NZ561669A

NZ561669A - A heat exchanger

Info

Publication number: NZ561669A
Application number: NZ561669A
Authority: NZ
Inventors: Kees Weel
Original assignee: P W R Performance Products Pty
Priority date: 2006-09-21
Filing date: 2007-09-19
Publication date: 2008-07-31
Also published as: US20080073059A1

Abstract

A heat exchanger is described such as for cooling air by using water, particularly for use as an intercooler in an internal combustion engine. The heat exchanger has an elongate and preferably cylindrical core assembly housed within a shell. The core assembly has a plurality of spaced apart tubes extending between a first inlet, for introducing the air into the tubes, and a first outlet, for exit of the air from the tubes; a plurality of flow means disposed between and in thermal contact with the tubes, the flow means adapted to pass water across the core assembly generally at right angles to the air flow to transfer heat between the tubes and the water; and baffles so that water enters the core assembly by a second inlet, propagates through the core assembly generally in the direction of the air flow axis, wherein the baffles cause the water to move along in a tortuous path, along which the water absorbs heat from the tubes to cool the air. Preferably, the baffles are alternatingly disposed along opposite sides of the core assembly, the baffles being of generally semicircular shape and configured to sealingly engage with the shell so as to define a plurality of adjacent longitudinal sections along the length of the core assembly arranged so that the water is able to move between respective adjacent longitudinal sections only on the side of the core assembly opposite to a respective baffle.

