US3759323A

US3759323A - C-flow stacked plate heat exchanger

Info

Publication number: US3759323A
Application number: US00199928A
Authority: US
Inventors: D Keedy; E Mangus; H Dawson; W Hoftiezer; E Patton; J Grandfield
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1971-11-18
Filing date: 1971-11-18
Publication date: 1973-09-18
Anticipated expiration: 1990-09-18
Also published as: GB1400794A; CA959043A; DE2251286C3; JPS54180350U; DE2251286B2; DE2251286A1; BE791533A; JPS4863349A

Abstract

A primary surface plate-type heat exchanger has sheets with triangular zones on opposite sides of a central rectangular area stacked alternately to provide a C-shaped flow path for two fluids. Corrugations in the sheet surface serve to direct fluid flow and to support adjacent sheets.

Description

United States Patent [191 Dawson et al.

[ Sept. 18, 1973 1 1 C-FLOW STACKED PLATE HEAT EXCHANGER [75] inventors: Harry J. Dawson, Dunlap; Wallace A. Hottiezer, Peoria; David E. Keedy, Pekin; Ervin E. Mangus, Brimfield; Eugene K. Patton; Joseph P. Grandlleld, both of Peoria, all of I11.

{73] Assignee: Caterpillar Tractor Co., Peoria, 111.

[22] Filed: Nov. 18, 1971 211 App]. No.: 199,928

[52] US. Cl. 165/166 [51] Int. Cl. F28b 3/04 [58] Field of Search 165/166, 167

[56] References Cited UNITED STATES PATENTS 8/1970 Rothman 165/166 3,183,963 5/1965 Mondt 165/166 X 3,249,155 5/1966 Huet 165/166 3,256,930 6/1966 Norback 165/166 3,364,992 1/1968 Biabaud 165/166 3,613,782 10/1971 Mason 165/166 Primary Examiner-Charles J. Myhre Assistant Examiner-Theophil W. Streuhler, Jr.

Attorney-Donald C. Feix et a1.

57 ABSTRACT A primary surface plate-type heat exchanger has sheets with triangular zones on opposite sides of a central rectangular area stacked alternately to provide a C- shaped flow path for two fluids. Corrugations in the sheet surface serve to direct fluid flow and to support adjacent sheets.

8 Claims, 12 Drawing Figures Patented Sept. 18, 1973 4 Sheets-Sheet l m w M m I wmwm GN E HNA W R IA G MNP Mwm

WEJ

WEA

AEP

Hmw

. ZTTORNEYS Patented Sept. 18, 1973 3,759,323

4 Sheets-Sheet 2 a W A 3114 92 MR INVENTORS HARRY J. DAWSON WALLACE A. HOFTIEZER DAVID E. KEEDY ERVIN E. MANGUS EUGENE K,PATTON JOSEPH P. GRANDFIELD ATTORNEYS Patented Sept. 18, 1973 4 SheetsSheet 5 A GA\? 52 m 54 G S HARRY J. DAWSON WALLACE A. HOFTlEZER DAVID E. KEEDY ERVIN E. MANGUS EUGENE K. PATTON JOSEPH P. GRANDFIELD ATTORNEYS 'Patentecl Sept. 18, 1973 INVFNTURS HARRY J. DAWSON WALLACE A. HOFTIEZER DAVID E. KEEDY ERVIN E. NGUS EUGENE K. PATTON JOSEPH F? ANDFIELD 1 C-FLOW STACKED PLATE HEAT EXCHANGER BACKGROUND OF THE INVENTION 2,321,110 issued June 8, 1943 3,042,382 issued July 3, 1962 3,216,494 issued Nov. 9, 1965 3,29l,206 issued Dec. 13, 1966 None of the prior art constructions, such as those indicated above, has heretofore presented a compact, relatively adaptable construction that could be mated with an internal combustion engine with a minimum of complex and expensive ducting.

SUMMARY OF THE INVENTION It is an object of this invention to provide a compact, low profile, primary surface heat exchanger.

Another object is to arrange an efficient primary surface heat exchanger so that the respective flow paths of fluids through the exchanger are generally C-shaped.

Another object is a heat exchanger compatible with typical engine arrangements to reduce costly ducting requirements and consequently to reduce flow dynamic losses attributed to ducting.

