EP1433958A2 - Upstream stator for turbomachine - Google Patents

Abstract

The inlet stator (12) has several inlet guide vanes (16) in the flow incidence region of a compressor wheel whose spin-generating vane angle can be varied depending on a fluid volumetric flow through the flow machine or turbo-compressor. The inlet guide vanes undergo variable deformation under varying flow conditions. The inlet guide vanes are made of a deformable material and are flexible.

Description

The invention relates to a Vorleitstator for Turbomachines with those in the preamble of the claim 1 mentioned features.

State of the art

To increase the air flow in internal combustion engines are suitable among other things exhaust gas turbochargers, the energy from the flow energy of the exhaust gas win for driving a compressor wheel that the combustion air supplied to the combustion chambers puts an increased pressure. The energy content of a the air-fuel mixture supplied to the internal combustion engine can be increased. turbocharger are both with internal combustion engines Auto ignition as well as those with spark ignition used. Point in particular for vehicle drives Exhaust gas turbochargers often have the disadvantage of being delayed or insufficient response behavior lower engine speeds. Here is the Flow energy of the exhaust gas so low that too the compressor can only apply a small amount of energy can. This only increases when the exhaust gas pressure is sufficiently large. That delay is also known as a so-called turbo lag. To also at low exhaust pressure the compressor on a torque request to react quickly are additional electric drives for the compressor wheel known. For example, US-A-6 029 452 describes one such improvement in responsiveness of a Exhaust gas turbocharger with the support of an additional electric drive.

Such an additional electrical drive can drive the drive shaft of an existing compressor support. Another type of electrical Support is a separate, purely electrical operated auxiliary loader, in the fresh air duct in series with a conventional turbine Exhaust gas turbocharger is operated and as a so-called called electric auxiliary compressor becomes.

Especially when operating such turbomachines there is the problem of a limited operating area, by the so-called compressor map is described. Should be a flow compressor even with lower mass flows work effectively, his map must be expanded that the surge limit is reduced. A known method for expanding the map or Map stabilization of turbo machines are et al adjustable or fixed stator elements, which as control elements before entry or after the exit of the bladed compressors or turbo wheels are arranged. Here is between not distinguish between adjustable and adjustable idlers. Adjustable idlers allow one higher effectiveness and better broadening a map. The adjustable elements are actively operated here.

Advantages of the invention

An inventive stator for turbomachines, especially for turbocompressors several arranged in the inflow area of a compressor wheel Inlet guide vanes on, their swirl-generating Bucket angle depending on one Fluid volume flow through the turbomachine or the turbocompressor is adjustable. The invention sees a variable deformation of the inlet guide vanes with changing flow conditions in front. In this way, the preliminary stator optimally adapted to different fluid volume flows be without a relatively complex Adjustability of guide vanes is necessary. Around to achieve this are the inlet guide vanes flexible in itself and consist of a deformable Material, especially plastic. The Guide vanes of the guide vane can affect this Way with increased mass throughput without external Demold control elements increasingly. This will a self-adjusting link for effective map expansion of turbomachinery and in particular Turbocompressors provided.

There is an axial flow guide stator in one embodiment of the invention, a radial compressor with axially flowed impeller. With increasing volume flow decreases the deformation of the inlet guide vanes, from what a variable blade angle between approx. 0 and 20 Degrees can result. With a high volume flow the blade angle is approximately 0 degrees while he with a low volume flow in one area up to about 85 degrees. The shovels are preferred in the relaxed state evenly arched to ideal flow conditions to enable. With a suitable geometry and Material choice can be an individually customizable Leading stator for the most different types of Flow machines are made available.

The elastic nature of the lead stator enables an automatic adaptation of the impeller flow through the acting volume flow itself. If the volume flow is low, the axial stator gives way little of its unstressed Position. The lead body creates a well-defined one Counter-whirl leading to a degradation the surge limit of the downstream flow compressor leads. Corresponds to the volume flow the design point of the radial machine with swirl-free Incoming flow, the guide body so the flow is almost parallel in that downstream impeller can get.

