DE102011004306A1 - Rib for a heat exchanger - Google Patents

Abstract

A fin (1, 1 ', 1 ") for a heat exchanger, comprising a fin sheet 2 corrugated in a longitudinal direction L and arranged between two structures, and a plurality of rib flanks 3, 3', 3" formed by the corrugation Ribbed plate 2 in a depth direction of a particular gaseous fluid for the transmission of heat between the structures and the gaseous fluid can be flowed through, and wherein in the fin plate 2 a plurality of successively on the rib flanks 3, 3 ', 3' 'arranged, on a neutral line 4, 4 'extending and substantially transversely to the depth direction extending gills 5, 5', 5 '' are provided with a Kiementiefe KT and a gill angle KW with respect to the depth direction. The rib flanks 3, 3 ', 3 "have, at least in regions, an essentially wave-shaped structure course, resulting in an arrangement of the gills 5, 5', 5" running on a wave-shaped neutral line 4, 4 '.

Description

The invention relates to a rib for a heat exchanger according to the preamble of claim 1.

In today's heat exchangers, such as coolant radiators or intercoolers, ribs with gills, which are produced by a rolling process as corrugated ribs, are often used for the heat transfer to the air or to a gas to be cooled. These corrugated fins are soldered with pipes or washers to ensure heat transfer. For example, corrugated ribs with inclined gills are known. Corrugated ribs with slanted gills are used because they may cause damage. a. allow a fast and cost-effective manufacturing process. Their shape is strongly influenced by the manufacturing process and they represent a compromise in terms of their function as a heat-transmitting rib, which contains weak points for the actual task of low-loss heat transfer.

For example, the corrugated fins are produced in a rolling process in which a forming roll pair in a metallic strip, z. As aluminum, imprinting a wave structure in which each up and down swing represents a rib. The gills are formed by the fact that the rollers consist of several discs, each of which is ground so that, in addition to the wave structure, gills are cut into the band during the rolling process. The gills usually have a constant depth of kite and a constant gill angle. This allows the use of many common parts when making tools. Alternatively, there are processes in which the gills are cut into the flat strip material and the ribs are subsequently corrugated. The gill angle is usually between 20 ° and 30 °. This should serve to adapt the ratio of pressure loss and heat transfer to the local flow state.

The DE 10 2009 021 179 A1 discloses a rib for a heat exchanger in which the gills have a gill angle between 14 ° and 30 ° and a gage depth either in the range of 0.3 mm to 0.6 mm or in the range of 1.1 mm to 1.8 mm.

• – Umlenk- und Stoßverluste, insbesondere bei der ersten Kieme, bei der Umlenkung in der Mitte und bei der letzten Kieme;
• – Verluste durch Ablösung: an den Umlenkungen treten in weiten Reynoldszahl-Bereichen auch Ablösungen auf die dazu führen, dass sich die nachfolgende Kieme im Ablösegebiet befindet und nicht richtig genutzt wird;
• – Bei einer Gleichverteilung von Kiementiefe und Kiemenwinkel kann es bei den üblichen Rippendichten dazu kommen, dass Kiemen in Strömungsrichtung nach nur einer Kiemenlänge fluchten und dadurch kein Grenzschichtneuanlauf entsteht.
• – Bei in Strömungsrichtung variierenden Kiemen entstehen ungleichmäßige Strömungsquerschnitte, die zu Druckverlusten und einer Ungleichverteilung der Massenstromdichte führen.

Investigations have shown, however, that constant gill angles and constant depths of kink reveal in practice, among others, the following weak points:

• - Deflection and shock losses, especially in the first gill, in the deflection in the middle and at the last gill;
• - Losses due to detachment: at the deflections occur in wide Reynolds number areas also detachments on the result that the subsequent gill is in the detachment area and is not used properly;
• - With an equal distribution of the depth of the kite and the angle of the gills, it can happen with the usual rib densities that gills are aligned in the direction of flow after only one gill length and thus no boundary layer revival occurs.
• - When varying in the direction of flow gills uneven flow cross-sections, which lead to pressure losses and an unequal distribution of the mass flow density.

The invention has for its object to provide a rib of the type mentioned, with the described vulnerabilities or loss mechanisms can be significantly improved or reduced.

This object is achieved by a rib with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

The object is achieved according to the invention in that the rib flanks have a substantially wave-shaped structure course at least in regions, resulting in an arrangement of the gills running on a wave-shaped neutral line. The individual gills are arranged directly following one another on the neutral line or shaped around it. This allows a uniform distribution of flow cross sections and optimal use of the gills. The waveform is preferably to be chosen so that the vertical offset of the gills by the wave structure compensates for the difference in the vertical adjustment of the successive gills due to different gill angles. Thus, successive gills preferably have at least slightly different gill angles. The gills run with their axial longitudinal center on the undulating neutral line and are preferably rotated slightly different around the longitudinal center. Depending on the number of gills or depending on the length of the rib flank, at least two gills of the same orientation can subsequently also be provided. The rib flanks are arranged regularly to improve the mechanical stability at an angle to each other, but can also run parallel to each other depending on requirements.

