Patent Application
20100000198
This application claims priority to German Patent Application DE102008031932.5 filed Jul. 7, 2008, the entirety of which is incorporated by reference herein.
This invention relates to a gas turbine with at least one multi-stage compressor unit.
On multi-stage compressors, e.g. multi-stage high-pressure compressors of aircraft engines, all compressor stages are jointly designed for high-load conditions. However, these compressors are also required to operate at part-load or idle conditions which are characterized by significantly lower compression ratios.
The several compressor stages are jointly designed only for high compression ratios at high-load conditions and are indivisible.
Therefore, part-load or idle operation is restricted to a considerable extent.
The required low compression ratio at part load or idle is distributed to all stages. Therefore, each stage must produce a very small compression ratio. This is not achievable in operation since some stages almost reach their particular, critical surge limits, which are to be avoided, as the entire compressor and, consequently, the whole engine are put at risk.
As counter-measure, the compressor is forced to operate at higher compression ratios in part load or idle. This entails a waste of power and, for example, also fuel. Therefore, the compressor is highly uneconomical in part-load or idle operation which may amount to quite a large part of the total operating time of, for example, an engine.
A broad aspect of the present invention is to provide a gas turbine with at least one multi-stage compressor unit, which while being simply designed, ensures easy and safe operation and can be adapted to different load conditions.
In accordance with the present invention, a gas turbine with at least one multi-stage compressor unit is therefore provided in which the compressor unit is composed of several, independent compressor modules which, independently of each other, are rotatably borne on a drive shaft and are each engageable with the drive shaft 1 by way of a variable transmission. The variable transmission is provided with variably adjustable speed-increasing or speed-reducing transmission ratios, respectively. This type of transmission can, for example, be designed in the form of a chain-disk drive with setting cones or in the form of a planetary gear drive or otherwise.
According to the present invention, the transmission (as compared to other gear drives) therefore has various speed-increasing or speed-reducing ratios, respectively, thereby enabling a percentage distribution of the loads to be obtained by distinctly allotting the relative speeds between the drive shaft and the individual compressor modules. This provides for an optimization of efficiency.
According to the present invention, the compressor modules are provided with variable transmissions (with variable speed or transmission ratios, respectively). This enables the individual transmission ratios thereof to be set as required (via system control). For each of the variable transmissions, three major modes basically exist which smoothly, or continuously, transit into each other:
1. The transmission ratio can, if required, be set such that power is transmitted from the drive shaft to the compressor module. The transmission ratio can here be set such that the respective compressor module is operated at the speeds which are optimum for the compressor stages included therein. This enables the efficiency of the compressor module and, thus, of the entire compressor to be considerably increased. Altogether, this results, for example, in significant fuel saving and, consequently, improved economical efficiency of, for example, engine operation.
2. The transmission ratio can, if required, be set such that power is transmitted from the compressor module, which is driven by the airflow, to the drive shaft. At certain operating conditions this would lead to optimum distribution/utilization of the total power, which is available only to a limited extent, thereby increasing system efficiency and, thus, system economy.
3. The transmission ratio can, if required, also be set such that no power at all is transmitted (in neither direction). This corresponds to the decoupled state of this compressor module.
Each of the variable transmissions is to be set, as required, by the control unit, actually according to the direction into which power is to be transferred on the respective compressor modules (no power transfer, if applicable) and, further, according to the optimum speeds of the respective compressor modules.
The present invention is more fully described in light of the accompanying drawing showing a preferred embodiment. In the drawings,
The compressor unit shown in
Between each of the compressor modules 3, 4, 5 and the drive shaft 1, a variable transmission 9, 10, 11 is interposed which can be actuated electrically, hydraulically, mechanically or in another manner. Actuation is by means of an EEC (electronic engine control) 12 which computes optimum speeds and optimum operating states of the individual compressor modules 3-5. Accordingly, as a first option, the variable transmission can be set to a neutral position, or a neutral gear, in which no power is transmitted between the compressor module 3-5 and the drive shaft 1 or, as a second option, the variable transmission can be set such that power is transmitted from the drive shaft to the compressor or, as a third option, the variable transmission can be set such that power is transmitted from the compressor to the drive shaft. Accordingly, by distributing the percentage power or torque transmissions, the modular compressor can be optimized. The individual compressor modules 3-5 here run at different speeds. The variable transmission can be provided as planetary gear drive or as chain-disk drive with setting cone. The latter option is exemplified in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2008 031 932.5 | Jul 2008 | DE | national |
