JPS59145497A - Heat exchanger - Google Patents

Abstract

PURPOSE:To enable the heat of jets to be utilized effectively without making a heat exchanger large in, size by providing a porous metal between jet ports of a heat transfer medium and a heat transfer wall, securing the porous metal to the heat transfer wall, and allowing the jets to transfer their heat to the heat transfer wall via the porous metal after the jets hit against the heat transfer wall, and the jet stream pass through the porous metal. CONSTITUTION:The jets 16 of a high temperature heat transfer medium are jetted through the jet ports 9 formed regularly in a jet outlet plate 10 into a jet section 11. The jets 16 pass through the porous metal 13 and hit against the heat transfer wall 12. While the jets 16 transfer their heat to the porous metal 13, they strike the heat transfer wall and the heat is transferred. Part of the jets 16 hit against the heat transfer wall flowing along the heat transfer wall, while major parts thereof flow back into the porous metal 13, passing through the porous metal to transfer the remaining heat thereto, and is discharged from the jet port 15. As the heat of the discharged heat transfer medium is exchanged efficiently, the temperature thereof becomes low. As the porous metal is desirable to be of a high porosity so that the resistance to the flow of the heat transfer may be less, and also desirable to have a large heat transfer area so as to be able to transfer heat efficiently. Thus the present heat exchanger having the same volume as that of the prior art can recover a large amount of heat so as to utilize the heat of jets efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat exchanger for recovering heat from a high-temperature heat medium, which effectively exchanges heat between high-temperature gas such as combustion gas and water or air, Conventionally, heat exchangers have been used to heat water or air to a high temperature and use it for hot water supply or space heating. Conventionally, heat exchangers exchange heat by colliding high-temperature jets against heat transfer walls. Since this heat exchanger has high heat transfer at the impingement portion of the jet, a large amount of heat can be transferred from the jet to the heat transfer wall even if the area of the heat transfer wall is small.

2. Mi At this time, if the jet is cooler than the heat transfer wall, the heat from the heat transfer wall can be transferred to the jet.

Such heat exchangers have the following drawbacks. The heat transfer coefficient and amount of heat transfer at the location where the jet collides with the heat transfer wall is high, but the heat of the jet cannot be completely transferred.

Therefore, much of the heat contained in the jet stream is not utilized and is released into the atmosphere, resulting in wasted thermal energy.

Therefore, after the collision of the jets, an additional heat transfer surface was provided to exchange heat, but in order to exchange heat sufficiently, the heat transfer area had to be increased, resulting in a large heat exchanger.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to effectively utilize the heat of the jet stream without increasing the size of the heat exchanger.

Structure of the Invention A porous metal is provided between a heat medium jet port and a heat transfer wall, and the porous metal is fixed to the heat transfer wall. This is a heat exchanger in which a jet stream collides with a heat transfer wall, passes through a porous metal, and transfers heat to the heat transfer wall via the porous metal.

Description of examples Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a conventional example, in which 1 is an ejection port, 2 is a heat transfer wall, 3 is a heat medium passage, and 4 is an ejection part. FIG. 2 is a cross-sectional view of a part of the outline of the embodiment of the present invention, FIG. 3 is an enlarged view of the same, FIG. 4 is a top view of the spout plate in FIG. 3, and FIG. An enlarged view of another embodiment, FIG. 6 is a top view of the spout plate in FIG. 5 is a heating medium inlet, 6 is a heating medium outlet, 7 is a heated medium inlet, and 8 is a heated medium outlet.

9 is a spout, 1o is a spout plate having a spout, 11 is a spout, 12I'i is a heat transfer wall, 13 is a porous metal provided on the surface of the heat transfer wall, 14 is a spout, and 15 is a jet stream. It is the exit.

In FIG. 3, jet ports 9 are regularly bored in the jet port plate 10.
The higher temperature heat medium becomes a jet stream 16 and is ejected to the ejection part 11 . The jet 16 passes through the porous metal 13 and impinges on the heat transfer wall 12 . The jet stream 16 collides with the heat transfer wall while transmitting heat to the porous metal 13 to exchange heat. A part of the jet 16 that collides with the heat transfer wall flows along the heat transfer wall, and most of it flows back inside the porous metal 13, exchanges the remaining heat through the porous metal, and then flows out from the jet outlet 15. be discharged. The heat of the discharged heat medium is effectively exchanged and the temperature becomes low.

It is desirable that the porous metal has a large porosity so that the flow resistance of the heat medium is low, and a material that has a large heat transfer area to effectively transfer heat.

In the conventional example, it was necessary to provide the jet part 4 so that the flow resistance would be reduced after the jet collided with the heat transfer wall, but in the present invention, since the porous metal has good air permeability, it is necessary to provide the jet part 4. Even if a porous metal is provided without changing the volume of the ejection part, the resistance of the heating medium is almost the same as in the conventional case.

The embodiment shown in FIG. 4 is provided with a jet flow path 17.

In the embodiment shown in FIG. 3, the jet reaches the heat transfer wall while colliding with the porous metal, so the jet spreads and the flow velocity at the heat transfer wall decreases. Therefore, as in the embodiment shown in FIG. 4, a jet flow path is provided to reduce the spread of the jet flow and increase the flow velocity at the time of collision. As a result, the amount of heat exchanged 6/·J was almost the same as in FIGS. 3 and 4, but the amount of porous metal could be reduced. The experimental results are shown in the table below.

At this time, heated air at 460°C was used as the jet stream, and water (inlet 80''C) was used as the medium to be heated.
ntalpi was 3o001alVh. In the table above, the volume indicates the space between the outlet plate and the heat transfer wall.

In the embodiment shown in FIG. 5, the heat transfer area was reduced by about 3% compared to the structure shown in FIG. 3, and the heat exchange amount showed the same value as in the embodiment shown in FIG.

It is necessary that the porous metal is firmly fixed to the heat transfer wall, and in this example, the porous metal and the heat transfer wall are electroplated with solder 61, and then both are bonded together. The porous metal and the heat transfer wall were adhered to each other by melting the solder in a high-temperature furnace.

Effects of the Invention As explained above, the F3A of the present invention provides a porous metal on the surface of the heat transfer wall, and allows a high-temperature jet to collide with the heat transfer wall through the porous metal from the jet nozzle provided on the jet nozzle plate. After that, it passes through a porous metal, and a large amount of heat can be recovered with the same volume as the conventional example, and the heat of the jet can be used effectively.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional heat exchanger, FIG. 2 is a schematic diagram of a heat exchanger according to an embodiment of the present invention, FIG. 3 is an enlarged view of the main part of FIG. FIG. 3 is a top view of one component of FIG. 3, FIG. 5 is a schematic diagram of a different embodiment of the invention, and FIG. 6 is a top view of one component of FIG. 9... Jet outlet, 10... Jet outlet plate, 1
1... Ejection part, 12... Heat transfer wall, 13
... Porous metal, 15 ... Spout outlet. Figure 1 Figure 3 G Figure 6

Claims (2)

[Claims] (1) A heat exchanger in which a porous metal is provided on the surface of a heat transfer wall that collides the heat medium ejected from a large number of ejection holes. (2) The heat exchanger according to claim 1, wherein a jet flow path is provided between the jet port and the heat transfer wall.