Other objects and advantages of the present invention will become more readily apparent upon reference to the accompanying drawings and following description.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is an exploded perspective view of a group of plates;

FIG. 2 is a sectional view taken in the direction of arrows II--II in FIG. 1 and FIG.

FIG. 3 is a sectional view taken in the direction of arrows III-III in FIG. 1 and FIG. 6;

FIG. 4 is a sectional view taken in the direction of arrows IV-IV in FIG. 1;

FIGS. 5 and 6 are plan views of an alternate arrangement of plates;

FIG. 7 is a sectional view taken in the direction of arrows VII-VII in FIG. 5;

FIG. 8 is a partial plan view showing the stacked relationship of adjacent sheets detailed in FIGS. 5 and 6;

FIG. 9 is a sectional view taken in the direction of arrows IX-IX in FIG. 8;

FIG. 10 is a perspective view of an alternative form of two adjacent plates;

FIG. 11 is a perspective view of a typical gas turbine engine showing one application of the subject invention; and

FIG. 12 is a schematic diagram illustrating fluid flow paths through the heat exchanger arrangement presented in FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, four

Sheets

2, 4, 6 and 8 are shown, with Sheet 2 identical to Sheet 6, and Sheet 4 identical to Sheet 8.

Each sheet contains three principal regions. For example, Sheet 2 has a corrugated central rectangular area 10 flanked by embossed triangular-

shaped zones

12 and 14 on both sides.

In the triangular zone 12, a base 16 is coincident with one side of the central rectangular area 10, so that the

sides

18 and 20 therefore form two of the six outer edges of Sheet 2.

Edge bars, such as 22 and 24 attached to

Sheet

2, 26 and 28 attached to

Sheet

4, and 30 and 32 attached to Sheet 6, serve to space the sheets apart as well as seal the edges, thus preventing leakage and intermixing of fluids.

One edge of each triangular shaped zone, such as 34 and 36 on

Sheet

8, and 110 and 112 on Sheet 6, is not sealed by an edge bar, thereby forming apertures when

Sheets

4, 6 and 8 are stacked.

While only four sheets are shown in FIG. 1, it should be understood that a large number of sheets are stacked in pairs, such as

Sheets

2 and 4, to form a heat exchanger core of the desired size.

Typical sections of the

Sheets

2 and 4 are shown in FIGS. 2 and 3, respectively.

As may readily be seen, when the Sheet 2 is placed on the Sheet 4 to form one pair of plates in a stack, the sheets will be supported and spaced apart by the

edge bars

26 and 28 and by the crowns 38 and the valleys 40 of corrugations in the central rectangular area of the sheets.

Likewise, dimples or thimbles embossed into the sheets in the triangular side zones provide support and spacing for these areas of the sheets.

In FIG. 4, it can be seen that the embossments 42 terminate short of the outer edge 44, thus providing a narrow flat margin 46 for the attachment of edge bars such as the bar 32.

This forms an effective seal to prevent leakage and intermixing of fluids.

An alternate arrangement, wherein the central rectangular area is flanked by two triangular shaped zones on each side, is presented in FIGS. 5 and 6.

In FIG. 5, the

edge bars

48, 50, 52, 54, 56 and 58 are attached to the Sheet 60.

In FIG. 6, the edge bars 62 and 64 are attached to the Sheet 66.

The Sheets and 66 are flat throughout the triangu lar side zones.

As shown in section in FIG. 7, filler Sheets 68 are placed in the zone to provide structural support and directional guidance of flow. These plates may be placed loosely on the Sheet 60, or attached to the edge bar 54 other so that corrugations on adjacent sheets will contact, thereby providing structural support and preventing nesting of the sheets.

A typical application of this invention is FIG. 11.

A heat exchanger or recuperator 84 formed by successively stacking the

sheets

60 and 66, detailed in FIGS. 5 and 6, is shown installed on a gas turbine engine 86.

The ducts 88 and 88' connect on a compressor discharge collector 90 to a recuperator 84, while the duct 92 connects the recuperator 841 to a combustor collector 94.

A recuperator housing 96, with openings for

ducts

88, 88', and 92, is placed on an exhaust collector 98.

