JPS6011222B2 - Heat exchanger and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention consists of a one-piece metal body with cooling channels through which at least one coolant, i.e. a propellant component, can flow, in particular for regenerative cooling of liquid rocket propulsion systems. The present invention relates to a fuel exchanger that can be used as a type combustion chamber.

The cooling conduit consists of an intermediate layer plated on the main body and having a thin wall, and an outer wall plated on the intermediate layer and consisting of a pressure jacket made of nickel or an equivalent metal, a copper cobalt alloy, or a nickel cobalt alloy and having a relatively thick wall thickness. It is covered by the part. Refueling exchanger structures known from rocket construction are generally made of materials with relatively low corrosion resistance;
This precludes the use of storable liquid propellants, such as red fuming nitric acid.

However, since a rocket propulsion system powered by storage-resistant liquid propellant is supplied with cryogenic propellant for its rapid readiness for use, the basic problem of the present invention is to
To create an economical heat exchanger with excellent corrosion resistance for all known storage-resistant liquid rocket propellants, and to create a heat exchanger that can be used as a regeneratively cooled smoke chamber in liquid rocket propulsion systems. be. The object of the invention is solved according to the invention by a heat exchanger having the construction described in the claims.

This heat exchanger has the following features. That is, the main body is made of corrosion-resistant special steel, and the intermediate layer is made of corrosion-resistant gold, copper, or a gold alloy. The solution to the basic problem of the present invention is based on the following recognition.

This means that in heat exchangers of this kind, only the walls of the cooling channels are not only not corroded by the oxidizing components of any liquid rocket propellant that is capable of being stored in the known manner, but also that they do not overheat under all normal conditions of use. All machines in which heat exchangers occur under normal conditions of use, with no resulting heat damming and with the intermediate layer adhering to both the body and the pressure jacket and having high mechanical rigidity themselves. This means that it can withstand physical and/or thermal loads. The intermediate layer of the heat exchanger according to the invention is preferably made of gold, especially for reasons of cost.
Furthermore, for reasons detailed below, it is especially made of copper or a gold alloy, especially a gold-copper alloy. The heat exchanger of this invention is manufactured as follows.

That is, the body is first made of a corrosion-resistant special steel, such as Nimonic alloy (Njmonlc75), in a manner known per se.
cr2 town i, tensile strength 38k9/rib 2], and the cooling channels are made by cutting, then the cooling channels are filled with a conductive and easily meltable material, especially wax-based material, and a thin Plating the middle layer of the wall and the thick pressure jacket of the wall on top of this middle layer,
Finally, the easily meltable material filling the cooling channels melts. In order to introduce readily meltable, conductive filling materials into the cooling channels, it has proven advantageous to preheat the body to the softening temperature of the filling material, especially when using wax-based filling materials. The cooling channels are conveniently filled as follows.

In other words, a soldering iron that is silver or silver-plated is charged with a string-like filling material that has been deformed and sized accordingly into the cooling pipe of the main body that has been preheated to the softening temperature of the filling material. melted by Particularly in the case of the process according to the invention, wax-based fillers and readily meltable waxes made electrically conductive by the addition of 15 to 25% of semi-colloidal graphite powder were particularly effective. Advantageously, excess filler material is removed by stripping and subsequent green polishing before plating the intermediate layer.

The plating of the intermediate layer and the pressure jacket can be carried out in any case in any known manner for ionizing the metal concerned.

As already mentioned, a gold interlayer is particularly preferred since gold is the least expensive of the noble metals of interest for the purposes of the present invention. The application of the ionized gold intermediate layer is satisfactory both to the special steel as the body material and to the pressure jacket. The mechanical rigidity of the plated gold intermediate layer is also 1.
It satisfies all requirements as long as it is not heated to a temperature of more than 5 picoC, especially more than approximately 20,000 degrees centigrade.

