This application claims priority to German Patent Application DE102008021683.6 filed Apr. 30, 2008, the entirety of which is incorporated by reference herein.
The present invention relates to an axial-flow compressor, with the conventional stator vanes being replaced by rotating units.
Present-day axial-flow compressors include a rotor 1 with mostly several rows of rotor blades 3 and a casing 2 in which stator vanes 4 are fitted. A row of stator vanes is arranged upstream of each row of rotor blades. The stator vanes 4 build up pressure by converting the kinetic energy of the fluid. Furthermore, they redirect the fluid to the subsequent rotor blade row. In most cases, only the forward stator vane rows are connected to an actuating mechanism 5, enabling the setting of the stator vanes to be varied in dependence of the speed of the axial-flow compressor.
It is known from the state of the art that the forward stator vanes 4 are settable by a drive train to redirect the air or fluid into an angle suitable for entry to the subsequent rotor blades.
From literature (for example GB 978,658) a design with rotating casing is known. Here, the casing with the stator vanes contained therein and the actual rotor rotates in different directions. However, this type of casing has to be considerably heavier than a usual casing to carry the centrifugal loading.
A broad aspect of the present invention is to provide an axial-flow compressor, which is capable of building up maximum pressure, while being simply designed and featuring short length and low weight.
According to the present invention, an axial-flow compressor with at least one stator vane row is therefore provided in which at least one vane of the stator vane row is provided as rotating unit and in which the rotating unit is completely rotatable about a drive axis. The drive axis is here essentially vertical to a rotary axis of the axial-flow compressor.
The present invention replaces the variable stator vanes according to the state of the art by rotating units, which are also referred to as new-type rotating stator units, which both redirect and further compress the air or fluid, respectively. Due to the contraction of the gas-wetted surfaces or the circumference of the inner space of the axial-flow compressor caused by the compression process through the rotor blades, the use of conventional gear-type or vane-type pumps is to be ruled out. Furthermore, the compressor is annular.
In order to avoid excessive circumferential spacing of the individual rotating units, it is advantageous to provide these in conical form. Advantageously, the inclination of the gas-wetted surfaces is ensured by an additional tilting rotor. The blades of the rotating unit and the blades of the tilting rotor are provided such that they are in engagement with each other.
It is further advantageous to connect the rotating unit via a drive shaft to a driving device. With the rotating unit and the tilting rotor being in engagement with each other, the tilting rotor will be driven in association when the rotating unit is driven by the driving device. Both the rotating unit and the tilting rotor are borne in the casing.
The tilting rotor is arranged such in the casing that a platform of the tilting rotor follows the contraction of the gas-wetted surface. The forced rotation of the tilting rotor and the inclined suspension relative to the rotating unit effect a relative movement between the rotating unit and the tilting rotor.
The axis of the tilting rotor and the axis of the rotating unit intersect at one point. Advantageously, the blades of the tilting rotor are spherically shaped towards this point. The blades of the rotating unit extend tangentially into these spherically shaped blades of the tilting rotor.
The principle described above is applicable to both the casing and the inner shroud.
It is further advantageous to curvilinearly shape the blades of the tilting rotor to minimize the gap between rotating unit and tilting rotor.
It is further advantageous to provide ribs between the rotating units. The ribs connect the casing to the inner shroud and provide the sideward confinement for the rotating units for compression of the fluid or air, respectively. Simultaneously, the clearance between the ribs serves as an inlet and an outlet opening for the fluid. Oil supply and discharge from the inner shroud, if applicable, is implementable via the ribs.
It is further advantageous to taper the rotating units or their blades, respectively. The taper provides for additional compression by centrifugal forces.
In a further advantageous development, the axis of the rotating unit is also tapered. Thus, the volume between the blades of the rotating unit and the ribs is constrained.
In a further advantageous development, the blades of the rotating unit are spirally arranged on the circumference of the rotating unit. Thus, air or fluid, respectively, is delivered from the radially inner areas to the radially outer areas and compressed.
Accordingly, the application of the axial-flow compressor according to the present invention provides for increased pressure build-up already in the forward stage of the compressor. This enables the same amount of pressure to be built up with fewer compressor stages. Consequently, the compressor can be shorter and lighter.
The present invention is more fully described in light of the accompanying drawings showing three embodiments. In the drawings,
Furthermore, identical or functionally identical parts are designated with the same reference numerals in all embodiments.
Obviously, application of the present invention already to the forward stages of the axial-flow compressor provides for increased pressure build-up. Consequently, less compressor stages than on conventional axial-flow compressors are required for the same pressure build-up. Therefore, the axial-flow compressor according to the present invention is shorter and lighter.
Number | Date | Country | Kind |
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10 2008 021 683.6 | Apr 2008 | DE | national |