Further advantageous embodiments of the invention result from the rest, in the dependent claims mentioned features.

drawings

Figur 1

eine schematische Schnittansicht eines Turboverdichters mit einem erfindungsgemäßen Vorleitstator im Anströmbereich eines Verdichterrades,

Figur 2

eine Draufsicht auf den Vorleitstator gemäß Figur 1 im entspannten Zustand,

Figur 3

eine schematische Schnittansicht des Turboverdichters bei hohem Volumenstrom und

Figur 4

eine Draufsicht auf den Vorleitstator mit verformten Schaufeln gemäß Figur 3.

The invention is explained in more detail in preferred embodiments with reference to the accompanying drawings. It shows:

Figure 1

1 shows a schematic sectional view of a turbocompressor with a preliminary stator according to the invention in the inflow region of a compressor wheel,

Figure 2

2 shows a plan view of the preliminary stator according to FIG. 1 in the relaxed state,

Figure 3

is a schematic sectional view of the turbocompressor at high volume flow and

Figure 4

a plan view of the Vorleitstator with deformed blades according to Figure 3.

Description of the embodiments

Figure 1 illustrates a Vorleitstator 12 a Turbo compressor 10 having a compressor wheel 14 is connected upstream. The compressor 10 is from above flows downwards, whereby the compressor wheel 14 rotates counterclockwise (cf. also Figure 2).

The pre-stator 12 has a plurality of inlet guide blades 16 on the lower leaf edges 26 a blade angle at a low volume flow with respect to a longitudinal axis 20 of up to approx. Can have 85 degrees. The angle shown is however, significantly smaller than this maximum value and is about 20 to 30 degrees. As with the Top view of Figure 2 is illustrated, are the Inlet guide vanes 16 each on transverse webs 18 arranged and are in the flow direction and in Suspended in the direction of its lower sheet edge 26. The suspension 24 on the crossbars 18 is here rigidly executed, while the inlet guide vanes 16 itself made of a flexible material exist and with increasing volume flow wrest. The blade angle approaches here a value of 0 degrees.

As can be seen from FIGS. 3 and 4, can the inflow conditions with a larger volume flow be improved by the fact that the Bucket angle is reduced, which is caused by stretching the compressor blades 22 is reached. This Extension of the compressor blades, which are flexible in themselves 22 is achieved by the flow pressure itself and not by external control elements.

With higher mass throughput, only a small one becomes Flow swirl generated, which with the appropriate Volume flow rate approaches a value of zero.

Vorleitstator 12 of the turbocompressor according to the invention 10 thus enables a map expansion of the compressor and a shift of it Pumping limit down, so even at low Volume flow through the compressor an effective Flow against the compressor wheel 14 is made possible.

Claims (9)

Vorleitstator for turbomachines, in particular for turbocompressors, with a plurality of inlet guide vanes arranged in the inflow region of a compressor wheel, the swirl-generating blade angle of which can be adjusted as a function of a fluid volume flow through the turbomachine or the turbocompressor, characterized by a variable deformation of the inlet guide vanes (16) when the flow conditions change. Vorleitstator according to claim 1, characterized in that the inlet guide vanes (16) made of a deformable material and are flexible in themselves. Vorleitstator according to claim 2, characterized in that the inlet guide vanes (16) are made of plastic. Vorleitstator according to any one of the preceding claims, characterized in that the Vorleitstator (12) is flowed through in the axial direction. Vorleitstator according to any one of the preceding claims, characterized in that the turbomachine is a radial compressor with an axially flowed impeller (14). Vorleitstator according to any one of the preceding claims, characterized by a deformation of the inlet guide vanes (16) which decreases with increasing volume flow. Vorleitstator according to any one of the preceding claims, characterized by a variable blade angle of the inlet guide blades (16) between 0 degrees and about 85 degrees. Vorleitstator according to any one of the preceding claims, characterized by a blade angle of approximately 0 degrees at a high volume flow. Vorleitstator according to any one of the preceding claims, characterized by a blade angle of more than 50, preferably up to about 85 degrees with a low volume flow.

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