WO1991002146A1

WO1991002146A1 - Circumferential heat exchanger

Info

Publication number: WO1991002146A1
Application number: PCT/US1990/004182
Authority: WO
Inventors: James C. Noe
Original assignee: Nomac Energy Systems, Inc.
Priority date: 1989-07-28
Filing date: 1990-07-25
Publication date: 1991-02-21
Also published as: AU6165190A

Abstract

A circumferential heat exchanger (10) comprising three concentric tube members; an outer member (12), a middle tube member (20) and an inner tube member (30). The outer and inner tube members (12, 30) each have an inlet port (14, 32) and an outlet port (16, 34) formed longitudinally along the axis (A) thereof and spaced approximately 180 degrees apart. The outer and middle tube members (12, 20) form a first annular fluid passageway (22) and the middle and inner tube members (20, 30) form a second annular fluid passageway (24). The ends of the first and second fluid passageways are sealed. A first heat exchange medium is directed into and out of said first fluid annular passageway (22) and a second heat exchange medium is directed into and out of the second annular fluid passageway (24) such that each medium flows both clockwise and counter clockwise about axis of the heat exchanger (10). The heat exchanger (10) surrounds a combustor (100) and a turbo-compressor (102).

Description

CIRCUMFERENTIAL HEAT EXCHANGER

BACKGROUND OF THE INVENTION

This invention relates to a heat exchanger and more particularly to a heat exchanger having circumferential flow around the axis of the heat exchanger.

Heat exchangers have long been used for efficiently transferring heat . from one medium to another, using alike or distinct mediums. Today the majority of high temperature, high efficient heat exchangers are either plate fin or fin tube design. The plate fin design requires extensive and expensive engineering for a particular application for which it is to be used. Plate fin heat exchangers are difficult to assemble, require intricate manifolding arrangements and experience significant end losses. The fin tube design requires a large number of connections, is difficult to assemble by comparison and is limited in its overall efficiency.

When either the plate fin or tube fin design is used in an application which requires high pressure heat exchange, a substantial amount of welding or brazing is required in order to maintain the pressure seal. These designs therefore pose severe quality control challenges. Furthermore, to conserve material and reduce costs, the flow passages tend to be small resulting in large pressure drops across the flow passages.

A typical application for a high pressure heat exchanger is a stationary gas turbine recuperator. These heat exchangers are subject to high pressure differentials but can reduce fuel consumption from 15% to 50% as compared to applications which do not utilize a recuperator. However, even with the significant reduction in fuel consumption, because of the high design costs, high capital costs and high pressure drop, plate fin and fin tube heat exchangers are used on less than 1% of stationary gas turbines.

SUMMARY OF THE INVENTION

The heat exchanger in accordance with the present invention comprises three concentric tube members having desired diameters which are sealed at each end thereof. The first and outer tube member includes an inlet « and outlet port formed therein. The inlet and outlet ports are formed along the axis of the first tube member as either a slit or a series of holes which are spaced approximately 180 degrees apart. The -second or middle tube member acts as a partition between a first fluid (gaseous and/or fluid) medium which flows in the first annular passageway formed by the outer and middle tube members and a second fluid (gaseous and/or fluid) medium flowing in a second annular passageway formed by the middle tube member and an inner tube member. The inner tube member includes an inlet and outlet port which can be formed as a slit or series of holes along the axis of the inner tube member in the same manner as the outer tube.

In Operation, the first fluid medium flows into the inlet port of outer tube member and then downward, both clockwise and counterclockwise, between the outer and middle tube members before exiting through the outlet port of the outer tube member. Correspondingly, the second heat exchange medium can enter the inlet port in the inner tube member and flow both clockwise and counterclockwise in the second annular passageway formed between the middle and inner tube members before exiting the heat exchanger through the outlet port formed in the inner tube member. by reversing the direction of flow in one of the passageways, the heat exchanger mediums are in parallel flow rather than counterflow. In either flow configuration, the heat transfer takes place across the middle tube member (primary surface) .