Description

<div class="application article clearfix" id="description"> 19/09 2007 13:02 FAX +61 2 6264 5154 Hodgkinson Mclnnes Pat. 1006/024 PATENTS FORM NO. 5 *10054693431* 561G 69 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION A Heat Exchanger Our address for service is: HODGKINSON McINNES PATENTS Australia & New Zealand HMcIP Ref: P2Q574NZ00 We, P.W.R Performance Products Pty Ltd, a company incorporated under the laws of Australia of 181 Jefferson Lane, Palm Beach QLD 4221, Australia hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: WTELLfCTUAL PROPERTY 0FRCE OFNZ 19 SEP 2007 RECEiVFn Received at IPONZ 5 June 2008 A HEAT EXCHANGES. TECHNICAL FIELD 5 The present invention relates to a heat exchanger for cooling air by water. In particular, the invention refers to a heat exchanger that can function as a charge air cooler in an Internal combustion engine. BACKGROUND OF THE INVENTION 10 Conventional heat exchangers, such as Intercoolers, are used in large numbers of modern motor vehicles. An Intercooier cools the hot air generated by the engine of a vehicle by passing the charge air through a plurality of parallel tubes, which are cooled by ambient air. To facilitate the cooling process, corrugated sheets, are inserted between the air tubes such that the sheets are in 3.5 thermal contact with the tubes. Ambient air is introduced on one side of the intercooier and is directed, aiong the surfaces of the corrugated sheets, to the other side of the intercooier. While moving through the cross section of the Intercooier, the ambient air is in thermal contact with the tubes and the corrugated sheets, The ambient air absorbs heat from the tubes and the 20 corrugated sheets, thus cooling the charge air passing through the tubes. Notably, the ambient air moves from one side of the intercooier to the other by simultaneously crossing the entire cross section of the intercoolar's body. While various improvements have been introduced to the size and configuration of the tubes and the arrangement between the tubes and 25 corrugated sheets, the search continues for more efficient arrangements which provide better cooling and therefore better fuel efficiency. lKi>< 7 Received at IPONZ 5 June 2008 3 SUMMARY OF THE INVENTION According to the invention, there is provided a heat exchanger for cooling a first fluid by a second fluid, the heat exchanger comprising art elongate core assembly extending along a first axis and housed within a shell, the core 5 assembly having: a piurality of spaced apart tubes aligned with the first axis and extending between a first Inlet, for introducing the first fluid into the tubes, and a first outlet, for exit of the first fluid from the tubes; a plurality of flow means disposed between and in thermal contact with the tubes, the flow means adapted to pass second fluid across the core assembly at right angles to the first axis and 10 to transfer heat between the tubes and the second fluid; a plurality of baffle means, wherein each one of said baffle means engages with the exterior of at least some of said tubes, the arrangement being such that the second fluid enters the core assembly by a second inlet, propagates through the core assembly via the flow means, and exits the core assembly through a second 15 outlet, wherein the second iniet and second outlet are displaced relative to each other along the first axis, and wherein the baffle means cause the second fluid to move along the first axis in a tortuous path, along which the second fluid absorbs heat from the flow means and the tubes to cool the first fluid, Preferably, the shell is of a cylindrical shape and the baffle means 20 comprise a piurality of baffies altematingly disposed along opposite sides of the core assembly, the baffies being of generally semicircular shape and configured to sealmgly engage with the shell so as to define a plurality of adjacent longitudinal sections along the length of the core assembly arranged so that the second fluid is able to move between respective adjacent longitudinal sections 25 only on the side of the core assembly opposite to a respective baffle; the arrangement being such that, in use, a pressurised second fluid is introduced in the exchanger via the second inlet at one side of the core assembly, the introduced second fluid being confined within a first of the longitudinal sections of the core assembly, by a respective baffle, and directed into the flow means in 30 a first direction through the cross-section of this longitudinal section, once reaching the opposite side of the core assembly, the second fluid being able to move to a second of the longitudinal sections, adjacent to the first longitudinal section, and second fluid being directed by the flow means through the cross- Received at IPONZ 5 June 2008 section of the second longitudinal section in a direction opposite to the first direction, thus the second fluid consecutively traversing the cross-sections of adjacent sections along the length of the core assembly in alternating directions, until reaching the second outlet and exiting the heat exchanger. 