Device for cooling high-thermally stressed parts

The invention relates to an arrangement according to the features of the preamble of claim 1 for cooling high heat-stressed components with a cooling medium, in particular the combustion chamber of gas turbines.

It is known that various components of a gas turbine, for example, the stator vanes and their platforms or the combustion chamber, in the wall to be cooled area slits with a variety of very small air intakes or, for example, with a cross-sectional area of ​​each about 1mm²Provided. Through this plurality of cooling air holes occurs from the outside inflowing, incident on the outer surface of the component cooling air, even through the respective wall region of the component in order to produce on the inner surface of the wall a cooling air curtain and thereby shield the wall directly opposite the hot combustion gases and below one of the maximum thermal load capacity of each component material to maintain appropriate temperature.

The combustion chambers of aircraft engines are known to be made of single, produced by non-cutting and metal-cutting shaping processes rings that are joined together by welding. In the circumferential paragraphs a Z-shaped combustion chamber wall and in the respective heat shield in the region of the burner fine cooling air holes are produced by laser drilling of the order of several thousand. The cost of laser drilling to produce the cooling air holes communicating with a significant share in any commercially reasonable proportion to the time spent on preparing the combustor total cost.

It is already known, the combustion chambers of aircraft turbines from manufactured in a casting process and by laser welding butted individual segments produce, however, the cooling air holes must also be created in this case, at great expense, using laser technology, since it is not possible even with the most modern investment casting integrating the production of the fine cooling air openings in the casting process.

In the <patcit id="pcit0001" dnum="WO03006883A1"><text>WO 03 / 006883A1</text></patcit> cooling exposed by the hot gases components of a turbine is described, wherein a supplied in the wall to be cooled by the cold side with cooling air, filled with a porous material or a tissue cavity is formed.

In one of the <patcit id="pcit0002" dnum="US5605046A"><text>US-A-5,605,046</text></patcit> known cooling for components of gas turbines are arranged between an outer wall with first apertures and an inner wall with a gap grating porous intermediate pieces, wherein the cooling air first flows into the free between the inner wall, outer wall and intermediate pieces spaces and then through the porous material and the column of the inner wall.

A highly efficient film cooling is not thereby guaranteed.

The invention has for its object to provide an arrangement for cooling air supply highly thermally loaded components of gas turbines, which can be with little manufacturing effort and therefore cost.

According to the invention the object is achieved with an arrangement according to the features of claim 1. Advantageous developments of the inventions result from the dependent claims 2 to. 7

The basic idea of ​​the invention at a to be cooled, shielded against hot gases wall surface of the respective component, in which at least one is formed on the open to cooling side cavity, open into the radiation emanating from the opposite wall surface, by casting producible cooling air openings to provide the required cooling air volume, it that the open side of the cavity is covered with a wire mesh of a certain openness. The cavity in this case represents an accumulator for the continuously supplied coolant that through the openings in the wire mesh smoothly flows and forms on the to be cooled and shielded panel uniform cooling air curtain, and also serves the self-cooling of the wire mesh.

The wire mesh which is positively and / or positively fastened in the edge region of the cavity and its openness is selectable between 5 and 95%, may be made with respect to the component material of a thermally more resilient material.

The cavity may be a groove-like channel with distributed over the length to be disposed cooling air apertures. Of course, one behind the other and / or be arranged in parallel to each other and a plurality of cavities.

The cooling arrangement of the invention is preferably used for cooling and heat shield in combustion chambers of gas turbines, but is equally applicable to other components.

The advantages of the invention are the cost-effective, also by casting realizable production, in the uniformity of the generated cooling air curtain and its variability due to the variable by different wire mesh openness of the wire mesh as well as in the material decoupling between the component material and the wire mesh material in conjunction with the resulting high mechanical and thermal stability. Especially when casting manufacturing the components can be produced economically, since the formation of the cooling air openings may be involved in the casting process.

An embodiment of the invention is explained in detail with reference to the drawing, in whose sole figure is a perspective sectional view of a portion of a Z-shaped wall of the combustor is shown a gas turbine.

The wall 1 of a combustion chamber segment produced here in a casting process of a gas turbine has due to their Z-shaped cross-sectional shape at a defined distance paragraphs 2, in which on the inner surface of the wall, that is, the air outlet side 3, a cavity 4 in the form of an air discharge side 3 open channel is formed. Into the cavity 4 open emanating from the outer surface of the wall or the air inlet side 5 cooling air openings 6 whose cross-sectional area is so large that with a certain number of cooling air openings 6, the necessary cooling for the inner surfaces of the wall 1 volume of air can be provided, and that the cooling air openings 6 can already be formed with the casting process for the production of combustion chamber segments.

The provided on the inner wall surface or air outlet side opening of the cavity 4 is non-positively and / or positively, "closed" with a wire mesh 7 having a certain openness. During the casting material must be sufficient for the wall 1 of the combustion chamber specific thermal and mechanical requirements, the wire mesh may be made of a different material with a lower mechanical, but higher thermal capacity. For example, a higher thermally resistant Aluminiumoxidbildner are provided as a casting material, a chromium oxide and a wire mesh material.

On the outer wall surface (air inlet side 5) of the combustion chamber inflowing cooling air passes through the cooling air openings 6 in the cavity 4 in which a uniform pressure is built up. By the wire mesh 7 8 an air curtain is produced which slowly along the inner surface (air outlet side 3) of the combustion chamber flows and the combustion chamber wall opposite the hot gases shields and cools.

The invention is not limited to the above described the example of the combustion chamber of an aircraft turbine embodiment. Rather, the basic idea of ​​the invention, the supplied in the formation of a through a few, sufficiently large cooling air intakes and covered with a wire mesh of certain openness, serving as an accumulator cavity consists of the shielded inner wall surface of the respective component, even with other components whose inner surface with any cooling medium film to be shielded, applicable.

LIST OF REFERENCE NUMBERS

<dl id="dl0001" compact="compact"><dt>1</dt><dd>Wall (of a component to be cooled)</dd><dt>2</dt><dd>Paragraph 1</dd><dt>3</dt><dd>Air outlet side</dd><dt>4</dt><dd>cavity</dd><dt>5</dt><dd>Air inlet side</dd><dt>6</dt><dd>Cooling air openings</dd><dt>7</dt><dd>wire Mesh</dd><dt>8th</dt><dd>Cooling air curtain</dd></dl>