In its preferred embodiment, the middle tube member is formed as a bellows having folds which have a height which is less than the radial distance between the outer and inner tube members. One end of the middle tube member or bellows has a first middle tube flange member extending radially inward and the other end having a second middle tube flange member extending radially outward. Thus, the first middle tube flange member has a diameter only slightly larger than the diameter of the inner tube member. Correspondingly, the outer tube member has an outer tube flange member at one end which includes a radially inwardly extending section which extends inwardly to a radial distance slightly greater than the first middle tube flange member and a cylindrical section which forms a concentric tube with the outer tube member. In addition, the inner tube member, at its end which is opposite the end of the outer tube flange member, includes an outwardly extending inner tube flange member. The inner tube flange member includes a radially outwardly extending section which extends outwardly a radial distance which is slightly less than the diameter of the second middle tube flange member and cylindrical section attached at the end thereof which forms a concentric tube with the inner tube. The ends of the heat exchanger can be sealed in order to seal the sides of the first and second annular passageways. BRIEF DES CRIPTION OF THE DRAWINGS

The "" accompanying drawings illustrate the invention. In such drawings:

FIGURE 1 is a perspective view of the heat exchanger of the present invention.

FIGURE 2 is a schematic view taken perpendicular^ to the axis of the heat exchanger of the present invention having non-mating ends.

FIGURE 3 is a schematic view of the heat exchanger of FIG. 1 taken along line 3-3 of FIG. 2.

FIGURE 4 is a schematic view taken perpendicular to the axis of the heat exchanger of the preferred embodiment.

FIGURE 5 is a cross sectional view of the heat exchanger of the* preferred embodiment taken along line 5-5 in FIG. 4.

FIGURE 6 is a cross- sectional view of the preferred embodiment having a corrugated middle tube.

FIGURE 7 is a cross- sectional view of the preferred embodiment having a middle tube formed as a bellows.

FIGURE 8 is a cross- sectional view of the preferred., embodiment^' taken along line 8-8 of FIG. 7.

FIGURE 9 is a cross-sectional view of the preferred embodiment in its disassembled state.

FIGURE 10 is a cross- sectional view of the preferred embodiment of the present invention detailing one embodiment of the manifolding.

FIGURE 11 is a cross-sectional view of the preferred embodiment of the present invention showing a second manifold design.

FIGURE 12 is a cross- sectional view of two circumferential heat exchangers of the present invention in series.

FIGURE 13 is a side view of multiple circumferential heat exchangers of the present invention. FIGURE 14 is a cross- sectional view of multiple circumferential heat exchangers.

FIGURE 15 is a schematic diagram of one particular arrangement utilizing the heat exchanger of the present invention with a gas turbine.

DETAILED DES CRIPTION OF THE INVENTION

Referring to FIGS. 1-3, shown is a heat exchanger 10 of the present invention. The heat exchanger 10 includes a first or outer tube member or duct 12, a second or middle tube member or duct 20 and a third or inner tube member 30 concentric with each other. The outer tube member 12 includes inlet and outlet ports 14 and 16 respectively. Inlet and outlet ports 14 and 16 are formed approximately 180 degrees apart from one another as shown in FIG. 1. Ports 14 and 16 could also be formed as series of holes which would extend axially along a portion of the outer tube member 12. The middle tube member 20 is concentric within outer tube number 12 and having a diameter sized to provide the desired radial distance between the two tube members thereby forming a first annular or first fluid passageway 22 therebetween. Concentric within the middle tube member 20 is the inner tube member 30 having a desired diameter thereby forming a second annular or second fluid passageway 24 between the middle and inner tube members, 20 and 30 respectively. As with other tube member 12, inner tube member 30 includes inlet and outlet ports, 32 and 34 respectively, which are approximately 180 degrees apart and are formed as a slit or a* series of holes extending axially along a portion of the inner tube member 30. Outlet port 34 is shown as being formed as a slit which extends axially along the portion of the bottom of inner tube member 30. Inner tube member 30 defines cylindrical space 31. At each end of the concentric tube members is a doughnut shaped seal 36 which is sealingly attached to the ends of each tube member. In this manner, seal 36 seals the first and second fluid passageways ^'22 and 24 from the environment while middle tube member 20 prevents communication of fluid between the two fluid passageways. If desired, fins (not shown) can be added to any of the three tube members to increase overall heat transfer.

