FIELD OF THE INVENTION
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The invention relates to a heat exchanger, in particular the heat exchanger for a motor vehicle.
BACKGROUND OF THE INVENTION
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Heat exchange capacity is one indicator for evaluating the performance of heat exchangers and media systems. The heat exchange capacity may vary due to differences in media flow rates in multiple heat exchange channels. The medium may be a gas-liquid two-phase medium in which a gas-phase medium and a liquid-phase medium are mixed. The addition of oil in the medium may also be present. In this case, the difference in the gas-liquid ratio between the gas-phase medium and the liquid-phase medium between the plurality of heat exchange passes may change the heat exchange performance. Thus there is a need to improve the global efficiency of the heat exchanger (e.g. chiller, water- cooled condenser) by improving its heat exchange capability.
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The stacked plate heat exchanger design, such as in chiller or water- cooled condenser is usually suited to transferring heat between medium- and low-pressure fluids. Welded, semi-welded and brazed heat exchangers are used for heat exchange between high-pressure fluids or where a more compact product is required. In place of a pipe passing through a chamber, there are instead two alternating chambers, usually thin in depth, separated at their largest surface by a corrugated metal plate. The plates used in a plate and frame heat exchanger are obtained by one piece pressing of metal plates. Stainless steel is a commonly used metal for the plates because of its ability to withstand high temperatures, its strength, and its corrosion resistance.
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The chiller is a compact heat exchanger using one medium used in vehicle's refrigeration system to cool down the other medium (e.g. water, coolant) used for cooling the batteries or electronics in a hybrid or electric vehicles. Consequently, the chiller must be robust and efficient.
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The know way for improving the efficiency is, for example increasing the heat exchange surface by providing bigger chiller core or by providing multiple passes in said heat exchanger. Another way to increase the efficiency is, for example providing a so-called U-flow for the fluid which allows increasing the heat exchange are and elongating the path for the fluid. However, providing the U-flow may lead to several problems including reduced pressure drop, dead zones and lack of homogenity of the fluid circulating within the passes.
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It would be advised to provide a heat exchanger of a U-flow type, capable of high heat exchange rate which is well balanced in terms of volume and mass. Finally, it would be desired to provide a homogenous flow through the heat exchanger in an inexpensive way, and without significant impact to its performance or external dimensions.
SUMMARY OF THE INVENTION
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The object of the invention is, among others, a heat exchanger for a heat exchange between a first fluid and a second fluid, comprising: a plurality of first heat exchange conduits for the first fluid, and plurality of second heat exchange conduit for the second fluid extending in a first direction (X1) from first side to a second side, the second side being opposite to the first side, wherein the second heat exchange conduit comprises a first planar element and a second planar element fixed to the first planar element to form a closed profile of the second conduit, a conduit inlet located at the first side, a conduit outlet located at the first side, so that intended second fluid flow path forms a U-turn zone for the second fluid, and a distribution means being sandwiched between the neighboring planar elements, wherein the distribution means comprises a first zone, a second zone and a third zone, wherein the first zone and the second zone are configured to provide an intended second fluid main path being parallel to the first direction, and wherein the third zone is configured to steer the second fluid from the first zone towards the second zone in the U-turn zone.
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Advantageously, the third zone is arranged downstream the first zone.
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Advantageously, the second zone is arranged downstream the third zone.
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Advantageously, the distribution means is offset fin.
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Advantageously, the third zone comprises a first portion, and at least second portion arranged next to the first portion.
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Advantageously, the first portion is disjointed from the first zone, and the second portion is disjointed from the second zone, and wherein the first portion is disjointed from the second portion.
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Advantageously, the first portion, and at least second portion are unitary with the first zone and the second zone, respectively.
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Advantageously, the first portion is configured to deflect the intended second fluid flow path towards the median portion of the second side.
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Advantageously, the first potion and the second portion are of the same size.
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Advantageously, the first potion is of different size than the second portion.
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Advantageously, the third portion comprises at least a first channel configured to selectively increase the cross section of the U-turn zone.
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Advantageously, the third portion further comprises a second channel arranged downstream the first channel, so that the first channel deflects the intended second fluid flow path from the first zone towards the second channel and said second channel deflects the intended second fluid flow path towards the second zone.
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Advantageously, the first channel and the second channel are incisions formed in the third zone.
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Advantageously, the first channel comprises a first channel axis, the second channel comprises a second channel axis, wherein the channel axes are arranged at angle with respect to the first direction, and wherein the first channel axis is arranged at an angle with respect to the second channel axis.
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The invention further allows reduction in fluidic pressure drop in a U-flow type heat exchanger thanks to specific features of internal elements which are tailored to the direction of fluidic circulation; and improved thermal performance thanks to a more homogeneous fluid distribution in the inlet and outlet distribution zones of the channel over its entire width and an increase in the exchange surface.
BRIEF DESCRIPTION OF DRAWINGS
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Examples of the invention will be apparent from and described in detail with reference to the accompanying drawings, in which:
- Fig.1 shows a perspective view of the heat exchanger.
