JPH038480B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heat exchanger with fins for gas-gas-liquid two-phase flow (or fluid), which is widely used in evaporators, condensers, etc. in the field of air conditioning equipment. It is something.

Prior Art As shown in the perspective view of FIG. 4, a conventional heat exchanger includes a group of flat fins 1 arranged in parallel at regular intervals;
It is composed of a group of heat transfer tubes 2 inserted at right angles to a group of flat plate fins 1, and airflow flows between the fins in the direction of arrow 3 to exchange heat with the fluid inside the tubes.

A plan view of the fins of flat fin group 1 is shown in FIG. This fin has a large number of slit-shaped cut and raised portions 7a to 7f between the heat transfer tubes of the flat fin 6. This fin shape has many cut and raised 7
A thin temperature boundary layer is formed at each of a to f, and the heat transfer performance at the cut and raised portion is good due to the so-called boundary layer leading edge effect. Note that the heat transfer tube 4 is passed through the flat plate fin via a fin collar 5 provided integrally therewith.

Problems to be Solved by the Invention The heat transfer performance of the fins shown in FIG. In b, the leading edge effect of the boundary layer is large and the heat transfer performance is high, but in the cut-and-raised portions 7c to f on the downstream side of the airflow, the gas heat exchanged in the cut-and-raised portion 7a in the front row does not mix with other gases, that is, in 7c. It was found that the heat transfer performance was low because ~f entered the temperature boundary layer generated at 7a and 7b. In addition, in the conventional example, a dead area where gas does not flow occurs on the downstream side of the heat transfer tube 4, and the heat transfer performance in this area is low, so that no dramatic improvement in the heat transfer performance of the fins has been observed.

Therefore, the heat exchanger with fins of the present invention improves the heat transfer performance of the fins by promoting the mixing of gas at the cut and raised portions and by reducing the dead area generated at the downstream portion of the air flow of the heat transfer tube.

Means for Solving the Problems The heat exchanger with fins of the present invention comprises flat plate fins arranged in parallel at regular intervals and through which air flows, and heat transfer tubes inserted at right angles to the flat plate fins through which fluid flows. The two side portions of the flat plate fins of the heat exchanger tubes in the step direction are opened by cutting and raising them parallel to the front edge of the flat plate fins, and the two side portions (legs) that are not open are made of flat plate fins. A group of cut-and-raises tilted at an angle from the normal direction of the fins is installed in series from the upstream side of the airflow to the downstream side of the flat fin, and this group of cut-and-raises A The two side portions of the flat plate fins between the heat transfer tubes arranged in the group and the row direction are cut and raised, as in the case of group A, from the upstream side to the downstream side of the airflow. Continuously cut and raise the front and back sides of the flat plate fins alternately to open them.
A trapezoidal cut-and-raised B in which the two sides (legs) that are not open form an angle from the normal direction of the front edge of the flat fin, and the two sides (legs) approach each other toward the downstream side of the airflow. group, and the trapezoidal cut and raised group C where the two side parts (legs) are separated from each other toward the downstream side of the airflow, and for the cut and raised group B, a line connecting the center lines of the heat exchanger tubes arranged in the step direction and a flat plate. The cut-and-raised group C is provided between the front edges of the fins, and the cut-and-raised group C is placed at a point symmetrical to the installation position of the cut-and-raised group B with respect to the center between the tubes of the heat transfer tubes arranged in the row direction, and the cut-and-raised group C is placed at a point symmetrical to the installation position of the cut-and-raised group B. The raised groups A, B, and C are arranged in an X-shape.

Effect According to the above configuration, the portion of the cut-and-raise provided on the downstream side of the airflow that enters the temperature boundary layer created by the upstream cut-and-raise is reduced, and the leading edge effect of the boundary layer at the cut-and-raise portion is fully utilized. , the heat transfer performance of the fins is improved. In addition, the cut and raised legs are installed at an angle with the airflow, so the airflow flowing inside the cut and raised airflow and the airflow flowing outside are mixed.
This mixing effect is also expected to promote heat transfer. Furthermore, the airflow with a swirling component induced by the legs not only enhances the above-mentioned mixing effect, but also has a great effect on reducing the dead zone at the downstream part of the heat transfer tube, and increases the effective heat transfer area of the fins. It also greatly improves heat transfer performance.

