JPS6226494A - Finned heat exchanger - Google Patents

Abstract

PURPOSE:To increase heat transfer coefficient between air and the surface of a fine by a method wherein the legs of groups of a plurality of cut-and-raised parts, provided alternately and adjacently at the front and rear sides of the fin, are provided with given angles with respect to the direction of main flow of air stream. CONSTITUTION:The legs 13a-18a, 13b-18b of the cut-and-raised parts are provided so as to have a given angle with respect to the main flow direction12 of air, therefore, air stream, having whirling component, is induced. This air stream mixes the air, whose heat is exchanged at the upstream side of the air stream, with fresh air and generates the turbulence of low at the downstream side of the air stream. Further, the air stream, induced by the legs 15a, 16b of the cut-and-raised parts, affects directly 6 a fin collar 10 while the air stream, induced by the legs 17a, 18a of the cut-and-raised parts, reduced dead water areas in the downstream of air stream of heat transfer tube 11, therefore, heat transfer performance between air and the surface of the fins is improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a finned heat exchanger widely used in the field of air equipment or refrigeration equipment.

2. Description of the Related Art A conventional finned heat exchanger, as shown in the perspective view of FIG. 2, air flows between the fins in the direction of arrow 3 and exchanges heat with the fluid inside the pipe.

In recent years, attempts have been made to improve the heat transfer coefficient between air and the fins by processing the fins of a finned heat exchanger having such a configuration.

FIG. 4 shows an improved example of the prior art, and FIG. 4A is a plan view, and FIG.

In the figure, 4 is a heat transfer tube, 5 is a fin collar, 6 is a fin, and 7a
~7h is the cut and raise, and 8 is the air flow. That is, between the heat exchanger tubes 4 adjacent in the step direction, a large number of cut and raised portions 78 to 7h are provided alternately on the front side and the back side of the fins 6. In this case, many cuts and raised 78 to 7 hours
A thin temperature boundary layer is formed in each case, and the heat transfer performance is improved due to the so-called boundary layer leading edge effect.

Problems to be Solved by the Invention The heat transfer performance of the fin shape shown in FIG.
The cut-and-raised parts 7a and 7b on the upstream side have a large boundary layer leading edge effect and high heat transfer performance, but the cut-and-raised parts 70 to 7h on the downstream side of the airflow 8 have the cut-and-raised parts 7a and 7 on the upstream side of the airflow 8.
The air that has been heat exchanged in advance in b flows without being mixed with other air. That is, since the cut and raised portions 70 to 7h enter the temperature boundary layer generated at the cut and raised portions 7a and 7b, the heat transfer performance is not high. Further, a dead zone is generated on the downstream side of the heat exchanger tube 4 with respect to the airflow 8, where no air flows, and the heat transfer performance is poor in this portion. For these reasons, no dramatic improvement in heat transfer performance was observed.

Therefore, the present invention promotes the mixing of air at the cut-and-raised portion and reduces the dead area generated on the downstream side of the airflow of the heat transfer tube. The purpose is to dramatically increase the transmission rate.

Means for Solving the Problems The finned heat exchanger of the present invention consists of fins arranged in parallel at regular intervals through which air flows, and heat transfer tubes inserted at right angles to the fins through which fluid passes. configured,
Seven line segments or 100 lines on the fin surface between the heat exchanger tubes in the row direction, that is, the line segment 11 connecting the centers of two heat exchanger tubes adjacent in the row direction, and the line segment 11 parallel to 11 and upwind from 11. ! I1
1, a straight line 12 separated by a distance of less than half the row pitch,
A straight line l3 parallel to gIK and spaced from el to the leeward side by the same distance as 11 and 12, the perpendicular bisector of l1 and e2
Two straight lines 14 and 15 that pass through the intersection of 12 and make an angle θ that is not a right angle with 12, and two straight lines e6 and 17 that pass through the intersection of 13 and the perpendicular bisector of el and make an angle θ with 3. Inside each of the six congruent isosceles triangles formed by intersecting each other, cut and raise two sides parallel to the two equal sides of the isosceles triangle as legs and two sides parallel to the other side as openings. A plurality of fins are arranged adjacent to each other alternately on the front side and the back side of the fin to form a cut-and-raised group.

