FR2978236A1 - THERMAL EXCHANGER, FLAT TUBE AND PLATE CORRESPONDING - Google Patents

Abstract

The invention relates to a heat exchanger for charge air cooling, said exchanger comprising at least one flat tube for the circulation of a fluid, formed by the assembly of a pair of plates (7) delimiting a first channel (23) and a second channel (25) of circulation, such that said channels (23,25) communicate with each other at one end to define a substantially "U" flow of said fluid. According to the invention, at least one plate (7) comprises at least a first rib (29) and a second rib (31) of generally "L" shape; such that said at least one first rib (29), respectively second rib (31), is arranged in said first channel (23), respectively second channel (25), circulation. The invention also relates to a flat tube for such an exchanger formed by a pair of plates of which at least one plate (7) comprises at least a first rib (29) and a second rib (31) of generally "L" shape. ; such that said at least one first rib (29), respectively second rib (31), is arranged in said first channel (23), respectively second channel (25), circulation. The invention also relates to such a plate (7) for flat heat exchanger tube.

Description

-1- Heat exchanger, flat tube and corresponding plate The invention relates to a heat exchanger especially for a motor vehicle.

A heat exchanger, for example used in the automotive industry and more specifically in an internal combustion engine of a motor vehicle, comprises heat exchange elements and fluid flow in which fluids exchanging heat exchange between them . Many fluid associations can be envisioned, be they liquids and / or gases. In particular, an "air-water" exchanger, such as a charge air cooler, may be provided. The heat exchange elements may for example comprise flat tubes, gas flow disrupting vanes and / or fluid flow disruptors or the like. Many structural configurations are possible. Exchangers are known comprising a bundle of plates arranged in pairs parallel to each other on one or more rows parallel to each other. The pairs of plates are arranged to define firstly a flow passage of a first fluid and secondly an interval between two pairs of neighboring plates through which a second fluid can flow by exchanging the fluid. heat with the first fluid. According to a known solution, each plate can define two or more circulation passes. Each pass is defined by a traffic channel. For example, a flat plate heat exchanger plate is generally defined with four passes. Plaques defined with two passes are also known. However, to ensure good mechanical strength, it is necessary to densify the plate. For this, it is known to make a multitude of bosses, for example brazing points. The object of the invention is to further improve the performance of known heat exchangers in terms of reduction of mechanical stresses and pressure drops. To this end, the subject of the invention is a heat exchanger for cooling charge air, said exchanger comprising at least one flat tube for the circulation of a fluid, formed by the assembly of a pair of plates. delimiting a first channel and a second circulation channel, such that said channels communicate with each other at one end to define a substantially U-shaped circulation of said fluid, characterized in that at least one plate comprises at least a first rib and a second ridge of general shape substantially in "L"; and in that said at least one first rib, respectively second rib, is arranged in said first channel, respectively second channel, of circulation. Said heat exchanger may further comprise one or more of the following characteristics, taken separately or in combination: said at least one plate comprises a central rib, said central rib 15 projecting into said at least one flat tube to delimit the first and second circulation channels ; said at least first and second ribs are symmetrical with respect to said central rib; said at least one first rib extends substantially at the center of the width of said first channel, and said at least one second rib extends substantially at the center of the width of said second channel; said at least one plate comprises a fluid inlet port disposed in said first circulation channel and a fluid outlet port disposed in said second circulation channel, and said at least one first rib is substantially aligned with the center said inlet port and said at least one second rib is substantially aligned with respect to the center of said outlet port; said substantially L-shaped ribs have rounded edges; said at least one plate has a plurality of bosses projecting into the flow passage of said fluid; Said at least one plate has a width less than or equal to 100mm. The invention also relates to a flat tube for heat exchanger according to any one of the preceding claims, said tube being formed by the assembly of a pair of plates delimiting a first channel and a second circulation channel, Such that said channels communicate with each other at one end to define a substantially U-shaped circulation of said fluid, characterized in that at least one plate comprises at least a first rib and a second rib of generally "L" shape. ; said at least one first rib, respectively second rib, being arranged in said first channel, respectively second channel, of circulation. Said tube may further comprise one or more of the following features, taken separately or in combination: the two plates of said pair of plates are substantially identical; said plates respectively comprise a central rib, and the central rib of a first plate is in contact with the central rib vis-à-vis the second plate; said first and second ribs of the first plate are respectively in contact with said first and second ribs vis-à-vis the second plate.

The invention also relates to a plate for a heat exchanger flat tube delimiting a first channel and a second circulation channel, said channels communicating with one another at one end so as to define a substantially U-shaped circulation of said fluid, characterized in that said plate comprises at least a first rib and a second rib of generally "L" shape; said at least one first rib, respectively second rib, being arranged in said first channel, respectively second channel, circulation.

Other characteristics and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings in which: FIG. side view of a plate heat exchanger, - Figure 2 shows a plate of the exchanger of Figure 1.

In these figures, the substantially identical elements bear the same references. The invention relates to a heat exchanger, in particular for cooling the supercharging air for a heat engine, such as a motor vehicle engine. Such an exchanger may be an exchanger called "air-water", that is to say an exchanger 10 in which the fluids that exchange heat are air and water. In the case of a charge air cooler; the water is preferably water from the so-called "low temperature" cooling circuit of said engine; it is typically brine.