An embodiment provides that the neutral line has a continuous wave profile with at least one shaft section, such that the shaft section runs parallel to the main flow direction starting continuously rising in an arc to the maximum deflection and then according to the increase again drops so that it runs parallel to the main flow direction. It is essentially similar to a cosine curve from 0 ° to 360 °. The wave-shaped neutral line here differs significantly from a production-induced deformation of the neutral line, which runs either V-shaped or in a circular arc without significant inflection points.

Preferably, several successive shaft sections can be provided per rib edge. The final number of shaft sections may depend on the length of the rib flank. For very deep systems, it may be useful to choose the wavelength so that several wave sections are formed in the flow direction. This limits the maximum deflection of the flow and makes better use of the heat transfer matrix at the pipe ends.

A further embodiment provides that at least one first and one second gill group are provided per shaft section, wherein the gill angles of the gill groups may have different orientations. Thus, for example, a fluid may first be directed in one direction through the fin plate and subsequently in the opposite direction.

Advantageously, results from the adjacent gills of two rib edges a non-aligned arrangement of the individual gills to each other.

For example, the gill angle between 20 ° and 60 °, preferably between 30 ° and 50 °, amount. Optionally, the gill angle may also be lower, for example, if a weaker design is not made possible by a reduced rib density. This may be necessary, for example, when the requirement for internal pressure resistance requires support of radiator tubes by a high fin density.

The rib density in the longitudinal direction is generally preferably between 70 Ri / dm and 120 Ri / dm. The unit Ri / dm is to be understood as the number of rib flanks given by the corrugation per decimeter.

The deflection per rib is ideally not more than 7 °. If the gill number is very high, so that each rib would require a deflection of less than 7 ° to reach the total deflection to the middle of the gill field, multiple gills can be made equal, reducing the complexity of the tool. Ideally, the gills are arranged so that the free flow area between the gills is 1/3 of the distance between the ribs (reciprocal ridge density value). This achieves a uniform distribution of the flow to the gills. The neutral line in the middle also reaches an offset of about 1/3 of the rib distance. More specifically, the undulating neutral line in the highest wave region may have an offset of preferably 1/3 to the straight portions of adjacent rib edges.

The object of the invention is also achieved for a heat exchanger according to claim 9 by providing a rib according to the invention.

In an advantageous detailed design of the heat exchanger is designed as a heat exchanger of a motor vehicle, in particular as an electric radiator, liquid-operated radiator, evaporator or condenser of a vehicle air conditioning, intercooler or coolant radiator. In motor vehicles, there is a particularly high requirement for the optimization of the heat exchanger performance with a given space. The rib according to the invention is particularly suitable for use with a radiator, since it allows for a given air flow and given temperature difference a particularly small pressure drop. This reduces noise and makes it possible, for example, to make a heating fan particularly small. In the case of a heat exchanger in the form of an electrically operated radiator, the structures are, for example, electric heating elements, preferably PTC heating elements (PTC = Positive Temperature Coefficient). In a possible alternative embodiment of a radiator, the structures may also be flat tubes or round tubes in which, for example, heated coolant flows through an engine cooling circuit.

Further advantages, features and details of the invention will become apparent from the following description in which embodiments of the invention are described with reference to the drawings. The features mentioned in the claims and in the description may each be essential to the invention individually or in any desired combination.

Show it:

1 the schematic representation of a rib according to the invention in a perspective view;

2 the schematic representation of a gill assembly according to the invention;

3 the schematic representation of another embodiment of a rib according to the invention.

1 shows a schematic representation of a rib 1 for a heat exchanger. The rib 1 comprises a ribbed plate corrugated in the longitudinal direction L. 2 with a plurality of rib flanks formed by the corrugation 3 ,

On the ribbed plate 2 are a plurality of consecutively on the rib flanks 3 arranged, on a wavy neutral line 4 extending and extending substantially transversely to the depth direction gills 5 intended.

The rib flanks 3 have, at least in some areas, a substantially wave-shaped structure course, whereby the wave-shaped neutral line 4 running arrangement of the gills 5 results.

2 shows the schematic representation of one on a rib 1' arranged gill arrangement 6 , Good to see is the wavy neutral line 4 ' , which has a continuous waveform with a shaft portion W, such that the shaft portion W parallel to the main flow S starting continuously rising in a curve B to the maximum deflection and then according to the increase again drops so that it runs parallel to the main flow S1.