5 Even more preferably., the flow means comprises a corrugated sheet made of a heat conducting material. Preferably, each corrugated sheet" is inserted between, and is abuttingly engaged with, at least a pair of adjacent tubes. In some embodiments, the core assembly further includes a pair of baffles extending along the first axis on two mutually opposing sides of the core 10 assembly to prevent the second fluid from moving around the periphery of the core assembly. Preferably, at least some of the tubes are flat tubes. Even more preferably, at least one tube has a cross-section with at least one dimension that is different from the respective dimension of at least one other tube. Also preferably, the core assembly and the heat exchanger have substantially 15 cylindrical shape. In some embodiments, the tubes include internal fins extending inside the tubes to improve the heat exchange between the tubes and the first fluid. Preferably, the first fluid is air and the second fluid Is water. In some embodiments, the heat exchanger Is arranged to function as an 20 air-cooler in an internal combustion engine of a motor vehicle, and especially as an intercooier in turbocharged and/or supercharged engine. BRIEF DESCRIPTOR OF THE DRAWINGS Preferred embodiments of the invention will now be described by way of 25 example only, and with reference to the accompanying drawings wherein: FIG, 1 is a plan view of the heat exchanger according to a first embodiment of the invention; 30 FIG. 2 is an elevation view of the heat exchanger of Fig. 1; Received at IPONZ 5 June 2008 FIG. 3 is a perspective view of the heat exchanger of Figs. 1 and 2; FIG. 4 is an end view of the heat exchanger of Fig, 3; FIG. 5 is a plan view of the heat exchanger of Rg. 1, with the shell removed; FIG. 6 is an elevation view of the heat exchanger of Fig, 2, with the shell removed; FIG. 7 is a perspective view of the heat exchanger of Fig, 3, with the shell removed; FIG 8 Is an end view of the heat exchanger opposite to the end view of Rg, 4; FIG 9 is a plan view of the core -assembly of the heat exchanger of Fig. i; FIG 10 Is ari elevation view of the core assembly of the heat exchanger of Rg. 2; FIG. 11 is a perspective view of the core assembly of the heat exchanger of Fig. 3; FIG. 12 is an end view of the core assembly of the heat exchanger of Fig, 4; FIG, 13 is a perspective view of the core assembly of a heat-exchanger according to a second embodiment of the invention; FIG. 14 is an end view of the core assembly of Fig. 13; and Received at IPONZ 5 June 2008 FIG. IS is an enlarged view of the portion shown in circle of Fig. 14. PREFERRED EMBODIMENT OF THE SNVENTION 5 The Figures depict one example of the heat exchanger according to the present invention. This is of a cylindrical intercooier, Intended to be used as a charge air cooler in a turbocharged or supercharged internal combustion engine. This works to improve the efficiency of the engine, by increasing the density of the air charge by means of tsochoric (ie, constant volume) cooling. The reduction 10 in the temperature of the air intake creates a denser charge of air into the engine, which causes better engine performance. In the present example, the heat exchanged uses water to cooS the air charge. Figures 1 to 4 depict a heat exchanger (i) for cooling air by water. It has a substantially cylindrical form around a longitudinal axis depicted as '"X" in 15 Figures 1 to 3. The heat: exchanger (1) has a cylindrical shell (9) surrounding a core assembly (3), and an inlet (10) and an outlet (11) for the entry and exit respectively of water, as the first fluid, Heat exchanger (1) also has Inlet (20) and outlet (21) for the entry and exit respectively of air as the second fluid. Figures 5 to 8 show heat exchanger (1) with shell (9) removed, thereby 20 showing core assembly (3) in more detail. Figures 9 to 12 show core assembly (3) by itself. Core assembly (3) comprises a piurality of spaced-apart fiat tubes (4) disposed parallel to axis "X". Tubes (4) are for passing air from inlet (20) to outlet (21). A plurality of corrugated sheets (5) are disposed between each pair of adjacent tubes (4) so as 25 to be abutted against and: in thermal contact with both tubes (4). Corrugated sheets {5} provide flow surfaces that allow the passage of water in a direction parallel to axis Shown in Figures 3 and 6. As can be. clearly seen, axis wY,f is at right angles to axis "X"', While in this example the tubes (4) are generally at right angles to the 30 corrugated sheets (5), it is possible in alternative embodiments of the Invention P-MVi 6 Received at IPONZ 5 June 2008 to have these elements at angles other that at right angles. Preferable, these elements are at an angle between 60 and 120 degrees to the perpendicular, so that they are within 30 degrees from being a right angle, These elements may be at a variety of different angles, or all at the same angle. They may be arranged 5 so that the average angle is about 90 degrees, but with some elements are at a higher angle and an equal number at a lower angle than 90 degrees. It is preferred that the elements are positioned to be close to, or at, right angles. Once water enters the inlet (10), ft is able to flow through corrugated sheets (S), following a tortuous path depicted fay arrow "R" in Figure 6, Ideally, 10 the water is restricted to this tortuous path via a plurality of baffles (8), which Is best shown in Figures 6 and 7, Each baffle (8) extends in a plane perpendicular to axis "X". As best shown in Figures 10 and 12,. there are two end baffles (8a) at opposed ends of core assembly (3). These end baffles (8a) have a circular periphery and the tubes (4) 15 pass through them, as shown in Figures 11 and 12. Other baffles {8b, 8c and 8d) are disposed in various orientations between the pair of end baffles (8a). Some of the baffles (8b and 8c) will each have a generally semi-circular form, each substantially half the size of end baffle (8a). In the example shown, there are two interior baffles (8b) and one baffle (8c). 