FIG. 1 shows, viewed from the side, a heat exchanger 1. The exchanger 1 has for example a generally parallelepipedal general shape. The exchanger 1 comprises a stack of flat tubes 3. The flat tubes 3 can be alternately arranged with interleaves 5. A spacer 5 is for example formed from a corrugated thin sheet heat-conducting, the ridges of which are in contact alternately with the two flat tubes 3 on either side of the insert 5. A flow of air can flow through the spacers 5, to exchange heat with the fluid flowing in the flat tubes 3 The spacers 5 disturb the flow of air so as to increase the exchange surface.

According to the embodiment described, all the flat tubes 3 are identical. Each tube is for example formed by assembling a pair of plates 7 opposite. The exchanger 1 is therefore of the plate type.

The assembled plates 7 define between them a passage 9 for the flow

A fluid, in particular a cooling fluid. Such a passage 9 may have a substantially constant thickness. A plate 7 (better visible in Figure 2) has a generally rectangular shape with a length L and a width 1. For example, the plate 7 has a width 1 less than or equal to 100mm. And, the plate 7 has for example a length L between 120 mm and 280 mm. Each plate 7 has orifices forming a fluid inlet 11 for introducing fluid into the fluid flow passage 9 and a fluid outlet 13 for discharging the fluid. A plate 7 further comprises at the level of the fluid inlet 11 and the fluid outlet 13 of the plates 7 of the bulges 15 (see FIG. 1). These bulges 15 are oriented towards the outside of the fluid flow passage 9. The bulges 15 of a plate 7 communicate with the bulges 15 of a plate 7 of a neighboring pair of plates 7. Due to the bulges 15, the stack of flat tubes 3 creates, between two pairs of adjacent plates 7, a gap. These intervals may be lined with an interlayer 5 as described above. In addition, as can be seen in FIG. 1, the exchanger 1 comprises 20 respectively two inlet and outlet pipes 17, for the passage of a fluid. These pipes 17 communicate respectively with the bulges 15 and associated orifices 11, 13 of the plates 7, to allow the circulation of the fluid between the plates 7.

Moreover, according to the embodiment illustrated in FIGS. 1 and 2, the plates 25 are made from stamped sheet metal. Such stamped plates 7 have a substantially bowl shape. Each plate 7 has a peripheral edge 19 forming a contour of the plate 7. The plates 7 of the same pair are joined together in a sealed manner over their entire contour at their respective peripheral edge 19 to define a passage 9 2978236 For the flow of the fluid. The plates 7 are arranged so that their concavities are facing each other. Alternatively, such a stamped plate 7 could be provided with a flat plate which rests on the peripheral contour 19 of the stamped plate 7 to define the flow passage 9 of the fluid. The plates 7 are sealingly connected, for example by brazing.

In addition, a stamped plate 7, as shown in FIG. 2, defines two circulation passes. For this purpose, the plate 7 comprises a central rib 21. This central rib 21 is disposed substantially at the center of the width 1 of a plate 7. This central rib 21 is arranged on the inner surface of the plate, that is, that is to say facing the fluid flow passage 9, so that the central rib 21 forms a projection in the fluid flow passage 9.

The central rib 21 is a longitudinal rib joining two plates 7 of a pair so as to define circulation passes for the fluid. In the case of a flat tube 3 formed by the assembly of two stamped plates 7, the central rib 21 of the first plate 7 is kept in contact with the central rib 21 opposite the second plate 7.

According to the variant with a plate 7 stamped assembled with a flat plate, the latter rests against the central rib 21 of the plate 7 stamped. This creates a separation in the flow passage 9 of the fluid. This separation delimits a first circulation channel 23 and a second circulation channel 25 thus forming two passes with a "U" circulation between the inlet 11 and the fluid outlet 13. The first pass is defined by the first circulation channel 23 and the second pass is defined by the second flow channel 25. In addition, this central rib 21 may have a rounded end 27.

Such a plate 7 further comprises at least a first secondary rib 29 and at least a second secondary rib 31. These two secondary ribs 29 and 31 provide a mechanical reinforcing function of the plate 7. The first rib 29 is arranged in the first circulation channel 23 so as to divide it into two subchannels 23a and 23b. Similarly, the second secondary rib 31 is arranged in the second fluid circulation channel so as to divide it into two subchannels 25a and 25b. Such an arrangement of the secondary ribs 29 and 31 in the "U" circulation channels makes it possible to channel the flow of the fluid in the fluid flow passage 9. In addition, the secondary ribs 29, 31 have a generally "L" -shaped general shape. This "L" shape makes it possible to combine mechanical strength and reduction of pressure drops. Indeed, using secondary ribs substantially "L", the Applicant has found a better compromise between mechanical stress and loss of loads. Furthermore, the secondary ribs 29, 31 substantially in "L" may have rounded edges, so as not to have a sharp angle, to better balance the flow of the fluid. In addition, these two ribs are thus arranged on either side of the central rib 21. More precisely, the first rib 29 and the second secondary rib 31 are symmetrical with respect to the central rib 21. In addition, for one better balancing of the flow, the secondary ribs 29 and 31 are respectively arranged substantially at the center, in the width direction, of the associated circulation channel 23,25. Indeed, the first rib 29 extends substantially at the center of the width of the first channel 23, and the second rib 31 extends substantially at the center of the width of the second channel 25. Furthermore, the first rib is according to the illustrated embodiment substantially aligned with the center of the inlet port 11. Also the second rib is substantially aligned with respect to the center of the outlet port 13. Finally, the plate 7 can still present a multitude of bosses 33 on its inner surface. Thus, these bosses 33 project in the passage 9 of the fluid flow. The bosses 33 are, for example, soldering points.

