JPH0481717B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to improving the heat transfer characteristics of a heat exchanger used in an air conditioner.

[Conventional technology]

6, 7, and 8 are cross-sectional views showing the main parts of the heat exchanger disclosed in Japanese Patent Application No. 59-264087 (see Japanese Patent Application Laid-open No. 61-143697), which form the basis of this invention, and its fins. These are a perspective view and a cross-sectional view showing the device, and in the figures, 1a, 1b, and 1c are heat exchanger plates each having a large number of through holes 2, and as shown in the figure, a plurality of sheets are arranged side by side in a stacked state at a predetermined interval, In between, as shown in FIG. 8, branch channels A1 and A2 for cooling fluid A such as outside air are formed mutually.
Reference numeral 3 denotes a bent wall portion repeatedly formed at the same pitch on each of the heat exchanger plates 1a, 1b, and 1c. Enlarged channels 4 and narrow channels 5 whose cross-sectional areas periodically differ are formed alternately back to back. Further, 6 in FIG. 6 indicates a distribution pipe for refrigerant, etc.

Since the heat transfer fin device in the conventional heat exchanger is configured as described above, the parallel heat transfer plates 1a,
When fluid A is passed between 1b and 1c, a pressure difference is created between the enlarged channel 4 and the narrow channel 5, which are arranged back to back, and the flow direction of the fluid passing through the branch channels A1 and A2 remains unchanged. A portion of the fluid flows through the large number of through holes 2 at the back-to-back locations from the enlarged flow path 4 to the narrow flow path 5, thereby causing each heat exchanger plate 1a, 1
The so-called temperature boundary layer that develops and forms along the surfaces b and 1c can be made thinner, making it possible to obtain a heat transfer fin device with an extremely high heat transfer rate.

[Problem that the invention seeks to solve]

As mentioned above, although it is expected that the heat transfer rate will improve with the conventional type, each heat exchanger plate has a large number of through holes, so the heat exchange area is naturally increased by the number of through holes. will decrease. This invention focuses on the above points, and aims to avoid reducing the heat exchange area of each heat exchanger plate as much as possible without reducing the improvement in heat transfer coefficient due to the opening of the through holes.

[Means for solving problems]

In the case of this invention, each of the through holes for the heat transfer fluid flowing from the enlarged flow path toward the narrow flow path in the state where the fluid flows into each branch flow path is placed on the narrow flow path side which is the exit side of the heat transfer fluid. It is formed by each cut-and-raised piece extruded toward the area, and the direction of each cut-and-raised piece is set so as to promote the flow of the heat transfer fluid through the part.

[Effect]

In the case of this invention, a cut and raised piece is integrally formed on the exit side of the heat transfer fluid passing through each through hole, so the heat exchange area increases by the area of this cut and raised piece, and each Since the cut and raised pieces are all formed on the exit side of the through hole through which the heat transfer fluid passes and promote the flow, the heat transfer rate due to the flow of the heat transfer fluid can be improved more reliably.

〔Example〕

FIG. 1 is a perspective view showing an embodiment of the heat exchanger of the present invention, and the same parts as in the conventional one are indicated by the same symbols. Multiple through holes with cut and raised pieces 2
A plurality of heat exchanger plates 1 having a trapezoidal wave shape and having a trapezoidal wave shape.
It is characterized by being composed of a laminate of a, 1b, and 1c. In addition, 6 in the figure is arranged so as to penetrate through each heat exchanger plate so as not to prevent the cooling fluid A such as outside air from flowing between the laminated heat exchanger plates 1a, 1b, and 1c. This is a refrigerant distribution pipe.
FIG. 2 is a front view of a heat transfer fin device comprising a laminate of heat transfer plates 1a, 1b, and 1c of the present invention having a bridge-like cut and raised piece 2a and a through hole 2 formed by the cut-and-raised piece,
Reference numeral 7 denotes a through hole for the refrigerant distribution pipe 6. Moreover, FIG. ₃ is an enlarged sectional view of FIG _. When viewed from the narrow channel 5 of the branch channels A ₁ and A ₂ , it is arranged on the inside, and when seen from the enlarged channel 4, it is disposed on the outside.