Effect According to the above configuration, the cut and raise has a boundary layer leading edge effect, and the legs of the cut and raise have an angle with respect to the mainstream direction of the airflow, so that the air flowing inside the cut and raise and the air flowing outside A mixed effect can also be expected. Furthermore, the airflow with a swirling component induced inside the cut and raised area is
In addition to enhancing the above-mentioned mixing effect, it also has the effect of reducing the dead zone at the downstream portion of the heat exchanger tube.

These effects make it possible to dramatically improve the heat transfer coefficient between the air and the fin surface.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view of a fin in a finned heat exchanger according to an embodiment of the present invention, FIG. 2a is a sectional view taken along line A-A in FIG. 2C is a cross-sectional view taken along the line CC in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line D-B in FIG. 1.

As shown in FIG. 1, heat transfer tubes 11 are inserted into fin collars 10 formed by purling at regular intervals on fins 9, and gas flows in the direction of arrow 12.

The fins 9 are formed by a line segment 11 connecting the centers of two heat exchanger tubes adjacent in the row direction, a straight line E2 parallel to the line molecule IK and spaced from the line e1 to the windward side by a distance of less than half the row pitch, and the line segment Parallel to 771, line segment 11 is also a line segment t to the leeward side! 1 and straight line l! A straight line 23 separated by the same distance as 2 and a line segment 1
Among the two straight lines that pass through the intersection of the perpendicular bisector of 1 and the straight line 127 and make an angle θ that is not perpendicular to the straight line e2 and do not intersect the heat exchanger tubes 4, the line 14 that is closer to the upper heat exchanger tube and the lower side The straight line 15, which is closer to the heat exchanger tube in Cut-and-raise groups 13 to 18 are provided inside each of six congruent isosceles triangles formed by the intersection of seven line segments or straight lines, ie, the straight line 16 and the straight line 777 closer to the lower heat exchanger tube. That is, the cut-and-raise group 13 is in the triangle formed by intersecting the line segment 11, the straight line l4, and the straight line 15, and the cut-and-raise group 1 is in the triangle formed by the intersection of the line segment e1, the straight line 16, and the straight line 17.
4 are straight line e2, straight line 14, and straight line l! A cut-and-raise group 15 is formed within the triangle formed by intersecting the line l! 2 and straight line l! A cut-and-raise group 16 is formed within the triangle formed by the intersection of 5 and the straight line l7, and the straight line 13, the straight line l4, and the straight line l! A cut-and-raise group 17 is formed within the triangle formed by intersecting the lines 13 and 6.
A cut-and-raise group 18 is provided within a triangle formed by the intersection of the straight line e5 and the straight line l7.

The cut-and-raise groups 13 to 18 each have two sides parallel to the two equal sides of the isosceles triangle serving as legs, and two sides parallel to the other side serving as openings. A plurality of them are formed so as to be adjacent to each other alternately on the front side and the back side. That is, the cut-and-raise group 13 has one side 13a parallel to the straight line l4 and one side 1 parallel to the straight line 15.
3. b is the leg, two sides 13c, 13 parallel to line segment 11
A plurality of cut and raised portions 13e having openings d are provided alternately adjacent to each other on the front side and the back side of the fin. Similarly, the cut-and-raise group 14 is composed of a plurality of cut-and-raise 15e made up of a plurality of cuts d consisting of leg portions 14a114b and openings 14c and 14d, and the cut-and-raise group 16 is made up of:
The cut-and-raise group 1 is composed of a plurality of cut-and-raised parts 16eK consisting of leg parts 16a116b and openings 16c and 16d.
7 is constituted by a plurality of cut and raised parts 17e consisting of leg parts 17a, 17b and openings 17c, 17d, and the cut and raised group 18 includes leg parts 18a, 18b and openings 19c, 18.
It is composed of a plurality of cut and raised portions 18θ consisting of d.