As a result, the heat exchanger with fins has a sufficient effect of increasing the size and performance of the heat exchanger.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of the fins in a heat exchanger with fins according to an embodiment of the present invention, and FIG.
The FF' cross-sectional view in the figure, Figure 3, is a view of the cut and raised portion viewed from the airflow direction.

As shown in FIG.
1 is inserted, and gas flows in from the direction of the arrow 12.

Between the heat exchanger tubes 11 arranged in the step direction of the flat plate fins 9, there are two side portions 15a, 15b facing the airflow 12.
is opened parallel to the front edge of the flat plate fin 9, and the two side portions (legs) 16a and 16b which are not open form an angle with the normal direction of the front edge of the flat plate fin 9, that is, tilted from the normal direction. , 16b are arranged in parallel, and as shown in FIG. It has been done. Further, in the flat plate fin 9 between the cut-and-raised group A13 and the heat exchanger tubes 11 arranged in the step direction, two side portions 17a and 17b facing the airflow 12 are formed at the front edge of the flat-plate fin 9, similar to the cut-and-raised group A13. Two side parts (legs) 18a, 1 that are opened by alternately cutting and raising the front and back surfaces of the flat plate fin 9 continuously from the upstream side of the airflow to the downstream side parallel to the air flow, and that are not open.
8b forms an angle from the normal direction of the front edge of the flat plate fin 9, and the trapezoidal cut-and-raised group B14a has two side parts (legs) 18a and 18b approaching each other toward the downstream side of the airflow, and the second side part ( Legs) 19a, 19
For the cut-and-raise group B14a, the trapezoidal cut-and-raise group C14b is separated from each other toward the downstream side of the airflow, and the cut-and-raise group B14a is located between the line connecting the center lines of the heat exchanger tubes 11 arranged in the step direction and the front edge of the flat plate fin 9 (see FIG. In,
For the cut-and-raise group C14b, the cut-and-raise group B14 is provided at the upper left of the cut-and-raise group A13.
A point-symmetrical position with the installation position of a (in Fig. 1,
The cut-and-raise group A13, B14a, and C14b are arranged in an "X" shape on the flat plate fins 9 between the heat transfer tubes 11 arranged in the step direction.

The effects of this embodiment are as follows. The two open sides of the cut-and-raised portions provided continuously from the upstream side to the downstream side of the airflow are provided so that the cut-and-raised portions do not overlap when viewed from the front edge of the flat plate fin 9 (as viewed from the airflow 12). There is always a part located outside the temperature boundary layer created by the upstream cut and raise of the airflow in the cut and raise on the downstream side of the airflow, and the heat transfer performance in that part is good. Since the cut and raised group A13 is provided between the heat transfer tubes at an angle with the front edge of the fin, the airflow flowing inside the cut and raised part and the airflow flowing outside are different in flow direction, and a slip occurs between the airflows. , disturbance occurs. This turbulence acts to destroy the temperature boundary layer that occurs when cutting and raising, improving the heat transfer performance of the fins. 2 side parts (cut and raised legs) that do not have openings 1
6, 18, and 19 are installed at an angle with the airflow direction, an airflow with a swirling component due to a secondary flow is induced from the legs. This airflow has the effect of (i) mixing the gas heat-exchanged at the cut and raised portion with fresh gas; (ii) Since the airflow has a swirling component toward the downstream part of the heat transfer tube, the dead area is reduced and the effective heat transfer area of the fins is expanded. Cut and raise group B14a
In this case, an air flow having a swirling component similar to that described above is induced from the cut and raised legs 18a and b, and (i) directly acts on the fin collar portion 10 of the heat transfer tube, improving heat transfer performance in this portion. and (ii) create turbulence in the airflow flowing into the cut-and-raised group on the downstream side of the airflow, thereby improving the heat transfer performance of the fins. Cut-up group C
As for 14b, the width of the two cut-and-raised open sides 17a and 17b increases toward the downstream side of the airflow, which deflects the airflow toward the downstream side of the heat exchanger tube and is highly effective in reducing the dead area. It is. moreover,
The swirling component of the airflow induced by the legs 19a and 19b is also effective in reducing the dead area, and also promotes turbulence on the downstream side of the airflow, improving the heat transfer performance of the fins.