20 Different numbers of these baffles may be employed. The baffles (8b) are both offset by 180 degrees from baffle (8c), which itself is disposed centrally along longitudinal axis "X" relative to and between the end baffles (8a). Baffles (8b) are disposed longitudinally either side of baffle (8c). Two further baffles (8d), are disposed opposite each other and parallel to 25 axis "X", so as to span between respective end tubes (4a) and the shell (9), Water inlet (10} and outlet (11), are disposed near the respective air inlet (20) and outlet (21). In the assembled configuration, the baffles sealingly engage the interior of cylindrical shell (9), defining a flow path schematically depicted by arrow in 30 Figure 6. Water entering at inlet (10) initially at location "A" follows the tortuous 7 Received at IPONZ 5 June 2008 8 path defined by the baffles (8). to pass through locations "B", "C and "D" prior to exiting at outiet. (11). In use, air enters in Eel (20), passes th rough tubes (4) end exits at outlet (21), as shown by arrow "Q" in Figure 6. Water enters inlet (10) near one end of 5 heat exchanger (1), then follows the earlier described tortuous path depicted by arrow and exits at outlet (11), The water is in effect flowing In a first direction from "A" to WB" parallel to axis "Y", and then from WB" to "C" it is flowing in an opposite direction. The water then once again changes direction between WC" and BD", and finally once again between WD" and outlet (11). 10 As the water follows the tortuous path, it is constantly in thermal contact with tubes (4) and corrugated sheets (5). Consequently, along its path, the water continuously absorbs heat from tubes (4), thereby cooling the air passing through the heat exchanger (1), generally perpendicular to the path taken by the water. 15 Tubes (4) and corrugated sheets (5) may be made of conventional materials having good thermal conductivity. One such suitable material is aluminium. The tubes extend the first inlet and first outlet. Preferably the tubes provide a direct route between, with a minimum path length, to allow the air to move through the exchanger with minimum disruption. The inlet and outiet may 20 each have a chamber that connects with the tube interiors. Preferably the exit and entrance to air flow may be of generally wide diameter, so as to minimally disrupt the air flow. As can be seen in the example shown in Figure 12, there are seven tubes (4), the central three of identical dimension, with the remaining four having 25 progressively decreasing dimensions to fit within the circular envelope of the core assembly (3), Other numbers of tubes may be used. Figures 13 to 15 depict a core assembly (3a), in a second embodiment. This core assembly (3a) has its baffle configuration similar to that of the previously described core assembly (3) shown in Figure 11. However, this core 30 assembiy (3a) differs in that it comprises twenty spaced apart tubes (4b), in staggered relationship. 8 Received at IPONZ 5 June 2008 9 As can be seen as an expanded view in Figure 15, tubes (4b) can include interna! fins (12). The fins extend inside the tubes and improve the heat exchange. It should be understood that such internal fins may also be used in the tubes (4) of the first embodiment, 5 It should be understood that in other embodiments the invention may involve other tube arrangements, as long as the tubes extend generally parallel to axis "X", such that air can pass through them. The tubes may not need to be exactly parallel to axis "X", but some or ail may depart by some acute angle from this arrangement. However, the arrangement with the tubes in the parallel 10 arrangement is preferred. Experiments with the above described system, used as an sir-cooler in an internal combustion engine, indicate that the arrangement provides an efficient heat exchange between the hot air and the water. The improved cooling provides a better fuel efficiency, The shape and configuration of the heat exchanger also 15 allows for an efficient heat exchange to occur in a compact design. Accordingly, the above described system offers a useful alternative to the conventional heat exchangers for motor vehicles. It should be appreciated that the disclosed heat exchanger is not limited to the particular embodiment described herein,, but also covers other arrangements 20 using similar concepts. For example, whilst the abovementioned embodiments depict two tube arrays in Figures 12 and 14, many other not-shown tube arrays are possible without departing from the scope of the present Invention. The terms "comprising" and "including" and their grammatical variations, as used herein, are used in the inclusive sense, and not in the exclusive sense of 25 "consisting only of". 9 Received at IPONZ 5 June 2008 10 </div>

