JPH0368320B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention comprises a number of tubes parallel to the axis guiding a medium on the inside and transverse fins arranged at a distance on the same axis on the outside; The transverse fins have, as guide members for the external medium flowing transversely through the tube, an embossed hole, approximately semicircular in cross section, embossed from its plane in the same axial direction, and this embossed hole is are arranged with the tubes at a distance, viewed in the direction of flow of the medium, in which case the stamped holes form on their inner surfaces guide channels for forcing the external medium and each run parallel to the outer wall of the tubes. Regarding heat exchangers.

German Patent No. 496 733 discloses that a stamped hole arranged with a tube without inlet and outlet openings, that is to say not designed as a guide channel, allows the medium to pass through in order to obtain a good heat transfer. Heat exchangers are described which conduct within the tubes.
In this case, the arrangement of the stamped holes in relation to the tube is such that the stamped holes reduce the passage cross-section for the medium between the fins further away from the tube, so that the medium flowing between the fins is For the aperture that dominates in position, it is chosen to be turned from this aperture position to a position located in the vicinity of the tube.

The known stamped holes thus form depressions. This is because the stamped holes must create a restriction between the tubes. However, this throttling causes that each deflection of the external medium is compensated for by significant pressure losses, ie energy losses. Another subsequent phenomenon is the creation of a new flow dead space behind the throttle location and an area where vortices can occur. Thereby, the heat transfer from one medium to another is forced to deteriorate.

In West German Patent No. 2809143, the stamped holes are not designed to generate a throttle position as in the case of West German Patent No. 496733, but instead they are formed in the guide channel. A heat exchanger of the abovementioned type is provided, which has a shape and whose guiding ducts produce a deflection of the medium exclusively in order to distribute it as optimally as possible within the tubes, without any restriction of the flowing medium. Are listed. This heat exchanger has proven effective in practice. A particularity in the case of the known heat exchanger according to DE 2 809 143 is that each tube is associated with four guide channels-embossed holes on each transverse fin, in which case this guide The longitudinal axis of the passage lies approximately on a circle having a predetermined radius centered on the longitudinal axis of the tube. The medium flowing on the upstream side into the inlet opening of the guide channel passes through the front embossed hole in the flow direction and exits through the outlet opening of this embossed hole, and the medium leaving the outlet opening generally passes through the next It reaches into the entrance opening of the guide passage. In other words, on each side of the tube two abutting stamped holes of considerable length are arranged, and the mass of the medium flowing into the first stamped hole is equal to that of this stamped hole. It is essentially the same mass as is displaced from the next stamped hole.

The object of the invention is furthermore to form a heat exchanger of the abovementioned type which achieves an improved cooling effect compared to known heat exchangers practically without swirl formation.

For this purpose, a number of stamped holes are provided at different radial distances from the tube to which they belong,
This is achieved by a heat exchanger characterized in that the front inlet openings of at least a few of the embossed holes, viewed in the flow direction, overlap the embossed holes adjacent to the outlet openings.

That is, in the case of the heat exchanger according to the invention,
a large number of stamped holes offset in the flow direction;
That is, a guide passage is provided. In the case of a medium flowing in contact along the surface of the tube, multiple distributions and turns are achieved by this offset arrangement of the stamped holes. That is, the medium is guided over the tube with good mixing and thus an increased heat transfer is achieved.

Particularly preferred embodiments of the invention are set out in claim 2 or 3. According to claim 2, two groups of stamped holes are provided, the stamped holes of the individual groups being arranged at different radii relative to the axis of the tube. .

One particularly advantageous embodiment of the invention, which comprises
(deserving the protection of an independent patent claim) is set forth in claim 3. Due to the conical and tapered design of the stamped holes formed as guide channels, the medium flowing along one side of the fin is
This is achieved by reducing the cross section of the individual guide ducts so that they are pushed to the opposite side of the respective transverse fin of the heat exchanger. That is, a cross-flow is generated in the heat exchanger system, which cross-flow, according to experience, has a positive effect on the heat transfer.

One embodiment of the invention will now be described in detail with reference to the drawings.

The fin tube heat exchanger section according to FIG. 1 on the one hand and the fin tube heat exchanger section according to FIGS. have in a column. The tubes 1 are arranged offset from each other parallel to the axis. The distance between the individual tubes 1 is the same at each location. The tube 1 has a circular inner and outer cross section. Across the tube 1, in a plane perpendicular to its longitudinal axis, the rectangular fins 2 are transitioned, with the same pleat distance between the fins. The fins 2 are fixed to the tube 1 in good heat-conducting contact over the entire surface with the outer wall of the respective tube, in particular by brazing. Furthermore, the fins 2 are held at a distance from each other by spacers (not shown) in a known manner.

The tube 1 allows an external medium to flow in the direction of arrow S perpendicular to the axis of the tube, and inside the tube there is an internal medium that is in a state of heat exchange with the external medium. The external medium can be, for example, a gaseous refrigerant.

The fins 2 of the fin tube heat exchanger are completely flat in the device according to FIG. It turns out that in the case of the device according to FIG. 1, a dead space is formed behind the tube 1, which separates the large circumferential area of the tube 1 from heat transfer.

