RU2578256C2 - Fan impeller or compressor and method of making same - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to compressor engineering. Impeller, in which blades are connected with support ring, front and rear flanges, blade root pinched auger blade attachment. Method for fabrication of impeller includes cutting material of blades and support ring, front and rear flanges. Cutting blades with output of outside contour of liner material shaped limited butts on support ring, front and rear flanges. During pressing blades material extending beyond shank is stored in initial state. Workpieces are then placed in separator of mould for processing front flange and profile of support ring. Blade in cavity of separator, impregnated with binder and material is laid, extending beyond shank. Method includes placing in mould an elastic puncheon, layers of material are laid thereon for blade attachment and rear flange.

EFFECT: objective of invention is reduction of weight and improving strength of impeller.

5 cl, 9 dwg

Description

The invention relates to the field of turbine construction, more specifically to the designs of the impellers of the fan and compressor and methods for their manufacture from composite materials for a gas turbine engine, mainly aircraft.

The desire to reduce the specific gravity of the impeller of the fan and compressor led to the creation of various designs. Known inventions aimed at reducing the mass of the fan blade (patent RU No. 2412017, publ. 02/20/2011; patent RU No. 2338886, publ. 11/21/2008), which provides for the manufacture of hollow blades, which reduces their weight compared to full metal blade, however, the cost of hollow blades increases sharply, because their production is much more complicated.

The use of composite materials for the production of various parts of aircraft, including gas turbine engines. A number of inventions (patent RU No. 2413590, publ. 03/10/2011; patent RU No. 2462620, publ. 09/27/2012) is aimed at creating blades from composite materials that are not inferior to titanium blades in their technical characteristics but significantly reduce the mass of the fan and compressor, while the complexity of manufacturing composite blades is much lower compared to hollow blades. However, there remains a bottleneck in the design of products fastening the blades of composite material to the rim of the titanium disk.

The invention is known (patent RU No. 2382910, publ. 02.27.2010). The compressor impeller, containing individual sectors of a layered composite material on a polymer basis, united into the impeller by bearing force rings of composite material, and the sector includes a working blade, the tail of which is made in the form of a leg with curvilinear geometry defined by shelves separated by grooves placed the height of the legs, under the corresponding power rings placed in these grooves. This design is much lighter in weight of the node, consisting of blades mounted on a titanium disk. However, the presence of grooves on the leg (shank) reduces the strength of the entire structure, because in the leg, the fibers of the composite material are cut. When using composite material, it is necessary to strive to ensure that the latter works in tension, which will create the most durable structure.

A known method of obtaining the impeller of the compressor (patent RU No. 2502601, publ. 12/27/2013) from composite material, including cutting layers of material of the blades, the layers have a length greater than the contour of the length of the blades by an amount exceeding the arc length of the support ring between the blades. Single layers are also cut out, from which the front and rear flanges and part of the support ring are obtained. Then, the blades are pressed, while the side of the root section is marked with the outline of the support ring and part of the layer of composite material remains in its original state. Next, the resulting semi-finished products are placed in the mold in the following sequence: the layers are laid first, from which the front flange and the support ring are formed, and the part of the layer from which the rear flange is formed remains free. After this, the blades are installed and the material remaining in the initial state is impregnated, placed in the cavity of the mold in which the support ring is formed, then an elastic punch is installed and layers of the composite material are laid on it to obtain the rear flange, the mold is finally assembled, heated press, disassemble. The resulting monolithic impeller is of lightweight construction, with increased strength characteristics and low specific gravity.

This method is applicable for impellers with small blades. For impellers of the first compressor stages, which have relatively large dimensions of the blades, and the fan impeller, this method is not applicable, because the place of attachment of the blade to the support ring is not reliable enough for the action of large forces (prototype).

This invention solves the problem of creating a highly loaded design of the impeller of the fan and compressor (hereinafter the impeller) of a composite material of increased strength and stiffness with a significant reduction in specific gravity.