During operation, a first fluid or heat exchange medium is directed to the inlet port 14 in outer tube member 12 via manifold 15 (FIG. 10) and flows within annular passageway 22 circumferentially in both directions about the axis of the tube members around the middle tube .--member 20 in the first fluid passageway 22 before exiting the outlet port 16 in outer tube member 12 into a manifold 17 (FIG. 10) . Similarly, a .-second fluid or heat exchange medium is directed to the inlet port 32 in inner tube member 30 which then flows both clockwise and counterclockwise within the second fluid passageway 24 before exiting at the outlet port 34 in inner tube member 30. Thus, as described* the heat exchanger is in counter-flow. However, it is envisioned that by reversing the direction of flow of one of the fluids, the heat exchanger could offer parallel heat exchange. Therefore, the inlet and outlet ports of the outer 12 and inner 30 tube members could act as entry or exit ports. Furthermore, it is understood that the ports do not have to be directly opposite each other and if desired, there could be more than one entry or exit ports for either or both fluid passageways 22 and 24. In addition, the tube members do not have to be concentric to one another but can be offset depending upon the application.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Shown in FIGS. 4 to 9 is the present invention in this preferred embodiment. As shown in FIG. 5 the ends of the outer, middle and inner tube members 12, 20 and 30 respectively, have been formed with flanges thereon. As shown, one end of outer tube member 12 has been formed with an outer tube flange member 50 which includes a radially inwardly extending portion 52 and a cylindrical section 54. Outer tube cylindrical section 54 is concentric with all three tube members and has a diameter slightly larger than the diameter of the inner tube member 30.

Similarly, inner tube member 30 has a flange member 58 at one end thereof which includes a radially outwardly extending portion 60 and a cylindrical section 62. Cylindrical section 62 is also formed to be concentric with each of the other tube members and has a diameter slightly smaller than the diameter of the outer tube member 12. Inner tube flange member 58 is formed on the end of inner tube member 30 which is opposite of the end of outer tube member 12 on which tube flange member 50 is formed.

Middle tube member 20 includes a first and a second middle tube flange member, 64 and 70 respectively each formed at one end thereof. The first middle tube flange member 62 is formed on the end of the middle tube member 20 which is adjacent the outer tube flange member 50 and includes a radially inwardly extending section 66 and cylindrical section 68 (FIG. 9) which has a diameter slightly larger than the diameter of inner tube member 30. At the outer end of middle tube member 20 is the second middle tube flange member 70 and it includes a radially outwardly extending section 72 and a cylindrical section 74 (FIG. 9) which has a diameter slightly smaller than the diameter of the outer tube member 12. When formed with the desired sizes, the cylindrical sections (68,74) of the first and second middle tube flange members (64,70) -8-

slidably fit or are press fit the outer tube flange member 50 and the inner tube member 30 at one end and the outer tube member 12 and the cylindrical section 62 of the inner tube flange member 58 at the other.

As described in reference to FIGS . 1 and 3 the heat exchanger of the preferred embodiment is formed with inlet and outlet ports in both the inner and outer tube members, 12 and 30 respectively, and the three tube members (12, 20 and 30) form the first and second fluid passageways 22 and 24 as described above. Once assembled the ends of the three tube members can be joined by either a weld or braze joint 80 or rolled or crimped 81 as shown in FIG. 6 depending on the application.

FIGS. 10 and 11 disclose two manifold designs which can be utilized with the present invention. As shown in FIG. 10, one end of inner tube member .is sealed with a circular end seal 82. A horizontal manifold 84 divides internal cavity 31 such that inlet and outlet ports 32 and 34 in the inner tube member 30 are separated from one another by the horizontal manifold 84. In this manner, the second heat exchange medium can be directed into one side of cavity 31, flow clockwise and counterclockwise within the second annular passageway 24 and exit into cavity 31 on the opposite side of horizontal manifold 84. In this configuration, second heat exchange medium enters and exits the heat exchanger 10 at the same end.

As shown in FIG. 11, a slanted, elliptically shaped manifold 86 can be used within cavity 31 to separate the inlet and outlet ports 32 and 34 of inner tube member 30. In this manner, the second heat exchange medium enters at one end of heat exchanger 10 and exits at the opposite end. While two examples of manifolding have been shown for the second heat exchange medium, it is evident that many other design schemes can also be used. Similarly, the manifolding 15 and 17 for the first heat exchange medium can be formed by any design which ducts the first heat exchange medium into and out of the inlet and outlet ports of the outer tube member 12.

FIG. 12 discloses two heat exchangers of the present invention in series. As shown, the first heat exchanger medium enters the first annular passageway 22 via inlet manifolding 15, flows circumferentially around the axis of the heat exchanger in heat exchange with the second medium and exits via manifold 17 which in turn directs the first heat exchange medium into the inlet port of the outer tube member of the second heat exchanger. The first medium then flows circumferentially around the axis of the second heat exchanger in heat exchange relationship to a third heat exchange medium as shown.

