JPS6238152Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a slit fin heat exchanger constructed by fitting slit fins into a large number of heat medium tubes.

1 and 2 show examples of the conventional structure of slit fins in a slit fin heat exchanger. In FIGS. 1 and 2, reference numeral 1 indicates a slit fin, and 2 indicates a heat medium tube for a heat medium W. A substrate 3 of the slit fin 1 has many cut and raised pieces 4,
4... and its cutout holes 8, 8... are formed. In this conventional example, each cut and raised piece 4 forms rising pieces 5 and 6 near the heat medium pipe 2, and a relatively long flat plate part 7 connects them.

In such a slit fin heat exchanger, the temperature of the fin substrate 3 and the cut and raised pieces 4 is closer to the temperature of the heat medium tube 2 as they are closer to the heat medium tube 2. The closer you get to the center of the fluid passage S between the holes 12, 12, the further away from the temperature of the heat medium pipe 2,
Therefore, a temperature distribution also occurs in the fluid A flowing through the fluid passage S. This tendency becomes more pronounced as the fluid flows downstream, generating a temperature boundary layer and reducing heat transfer performance.

Figures 3 to 6 are explanatory diagrams of experiments conducted to empirically confirm such phenomena. In Figures 3 and 4, symbol F indicates a flat fin;
F ₁ , F ₁ is an acrylic plate to ensure air passage, H is a high temperature heat source (heated to about 35℃) S
indicates a fluid passage.

In this case, the fin temperature distribution in the fin F from the edge part F' to the intermediate part F'' is shown in FIG. The fin temperatures T and F' at the edge F' are about 4°C lower.For this reason, the fluid (air) flowing through the fluid passage S
Also, the temperatures of the end flow A' flowing through the passage edge S' and the intermediate flow A'' flowing through the passage middle part S'' are different. Figure 6 shows the temperature distribution of fluid A flowing through fluid passage S (4 mm from the downstream end of fin F).
In this experimental example, there was a temperature difference of about 2°C between the end flow temperatures T, A' and the intermediate flow temperatures T, A''.

When a temperature boundary layer is formed in the fluid A flowing through the fluid passage S, the heat transfer effect is reduced, but as a means to improve this problem, the present inventor proposed an end flow A of the fluid flowing through the fluid passage S. We focused on averaging the temperature of fluid A by mixing it with intermediate flow A'', and conducted experiments as shown in FIGS. 7 to 10 to confirm its effectiveness.

In the experimental examples shown in FIGS. ₇ and 8, inclined plates D, _D , . When the fluid A is made to flow through the fluid passage S in this state, the intermediate flow A'' of the fluid is deflected by the inclined plate D and mixes with the end flow portion A', thereby causing the end portion of the fluid As shown in FIG. 10, the flow temperatures T, A' and intermediate flow temperatures T, A'' are averaged compared to the case without the inclined plate D (FIG. 6). This fluid temperature averaging effect increases as the inclination angle θ (Fig. 7) of the inclined plate D increases, but on the other hand, the fluid flow resistance increases, so the inclination angle θ should also be set within an appropriate range. There is a need. Incidentally, FIG. 9 is a graph showing the temperature distribution on the fin F, similar to FIG. 5.

Curves X and Y in FIG. 11 represent the amount of heat transfer (amount of heat transferred from high-temperature heat source H to fluid A) Q and fluid flow resistance ΔP in the experimental examples shown in FIGS. 3 and 4, as shown in FIG.
This shows the results of comparing the amount of heat transfer (same as above) Q' and the fluid flow resistance ΔP' in the experimental example shown in Figure 8. According to this, the inclination angle θ of the inclined plate D is 15
It can be seen that when the temperature exceeds 100°, the heat transfer effect is not significantly improved although the flow resistance increases significantly.

The present invention was developed based on the results of the above experiments, and the purpose is to improve heat transfer performance.In order to achieve this purpose, a fluid passageway spanning between adjacent heat medium tube insertion holes is constructed. In a slit fin heat exchanger configured by fitting a slit fin into a heat medium pipe, the slit fin has a plurality of rows of cut and raised pieces in the fluid flow direction formed by extending a horizontal frame piece between a pair of rising pieces, In a predetermined row of the plurality of rows of cut and raised pieces, at least a pair of cut and raised pieces are formed in the same row in the left-right direction, and between the cut and raised pieces in the same row, they are located closer to the center of the fluid passage and are mutually connected. A pair of rising pieces adjacent to each other are parallel to each other and inclined with respect to the center line of the fluid passage, and the direction of inclination with respect to the center line of the fluid passage is the same as that of the inclined rising pieces of the other row adjacent to the fluid flow direction. The directions of inclination are opposite to each other.

Thereby, the intermediate flow and the end flow in the fluid passage are effectively mixed, and the temperature of the fluid flowing through the fluid passage can be averaged.

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 12 and 13 show the first embodiment, and FIG. 14 shows the second embodiment.