Here, in this embodiment, as shown in FIG.
The cut-and-raise groups A, B, and C are arranged so that the cut-and-raise directions are alternately above and below the flat plate fin 9. In addition, if the above cut-and-raised direction is the upper and lower two pieces of cut-and-raised,
The same effect as described above also occurs when a space is left between this cut-and-raised pair and an adjacent cut-and-raised pair, that is, when an uncut and raised portion of the flat plate fin 9 exists between the pairs. and is practically effective.

Effects of the Invention The present invention cuts and opens the two side portions facing the airflow between the heat transfer tubes in the step direction of the flat plate fin, and the two side portions (cut and raised legs) that do not open are placed on the front edge of the flat plate fin. A cut-and-raise group A in which cut-and-raises tilted at an angle with the normal direction are continuously provided alternately on the front and back surfaces of the flat fin from the upstream side of the airflow to the downstream side;
Since B and C are effectively arranged, efficient use of the leading edge effect of the boundary layer can be achieved on the two open sides, and the two openings installed at an angle from the normal direction of the flat plate fin front edge can be used effectively. By making the most of the mixing effect of the swirling component in the airflow induced by the sides (cut and raised legs) and the airflow caused by turbulence, the turbulence promotion effect, and the dead area reduction effect, the flat fin Great heat transfer performance is achieved. As a result, the heat transfer performance of the heat exchanger with fins is significantly improved, which is highly effective in realizing a smaller size and higher performance.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a heat exchanger with fins according to an embodiment of the present invention, FIG. 2 is a sectional view taken from the FF′ plane of FIG.
The figures are a cross-sectional view of the GG' plane of Fig. 1, Fig. 4 is a perspective view of a conventional heat exchanger with fins, Fig. 5 a is a plan view of the fins of the heat exchanger, and b is a diagram of the heat exchanger. FIG. 9...Flat fin, 10...Fin color, 1
1... Heat exchanger tube, 12... Air flow, 13... Cut-and-raise group A, 14a... Cut-and-raise group B, 14b...
Cut-and-raised group C, 15a, b...Two open side parts (cut-and-raised A), 16a, b... Legs of cut-and-raised A, 17a, b... Two open side parts (cut-and-raised B, C), 18a, b...Cut up B
Legs of 19a, b... Legs of cut and raised C.

Claims (1)

[Claims] 1 Consisting of flat plate fins that are arranged in parallel at regular intervals and through which air flows, and heat transfer tubes that are inserted at right angles to the flat plate fins and into which fluid flows, the heat transfer tubes that are inserted into the flat plate fins. Two side portions opposing the airflow are opened between the tubes in the step direction by cutting and raising them parallel to the front edge of the flat fin,
In addition, the two side portions (legs) that are not open are cut and raised at an angle from the normal direction of the flat fin, and are continuously cut and raised alternately from the upstream side of the airflow to the downstream side of the airflow on the front and back surfaces of the flat fin. A cut-and-raised group A is installed in the flat plate fins between the cut-and-raised group A and the heat transfer tubes arranged in the row direction, and two side portions opposing the airflow are parallel to the front edges of the flat plate fins. The front and back surfaces of the flat fins are continuously cut and raised alternately from the upstream side of the airflow to the downstream side of the airflow, and the two side parts (legs) that are not opened are aligned with the normal line of the front edge of the flat fins. Trapezoidal cut and raised group B forming an angle from the direction, the two side parts (legs) approaching each other toward the downstream side of the airflow, and the two side parts (legs) separating from each other as they go toward the downstream side of the airflow. For the cut and raised group B, trapezoidal cut and raised groups are provided between a line connecting the center lines of the heat exchanger tubes arranged in the step direction and the front edge of the flat plate fin; The heat exchanger with fins is provided at a position symmetrical to the installation position of the cut and raised group B with respect to the center between the heat exchanger tubes arranged in the direction.