JPS5916693Y2 - Heat exchanger - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat exchanger in which air is used to cool air or other gaseous bodies are cooled with air.

Conventionally, air-to-air heat exchangers, such as intercoolers that cool air discharged from an engine's supercharger, generally use cross-flow type heat exchange elements.

FIG. 1 shows this cross-flow type heat exchange element, where 1 and 2 are tanks, 3 is a flat pipe, and 4 is a fin provided at right angles to the flat pipe 3.

In this heat exchange element, gas to be cooled generally passes through a flat pipe 3, and gas to cool the outside thereof flows perpendicularly to this flat pipe.

Since both gases flow in perpendicular directions, the inlet temperature of the gas to be cooled is set to T1, as shown in FIG.
, the outlet temperature is T2, the outlet temperature T of the gas to be cooled is
2 must be lower than the outlet temperature T2 of the gas to be cooled, and the outlet temperature T2 of the gas to be cooled may be lower than the outlet temperature t2 of the gas to be cooled. In order to reduce the difference in gas outlet temperature, a large heat radiation area and a large overall heat transfer coefficient are used to perform a predetermined heat exchange.

However, in order to increase this heat dissipation area, the first
The thickness h of the core of the heat exchange element shown in the figure is increased (h
(increasing the number of pipes in the direction), the resistance of the cooling gas increases by the increase in core thickness, and the flow rate decreases, but if a fan is used to compensate for this decrease in flow rate, , the fan input increases, which goes against energy conservation.

In addition, in a heat exchange element, if the width of the core (w: h, l is the width in the perpendicular direction) is increased, the spread of the cooled gas becomes large, which not only causes unevenness in the flow rate of the internal gas, but also causes The flow velocity of the heat exchange element decreases, and the heat transfer coefficient also decreases, so even if the heat exchange element is made larger, the effect of the increase in size does not increase.

Furthermore, when the length l of the core is increased, the flow resistance of the gas to be cooled passing through the inside increases, and there is a drawback that the cooling efficiency does not increase as much as the length of the core increases.

The present invention provides a heat exchanger in which an external fluid flows in the opposite direction to the fluid flowing inside the heat exchanger, thereby increasing the heat exchange efficiency even though the heat exchanger is small in size, in order to eliminate the drawbacks of the conventional example.

Hereinafter, embodiments will be described in detail with reference to the drawings.

First, before explaining the embodiments of the present invention, the principle will be explained.

The basic theory of this reverse AC heat exchanger is described in the heat transfer engineering materials edited by the Japan Society of Mechanical Engineers published in April 1955.

As shown in Figure 3, the number of units NTU and temperature efficiency φ
The relationship between
When TU=3, it is about 0.61 (provided that the side with the larger water equivalent mixes), whereas in the case of reverse AC, it is about 0.74, and as shown in Figure 4, the cooling The exit temperature t of the gas that cools the exit temperature T2 of the gas
It is possible to make it lower than 2.

Figure 5 shows the basic core part of reverse AC (that is, the part that performs heat exchange), and in the heat transfer engineering materials mentioned above, the fluid to be cooled and the fluid to be cooled are indicated by the arrows A. , as shown in B, are expressed in opposite directions,
Based on this heat transfer engineering material, a reverse AC heat exchanger can be easily considered, but in the case of gas-to-gas, the pressure drop due to the passage resistance of the inner gas (gas to be cooled) is 350 to 400 m
mAq, and the static pressure of the external gas is considered to be around 50 to 80 mmAq based on the general performance of the fan, so the louver corrugated fins whose length in the direction along the flow can be within that pressure drop. Or it is necessary to provide corrugated fins.

The present invention was constructed taking the above points into consideration, and the distance in the fluid flow direction is made shorter than the width of the plane perpendicular to the direction of passage of the internal and external fluids, and the distance between the internal and external fluids is reduced to the core. The inlet/outlet lobe is provided in a place where it is not affected by the flow of external gas (for example, on the side of the core or in a place away from the core), and the introduction passage on the internal gas side and the wall of the heat exchanger are connected with the same member,
It has an internal passage.

Figures 6 and 7 show one embodiment of the present invention.
Reference numerals 5 and 6 denote gas inlet/outlet levers provided in parallel; numerals 7 and 8 denote a plurality of flow path portions protruding perpendicularly from the gas inlet/outlet levers 5 and 6 and arranged in parallel at regular intervals; It communicates with 6.

Reference numeral 9 denotes flow path portions 7.9 facing each other between the two flow path portion groups.
These are a plurality of heat dissipating parts each having a heat dissipating fin 10 (louver corrugated fin) on the outside connecting the two thin plates. A large number of passages are formed inside.

FIG. 8 shows another embodiment of the present invention, in which the same reference numerals as in FIG. 6 indicate the same parts, but in this embodiment, instead of providing a recess in the heat radiation part 9 , is different in that a louver fin 12 is provided inside.

In this embodiment configured in this way, since the gas to be cooled generally has a large amount of water, the louver fins 10 and 12 provided inside and outside of the heat dissipation section 9 are
Specifically, by setting the heat transfer area ratio of each gas side to the ratio of their water equivalents, the heat exchanger can be designed with good performance because it matches the tendency of pressure drop.

For example, the static pressure inside can be set to 350 to 400 mmAq: the static pressure outside = 1:1/3 (water equivalent), and can be appropriately corrected depending on the density of the internal and external gases and the required static pressure.

As explained above, according to the present invention, by adopting the reverse AC system, it is possible to achieve the characteristics shown in Fig. 4, that is, to make the outlet temperature of the cooled gas lower than the outlet temperature of the cooled gas. At the same time, by providing fins in the internal and external gas flow paths in accordance with the required pressure drop and appropriately setting the heat transfer area ratio, the overall heat transfer coefficient can be increased, and the heat dissipation area will become smaller. In addition, since the temperature difference between the inlet and outlet of the gas to be cooled can be set high, the amount of gas flowing outside can be reduced, and the entire device can be made compact.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional gas-to-gas heat exchanger;
The figures show the temperature field of the heat exchanger in Fig. 1, Fig. 3 shows the relationship between NTU and φ, Fig. 4 shows the temperature field of reverse alternating current, and Fig. 5 shows the temperature field of the heat exchanger in Fig. 1. The figure is the basic diagram of reverse alternating current, Figure 6,
7 is a front view and a side view of an embodiment of the present invention, and FIG. 8 is a partially sectional perspective view of another embodiment of the present invention. 5.6... Input and exit lobby, 7,8...
Flow path section, 9... Heat dissipation section, 10... Heat dissipation fin, 11... Concave portion, 12... Louver corrugated fin.

Claims (3)

[Scope of utility model registration request] (1) A first and a second set arranged in parallel with a certain distance between them.
pipes projecting from the first and second pipes in the same direction and at right angles to their respective axial directions, and arranged in parallel at regular intervals, communicating with the first and second pipes, respectively. a first and second channel group; a heat radiating section group connecting the opposing channel sections between the first and second channel groups, and each having a heat radiating fin on the outside thereof; The gas to be cooled is introduced from either one of the first and second pipes and discharged from the other, and the gas to be cooled flows through the heat radiation part group in the opposite direction to the direction in which the gas to be cooled flows through the heat radiation part group. A heat exchanger characterized by flowing cooling gas into the gap between the groups. (2) Each of the heat radiating parts has a plurality of recesses along the flow direction of the object to be cooled, and a plurality of flow paths are formed inside, Utility Model Registration Claim No. (1) Heat exchanger as described in section. (3) The heat exchanger according to claim (1), wherein each of the heat radiating parts is provided with a louvered corrugated fin therein.