Patent Application
20200248710
The present disclosure relates generally to turbomachinery, and more specifically to low cost compressor or turbine stages constructed with blades fabricated by stamping and retained in position at least by a disc for use in axial-flow and centrifugal fluid compressors as well as other turbomachinery.
Turbomachines such as compressors and turbines are used in a variety of applications to either (1) compress a fluid from an inlet pressure to a discharge pressure which is higher than inlet pressure or (2) expand a fluid from an inlet pressure to a discharge pressure that is lower than the respective inlet pressure while extracting work. Turbomachines typically comprise a rotatable element of a plurality of blades mounted to a rotor and a static element of a plurality of vanes mounted to a casing.
Applications of turbomachines include gas turbine engines, where a compressor supplies high pressure air to a combustor while a turbine expands the heated fluid to extract work. The rotor of the compressor/turbine may be coupled to at least a portion of the rotor of the turbine component in the gas turbine engine. In aviation applications such as a compressor used in an engine for an aircraft, missile, or other airborne element, the cost of the compressor can significantly affect its compatibility or applicability for certain markets.
The growth and capabilities of the expendable gas turbine market will depend on low cost alternatives to today's accepted manufacturing technology. The emerging markets for expendable gas turbine engines for the missile/drone market do not require long life. They do, however, favor low cost and this desire to reduce costs may offset any reduced aerodynamic efficiency encountered.
Typically, compressor or turbine stages are fabricated by machining disks (wheels) and blades that are assembled into a single unit. As designs evolved, compressor stage blisks (integral blades and disk) are being fabricated by machining a single block of material. These two methods generally provide a turbine stage having good aerodynamic characteristics over a long service life and with low risk associated with the configuration. However, these methods also carry a high economic price.
It is thus desired for an improvement in the art of fabricating turbomachinery components, and particularly compressors, to provide less expensive alternative to current fabrication of turbomachinery.
According to an aspect of the present disclosure, a turbomachine comprises a hub comprised of a fore wheel and an opposing aft wheel, the fore and aft wheels being co-axial, the hub having a bore coaxial with the wheels and a blade nesting surface; and a plurality of blade elements. Each one of the plurality of blades elements is formed from a stamped blank and comprises a blade section; a tang section; and a platform section connecting the blade section at a first end of the platform section and the tang section at a second end of the platform section, wherein the first and second ends of the platform transitions into the blade and the tang sections respectively. In some embodiments the plurality of blade elements are arranged circumferentially around the hub, each of the platforms of the respective blade elements overlapping the tang section of an adjacent blade element and retained in position between the fore and aft wheel by the engagement with the fore and aft wheel and attachment with the adjacent blade, wherein each blade element abuts the blade nesting surface of the hub.
In some embodiments the turbomachine is an axial compressor. In some embodiments the fore wheel abuts the aft wheel on opposing inner faces. In some embodiments the tang sections of each of the plurality of blade elements extend axially beyond the platform section and are received in co-axial slots on opposing outer faces of the respective wheels.
In some embodiments the blade nesting surface is normal to the radial direction. In some embodiments the hub has a shape from the group consisting of cone, conical frustum, cylinder, zone, paraboloid, hyperboloid and semi-spheroid. In some embodiments the turbomachine further comprises a slot and a tab, the slot in the platform section proximate the second end for receiving a corresponding tab on an adjacent platform section proximate the first end of the adjacent blade element.
In some embodiments a second tang section extends axially forward and aft from an overlapping portion of the blade platform proximate the second end. In some embodiments the plurality of blade elements are stamped from a sheet of metal or metal alloy. In some embodiments the attachment with the adjacent blade is selected from the group comprising an interlock, an adhesive bond, a weld, and a braze.
In some embodiments the sheet is a sheet of high carbon steel or nickel alloy. In some embodiments the turbomachine is a centrifugal compressor. In some embodiments the blade nesting surface is normal to the axial direction. In some embodiments the aft wheel is a disc and the fore wheel is a spindle.
According to another aspect of the present disclosure, a method of manufacturing a bladed hub of a turbomachine comprises blanking blanks from a sheet of metal or metal alloy; bending the blanks to form a plurality of blade elements, each of the plurality of blade elements comprising a blade section; a tang section; a platform section connecting the blade section at a first end of the platform section and the tang section at a second end of the platform section, wherein the first and second ends of the platform transitions into the blade and the tang sections respectively; arranging each of the plurality of blade elements circumferentially about an axis, wherein the respective platform of each respective blade element overlaps the respective tang section of adjacent blade elements; and securing each of the plurality of blade elements between fore and aft wheels and fixing each of the plurality of blade elements to a respective adjacent blade element.
In some embodiments the plurality of blade elements are secured between the fore and aft wheels via the tang section being received in concentric grooves on opposing outer faces of the fore and aft wheels. In some embodiments the step of fixing each of the plurality of blade elements to a respective adjacent blade element comprises interlocking, adhesively bonding, welding or brazing the adjacent blade elements along an intersection of the first end of the platform of a blade element and the second end of the platform of an adjacent blade element. In some embodiments the steps of blanking and bending are performed simultaneous.
According to yet another aspect of the present disclosure, a pair of blade elements for a turbomachine comprise a first stamped blank formed into a first blade, a first platform, and a first tang; a second stamped blank formed into a second blade, a second platform, and a second tang. The first blade extends from a blade end of the first platform at approximately 90 degrees, and the first tang extends from a tang end of the first platform. The second blade extends from a blade end of the second platform at approximately 90 degrees, and the second tang extends from a tang end of the second platform. A top surface of the first tang is recessed from a top surface of the first platform by an amount equal to the thickness of the second platform, and the top surface of the first tang is shaped to seat a bottom surface of the second platform thereon. The radial distance from a center point to the top surface of the first platform is the same as the radial distance from the center point to a corresponding top surface of the second platform;
In some embodiments the first platform is secured to the second platform via an interlock, an adhesive bond, a weld, or a braze.