The problem is solved in that in the impeller of the composite material, the blades are made in one piece with the support ring, which in turn is connected in one piece with the front and rear flanges so that in the cross section along the axis of the wheel a channel-like figure is obtained. The blades are equipped with a shank, which is inseparably connected with the support ring and with the inner surfaces of the front and rear flanges, in addition, for strength, the shanks are reinforced with an inter-blade mount made of composite material made in the form of a surface formed by the shanks of the blades on the inner surfaces of the support ring, front and rear flanges . The result is a monolithic impeller made of composite material with high rigidity and strength and low specific gravity.

For the manufacture of the proposed impeller requires a certain sequence of technological steps. When cutting the source material (carbon fabric, fiberglass, etc.), blade blanks and single blanks for the support ring, front and rear flanges are performed. A feature of the blade blank is that part of the material, in the form of internal surfaces on the support ring, front and rear flanges bounded by the shanks of the blades, extends beyond the shank contour from the side adjacent to the front flange, and from the side adjacent to the rear flange, in shape surfaces on the rear flange between the shanks of the blades. When designing the aerodynamic profile of the feather of the blade and the shank of the latter along the side adjacent to the front flange, a rib 2 ... 10 mm high is formed, the rest of the material that extends beyond the contour of the shank is not impregnated with a binder. When cutting layers of material for the flanges and the support ring, their dimensions are taken into account so that the blanks for them can be obtained from a single layer. They impregnate the material layers, if an impreg is used, and lay them in the mold, while part of the composite material is laid in the cavity of the mold separator, in which the front flange and the aerodynamic profile of the support ring are formed. Then the blades are inserted into the separator, which provides the nominal location of the blades in the mold, and this in turn fulfills the requirements of the design documentation for the impeller. After that, the material that extends beyond the contour of the shank of the blades is impregnated with a binder and preformed in the separator cavity in addition to the material of the support ring and the front flange there. Then, an elastic punch is installed in the mold, which forms the front flange with the lower part, a support ring with the peripheral surface, and layers of composite material extending beyond the contour of the shank of the blade are laid on the upper surface of the elastic punch, and layers of composite material are laid on it to obtain a rear flange , set the pressure punch, under the action of which the elastic punch is formed back flange, and give pressure on the elastic punch. Curing is carried out according to the mode necessary for a particular composite material, and the disassembly of the mold by known technological methods. Thus, a monolithic impeller of a rigid and strong design with a minimum specific gravity is obtained.

Figure 1, figure 2 shows a General view of the impeller.

Figure 3 shows the cutting of a layer of composite material for forming the front and rear flanges and the support ring.

Figure 4 presents the cutting material of the scapula.

Figure 5, figure 6 - mold for the manufacture of the blades.

Fig.7, Fig.8, Fig.9 is a mold for assembling and pressing the impeller.

The impeller (Fig. 1, Fig. 2) consists of blades 1 (aerodynamic profile not shown conventionally), a support ring 2, a front flange 3, a rear flange 4. A support ring 2 with an aerodynamic profile is formed from the composite material 5 of the workpiece (Fig. 3), from the same workpiece, the front 3 and rear 4 flanges are formed (Fig. 1, Fig. 2, Fig. 3). Strong fastening in the impeller of the blades is achieved by an additional interscapular fastening made by composite material 6 of the support ring 2, on the front 3 and rear 4 flanges of the material 7, 8, respectively (figure 4). Thus, the shank 9 of the blade 1 is rigidly pinched in the impeller.

This design takes into account that composite materials have the greatest tensile strength along the fibers, and the most loaded due to the action of centrifugal, bending, and other forces is the place of attachment of the blades 1 to the support ring 2, so the latter is strengthened by flanges 3, 4, forming a rigid the power element of the impeller, in which the fibers work primarily in tension, because flanges are fasteners through which the forces generated by rotation are transmitted. The channel-shaped cross section of the power element (flanges and support ring) provides high specific strength of the entire design of the impeller. To rigidly pinch the blades 1 in the impeller and increase its rigidity and strength, interscapular fastening elements 6, 7, 8 (Fig. 1, Fig. 2, Fig. 4) are introduced, which are seamlessly connected to the support ring 5 and flanges 3, 4, respectively .