Thus, such plates 7 with the secondary ribs 29, 31 substantially in "L" substantially in the middle of each fluid circulation channel 23, 25 make it possible to reinforce the mechanical strength of the plate 7 while balancing the flow of the fluid. . This arrangement is particularly suitable for the plates 7 of width less than 100mm. Indeed, for such plates, the Applicant has found that the use of plates in two passes has a better compromise than the use of plates in several passes; each pass being formed by a circulation channel. And, the separation of the two channels of the plate in two passes using the secondary ribs in "L" can further increase the performance in terms of mechanical strength and losses. In addition, the Applicant has found a reduction in mechanical stresses of up to 35% using such plates 7 according to the invention, compared to stamped plates defining two passes but not having the secondary ribs "L" substantially at middle of the two passes. This new type of plate 7 in two passes subdivided by ribs in "L" thus allows to further increase the thermal performance of the exchanger 1. 25

Claims (13)

REVENDICATIONS1. A heat exchanger for charge air cooling, said exchanger comprises at least one flat tube (3) for the circulation of a fluid, formed by the assembly of a pair of plates (7) delimiting a first channel (23). ) and a second channel (25) of circulation, such that said channels (23,25) communicate with each other at one end to define a substantially "U" -circulation of said fluid, characterized in that: - at least one plate (7) ) has at least a first rib (29) and a second rib (31) of generally "L" shape; and in that said at least one first rib (29), respectively second rib (31), is arranged in said first channel (23), respectively second channel (25), circulation. 2. Exchanger according to claim 1, characterized in that said at least one plate (7) comprises a central rib (21), said central rib (21) projecting into said at least one flat tube (3) to delimit the first (23) and second (25) circulation channels. 3. Exchanger according to claim 2, characterized in that said at least one first (29) and second (31) ribs are symmetrical with respect to said central rib (21). 4. Exchanger according to any one of the preceding claims, characterized in that said at least one first rib (29) extends substantially at the center of the width of said first channel (23), and in that said at least one second rib (31) extends substantially at the center of the width of said second channel (25). 5. Exchanger according to any one of the preceding claims, characterized in that said at least one plate (7): 2978236 -10- comprises a fluid inlet (11) arranged in said first channel (23) circulation and an outlet (13) of fluid arranged in said second channel (25) for circulation, and in that said at least one first rib (29) is substantially aligned with respect to the center of said inlet port (11). ), and said at least one second rib (31) is substantially aligned with respect to the center of said outlet (13). 6. Exchanger according to any one of the preceding claims, characterized in that said ribs (29,31) substantially in "L" have rounded edges. 10 7. Exchanger according to any one of the preceding claims, characterized in that said at least one plate (7) has a plurality of bosses (33) forming projections in the flow passage of said fluid. 8. Exchanger according to any one of the preceding claims, characterized in that said at least one plate (7) has a width (1) less than or equal to 100mm. 9. Flat tube for heat exchanger according to any one of the preceding claims, said tube (3) being formed by the assembly of a pair of plates (7) delimiting a first channel (23) and a second channel (25). ), such that said channels (23, 25) communicate with each other at one end to define a substantially U-shaped circulation of said fluid, characterized in that at least one plate (7) comprises at least one first rib ( 29) and a second rib (31) of general shape substantially in "L"; said at least one first rib (29), respectively second rib (31) being arranged in said first channel (23), respectively second channel (25), circulation. 25 10. Flat tube according to claim 9, characterized in that the two plates (7) of said pair of plates are substantially identical. 2978236 -11- 11. Flat tube according to claim 10, characterized in that said plates (7) respectively comprise a central rib (21), and in that the central rib (21) of a first plate (7) is in contact with the central rib (21) vis-à-vis the second plate (7). 5 12. Flat tube according to one of claims 10 or 11, characterized in that said first (29) and second (31) ribs of the first plate (7) are respectively in contact with said first (29) and second (31) ) ribs vis-à-vis the second plate (7). Plate for a heat exchanger flat tube according to any one of claims 9 to 12, defining a first channel (23) and a second channel (25) for circulation, said channels (23, 25) communicating with each other at one end so as to define a substantially U-shaped circulation of said fluid, characterized in that said plate (7) comprises at least a first rib (29) and a second rib (31) of generally "L" -shaped shape; said at least one first rib (29), respectively second rib (31) being arranged in said first channel (23), respectively second channel (25), circulation.