- Fig. 2 shows an exploded view of the planar elements with distribution means.
- Fig. 3 shows a top view of the plate with distribution means with the third section in one variant.
- Fig. 4 shows a top view of the plate with distribution means with the third section in other variant.
DETAILED DESCRIPTION OF THE INVENTION
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The subject- matter of the invention relates to a heat exchanger 1. The heat exchanger 1 may be configured for a heat exchange between a first fluid and a second fluid. The first fluid may be, for example, a refrigerant, and the second fluid may be a different fluid, for example, a coolant.
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The heat exchanger 1 may comprise a plurality of first heat exchange conduits 111 for the first fluid. It should be noted that the first fluid may be a fluid comprising two or more phases. For example, the first fluid may be a mixture of oil, liquid and gas.
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The heat exchanger 1 may further comprise a plurality of second heat exchange conduits 222 for the second fluid. The second fluid may be, for example, a coolant. The second heat exchange conduits 222 may be arranged alternately with the first heat exchange conduits 111 so that the heat exchange between the first fluid is maximized due to increase of the heat exchange surface vis-à-vis two fluids.
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The term first heat exchange conduits 111 and second heat exchange conduits 222 refer in general to the means of fluid-tight fluid transfer. In order to maximize the heat exchange area, it is preferable that the conduits 111, 222 have big heat exchange area. Thus it is preferred that the conduits 111, 222 have e.g. rectangular shape.
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The example of such configuration may be present, for example in a plate type heat exchanger for a motor vehicle. Most popular examples of such heat exchangers 1 may be, for example, a chiller or a water- cooled condenser. However, other types of the heat exchangers 1 are also envisaged. For the sake of clarity and conciseness, the subject matter of the present invention is described based on the chiller characteristics and such characteristics are present in the accompanying figures.
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Accordingly, the plurality of first heat exchange conduits 111 for the first fluid, and plurality of second heat exchange conduits 222 for the second fluid may extend in a first direction X1. The first direction X1 may extend from a first side of the conduits 111, 222 to a second side of the conduits 111, 222. The second side being opposite to the first side. In other words, the first direction X1 is the axis of the extension of the conduits 111, 222. The second heat exchange conduit 222 may comprise a first planar element 200A and a second planar element 200B fixed to the first planar element 200A to form a closed profile of the second conduit 222. Similarly, the first heat exchange conduit 111 may comprise a primary planar element and a secondary planar element fixed to the first planar element to form a closed profile of the first conduit 111. The primary planar element and the secondary planar element have no reference in the figures, as the second conduit 222 is of the most interest.
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The second conduit 222 may further comprise a conduit inlet 201A located at the first side, and conduit outlet 201B which is also located at the first side, so that intended second fluid flow path forms a U-turn zone 299 for the second fluid. The U-turn zone 299 may further comprise a baffle formed any of the planar elements 200A, 200B which extends from the first side (on which the conduit inlet 201A and conduit outlet 201B are located), towards the second side, yet said baffle comprises a free and which is not in contact with the second side. The intended fluid flow path is regarded as the path for the fluid between the conduit inlet 201A and the conduit outlet 201B.
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The second conduit 222 may further comprise a distribution means 500. The distribution means 500 may be sandwiched between the neighboring planar elements 200A, 200B so that the second fluid passes through said distribution means 500. The purpose of the distribution means is to provide as homogenous flow of the fluid as possible. This allows enhanced heat transfer between the conduits 111, 222.
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In order to further improve the fluid distribution across the second conduit 222, the distribution means 500 may comprise a first zone 551, a second zone 552 and a third zone 553. The first zone 551 and the second zone 552 may be configured to provide an intended second fluid main path which is concurrent to the first direction X1. In other words, the intended second fluid flow path in the first zone 551 and the second zone 552 is straight and parallel to the axis of extension of the planar elements 200A, 200B.
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With regard to the conduit inlet 201A, it may be arranged at the confluence of one of the longer walls and the first side. The conduit outlet 201B may arranged the confluence of the other longer wall and the first side. This allows forming a U-turn for the fluid. In case the heat exchanger 1 comprises more than one U-turn 299, the conduit outlet 201B may be arranged either at the confluence of the other longer wall and the first side, or conduit outlet 201B may arranged the confluence of the other longer wall and the second side.
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The first planar element 200A and a second planar element 200B allow the first fluid to pass through so that the first conduits 111 remain in fluidal communication. Therefore, first planar element 200A and a second planar element 200B may comprise a pair of first fluid manifolds 290A, 290B for the first fluid. The first fluid manifolds 290A, 290B may be fluidly insulated from the second conduit 222 to allow fluidal communication between neighboring first conduits 111.
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When assembled, the planar elements 200A, 200B are in contact with each other. The distribution means 500 may be at least partially immobilized with respect to the planar elements 200A, 200B by means of its specific shape.
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It should also be noted that disruptor means 500 may be made out of so-called offset fin. Namely, the first zone 551 and second zone 552 and the third zone 533 are all made of offset fin.
