DE102017129884B4 - Adjustable swirl generation device for compressors - Google Patents

Abstract

Adjustable swirl generating device (1) for compressors with a compressor inlet (3) whose inside diameter decreases in the flow direction of the compressor flow, a hollow truncated cone (2) that can be displaced axially in the compressor inlet (3) between a first end position and a second end position and whose outside diameter changes in the flow direction of the compressor flow reduced, with a central main flow duct (5) through an inner lateral surface (4) of the hollow truncated cone (2) and a central main flow duct (5) through an outer lateral surface (6) of the hollow truncated cone (2) and an inner lateral surface (7) of the compressor inlet (3) coaxially enveloping bypass duct (8), with at least one flow guide element (15, 16) in the bypass duct (8), a first sealing seat (9), which is formed by a first compressor inlet sealing surface (10) and a first hollow truncated cone sealing surface (11) and in the first end position, the first compressor inlet sealing surface (10) and the first hollow truncated cone sealing surface (11) are in contact with one another, so that the central main flow duct (5) is opened and the coaxially encasing secondary flow duct (8) is closed, a second sealing seat (12), which is formed by a second compressor inlet sealing surface (13) and a second hollow truncated cone sealing surface (14) and in the second end position the second compressor inlet sealing surface (13) and the second hollow truncated cone sealing surface (14) are in contact with one another, so that the central main flow channel (5) is closed and the coaxially encasing bypass channel (8) is open.

Description

technical field

The present invention relates to an adjustable swirl generation device for compressors according to the features of patent claim 1.

State of the art

To influence the characteristics of compressors, adjustable swirl generation devices are used to influence the flow onto the compressor impeller in order to shift the surge limit towards higher pressure differences or lower mass flows and thus to stabilize the operation of the compressor. The adjustable swirl generation devices can be used for axial compressors, radial compressors and diagonal compressors and are located on the suction side of the compressor. In order to stabilize the inflow, it may be sufficient to impose a twisting movement on only part of the inflow, in order to increase the flow losses due to the devices for producing the twist only to a small extent.

From the disclosure document DE 195 14 707 A1 a pre-guiding device is known, which is constructed from an axially conducting main gas channel and from at least one radially conducting secondary gas channel for controlling the impeller inflow of a centrifugal compressor. To control the flow direction, the channels can be opened alternately or jointly by means of an axially displaceable and rotatable sleeve. However, due to the radially conducting, snail-shaped secondary gas channel, no uniform swirl flow can be generated over the peripheral region of the compressor impeller.

From the disclosure document DE 196 44 892 A1 a pre-guidance device with a swirl duct emerges, by means of which pressure differences in the flow field of the inflow and the resulting noise disadvantages and efficiency losses can be reduced and, on the other hand, a simple, controllable throttle function is provided. The feed device has a swirl or guide channel arranged in the housing and a closure body arranged in the housing, with both the swirl or guide channel and the closure body being arranged such that they can be displaced axially separately from one another. The swirl or guide channel has a central outlet opening. The arrangement of the swirl or guide channel results in a central, swirling inflow and a surrounding, swirl-free inflow onto the compressor impeller. For swirl-free operation, the swirl or guide channel is shifted into an upper rest position, so that it is closed by the closure body. There is then a twist-free flow through the surrounding cross-section. For operation with maximum swirl, the swirl or guide channel is shifted to a lower rest position, so that the swirl-free flow surrounding the swirling flow comes to a complete standstill. There is a swirling flow through the swirl or guide channel.

From the disclosure document DE 10 2010 026 176 A1 a variably adjustable cone for the characteristic map stabilization of a compressor emerges. In an embodiment shown, the cone is formed from a plurality of lamellae which are arranged over the inner circumference of the inflow region and are held in place by means of an elastic ring and a displaceable ring. A variable, tapering funnel shape is formed by the axial displacement of the ring. This changes the trim to stabilize the inflow.

From the patent DE 10 2011 121 996 B4 a device for operating a compressor is known, which has a variably constrictable element with a first flow cross section and a second, variable flow cross section spaced apart in the direction of flow and the flow can be imparted with a twisting motion. For this purpose, additional flow guide elements are provided on the inner circumference of the element, which are coupled in a rotationally fixed manner to the compressor inlet in the region of the first flow cross section and twist or twist as the second flow cross section decreases relative to the first flow cross section. In one embodiment, the flow guide elements are formed by lamellae and are in active contact with drivers, which cause twisting or twisting when the second flow cross section is initially reduced only slightly.

