EP0109393B1

EP0109393B1 - Turbulator radiator tube for a radiator construction

Info

Publication number: EP0109393B1
Application number: EP82902115A
Authority: EP
Inventors: Eugene E. Rhodes
Original assignee: Ford Werke GmbH; Ford France SA; Ford Motor Co Ltd
Current assignee: Ford Motor Co Ltd
Priority date: 1982-05-19
Filing date: 1982-05-19
Publication date: 1987-08-12
Also published as: WO1983004090A1; DE3276959D1; EP0109393A1; EP0109393A4; JPS59500877A

Abstract

An improvement to the construction of an elongated turbulator radiator tube (114) and a radiator construction produced thereby. In general, the turbulator radiator tube has a first principal heat transfer surface (120) and a second principal heat transfer surface (122), both of which have a first edge (124) and a second edge (126). Interconnecting surfaces (128) and (130) are provided for independently interconnecting both the first edges and the second edges of the first principal heat transfer surface and the second principal heat transfer surface. The improved construction is characterized in the following manner. Each of the principal heat transfer surfaces having a plurality of flow diverting members (152) placed along the length thereof. Each of the flow diverting members is deformed from the principal heat transfer surfaces toward the interior of the tube. The flow diverting members as a group extend from about the first edge of the principal heat transfer surface to about the second edge of the principal heat transfer surfaces. These flow diverting members are so arranged that the first principal heat transfer surface and the second principal heat transfer surface are bowed outwardly from the interior of the tube when interconnected by the interconnecting surfaces.

Description

The invention relates to a radiator construction having an elongated turbulator radiator tube.
EP-A-30072 discloses a heat exchanger comprising a tube of a flat cross-sectional shape formed of metal and permitting a heat exchanging medium to flow therethrough, fins in thermal contact with said tube for promoting exchange of heat between the heat exchanging medium and a fluid and a plurality of projections formed on one side of said tube and arranged in a direction intersecting the axis of said tube, said projections each extending from said tube by a distance less than the thickness of a wall of said tube.
It is a principal object of this invention to provide a new construction for an elongated turbulator radiator tube which permits the tube to be assembled with other radiator forming components in a manner which provides better heat transfer characteristics from the radiator tube to other components of the radiator structure. This better heat transfer characteristic permits more rapid cooling of a coolant passing through the radiator tube and can reduce the size of radiator required in order to give a predetermined amount of cooling capacity.
According to the invention there is provided a radiator construction having an elongated turbulator radiator tube having an interior defining a fluid conduit, which turbulator radiator tube comprises; a first principal heat transfer surface. having a first edge and a second edge a second principal heat transfer surface having a first edge and a second edge interconnecting surface means for independently interconnecting both said first edges and said second edges of said first principal heat transfer surface and said second principal heat transfer surface characterised by, each of said principal heat transfer surfaces having a plurality of flow diverting members placed along the length thereof, each of the flow diverting members being deformed from said principal surfaces toward said interior of said tube said flow diverting members being offset from one another and being arranged as discontinuous indentations across the principal heat transfer surfaces from said first edge to said second edge of said principal heat transfer surfaces whereby said first and second principal heat transfer surfaces are bowed outwardly from said interior of said tube.
The shape of the deformations used to form the flow diverting members, which may take the form of a turbulator barrier as will be defined hereinafter, may come in a variety of configurations. However, the most preferred configuration is one in which each turbulator barrier is formed from a plurality of elongated, rectangular deformations which extend perpendicularly across each of the principal heat transfer surfaces from the first edge thereof to the second edge thereof. Also in accordance with the preferred embodiment, the turbulator barriers on the first principal heat transfer surface are in a staggered relationship with respect to the turbulator barriers formed on the second principal heat transfer surface.
The invention wi!! now be described by way of example with reference to the accompanying drawings in which:

Figure 1 is a partial elevation view of a radiator construction;
Figure 2 is a view showing a principal heat transfer surface of a turbulator radiator tube known in the prior art;
Figure 3 is a view of a principal heat transfer surface of a turbulator radiator tube formed in accordance with the teachings of the preferred embodiment of this invention;
Figure 4 is an enlarged cross-sectional view taken along the line IV-IV of Figure 2 showing in greater detail the prior art construction of a turbulator radiator tube;
Figure 5 is an enlarged cross-sectional view taken along the line V-V of Figure 3 showing the details of the turbulator radiator tube construction in accordance with the preferred embodiment of this invention;
Figure 6 is a view taken along the line VI-VI of Figure 5 showing in greater detail the construction of the turbulator radiator tube in accordance with the preferred embodiment of this invention; and
Figures 7A through 7G are other alternate embodiments of how a principal heat transfer surface of a turbulator radiator tube may be . deformed in order to obtain the advantages of the turbulator radiator tube disclosed in this specification.

A radiator construction, generally identified by the numeral 10, as is shown in Figure 1, is joined to a coolant tank 12.
In Figure 1 there is seen only the right-hand coolant tank 12, but, of course, as is obvious to any skilled artisan, the radiator construction 10 would also have a left-hand coolant tank. In this manner coolant may be passed from a tank on one side of the radiator to a tank on the other side of the radiator through a plurality of hollow turbulator radiator tubes 14. Corrugated heat transfer fins 16 are mounted between juxtaposed of the turbulator radiator tubes extending between the coolant tanks. As the coolant flows through the turbulator radiator tubes, heat is given up from principal heat transfer surfaces thereof in contact with the heat transfer fins whereby the temperature of the coolant is reduced. The turbulator radiator tubes and heat transfer fins may be joined to one another in a fluxless aluminum brazing operation which is well known in the art.
In Figures 2 and 4 of the drawings there is shown a prior art construction for the turbulator radiator tubes 14. There is also shown, in Figures 3, 5, 6 and 7 the construction of a new turbulator radiator tube 114, in accordance with the teachings of this invention. The significant difference between the prior art construction 14 and the new construction 114 is that the new construction provides an improved physical contact between the turbulator radiator tube and its associated heat transferfins. By use of this new construction, more heat may be extracted from a coolant flowing through the turbulator radiator tubes per unit volume of radiator construction 10. How this improved heat transfer contact is achieved will be explained in greater detail hereinbelow.
The turbulator radiator tube 14 of prior art construction is seen best in Figures 2 and 4. In this construction a first principal heat transfer surface 20 and a second principal heat transfer surface 22 are respectively facing and underneath the surfaces as shown in Figure 2 and top and bottom surfaces as shown in Figure 4. These surfaces define generally planar surfaces which when associated with heat transfer fins 16 provide the principal area of transferring heat from the turbulator radiator tubes to the heat transfer fins for dissipation to the atmosphere. Each of these principal heat transfer surfaces have a first edge 24 and a second edge 26. The edges are not sharply defined but generally are the areas at which the generally planar portions of the principal heat transfer surfaces come to an end.
As best seen in Figure 4, the first edges 24 of the first principal heat transfer surface 20 and the second principal heat transfer surface 22 are interconnected by a generally continuous surface 28 which is integrally formed with the principal heat transfer surfaces. The second edges 26 of the first principal heat transfer surface and the second principal heat transfer surface are interconnected by interconnecting surfaces 30 which, in association with solder 32 used in conjunction therewith, form a sealed construction for the turbulator radiator tube 14. The method of forming and sealing such a turbulator radiator tube is well known in the industry and forms no part of this invention.
The prior art turbulator radiator tube 14 has a plurality of elongated turbulator elements 34 extending across the length thereof generallyfrom the first edge 24 to the second edge 26 of each of the principal heat transfer surfaces 20 and 22. As is best seen in Figure 2, these turbulator elements are staggered and are generally formed by deforming the material forming the turbulator radiator tubes toward the interior of the tube. Normally the material forming the tube is aluminum or some suitable aluminum alloy.
The difficulty with this type of construction for a turbulator radiatortube 14 is that the principal heat transfer surfaces 20 and 22 are relatively flat. The tube 14 is flexible in the sense that it may be twisted if opposite ends of the tube are gripped and rotated in opposite directions. However, when the tube is returned to its normal, flat condition the principal heat transfer surfaces 20 and 22 once again achieve the relatively flat condition. The difficulty with this condition is that when a plurality of such tube and heat transfer fins are laid up for the purpose of assembly there is no flexibility in the turbulator radiator tubes to take up assembly tolerances. Therefore, while generally acceptable heat transfer contact is established between the heat transferfins and the turbulator radiatortubes, the maximum heat transfer capability of the unit is not achieved because of the inflexibility of the turbulator radiator tubes to accommodate dimensional tolerance differences in the heat transfer fins. The heat transfer fins normally have a great deal of dimensional variation in the units because they are made from relatively thin materials and precise control of the dimensions of these fin units is extremely difficult, if not impossible. Thus, when the fins and the turbulator radiator tubes have pressure applied thereto to form them into a unit, any tolerances to be taken up are taken up almost totally by the heattransferfins. This tolerance take- up causes many of the V-shaped contacting edges of the heat transfer fins to be crushed, away from a line contact with the turbulator radiator tube, thus reducing the heat transfer contact therebetween and, in many cases, causing spaces or slight voids between the heat transfer points.