Although partially hidden in FIG. 11, the total recuperator system shown consists of two heat exchanger units, shown generally at 100 and 100' in schematic fashion in FIG. 12.

Identical elements in the two units are identified by like reference numbers, but set apart by a prime designation.

illustrated in OPERATION While the operation of the present invention is believed clearly apparent from the foregoing description, further amplification will subsequently be made in the following brief summary of such operation.

A typical application for this invention is on a gas turbine engine wherein heat energy available in the exhaust gas is recovered by the heat exchanger assembly and is transferred to combustion inlet air. It is the application that will be used to demonstrate the operation of this invention.

For continuity, the flow path of relatively hot engine exhaust gas will be indicated on the drawings by solid line arrows.

Similarly, the convention of representing the relatively cooler compressor discharge air by phantom line arrows will be adopted.

The advantages to be gained, such as operating economy and increased efficiency, by employing a stacked plate heat exchanger with an internal combustion engine, are well known.

The generally C-shaped paths described by the air flow can easily be seen in FIG. 1. For instance, air flow 102 between the

sheets

2 and 4 is directed by the locations of the entrance opening 104 and exit opening 106 provided between the two sheets.

The edge bars 26 and 28 effectively seal all edges around the periphery of the sheets except for the aforementioned flow entry and exit

apertures

102 and 104.

Similarly, a somewhat shallower C-shaped flow path 108 is provided for gas flow, as indicated between the sheets 4 and 6.

The edge bars 30 and 32 effectively seal the appropriate edges as shown, thus creating the entrance opening 110 and the exit opening 112.

As can be seen, the location of the apertures encourages a natural, and highly desirable, counterdirectional flow path for the respective fluids across the central rectangular zone.

The corrugations in the central rectangular zone provide not only structural support, as previously mentioned, but also aid in flow control.

The chevron pattern illustrated in FIG. 1, sectioned in FIGS. 2 and 3, and shown in stacked position in FIG.

8, encourages mixing of the fluid flow during its travel across the zone, thus preventing buildup of a laminar flow condition which would be detrimental to efficient heat transfer.

Likewise, the wavy corrugation pattern, illustrated in FIGS. 5 and 6, has characteristics similar to the chevron pattern.

Another alternative, the skewed straight passage, is shown in FIG. 10. As a result of crossing of crowns and valleys of corrugations in adjacent sheets, all three pat terns provide structural support, directional flow control, and mixing of the flow within the respective passage to encourage efficient heat transfer with minimum pressure loss.

Also, since the subject primary surface heat exchanger does not depend upon finned surfaces for the bulk of its heat transfer, the relatively thin patterned sheets outlined above may be fabricated from metal, ceramic, or other nonmetallic material without affecting overall performance. For example, materials such as silicon nitride, silicon carbide, and lithium-aluminasilicate currently being evaluated by the industry for high temperature applications, may be used to form the sheets of the heat exchanger disclosed herein.

The two outside edges of the triangular side zones may be varied in length, with respect to each other, to accommodate specific flow density and duct work requirements. Normally, the edge corresponding to compressor discharge air flow will be shorter than the adjacent leg corresponding to exhaust gas flow due to the greater density of the compressed, cooler compressor discharge air.

The particular flow path of fluid through a typical engine is presented in FIGS. 11 and 12.

Compressor discharge air is directed to the collector and subsequently routed by the ducts 88 and 88' to the

inlet apertures

114, 114', 116, and 116' of the

heat exchangers

84 and 84'.

The air then passes in generally C-shaped flow paths through the central rectangular areas receiving heat energy in the'known manner by transfer through the cor rugated sheets from hot exhaust gas.

The air, thus heated, is conducted from the discharge ports (or apertures) 118, 118, 120 and 120 of

exchangers

84 and 84 to the combustor collectors by the ducts 92 and 92'.

The air then proceeds on through the engine in the conventional manner i.e., being heated further by the introduction of fuel into the air, subsequent ignition of the fuel thus forming a hot gas which in turn passes over one or more turbine rotors or stages transforming heat energy in the gas into mechanical energy in a rotating member, then discharging into the exhaust collector 98.