This is of course true under certain conditions of use, as the temperature of the plated gold interlayer rises far above the predetermined limits and/or for longer periods of time, a rapid decrease in tensile strength occurs, likely due to structural changes. This defect of the heat exchanger according to the invention, which is only a hindrance in certain cases, can be eliminated in accordance with an advantageous embodiment of the invention as follows. That is, instead of a pure noble metal interlayer, especially a gold interlayer, an interlayer consisting of at least two phases is plated. In that case, the first layer, i.e. the layer directly on the body, consists of corrosion-resistant gold, and the next layer, especially the thin layer, consists of copper or is similar to copper with respect to the plating technology and metallurgical properties, and is made of gold alloy rules. It is comprised of a metal that can be layered over the first layer and that can form a more heat resistant alloy at relatively low temperatures and diffuse into the first layer. If such an intermediate layer of two or more layers is heated to about 150 qo, especially about 200 oo or more, the alloying metal will diffuse into the underlying or overlying metal.

The metal thereby has good heat resistance, probably due to mixed crystal formation. This process can be facilitated by the use of pressure.

In particular, the characteristics of the preferred embodiments of the heat exchanger according to the invention are utilized here. That is, the coefficient of thermal expansion of the main body is greater than that of the material of the pressure jacket. In addition to nickel, in particular copper-cobalt alloys and nickel-cobalt alloys can be used as materials for the pressure jacket.

The present invention will be explained in more detail based on figures showing examples.

The heat exchanger with propulsion nozzle consists of a body 1 made of special steel.

This body can be prefabricated from a block by forging and manufactured by machining in a conventional manner. A longitudinally extending cooling channel 2 is formed in the body 1. Web 3 exists in the darkness of these cooling pipes. For the production of a multilayer outer jacket covering these cooling channels 2, the cooling channels are filled with an easily meltable electrically conductive material. The body 1 is then provided with a thin-walled intermediate layer 4, for example of gold or of alternating phases of gold and copper or a gold alloy, by plating. On this intermediate layer 4, nickel or an equivalent metal,
A thick pressure jacket 5 made of copper cobalt alloy or nickel cobalt alloy is plated. This pressure jacket is subjected to the high internal pressure of the combustion chamber. The intermediate layer 4, shown in enlarged section in FIG. 3, has several phases 4a to 4a'' of gold or phases 4b and 4b' of copper or gold alloys.

The thickness of this intermediate layer, like that of all intermediate layers of the heat exchanger according to the invention, is in particular about 20 to 100 m;
The thickness of the gold phases 4a to 4a'' is preferably 5 to 2 mm, particularly 7 to 1 mm, respectively.
0 m, and the thickness of the copper or gold alloy phase is particularly 2 m.
-1, especially 3 to 5 mm.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the heat exchanger, FIG. 2 is a sectional view taken along the Rolo line in FIG. 1, and FIG. 3 is an enlarged sectional view of the intermediate layer. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A thin intermediate layer with a cooling pipe plated on the main body, and a relatively thick intermediate layer plated with nickel or an equivalent metal, copper-cobalt alloy, or nickel-cobalt. A heat exchanger consisting of a one-piece body made of metal having a cooling channel through which at least one propellant component can flow, covered by an outer wall formed by a pressure jacket made of an alloy, an intermediate layer; is made up of several layers plated with different metals alternately, the main body being made of corrosion-resistant special steel, each first layer of the middle layer, which is closer to the main body, being made of gold; A heat exchanger characterized in that each adjacent second layer consists of a copper or gold alloy diffused into the first layer. 2. A thin intermediate layer with a cooling pipe plated on the main body, and a pressure-resistant jacket made of nickel or an equivalent metal, a copper-cobalt alloy, or a nickel-cobalt alloy, with a relatively thick wall plated on this intermediate layer. A heat exchanger consisting of a one-piece body of metal having cooling channels through which at least one propellant component can flow, covered by an outer wall formed of It consists of several layers plated with different metals, the main body being made of corrosion-resistant special steel, each first layer of the intermediate layer near the main body being made of gold, and each layer adjacent to the first layer being made of gold. The second layer is made of copper or gold alloy diffused into the first layer. In the method of manufacturing a heat exchanger, a body with cooling channels is manufactured, and the cooling channels are filled with an easily meltable conductive filling material. A heat exchanger characterized in that a thin intermediate layer is plated on the main body, a relatively thick pressure-resistant jacket is plated on the intermediate layer, and then the conductive filling material is eluted from the cooling pipe. manufacturing method.