Claims

<div class="application article clearfix printTableText" id="claims"> CLAIMS:

1. A heat exchanger for cooling a first fluid by a second fluid, said heat exchanger comprising an elongate core assembly extending along a first axis and housed within a shell,, said core assembiy having: a plurality of spaced apart tubes in a closed path aligned generally with said first axis and extending between a first inlet, for introducing ssid first fluid into the tubes, and a first outlet, for exit of said first fluid from the tubes; a plurality of flow means disposed between and in thermal contact with said tubes, said flow means adapted to pass said second fluid across said core assembiy about at right angles to said first axis and to allow heat transfer between the tubes and the second fluid; and a plurality of baffle means, wherein each one of said baffle means engages with the exterior of at least some of said tubes, the arrangement being such that said second fluid enters the core assembly by a second inlet, propagates through the core assembiy through said flow means, and exits the core assembiy through a second outiet, wherein said second inlet and said second outlet are displaced relative to each other along said first axis, and wherein the baffle means cause the second fluid to move along said first axis in a tortuous path, along which the second fluid is allowed to absorb heat from the flow means and the tubes so as to cool the fii'st fluid,

2. A heat exchanger according to claim 1, wherein: said shell is of a cylindrical shape and the baffle means comprise a plurality of baffles alternatingly disposed along opposite sides of the core assembly, the baffles being of generally semicircular shape and configured to seallngiy engage with said sheil so as to define a plurality of adjacent longitudinal sections along the length of the core assembiy arranged so that the second fluid is able to move between respective adjacent longitudinal sections only on the side of the core assembly opposite to a respective baffle; the arrangement being such that, in use, a pressurised second fluid is introduced in the exchanger via the second inlet at one side of the core assembiy, the introduced second fluid being confined within a first of said longitudinal sections of the core assembly, by a respective baffle, and directed 10 Received at IPONZ 5 June 2008 11 into the flow means in a first direction through the cross-section cf this longitudinal section, once reaching the opposite side of the core assembly, the second fluid being abie to move to a second of said longitudinal sections, adjacent to the first longitudinal section, and second fluid being directed by the flow means through the cross-section of the second longitudinal section in a direction opposite to the first direction, thus the second fluid- consecutively traversing the cross-sections of adjacent sections along the length of the core assembly in alternating directions, until reaching the second outlet and exiting the heat exchanger.

3. A heat exchanger according to claim 1 or claim 2, wherein each said flow means comprises a corrugated sheet made of a heat conducting material.

4. A heat exchanger according to claim 3, wherein each corrugated sheet is inserted between, and is abuttingiy engaged with, at least a pair of adjacent tubes,

5. A heat exchanger according to any one of claims 2 to 4, wherein the core assembiy further includes a pair of baffles extending along the first axis on two mutually opposing sides of the core assembiy to prevent the second fluid from moving around the periphery of the core assembly.

6. A heat exchanger according to claim 1 or claim 2, wherein at least some of the tubes are flat tubes.

7. A heat exchanger according to claim 6, wherein at least one tube has a cross-section with at least one dimension that is different from the respective dimension of at least one other tube,. CrtO:' Received at IPONZ 5 June 2008 12

8. A heat exchanger according to any one of the preceding claims., wherein the core assembiy and the heat exchanger have- substantially cylindrical shape.

9, A heat exchanger according to anyone of the preceding claims, wherein the tubes include interna! fins extending inside the tubes to improve the heat exchange between the tubes and the first fluid.

10. A heat exchanger according to any one of the preceding claims,, wherein the first fluid is air and the second fluid is water.

11. A heat exchanger according to anyone of the preceding claims, that functions as an air-cooler in a motor vehicle internal combustion engine.

12. The heat exchanger according to claim 11, that functions as an intercooier in a supercharged and/or turbocharged motor vehicle interna! combustion engine.

13. A heat exchanger substantially as herein described with reference to the drawings, :* 'Ji 12 </div>