The relatively hot exhaust gas then passes into the recuperator housing 96 and 96', passing through the

heat exchanger

84 and 84, giving up heat energy to the cooler combustor inlet air by transfer through the plates of said exchanger, and finally passing out of the housing into the atmosphere.

In view of the foregoing, it is readily apparent that the structure of the present invention provides a compact, low profile, primary surface heat exchanger, compatible with typical engine arrangements, so that the respective fluid flow path of fluids through the exchanger describes a general C-shape.

While the invention has been described and shown with particular reference to the preferred embodiments, it is apparent that variations might be possible that would fall within the scope of the present invention which is not intended to be limited, except as defined in the following claims We claim:

1. A primary surface heat exchanger comprising first and second sheets alternately arranged to form a stack, said sheets each having a corrugated central rectangular area with opposite sides and ends, and triangularshaped areas having first and second edges and a base coincident with each of said rectangular area sides, portions of adjacent sheets abutting to provide structural support for said sheets and to maintain generally uniform flow paths between the sheets, said first and second edges of said triangular-shaped areas forming acute angles with the adjacent side of the rectangular area, side sheets defining therebetween a first C-shaped fluid flow path entering and exiting between said first edges of the triangular-shaped areas for travel across said rectangular area from side to side, and a second C-shaped fluid flow path immediately adjacent said first flow path in the stack and entering and exiting between said second edges for travel across said rectangular area from side to side in substantially counter-flow relation to said first flow path.

2. The invention of claim 1 including seal means attached to said first and second sheets to seal appropriate edges of said sheets and to form noncommunicating fluid passages and to provide structural support for said 6 stack.

3. The invention of claim 1 wherein said central rectangular area further comprises corrugations which are chevron-shaped and have crowns and valleys arranged in ranks and aligned so that crowns of said corrugations in said first sheets contact valleys of said corrugations of said second sheets, thus providing structural support for said sheets.

4. The invention of claim I wherein said central rectangular area further comprises corrugations which are wave-shaped and have crowns and valleys arranged in ranks and aligned so thatcrowns of said corrugations in said first sheets contact valleys of said corrugations of said second sheets, thus providing structural support for said sheets.

5. The invention of claim 1 wherein said central rectangular area further comprises straight corrugations which are arranged in ranks and aligned so that said corrugations of said first sheet are skewed in relation ship to said corrugations of said second sheet.

6. The invention of claim I wherein said triangularshaped areas have dimples embossed thereon to provide structural support for said sheets.

7. The invention of claim 1 further comprising at least two triangular-shaped corrugated sheets coincident with the triangular-shaped areas, thus providing structural support for said sheets.

8. The invention of claim 1 wherein the corrugated sheets are made of nonmetallic material.

Claims

1. A primary surface heat exchanger comprising first and second sheets alternately arranged to form a stack, said sheets each having a corrugated central rectangular area with opposite sides and ends, and triangular-shaped areas having first and second edges and a base coincident with each of said rectangular area sides, portions of adjacent sheets abutting to provide structural support for said sheets and to maintain generally uniform flow paths between the sheets, said first and second edges of said triangular-shaped areas forming acute angles with the adjacent side of the rectangular area, side sheets defining therebetween a first C-shaped fluid flow path entering and exiting between said first edges of the triangular-shaped areas for travel across said rectangular area from side to side, and a second C-shaped fluid flow path immediately adjacent said first flow path in the stack and entering and exiting between said second edges for travel across said rectangular area from side to side in substantially counter-flow relation to said first flow path.

2. The invention of claim 1 including seal means attached to said first and second sheets to seal appropriate edges of said sheets and to form noncommunicating fluid passages and to provide structural support for said stack.

4. The invention of claim 1 wherein said central rectangular area further comprises corrugations which are wave-shaped and have crowns and valleys arranged in ranks and aligned so that crowns of said corrugations in said first sheets contact valleys of said corrugations of said second sheets, thus providing structural support for said sheets.

5. The invention of claim 1 wherein said central rectangular area further comprises straight corrugations which are arranged in ranks and aligned so that said corrugations of said first sheet are skewed in relationship to said corrugations of said second sheet.

6. The invention of claim 1 wherein said triangular-shaped areas have dimples embossed thereon to provide structural support for said sheets.