The entire purpose of the structure of the turbulator radiator tube 114 of this invention is to provide flexibility not only in the heat transfer fin 16 but also in the turbulator radiator tube 114 so that both elements may be brought into the best physical contact to ensure the best heat transfer characteristics from the entire radiator construction 10. Thiswill be better understood from the discussion set forth hereinbelow.
The turbulator radiator tube 114, as seen in Figures 3, 5 and 6, has a first principal heat transfer surface 120 and a second principal heat transfer surface 122. These principal heat transfer surfaces have first edges 124 and second edges 126 in juxtaposition to one another. Again, these edges are not sharply defined, but merely define a transition from the principal heat transfer surface to some type of an interconnecting surface. For example, in the case of the first edges 124, they are interconnected by a continuous surface 128 (Figure 5) which is integrally formed with the entire structure. In the same manner, the second edges 126 are interconnected by interconnecting surfaces 130 and the solder 132 associated therewith.
In accordance with the teachings of a preferred embodiment of this invention, as is best seen in Figure 3, turbulator barriers, generally identified by the numeral 150, are placed along the length of both the first principal heat transfer surface 120 and the second principal heat transfer surface 122. In accordance with the teachings of the preferred embodiment, the turbulator barriers'are formed from two or more indentations 152. In the case of the preferred embodiment, the first principal heat transfer surface 120 has four indentations 152 to define the turbulator barrier 150, while the second principal heat transfer surface 122 has three indentations 152 to define the turbulator barrier 150. The turbulator barriers 150 formed on both the first and second principal heat transfer surfaces extend generally from the first edge 124 to the second edge 126 of each of the principal heat transfer surfaces.
The entire purpose for making the turbulator barriers 150 discontinuous across the principal heat transfer surfaces 120 and 122 is so that when the surfaces are being formed into the turbulator radiator tube 114 by soldering the interconnecting surfaces 130 the principal heat transfer surfaces may be bowed outwardly from the interior of the tube to give a slight crown to both of the principal heat transfer surfaces. This crowned effect may best be seen in Figure 5. This slight crown is much different than the very flat surfaces achieved for the prior art turbulator radiator tube 14, as is seen in Figure 4. The bowing or crowning of the turbulator radiator tube 114 permits itto also take up tolerances when it is brought into an assembled condition with a plurality of heat transfer fins 16 in order to form a radiator construction 10. The bowing or crowning of the principal heat transfer surfaces of the turbulator radiator tube 114 allows a flexing of that surface to take up tolerances when it is assembled with the heat transfer fins in an assembly operation.
By being able to take up tolerances, the turbulator radiator tube 144 of this invention makes more intimate contact with associated heat transfer fins and thereby improves the unit heat transfer capability of each unit area of the radiator construction 10. This improved heat transfer efficiency allows for two options. A radiator construction of the same size using prior art turbulator radiator tubes 14 as compared with a radiator construction using turbulator radiator tubes 114 would result in dimensionally the same size radiator, but the construction made with the improved turbulator radiator tubes 114 would have the capacity for handling a greater cooling load. On the other hand, if one desired the radiator construction to have the same cooling capacity, then the radiator construction using the turbulator radiator tubes 114 of the present invention would require that the overall size of the radiator construction be reduced, that is, less fin and tube area would be required in order to do the same cooling job as would be accomplished by a larger size radiator containing the prior art type turbulator radiator tubes 14.
While the preferred type of turbulator barrier 150 has been illustrated in Figures 3, 5 and 6, many other types of barrier constructions may be used which still result in a turbulator radiator tube 114 which has a crowned construction and thus has the ability of taking up tolerances when assembled with heat transfer fins. It should be kept in mind that it is not necessary to space barriers on the first principal heat transfer surface and the second principal heat transfer surface in a staggered relationship, although this is preferred. The barriers may be placed one below the other. In this specification the term "turbulator barrier" is used to mean a series of indentations made in a principal heat transfer surface which may be generally aligned in some configuration. It is not necessary to achieve the benefits of this invention to have such a turbulator barrier as one may have a random placement of indentations in the principal heat transfer surfaces so long as the indentations are discontinuous thus allowing a bowing or crowning of the construction to achieve the advantages set forth above. However, once again, it is easiest to place a uniform set of indentations generally defining a turbulator barrier in a heat transfer surface than it is to place random indentations in such a surface.
In Figures 7A through 7G a number of different patterns are shown which, if placed on the principal heat transfer surfaces, would produce the benefits of this invention. In Figure 7A the individual indentations are formed into a turbulator barrier generally having an arrowhead shape. In Figure 7B the indentations are placed to define a turbulator barrier having a generally curved configuration. In Figure 7C the indentations are placed to define a turbulator barrier having a generally herringbone construction. In Figure 7D the indentations are placed in the principal heat transfer surface in a manner which defines a turbulator barrier formed of a plurality of triangular members. In Figure 7E the indentations are placed in the principal heat transfer surface in a manner which defines a turbulator barrier extending generally at an angle between the edges of the principal heat transfer surface. In Figure 7F circular indentations are placed in the principal heat transfer surface generally in aligned position. In Figure 7G the indentations are placed in the principal heat transfer surface generally in a random fashion and therefore do not define a turbulator barrier per se as no generally associated structure .extends from one edge of the principal heat transfer surface to the other edge thereof.