In the above configuration, if we consider the fluid flowing through the branch channels A ₁ and A ₂ in terms of a cross section in which the narrow channel 5 and the enlarged channel 4 are adjacent to each other back to back, the enlarged channel 4
Since the cross-sectional area of is larger than the cross-sectional area of the narrow channel 5, the flow velocity of the fluid flowing through the enlarged channel 4 at that portion is smaller than the flow velocity of the fluid flowing through the narrow channel 5, and the narrow channel 5 and the enlarged channel 4, and as a result, a part of the fluid, the so-called heat transfer fluid, flows from the enlarged channel 4 into the narrow channel 5 from each of the through holes 2. , it flows in the direction of the illustrated arrow along each bridge-like cut and raised piece 2a located on the exit side.

In addition, the formation direction of the bridge-like cut and raised pieces 2a is positioned so as to protrude toward the outlet side of the heat transfer fluid, so that the fluid in each of the branch channels A ₁ and A ₂ can pass between them. On the flow path side, the temperature boundary layer generated on the surface of each heat transfer plate due to the flow of the heat transfer fluid to the narrow flow path side is thinned, and on the narrow flow path side, a bridge-shaped cut and raised piece 2a is formed.
By cutting the temperature boundary layer in the flow direction and preventing its development, it is possible to increase the heat transfer efficiency in both channels.

Since the total surface area of each of the other bridge-like cut and raised pieces 2a is added to the surface area of the heat exchanger, it is possible to prevent the heat exchange area of the heat exchanger from decreasing due to the case where there are only simple through holes. .

In the embodiments shown in FIGS. 2 and 3, the bridge-like cut and raised pieces 2a are formed on each of the heat exchanger plates 1a, 1b, and 1c, thereby forming the respective through holes 2. However, Fig. 4,
As shown in the other embodiment of FIG. 5, this is done by leaving a rising leg located on the upstream side of the fluid in each of the branch channels A ₁ and A ₂ and with the other end being horizontal to the outlet side of the heat transfer fluid. The hook-shaped cut and raised piece 2b is extruded into a through hole 2 that creates a negative pressure in each opening.
may be formed.

〔Effect of the invention〕

As described above, the present invention configures the through holes provided in each heat transfer plate by forming bridge-like or hook-shaped cut and raised pieces, and furthermore, the extrusion direction of each cut and raised piece is set to allow heat transfer through the portion. In order to promote fluid flow, they are all located on the outlet side of the narrow flow path, so the surface area of this cut and raised piece is increased compared to the case of only a simple through hole. On the enlarged channel side, the temperature boundary layer formed on the surface of each heat transfer plate is thinned by the outflow of the heat transfer fluid to the narrow channel side, and on the narrow channel side, the temperature boundary layer is thinned by the above-mentioned cut and raised pieces. By cutting in the flow direction and inhibiting their development, a remarkable effect can be obtained in that the heat transfer efficiency can be increased in both channels.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the heat exchanger of the present invention, FIG. 2 is a front view of the heat transfer fin device in FIG. 1, FIG. 3 is a cross-sectional view of FIG.
The figure is a front view showing another embodiment of the fin device of the present invention, FIG. 5 is an enlarged sectional view of FIG. 4, FIG. 6 is a sectional view of main parts of a conventional heat exchanger, and FIG. is a perspective view showing the combined state of the heat exchanger plates in FIG. 6;
FIG. 8 is an explanatory diagram of the main part shown in cross section of the one shown in FIG. 7. In the figure, A is the fluid, A ₁ and A ₂ are the branch channels,
1a, 1b, and 1c are heat exchanger plates, 2 is a through hole, 2a is a bridge-like cut and raised piece, 2b is a hook-like cut and raised piece, 4 is an enlarged channel, and 5 is a narrow channel. In other figures, the same reference numerals indicate the same parts.

Claims (1)

[Claims] 1. From a plurality of heat exchanger plates that are installed facing each other so that the cross-sectional areas of the branch channels between them differ periodically along the flow direction of the fluid flowing between them, and each of which has a large number of through holes. The pressure difference between the enlarged channel and the narrow channel, which are formed back to back in each branch channel, generates a heat transfer fluid passing through the through-holes between them, and all the through-holes are connected to the branch channel. A bridge-shaped cut-and-raised piece extruded toward the narrow channel that is the exit side of each heat transfer fluid or located on the upstream side of the fluid in each branch channel so that the fluid in the channel can pass through. A heat exchanger characterized in that a rising leg is left and the other end is formed by a hook-shaped cut and raised piece that is extruded horizontally into the narrow flow path that is the exit side of each heat transfer fluid. vessel.