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As mentioned in previous paragraphs, the first zone 551 and the second zone 552 are configured to provide an intended second fluid main path being parallel to the first direction X1. By contrast, the third zone 553 is configured to steer the second fluid from the first zone 551 towards the second zone 552 in the U-turn zone 299. In other words, the third zone 533 is different than the first zone 551 and the second zone 552 by that it may enhance fluid distribution in the U-turn zone(s) 299 in the conduits 111, 222. This allows the reduction of the pressure drop and increases overall efficiency of the heat exchanger 1. The beginning of the third zone 553 may be defined, for example, by the free end of the baffle which forces the U-flow in any of the conduits 111, 222.
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The intended second fluid flow path extends between the conduit inlet 201A and the conduit outlet 201B. Accordingly, the third zone 553 may arranged downstream the first zone 551, the downstream being defined as subsequent with respect to the intended second fluid flow path. Accordingly, the second zone 552 may be arranged downstream the third zone 553.
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In one of the examples, wherein the third zone 553 may comprise a first portion 553A, and at least second portion 553B arranged next to the first portion 553A. In other words, the third zone 553 may comprise two or more elements deflecting the intended second fluid flow path in different direction, namely the first portion 553A deflecting the fluid in one direction, and the second portion deflecting the intended second fluid flow path in the other direction, being different than the first direction.
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To be more precise, the first portion 553A may be configured to deflect the intended second fluid flow path towards the median portion of the second side. The second portion may be configured to deflect the intended second fluid flow path from the median portion of the second side towards the second zone 552 and consequently, towards the conduit outlet 201B. This all allows more uniform and unobstructed flow of the fluid while maintaining high heat exchange.
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The first portion 533A may be disjointed from the first zone 551, and the second portion 553B may be disjointed from the second zone 552. This means that the first portion 553A and the second portion 533B are separate sub-components than the first zone 551. Further, the first portion 553A may be disjointed from the second portion 553B, so that they are separate sub-components. This allows to reduce the cost of providing the third zone 553, as it would only require cutting the disruptor means 500 (e.g. offset fin) in several pieces and arranging them in a way that allows to observe the aforementioned desired effects.
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Accordingly, the first potion 553A and the second portion 553B are of the same size. The size may be measured, for example, as the surface of the first potion 553A and the second portion 553B. In this example, it is preferred that the first potion 553A does not protrude beyond the median portion of the second side.
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Alternatively, wherein the first potion 553A is of different size than the second portion 553B. For example, the first portion 553A may be bigger than the second portion 553B.
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Alternatively, the first portion 553A, and at least second portion 553B may be unitary with the first zone 551 and the second zone 552, respectively. This means that the entire distribution means 500 is made out of one piece (e.g. one piece of offset fin). It is preferred that in this example the third zone 553 is carried out in a specific way that is discussed in further paragraphs.
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In one of the examples, the third portion 553 may comprise at least a first channel 553C configured to selectively increase the cross section of the U-turn zone 299. The term "selectively increase" means that the third portion 553 comprises areas which provide less obstructed flow for the fluid. Preferably, this selectively increased the cross section of the U-turn zone 299 is adapted to be U-shaped or V-shaped to enhance the fluid flow in the U-turn zone 299.
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Further, the third portion 553 may comprise a second channel 553D arranged downstream the first channel 553C, so that the first channel 533C deflects the intended second fluid flow path from the first zone 551 towards the second channel 553D and said second channel 553D deflects the intended second fluid flow path towards the second zone 552. The second channel 553D may be simply another means for adapting the third zone 553 to promote U-shaped or V-shaped flow of the fluid to enhance the fluid flow in the U-turn zone 299.
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In simplest variant, the first channel 553C and the second channel 553D are incisions formed in the third zone 553. In other words, the gap may be formed in the structure of the distribution means 500 which is devoid of the offset fin structure to promote the fluid flow locally. Thus, to further promote such flow, the first channel 553C and the second channel 553D may be arranged in a specific manner that is described in further paragraphs.
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Accordingly, the first channel 553C may comprise a first channel axis Z1. The first channel axis Z1 should be regarded as the general axis of extension of the first channel 553C.
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Further, the second channel 553D may comprise a second channel axis Z2. The second channel axis Z2 should be regarded as the general axis of extension of the second channel 553D.
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The channel axes Z1 ,Z2 are may be arranged at angle with respect to the first direction X1, and wherein the first channel axis Z1 is arranged at an angle with respect to the second channel axis Z2. It means that the first channel 553C is adapted to direct the flow in an angular direction with respect to the first direction X1. For example the first channel axis Z1 may be arranged with respect to the first direction X1 at an angle between fifteen to sixty degrees. Similarly, the second channel axis Z2 may be arranged with respect to the first direction X1 at an angle between fifteen to sixty degrees. The first channel axis Z1 may be arranged with respect to the second channel axis Z2 at an angle between fifteen to ninety degrees.
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Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of drawings, the disclosure, and the appended claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to the advantage.