In the first embodiment, each row of cut and raised pieces formed across the fluid passage S extending between the heat medium tube insertion holes 12, 12 adjacent to each other is formed into a pair of left and right small cut and raised pieces. It is also composed of pieces 14 and 24. One of each cut and raised piece 14, 24 (heat medium pipe 2 side)
The inclination angles of the rising pieces 15 and 25 are determined so as to follow the outer periphery of the heat medium pipe 2, while the other rising pieces 16 and 26 (closer to the center line l of the fluid passage S) are aligned with the center line l of the fluid passage S. They are formed at an inclination angle θ (approximately 7 degrees) with respect to each other, and the adjacent rising pieces 16 and 26 are parallel to each other. or,
The cut and raised pieces 14 and 24 on the upstream side of the flow of fluid A (for example, air) and the cut and raised pieces 1 in the row immediately downstream thereof
4 and 24, the directions of inclination of the rising pieces 16 and 26 closer to the center are opposite to each other, and as a result,
A wave-shaped passage 10 is formed in the center of the fluid passage S from the upstream side to the downstream side of the fluid flow.
The horizontal pieces 17 and 27 of each cut and raised piece 14 and 24 are parallel to each other and perpendicular to the flow direction of the fluid A.

When fluid A is supplied between the slit fins 1, 1, . . . of the slit fin heat exchanger shown in FIGS. Intermediate flow flowing through intermediate part S″
A'' is mixed with each other by the action of the cut and raised pieces 16, 26, and passes through the slit fins 1, 1, . . . in a uniform temperature state.

In the second embodiment shown in FIG. 14, similarly to the first embodiment, each row of cut and raised pieces is a pair of small cut and raised pieces 14 and 24, and each small cut and raised piece 1
The positions of the rising pieces 16, 26 (inclination angle θ=7°) near the center of the fluid passage S at 4, 24 are discontinuous in the front and rear. Further, the inclination directions of the rising pieces 16 and 26 are opposite to each other in the cut and raised pieces on the upstream side of the fluid flow and the cut and raised pieces in the row immediately downstream thereof.

In the second embodiment, as in the case of the first embodiment, the rising pieces 16 and 26 of the respective cut and raised pieces 14 and 24 promote the mixing of the fluid A, and thereby the slit fin 1, 1... and the fluid A has the effect of promoting heat transfer.

Furthermore, in this embodiment, the heat medium tubes are arranged in a single row, but two or three rows may also be used. But that's fine.

Next, to explain the effects of the present invention, the slit fin heat exchanger of the present invention has the raised pieces 16, 26 near the center of the fluid passage S in the cut and raised pieces 14, 24 formed on the slit fin 1 to the center line of the fluid passage.
By slanting the fluid path S, the mixing of the fluid A flowing through the fluid passage S is promoted, thereby improving the heat exchange efficiency.

Furthermore, in the present invention, the center-oriented rising pieces 16, 26 of each of the cut and raised pieces 14, 24 are replaced by the center-oriented rising pieces 16, 16, 2 in adjacent rows in the fluid flow direction.
Since the sections 6 and 26 are inclined in opposite directions, the fluid flow flowing through the central portion of the fluid passage S becomes a meandering flow, which has the effect of further promoting improvement in heat exchange performance.

[Brief explanation of the drawing]

Figure 1 is an enlarged view of the cut-and-raised slit fin section of a conventional slit fin heat exchanger, Figure 2 is a cross-sectional view of Figure 1, and Figures 3 and 4 are heat transfer experiments between the fin piece and the fluid. 5 is a temperature distribution diagram on the fin surface shown in FIGS. 3 and 4; FIG. 6 is a temperature distribution diagram of the fluid passing through the inter-fin fluid passage shown in FIGS. 3 and 4; Figures 7 and 8 are diagrams of other heat transfer experimental equipment between the fin piece and the fluid, Figure 9 is a temperature distribution diagram on the fin surface shown in Figures 7 and 8, and Figure 10 is the diagram of the fin surface shown in Figure 7. and the 8th
Figure 11 is a graph showing the relationship between the inclination angle of the inclined plate, the heat transfer effect on the fluid, and the flow resistance in the experimental apparatus shown in Figures 7 and 8. , FIG. 12 is an enlarged view of the slit fin cut-and-raised piece portion of the slit fin heat exchanger according to the first embodiment of the present invention, FIG. 13 is a cross-sectional view taken from FIG. 12, and FIG. FIG. 2 is an enlarged view of a cut and raised piece of the slit fin in the slit fin heat exchanger of the embodiment. 1... Slit fin, 2... Heat medium pipe, 4,1
4, 24... cut and raised piece, 5, 15, 25... rising piece, 6, 16, 26... rising piece, 7, 17,
27...Horizontal piece, 12...Heat medium tube insertion hole, S...
...Fluid passage, l...Fluid passage center line.

Claims (1)

[Scope of utility model registration request] A horizontal frame piece 7 is provided between the pair of rising pieces 5, 6, 15, 16, 25, 26 across the fluid passage S spanning between the heat medium tube insertion holes 12, 12 adjacent to each other.
17, 27 cut and raised pieces 4, 14,
The slit fin heat exchanger is constructed by fitting slit fins 1, 1, .
In a predetermined row of the plurality of rows of cut and raised pieces, at least a pair of cut and raised pieces 14, 24 are formed in the same row in the left-right direction, and the cut and raised pieces 14, 24 in the same row are formed.
24, a pair of rising pieces 16, 26 adjacent to each other and located near the center of the fluid passage S are parallel to each other and inclined with respect to the center line l of the fluid passage S. A slit fin heat exchanger characterized in that the direction of inclination with respect to the center line l is mutually opposite to the direction of inclination of the inclined rising pieces 16, 26, 16, 26 of other rows adjacent in the fluid flow direction.