FIGS. 13 and. 14 disclose a plurality of circumferential heat exchangers 10 of the present invention arranged to show the versatility and compactness of the present invention. As shown, four heat exchangers (10A, 10B, IOC and 10D) having the horizontal manifold shown in FIG. 10 have been arranged such that each heat exchanger longitudinally contacts the outer tube member of the two other heat exchangers. While any number of heat exchangers could be used, the use of four heat exchangers discloses the principles and complexity involved in the system. The line 88 along which each heat exchanger contacts the adjacent heat exchanger is sealed thereby forming an internal chamber 89 among the four heat exchangers. Inlet ports 14 formed in the outer tube member 12 of each heat exchanger open into internal chamber 89. The outlet ports 16 of the outer tube members 12 open into a chamber 91 formed by a manifold 90 which encompasses all four circumferential heat exchangers. Similarly, the second fluid medium is manifolded into one side of chamber 31A formed within each inner tube member 30 by horizontal manifold 84, flowing simultaneously into the second annular passageway of each of the four heat exchangers and exiting into chamber 3 IB before being recombined with the outlet flow from each of the other three heat exchangers. _

The circumferential heat exchanger of the present invention is especially suited to be used in a heat exchanger system, for example, a sub atmospheric gas turbine, a positive pressure gas turbine, an air cycle heating or cooling system or the like. The components of the system can be located entirely or partially within cavity 31. In this manner a very compact heat exchanger system is formed in which there is a large reduction in the ducting required and therefore a substantial reduction in efficiency losses associated with a high pressure drop. In addition, there is a substantial reduction in radiant heat losses since any heat from the system components is absorbed by the fluid medium within the sfeέond annular passageway 24.

. By ray of example, shown in FIG. 15 is the heat exchanger 10 of the present invention in combination with a mechanical system such as a sub atmospheric gas turbine comprising a combustor 100 and a turbo-compressor 102. As shown, ambient air enters the inlet port 12 of the first annular passageway 22, flows circumferentially around the axis of the heat exchanger and exits the first annular passageway 22 into outlet manifolding 17 wherein it is directed to combustor 100. Within combustor 100 the heated ambient air is added to natural gas for combustion therein. The hot gases exhaust combustor 100 and are directed to the turbine 104 of turbo-compressor 102. The hot gases expand through the turbine 104 and exhaust within cavity 31 as shown.

Cavity 31 is divided by an elliptically shaped manifold 86 as shown and has a circular end seal 82. Thus, the turbine discharge gas flows directly in the second annular passageway 24 (hot side of heat exchanger) via inlet ports formed in the inner tube member 30 as described above. The turbine exhaust gases are cooled during heat exchange with the ambient air, and thereafter exit the second annular passageway 24 and the heat exchanger 10 into cavity 31 on the opposite side of manifold 86. The exhaust gases thereafter enter compressor 106 via inlet 112 of turbo-compressor ,102 wherein the gases are compressed to ambient pressure and thereafter discharged via the compressor outlet 113. The turbine 104 drives the compressor 106 and can also be used to drive an electrical, mechanical, pneumatic or hydraulic load (not shown) .

Although there have been described above specific embodiments of a heat exchanger in accordance with the invention for the purpose of illustrating the manner in which the invention may be used to advantage, it will be appreciated that the invention is not limited thereto. Accordingly, any and all modfications, variations or equivalent arrangements which may occur to those skilled in the art should be considered to be within the scope of the invention as defined in the appended claims.

Claims

WHAT IS CLAIMED IS ;

1. A system, comprising: heat exchanger means for defining a first and a second annular passageway and a cavity internal to said first and second annular passageways;

-means for directing fluid medium(s) into each of said first and second annular passageways; means for collecting fluid medium from at least one of said annular passageway; and system means, located at least partially within said cavity, for utilizing the fluid medium(s) exiting at least one of said annular passageways.

2. The system of claim 1 wherein said heat exchanger means comprises: an inner tube member; a middle tube member about said inner tube member; an outer tube member about said middle tube member, thereby defining said first annular passageway between said middle and outer tube members, and said second annular passageway between said inner and middle tube members; and means for sealing the ends of each annular passageway.

3. The system of claim 1 wherein said system means comprises: a combustor.

4. The system of claim 1 wherein said system means comprises: gas turbine including a combustor and a turbo-compressor.

5. The system of claim 4 wherein the means for collecting fluid medium from at least one of said annular passageways comprises a first manifold means for collecting the fluid medium exiting the first annular passageway and directing said fluid medium to said combustor.

6. The system of claim 5 wherein said means for directing a fluid medium into said second annular passageway comprises a second manifold means separating said cavity into a first and a second chamber, aid first chamber enclosing the combustor and turbine portion of the turbo-compressor and the second chamber enclosing the compressor portion of the turbo-compressor.