According to the above configuration, ■Cut and raised legs 13a, 13b, 14a.

14b, 15a, 15b116a, 16b.

Since 17a, 17b, 18a, and 18b are provided at all angles with the main air flow direction 12, an airflow with a swirling component due to a two-dimensional flow is induced.

This airflow has the effect of mixing fresh air with the air heat exchanged on the upstream side of the airflow, and also promotes turbulence of the flow on the downstream side.

■ The airflow having a swirling component induced by the cut and raised waste portions 15a and jabs acts directly on the fin collar 10,
Improves heat transfer performance in this area.

(2) The airflow having a swirling component induced by the cut and raised legs 17a and 18b reduces the dead zone in the airflow trailing portion of the heat transfer tube 11, thereby expanding the effective heat transfer area of the fins.

■ The cut-up group 13.17.18 has its opening 13
The widths of c, 17c, and 18c are formed so that they become wider toward the downstream side of the airflow. Therefore, there is a portion where the heat transfer performance is good.

These various effects result in a dramatic improvement in the heat transfer coefficient between the air and the fin surface.

Effects of the Invention The present invention provides a cut and raise opening in the airflow direction between the heat exchanger tubes of the fins so that the cut and raised legs form an angle with the airflow direction. By inducing flow and turbulence with a swirling component and taking advantage of the airflow mixing effect, turbulence promotion effect, dead area reduction effect, and boundary layer old edge effect, the heat transfer performance between the air and the fin surface is greatly improved. Get better.

[Brief explanation of drawings]

Fig. 1 is a plan view of the fins of a finned heat exchanger showing an embodiment of the present invention, Fig. 2 is a sectional view of the main part taken along line A-A in Fig. 1, and Fig. Figure C is a cross-sectional view of the main part taken along the line B-B;
The figure is a sectional view of the main part taken along the line D-D in Fig. 1, and Fig. 4a is a plan view of the fins of the conventional improved heat exchanger with fins. A partial sectional view and FIG. 5 are perspective views of a conventional finned heat exchanger. 9...Fin, 10...Fin color,
11... Heat exchanger tube, 12... Air flow, 13
~18...Cut and raised group, 13a~18a
, 13b~18b--cut and raised leg portion, 13c~
18c113d to 18d...Cut and raised opening, 13e to 18e...Cut and raised. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figures (a-n, Figure 3, Figure 4, C-2, 7/, 7i, 7U, Figure 5)

Claims (1)

[Claims] It consists of fins arranged in parallel at regular intervals, through which gas flows, and heat transfer tubes inserted at right angles to the fins, through which fluid passes, and on the fin surface between the heat transfer tubes in the step direction. Seven line segments or straight lines, that is, line segments l1 connecting the centers of two heat exchanger tubes adjacent in the step direction, and l1
A straight line l2 parallel to l1 and spaced from l1 to the windward side by a distance less than half the row pitch, and a line l2 parallel to l1 and spaced from l1 to the leeward side.
A straight line l3 separated by the same distance as the distance between 1 and l2, and l1
Two straight lines l4 and l5 that pass through the intersection of the perpendicular bisector of l2 and l2 and make an angle θ that is not a right angle with l2, and two lines that pass through the intersection of the perpendicular bisector of l1 and l3 and make an angle θ with l3. straight line l
In each of the six congruent isosceles triangles formed by intersecting 6 and l7, two sides parallel to the two equal sides of the isosceles triangle are legs, and two sides parallel to the other side are openings. A heat exchanger with fins in which a plurality of cut and raised sections are provided alternately adjacent to the front and back sides of the fins to form a group of cut and raised sections.