A method of manufacturing an impeller consists in cutting various sizes of material layers (Fig. 4) of the blade 1, while the layers are cut taking into account that part of the material (Fig. 1, Fig. 2, Fig. 4) is shaped according to the shape of the inner surfaces of the support ring , the front and rear flanges bounded by the shanks of the blades, extends beyond the contour of the shank from the side adjacent to the front flange (zones 6, 7, 8 of FIG. 4), and from the side adjacent to the rear flange, according to the shape of the surface on the back flange between the shanks blades (zone 8, figure 4). Material extending beyond the shank contour is necessary for forming the interscapular fastening of the support ring part 6, part 7, 8 for reinforcing the flanges 3, 4, respectively, and for firmly securing the shank 9 in the impeller (Fig. 1, Fig. 2, Fig. 4 )

Also, the layers of material are cut (Fig. 3) for the design of the front 3, rear 4 flanges and the support ring 2 part 5 (Fig. 1, Fig. 2). The number of layers and their sizes are calculated for each specific wheel, taking into account the configuration of the blade, support ring, flanges and the required strength. Next, each layer that forms the feather 1 and the shank 9 of the blade (FIG. 4) is impregnated with a binder in zones 1 and 9 and partially in zone 7 along the shank 2 ... 10 mm wide, then the layers are laid out in the matrix 10 (FIG. 5, FIG. .6) molds, set the punch 11 and pressed in accordance with the technological regime for the applied composite material. The manufactured blade 1 along the shank 9 has a rib 12 with a height of 2 ... 10 mm for precise fixation in the mold (Fig. 7, Fig. 8, Fig. 9). The rib 12 is made along the shank 9 on the side that is in contact with the front flange 3 (Fig. 1). The material in zones 6, 7, 8 (Fig.6) remains in its original state. Next, if impregnation is used, cut the layers (Fig. 3) and lay them out in the mold, while the annular part 3 (Fig. 3) is laid in the separator 11 (Fig. 7) in the cavity 13, where the front flange 3 is formed (Fig. 1, Fig. 3, Fig. 7, Fig. 9), and the cutting part 5 (Fig. 3) fits into the cavity 14 of the separator 11 (Fig. 7), in which a part 5 of the support ring 2 with an aerodynamic profile is formed (Fig. 1), when laying, the slots 15 (Fig. 3) are combined with the slots 16 of the separator 11 (Fig. 8). As you know, in the composite material, the reinforcing element - the fabric is made of threads: warp and weft, so the strength of the strip cut at different angles to the warp will differ. Based on the foregoing, in order to obtain an equally durable product when laying the nesting (Fig. 3) in the mold, each next layer is rotated in the same direction by an angle equal to a multiple of the angle between the blades, and the basis of the fabric is taken for reference. When forming the rear flange 4 (Fig. 1) in each layer, the joint of the elements 4 (Fig. 3, Fig. 7, Fig. 9) is a weak point in terms of strength. To create an equal-strength flange, the angle α between the axis of the element 4 and the cutting diameter is changed from 0 ° to 30 ° in increments of, for example, 10 °, and when laying in the mold, the angle α of the element 4 is alternately changed clockwise and counterclockwise relative to the diameter of the cutting (figure 3). Thus, equal strength of the rear flange is achieved.