7. The system of claim 6 wherein said means for collecting fluid medium further comprises an end seal at each end of said cavity.

8. The system of claim 7 further comprising a third manifold means for directing the fluid medium exiting the compressor to a point outside of said system.

9. A gas turbine combustor system comprising: a combustor; heat exchanger means for defining a first annular passageway and a second annular passageway wherein flow within each passageway is in both directions about the axis of each annular passageway; means for introducing ambient air and extracting heated ambient air from said first annular passageway; first manifold means for directing said heated ambient air to said combustor; turbine means for expanding the exhaust gases of said combustor; second manifold means for directing the expanded exhaust gases into said second annular passageway; third manifold means for directing the exhaust gases exiting the second annular passageway to a compressor; and a compressor outlet manifold means for directing the compressed exhaust gases outside the system.

10. The gas turbine combustor system of claim 9 wherein said means for defining a first and a second annular passageway comprises: an outer tube member including an inlet and an outlet port formed longitudinally along said outer tube member; a middle tube member within the outer tube member, said outer tube member and said middle tube member forming a first annular passageway therebetween; an inner tube member including an inlet and an outlet port formed longitudinally along said inner tube member within said middle tube member, said inner tube members and said middle tube member forming a second annular passageway therebetween; means for sealing said first and second annular passageways between each end of said three tube members; an outer tube member inlet manifold flow connected to said inlet port of said outer tube which directs a first heat exchange medium to said first annular passageway-; an outer tube member outlet manifold flow connected to said outlet port of said outer tube member which collects the first heat exchange medium; and a second passageway manifold means for directing a second heat exchange medium to said inlet port in said inner tube member and collecting said second heat exchange medium from said outlet port of said inner tube member.

11. The gas turbine combustor system of claim 10 wherein said means for sealing comprises: a radially outwardly extending flange member on one end of said inner tube member having a diameter slightly smaller than the outer tube diameter; a first middle tube flange member extending radially outwardly from one end of said middle tube member having a diameter slightly smaller than the outer tube member diameter and a radially inwardly extending flange member on the other end of said middle tube member having a diameter slightly larger than the inner tube member diameter; a radially inwardly extending flange member at one end of said outer tube member having a diameter slightly larger than the radially inwardly extending flange member of said middle tube member, said outer tube flange member formed at the opposite end of said inner tube flange member; and means for sealing the ends of each of said inner tube flange member, the first middle tube flange member and the end of said outer tube opposite of said outer tube flange member together and the other end of the inner tube, the second middle tube flange member and the outer tube flange member together in sealed relationship. 12. The gas turbine combustor system of claim 9 wherein said means for defining a first and a second annular passageway comprises: at least three concentric tubular members thereby defining an innermost and outermost tubular member; means to seal the radial space between the inner most and outermost concentric tubular members; means to introduce and extract a first fluid medium through circumferentially spaced apart locations in the outermost of said concentric tubular members,

13. The gas turbine combustor system of claim 12 wherein said means to seal comprises: a radially outwardly extending flange member on one end of said inner tube member having a diameter slightly smaller than the outer tube diameter; a first, middle tube flange member extending radially outwardly from one end of said middle tube member having a diameter slightly smaller than the outer tube member diameter and a radially inwardly extending flange member on the outer end of said middle tube member having a diameter slightly larger than the inner tube member diameter; a radially inwardly extending flange member at one end of said outer tube member having a diameter slightly larger than the radially inwardly extending flange member of said middle tube member, said outer tube flange member formed at the opposite end of said inner tube flange member; and means for sealing the ends of each of said inner tube flange member, the first middle tube flange member and the end of said outer tube opposite of said outer tube flange member together and the other end of the inner tube, the second middle tube flange member and the outer tube flange member together in sealed relationship.

14. The system according to claim 1 wherein said system means for utilizing the fluid mediu (s) comprises: an air cycle turbomachine.

16. A heating/ refrigeration system comprising: a heat exchanger defining a first and a second annular passageway, each having an inlet and an outlet, said second annular passageway within said first annular passage and second annular passageway defining a cavity; means for directing a first fluid medium into said first annular passageway; first manifold means flow connected to the outlet of the first annular passageway; combustor means, receiving said first fluid medium, for producing energy; system means for producing work; second manifold means for directing said first fluid medium into the inlet of said second annular passageway; third manifold means for collecting the fluid medium exiting the second annular passageway and directing it back into said system means; and fourth manifold means for directing the fluid exiting the system means outside of the heating/ cooling system.