The gills 5 ' are consecutive about an axial longitudinal center 7 on the neutral line 4 ' arranged and in each case to the neighboring gill 5 ' arranged slightly offset. The neutral line 4 ' around the gills 5 ' is thus not currently executed as usual (see L1), but along the undulating neutral line 4 ' , This arrangement allows a uniform distribution of the flow cross sections 8th and optimal use of the gills 5 ' , This results from the adjacent gills 5 ' two rib edges 3 ' . 3 '' a non-aligned arrangement of the individual gills 5 ' to each other (see 9 ).

The gills 5 ' have a gill angle KW which is preferably between 30 ° and 50 °. 2 shows that the gills 5 ' in the depth direction as two consecutive gill groups 10 . 11 of different gills 5 ' are provided, the gill course of the two groups 10 . 11 the same, but inverted in the direction. Thus, the air is, for example, first in one direction and then passed in the reverse direction through the fin plate.

At the beginning of the first gill group 10 and at the end of the second gill group 11 is each a gill 5a and 5b intended. Between the gills groups 10 . 11 is each a gill 5c provided for a transition between the differently directed gill groups 10 . 11 provides.

The gills 5 ' are arranged so that the free flow cross section between the gills 5 ' preferably makes 1/3 of the distance between the rib edges. This will give a uniform distribution of flow to the gills 5 ' reached. It also reaches the neutral line 4 ' in the middle M an offset of about 1/3 of the rib distance.

3 shows one on a floor or collector 12 arranged rib 1'' , On the rib 1'' are several gills 5 '' arranged in undulating course. In the embodiment shown here, two shaft sections W 'and W "are arranged one behind the other. Each shaft section W 'and W "consists of two gill groups 13 . 14 and 15 . 16 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009021179 A1 [0004]

Claims (10)

Rib ( 1 . 1' . 1'' ) for a heat exchanger, comprising a corrugated sheet metal corrugated in a longitudinal direction L and arranged between two structures 2 , and a plurality of rib flanks formed by the corrugation 3 . 3 ' . 3 '' , where the ribbed sheet 2 in a depth direction of a particular gaseous fluid for the transmission of heat between the structures and the gaseous fluid can be flowed through, and wherein in the fin plate 2 a plurality of successively on the rib flanks 3 . 3 ' . 3 '' arranged, on a neutral line 4 . 4 ' extending and extending substantially transversely to the depth direction gills 5 . 5 ' . 5 '' are provided with a Kiementiefe KT and a gill angle KW with respect to the depth direction, characterized in that the rib flanks 3 . 3 ' . 3 '' at least in some areas have a substantially wave-shaped pattern, resulting in a wave-like neutral line 4 . 4 ' running arrangement of the gills 5 . 5 ' . 5 '' results. Rib according to claim 1, characterized in that the neutral line 4 . 4 ' a continuous wave with at least one shaft portion W, W ', W'', such that the shaft portion W, W', W '' parallel to the main flow S, S1 continuously rising in a curve B to the maximum deflection and then according to the slope again drops so that it runs parallel to the main flow direction S, S1. Rib according to claim 2, characterized in that per rib flank 3 . 3 ' . 3 '' a plurality of consecutive shaft sections W, W ', W''are provided. Rib according to at least one of the preceding claims, characterized in that per shaft portion W, W ', W''at least a first and a second gill group 10 . 11 . 13 . 14 . 15 . 16 is provided, wherein the gill angle KW of the gill groups 10 . 11 . 13 . 14 . 15 . 16 have different orientations. Rib according to claim 4, characterized in that the orientations are designed such that they pass through the adjacent gills 5 . 5 ' . 5 '' two rib edges 3 . 3 ' . 3 '' a non-aligned arrangement of the individual gills 5 . 5 ' . 5 '' gives each other. Rib according to at least one of the preceding claims, characterized in that the gill angle KW between 20 ° and 60 °, preferably between 30 ° and 50 °. Rib according to at least one of the preceding claims, characterized in that the maximum deflection per rib edge 3 . 3 ' . 3 '' preferably 7 °. Rib according to at least one of the preceding claims, characterized in that the undulating neutral line 4 . 4 ' in the highest wave range, an offset of preferably 1/3 to the straight sections of adjacent rib edges 3 . 3 ' . 3 '' having. Heat exchanger comprising a rib 1 . 1' . 1'' according to one of the preceding claims. Heat exchanger according to claim 9, characterized in that the heat exchanger is designed as a heat exchanger of a motor vehicle, in particular as an electric radiator, liquid-operated radiator, evaporator of a vehicle air conditioner, condenser of a vehicle air conditioning, intercooler or coolant radiator.

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