The present application discloses one or more of the features recited in the appended claims and/or the following features which, alone or in any combination, may comprise patentable subject matter.
The following will be apparent from elements of the figures, which are provided for illustrative purposes and are not necessarily to scale.
While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the present disclosure is not intended to be limited to the particular forms disclosed. Rather, the present disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.
For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to a number of illustrative embodiments illustrated in the drawings and specific language will be used to describe the same.
This disclosure presents turbomachinery systems and methods of fabricating and assembling turbomachinery to achieve less expensive compressor or other turbomachine components than is currently available in the art. More specifically, the present disclosure describes a stamped blade for an axial flow or centrifugal compressor which comprises a hub having a plurality of blade elements arranged on the hub.
Stamping (also known as pressing) is the process of placing flat sheet metal in either blank or coil form into a stamping press where a tool and die surface forms the metal into a net shape. Stamping includes a variety of sheet-metal forming manufacturing processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining. This could be a single stage operation where every stroke of the press produces the desired form on the sheet metal part, or could occur through a series of stages.
A blade element 1 is illustrated in
As shown in
The tang 7 as shown extends from the platform 5 on the tang end and is generally recessed from the platform 5 by the thickness of the platform 5 and shaped so as to receive the bottom platform surface of an identical blade element 2 (see
Blade elements 15 may be arranged circumferentially around a hub 100 as shown in
In
The hub 100 may have various shapes including but not limited to the shape of a cone, conical frustum, cylinder, zone, paraboloid, hyperboloid or semi-spheroid. The shape of the hub 100 would typically be a function of the blade element 1, the flow path of the working fluid, and the shaft to which the compressor attaches.
The hub 100 is adapted to be rotatable about an axis passing there through. Hub 100 may be hollow having a tubular structure. For example the hub may be a nose cone and thus of conical or paraboloid shape. In some embodiments hub 100 is formed from metal or a metal-based compound or alloy. The hub 100 may also be assembled from numerous hub segments as previously noted.
Another embodiment of the current subject matter includes a centrifugal compressor.
In the embodiments described above the platform 5 and blade 3 and tang 7 are integrally formed as a single component from a single blank. However, it is envisioned that the blade elements 1 may also be formed from more than one stamped pieces welded or brazed together, or a plurality of blanks assembled and subsequently stamped.
The bottom surface of the tang 7, or radially-inward facing surface of the tang 7 may be beneficially contoured to match or substantially conform to the blade nesting surface 17 of hub 100.
In some embodiments, blade 3 or blade element 1 may further be coated with a protective material. For example, to protect the exposed areas, specifically the blade 3 and top surface of the platform 5 of the blade element 1 from oxidation encouraged by the elevated temperature, these components may be coated with Nanovate™. Nanovate is an electrodeposited (plated) nanocrystalline metal.
The blade elements 1 may be coupled to hub 100 using mechanical interlocks, bolts, brazing, welding, adhesive, glue, epoxy, or similar material. The adhesive may be applied to the bottom of the tang 7, top of the tang 7, bottom of the platform 5 and/or side surfaces of each blade element 1 in order to couple each blade element 1 both to the hub 100 and to adjacent blade elements 2. In some embodiments the adhesive is necessary only to hold blade element 1 to hub 100 while blade elements 1 and hub 100 are assembled.
In some embodiments the assembly may be used in conjunction with additional assemblies which may be arranged in stages. The stages may be arranged or spaced to provide a gap for stator vanes between each assembly. In some embodiments spacers may separate the stages.
In some embodiments blade elements 1 may be arranged on hub 100 substantially parallel to the axis of rotation. In other embodiments blade elements 1 may be arranged on hub 100 at an angle relative to the axis of rotation of the shaft (not shown). Once the compressor is assembled as described above, it may be coupled to a rotatable shaft.
The disclosed turbomachinary as described above has numerous and varied applications in the field of fluid compression and expansion. Such applications include, but are not limited to, aviation applications such as gas turbine engines for aircraft and unmanned aerial vehicles (UAVs), expendable compressor applications such as for missile propulsion systems, land- and sea-based gas turbine engines providing electrical generation and/or propulsion, and any rotating machinery generally. Likewise, other turbomachineary, such as turbines, vanes and centrifugal compressors are also envisioned being arranged in accordance with this disclosure.
The present disclosure provides many advantages over previous compressors. By constructing a rotatable element entirely or partially from stamped rather than machined materials, the rotatable element achieves a significant reduction in cost and speed of manufacture. Particularly for aviation application, this cost and time reduction provides a substantial advantage over prior art compressors fabricated extensively from machined metals and metal-based materials. The use of traditional materials when fabricating the compressor may additionally lead to a cost savings due to lower prices of raw materials used in the compressor. Additional cost savings may be achieved through the reduction or elimination of numerous fasteners, discs, and seal assemblies currently required in advanced compressor designs. Finally, yet further cost savings may be achieved by faster and more simple manufacturing processes which are afforded by the rotatable element presently disclosed.
Although examples are illustrated and described herein, embodiments are nevertheless not limited to the details shown, since various modifications and structural changes may be made therein by those of ordinary skill within the scope and range of equivalents of the claims.
This application is a divisional of U.S. Utility patent application Ser. No. 15/419,990, filed Jan. 30, 2017. This prior application is hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15419990 | Jan 2017 | US |
| Child | 16714220 | US |