According to FIGS. 2 and 3, the stamped holes 3a, 3
b, 3c are embossed into the fin 2, this embossed hole forming a guide channel for the external medium.

As shown in the upper right of FIG. 2, the stamped holes 3a, 3b, 3c, each surrounding the tube 1, lie on a circle centered on the axis of the respective tube 1 in the direction of the central longitudinal axis. In this case, for this embodiment,
In particular, the three circles are defined by different radii,
That is, a circle of average size is defined by radius R ₁ , a large circle is defined by radius R ₁ + △R _a ,
Moreover, the radius of the small circle is defined by R ₁ −ΔR _i .

It can be seen that the embossing holes 3a are arranged on a circle with radius R ₁ in the longitudinal direction, thus forming a first group of embossing holes. radius
On the large circle with R ₁ + △R _a , there is a stamped hole 3
A stamped hole 3c is arranged on a small circle having radius R ₁ +ΔR _i . Embossing holes 3b and 3c form a second embossing hole group.

Furthermore, as can be seen from FIGS. 2 and 3, the pair of stamped holes 3b and 3c in the outer or inner circle, respectively, form two holes in the first group on the average-sized circle. It exists between the stamped holes 3a arranged at a distance in the circumferential direction. Furthermore, an additional stamped hole 3d, still isolated, is provided in FIG. 2 to cover the heat transfer area.

As shown in FIG. 2, the medium entering the heat exchange section corresponding to the arrow S passes along the dotted line, partially through the guide passage and into the stamped holes 3a, 3b, 3c; and a portion flows along the walls of the stamped holes 3a, 3b, 3c, in which case a distribution and mixing of the medium takes place during the passage through the heat exchange section, so that the outer surface of the tube 1 is always free of fresh medium. , so that optimum heat transfer takes place between the medium outside the tube 1 and the medium inside the tube 1.

As shown in the lower right of FIG. 2, for example, in the case of heat transfer from the embossing hole 3a to the embossing hole 3c, an overlapping range 4 exists, and this overlapping range corresponds to the embossing hole 3c. It is shown that a portion of the medium exiting from 3a enters the later stamped hole 3c. This behavior also exists in the case of heat transfer from the stamped holes 3a to the stamped holes 3b or from the stamped holes 3b, 3c to the stamped holes 3a.

As can be seen from FIG. 3, the stamped holes 3a, 3b, 3c used as guide passages are tapered conically in the flow direction S. That is, the inlet opening 5a of each of the stamped holes 3a, 3b, 3c has a larger cross section than the outlet opening 5b of the stamped holes 3a, 3b, 3c. When the flow medium enters the inlet opening 5a, it is forced to the rear side of the fin 2 through the embossed holes 3a, 3b, 3c during its passage. Thereby, a cross flow occurs in a part of the heat exchanger which improves the heat transfer even further between the external medium and the medium inside the tubes 1.

The cross-sectional reduction of the embossing holes 3a, 3b, 3c can be linear or non-linear, according to FIG.

[Brief explanation of drawings]

FIG. 1 is a partial plan view schematically showing a part of a fin tube heat exchanger according to the prior art, viewed in the axial direction of the tube, and FIG. 2 is a partial plan view of a fin tube heat exchanger according to the present invention. FIG. 3 is a perspective view of a portion of the fin tube heat exchanger according to the section of FIG. 2; 1... Pipe, 3a, 3b, 3c... Embossed hole, 5
a... Entrance opening.

Claims (1)

[Claims] 1. It has a number of tubes parallel to the axis, guiding a medium on the inside, and has transverse fins arranged at a distance on the same axis on the outside, which transverse fins are arranged at a distance along the same axis. It has as a guide element for the external medium flowing transversely through the tube an embossed hole, which is embossed from the plane in the same axial direction and is approximately semicircular in cross section, and which embossed hole is in the direction of flow of the external medium. in the heat exchanger, which are arranged at a distance from each other with the tubes, in which case the stamped holes form on their inner surfaces guide channels for forcing the external medium and in each case run parallel to the outer wall of the tubes. , a number of stamped holes 3a, 3b, 3c are provided at different radial distances from the pipe 1 to which they belong, the front face of at least a few stamped holes 3a, 3b, 3c seen in the flow direction. A heat exchanger characterized in that the inlet opening 5a of the heat exchanger overlaps the stamped holes 3a, 3b, 3c adjacent to the outlet opening. 2 Each tube 1 has stamped holes 3a, 3b, 3c
The stamped holes 3a of one group exist approximately on a circle having a radius R ₁ centered on the axis of the tube in the longitudinal axis direction, and the stamped holes 3a of the other group co-belong to two groups. 3b and 3c lie on two circles having radius R ₁ +△R _a or radius R ₁ -△R _i centered on the axis of the tube in the longitudinal axis direction, and each has a pair of embossing from the other group. The holes 3b and 3c are 2 of the first group when viewed in the circumferential direction.
A heat exchanger according to claim 1, which is located between two stamped holes 3a. 3. The embossing holes 3a, 3b, 3c, especially at least a part of all the embossing holes 3a, 3b, 3c, are conical and tapered when viewed in the flow direction. The heat exchanger according to item 2.