM>. Heat can be applied to either side or both sides of the evaporator body <NUM>. A plurality of swirl generators generally referred to as <NUM> are disposed in respective ones of the plurality of outlet ports <NUM>. One swirl generator 200a, which is the swirl generator 200a of <FIG>, is illustrated in cross section. Through the plurality of swirl generators <NUM>, the respective ones of the plurality of outlet ports <NUM> may fluidly connect to respective ones of the plurality of evaporator passages <NUM>.

The outlet port 70a in the header includes one portion <NUM> that is sized to receive the evaporator body <NUM>. As indicated, the one side 340a of the swirl generator body <NUM> is received within the evaporator passage 80a. Another portion <NUM> of the outlet port 70a is sized to receive the other side 340b of the swirl generator body <NUM>. An intermediate portion <NUM> of the outlet port 70a is sized to receive the flange <NUM> of the swirl generator 200a. The flange <NUM> prevents movement of the swirl generator 200a relative to the header <NUM> and the evaporator body <NUM>. The evaporator passage 80a has a larger flow area than the one portion <NUM> of the outlet port 70a. Therefore, as indicated, the one side 340a of the swirl generator body <NUM> has a larger diameter than the other side 340b of the swirl generator body <NUM>. However, as indicated, this configuration is not intended on limiting the relative sizing of the opposing sides <NUM> of the swirl generator body <NUM>.

The curved outer boundary <NUM> of the swirl generator body <NUM>, and thus the swirl passage outlet 300a, is adjacent to and at least partially faces the sidewall <NUM> of the evaporator passage 80a. This configuration enables the creation of a swirl flow <NUM> within the evaporator passage 80a. That is, after flowing into the swirl generator 200a, the single-phase liquid or two-phase fluid is guided into the plurality of swirl passages <NUM>. The fluid exits the swirl generator 200a along a tangential direction relative to the flow path <NUM> of the fluid and with the angle <NUM> with respect to the centerline <NUM> of the evaporator passage 80a. Due to the orientation of the plurality of swirl passages <NUM>, the fluid exiting the swirl generator 200a will have both an axial velocity component AV and a radial velocity component RV relative to the geometry of the evaporator passage 80a. Once inside the evaporator passage 80a, the radial flow velocity component RV moves the fluid towards a sidewall <NUM> of the evaporator passage 80a and the axial velocity component AV moves the fluid downstream in the evaporator passage 80a.

The swirl generator 200a may be used in different types of evaporator assemblies for example with evaporator bodies having different flow passage geometries. Two exemplary evaporator bodies <NUM>, <NUM>, defining respective evaporator flow passage surfaces having a smooth inner geometry and a grooved inner geometry, are respectively shown in <FIG>. It should be noted that a variety of flow passage geometries may be implemented and fit within the scope of the present disclosure.

The disclosed embodiments provide an efficient evaporation process inside an evaporator and result in a more uniform temperature distribution on outside surface of the evaporator.

Turning to <FIG>, a method is disclosed for evaporating a single-phase liquid or two-phase fluid with the evaporator assembly <NUM>. As show in block <NUM> the method includes directing a single-phase liquid or two-phase fluid into the header <NUM>. Block <NUM> shows that the method includes directing the fluid into the center passage <NUM> of the swirl generator 200a from the outlet port 70a of the header <NUM>. As shown in block <NUM> the method includes directing the fluid into the swirl passage 270a defined by the swirl generator 200a.

As shown in block <NUM> the method includes directing the fluid into the evaporator passage 75a of the evaporator body <NUM>, from the swirl passage 270a. As shown in block <NUM> the method includes forming a swirling fluid stream as the fluid exits the swirl passage 270a. From this configuration the fluid moves towards the sidewall <NUM> of the evaporator passage 80a and moves downstream along the evaporator passage 80a.

Claim 1:
An evaporator assembly (<NUM>) including:
a header (<NUM>) that defines an outlet port (<NUM>);
an evaporator body (<NUM>) that defines an evaporator passage (<NUM>) in fluid communication with the outlet port;
an swirl generator (200a) for the evaporator, comprising:
a swirl generator body (<NUM>) that extends along a body-center axis (<NUM>) between opposing inlet and outlet ends (<NUM>), the swirl generator body including a fluid inlet at the inlet end,
wherein the swirl generator body includes an outer surface (<NUM>) that, at the outlet end, defines an outlet region that includes a curved outer boundary (<NUM>) that forms a convex curve that extends radially inward from an outer diameter surface of the body to an outer axial surface of the body;
a center passage (<NUM>) formed within the swirl generator body that extends from the inlet towards the outlet along the body-center axis; and
a swirl passage (270a) formed at the outlet end of the swirl generator body,
the swirl passage extending between the center passage and the curved outer boundary along a swirl passage axis such that a fluid entering the center passage from the inlet end exits the swirl generator body at the curved outer boundary, wherein the swirl passage axis forms an acute angle (<NUM>) with the body-center axis, wherein the curved outer boundary of the swirl generator body is adjacent to and at least partially faces a sidewall of the evaporator passage.