Then, in the slot 16 of the separator 11 (Fig. 8) and in the slot 15 of the cutting (Fig. 3), the blades 1 (Fig. 7, Fig. 8) are inserted all the way into the mold body 17, the material of the interscapular mount 7 and 6 is laid ( 4, FIG. 7), having previously been impregnated with a binder, in the cavities 13 and 14 of the mold separator, respectively. Next, an elastic punch 18 (Fig. 7, Fig. 8, Fig. 9) is installed in the mold, for example, of rubber, polyurethane, pneumatic, etc. The impregnated part 8 of the interscapular attachment of the cutting on the blade 1 (Fig. 4, Fig. 7, Fig. 9) and part 4 (Fig. 3, Fig. 7, Fig. 9) are laid on it and a pressure punch 19 is installed (Fig. 9), which gives the shape and dimensions of the rear flange, and fasten with a separator, for example, bolts (not shown). The elastic punch 18 is supplied with pressure, for example, by the cone 20 (Fig. 7, Fig. 8, Fig. 9), under the action of which the elastic punch 18 creates pressure on the composite material intended for the support ring 2 containing elements 5, 6 (Fig. .1, Fig. 9), the front flange 3 with the interscapular mount part 7, the rear flange 4 with the interscapular mount part 8. Thus, the elastic punch creates pressure on all elements of the composite material, combining them into a single whole. Curing is carried out according to the mode corresponding to the applied composite material for the impeller.

After disassembling the mold, a monolithic impeller is obtained (Fig. 1), containing a support ring, front and rear flanges, impellers, which are firmly pinched in the impeller, incl. and interscapular mount.

This invention solves the problem of creating a highly loaded impeller of a fan or compressor from a composite material of high rigidity and strength, with a low specific gravity.

Claims (5)

1. The impeller of a fan or compressor made of composite material, including blades, one-piece made with a support ring having an aerodynamic profile, front and rear flanges, and assembled in a monolithic unit, characterized in that the blades are inseparably connected to the front and rear flanges and pinched interscapular mount, made in the form of a surface limited by the shanks of the blades on the support ring, the front and rear flanges, and connected seamlessly with the latter. 2. A method of manufacturing a fan or compressor impeller from composite material, comprising cutting layers of composite material to produce a workpiece designed to form the front and rear flanges and part of the support ring with an aerodynamic profile, cutting layers of composite material for the blades, pressing the blades, laying in a press - the shape of the workpiece designed to form the front and rear flanges and part of the support ring, with the location of the parts of the said workpiece in the cavity the arator of the mold designed to form the front flange and the aerodynamic profile of the support ring, the subsequent laying of the blades in the slot of the separator, providing the nominal location of the blades on the support ring, installation of an elastic punch in the mold for forming the inner surfaces of the front and rear flanges and the supporting rings, on which the layers of material for the back flange are laid, installation of the compression mold punch, its fastening with the separator and the formation of monolithic of the impeller by pressing by applying pressure to an elastic punch, characterized in that the layers of the composite material for the blades are opened to ensure that the blade contour extends beyond the contour of the blade from the side adjacent to the front flange from the longitudinal axis of the blade, the material in the form of a surface limited by shanks support ring, front and rear flanges, and from the side of the shank adjacent to the rear flange, according to the shape of the surface on the rear flange between the shanks, intended for clamping the shank with interscapular fastening, the pressing of the blades is carried out with the material leaving the contour of the shank in the initial state, and before laying them in the separator, they are impregnated with a binder, then the preliminary formation of the interscapular surface of the front flange and the support ring is carried out, after the elastic punch is installed, layers are laid on it interscapular mount material and rear flange. 3. The method according to claim 2, characterized in that when the design of the blades with a shank at the latter along the side adjacent to the front flange, form a rib height of 2 ... 10 mm 4. The method according to claim 2, characterized in that each subsequent blank for the support ring, front and rear flanges when laying in the mold is turned in one direction by an angle equal to a multiple of the angle between the blades, while the angle is counted from the base of the fabric (carbon fabric, fiberglass, etc.). 5. The method according to claim 2, characterized in that when cutting the blanks for the support ring, front and rear flanges, the angle between the axis of the element forming the rear flange and the cutting diameter is changed from 0 to 30 ° in increments of, for example, 10 °, and when laying in the mold, the workpieces are alternately changed with an angle between the axis of the element forming the rear flange and the cutting diameter so that the angle changes clockwise and counterclockwise relative to the diameter of the workpiece.

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