Claims

1. Radiator construction having an elongated turbulator radiator tube having an interior defining a fluid conduit, which turbulator radiator tube comprises; a first principal heat transfer surface (120) having a first edge (124) and a second edge (126), a second principal heat transfer surface (122) having a first edge (124) and a second edge (126), interconnecting surface means (128, 130, 132) for independently interconnecting both said first edges (124) and said second edges (126) of said first principal heat transfer surface (120) and said second principal heat treansfer surface (122) characterised by, each of said principal heat transfer surfaces (120, 122) having a plurality of flow diverting members (152) placed along the length thereof, each of the flow diverting members (152) being deformed from said principal surfaces (120, 122) toward said interior of said tube (114), said flow diverting members being offset from one another and being arranged as discontinuous indentations across the principal heat transfer surfaces (120, 122) from said first edge (124) to said second edge (126) of said principal heat transfer surfaces whereby said first and second principal heat transfer surfaces (120, 122) are bowed outwardly from said interior of said tube (114).

2. Radiator construction as claimed in Claim 1,. wherein said flow diverting members are arranged as barriers discontinuous across the principal heat transfer surfaces, each of said barriers being formed from two or more indentations.

3. A radiator construction as claimed in Claim 2, wherein said turbulator barriers are in the form of a plurality of rectangular deformations extending generally perpendicularly across said principal heat transfer surfaces from said first edge thereof to said second 15 edge thereof.