From the patent DE 10 2013 018 368 B4 an adjustable swirl generation device for compressors is known, by means of which stabilization of the flow through a compressor inlet onto a compressor wheel of the compressor is intended to take place. For this purpose, a plurality of flow guide elements are positioned on the inner circumference of the compressor inlet, the flow guide elements being rotatably and pivotably mounted in a housing by means of a first axis of rotation. For this purpose, the first axis of rotation is rotatably and pivotably mounted in a first bearing point and rotatable and displaceable perpendicularly to the longitudinal direction of the compressor inlet in a second bearing point spaced apart from the first bearing point in the direction of flow. The twist generation device changes the trim ratio with a simultaneous change in the twist generation ment provided with an increase in spin generation being achieved as the trim ratio is reduced.

From the disclosure document DE 10 2014 007 229 A1 An adjustable swirl generation device for compressors is known, which has a plurality of pivotable flow guide elements which are circular in relation to one another and are oriented mainly in the longitudinal direction of the compressor at a distance from the inner circumference of a compressor inlet of the compressor. As a result, a main duct and a secondary duct arranged coaxially to the main duct are formed in the compressor inlet, the secondary duct spatially encasing the main duct and being separated from the main duct by means of the plurality of flow guide elements. Furthermore, several swirl generators are arranged on the flow guide element or on the inner circumference of the compressor inlet in the secondary duct. The twist generation device provides a change in the trim ratio with a simultaneous change in the generation of twist, with an increase in the generation of twist being achieved when the trim ratio is increased.

Due to the use of several flow guide elements in the inlet area of the compressor, increased manufacturing and assembly costs are necessary. Expensive adjustment devices are then required, in particular for a controlled adjustment of the flow guide elements.

From the disclosure document DE 10 2014 006 463 A1 an adjustable air supply device for a compressor arranged in the intake tract of an internal combustion engine is known. The air supply device has an air duct and an adjustable flow component designed as a cone for variable setting of the flow cross section in the air duct. With the adjustment of the flow component, the flow cross section of a flow path lying on the outside of the flow component is changed. Furthermore, the flow component is designed as a hollow body, as a result of which an additional internal flow path is formed that is independent of the flow path on the outside of the flow component. However, there is no provision for generating a swirl to stabilize the flow onto the compressor impeller in the area of the surge limit.

From the disclosure document DE 10 2015 007 410 A1 discloses a compressor for an exhaust gas turbocharger of an internal combustion engine, which has an annular blocking element. The blocking element can be rotated about an axis of rotation into at least one closed position fluidically blocking a compressor inlet and at least one open position releasing the compressor inlet. During the operation of the compressor, the blocking element is at least temporarily rotated several times completely around the axis of rotation at a constant speed by means of a drive device in order to pulse the inflow to improve the surge limit.

object of the invention

The object of the invention is to provide an improved, adjustable swirl generation device for compressors, by means of which the flow onto the compressor impeller is further stabilized in the region of the surge limit.

solution of the task

The object is achieved by the adjustable swirl generation device for compressors with the features of patent claim 1. Advantageous developments result from the dependent claims and the exemplary embodiment.

Description of the invention

The invention provides an adjustable swirl generation device for compressors, which is advantageous according to the invention and by means of which a further stabilization of an inflow onto a compressor impeller of a compressor takes place under different operating conditions, in particular in the region of the surge limit.

For this purpose, the adjustable swirl generation device for compressors that is advantageous according to the invention is provided with a compressor inlet as part of a compressor housing, the inner diameter of which decreases in the flow direction of the compressor inflow, with a hollow truncated cone that can be axially displaced in the compressor inlet between a first end position and a second end position, the outer diameter of which decreases in the flow direction of the compressor inflow , wherein a central main flow duct is formed by an inner lateral surface of the hollow truncated cone and by an outer lateral surface of the hollow truncated cone and an inner lateral surface of the compressor inlet a secondary flow duct coaxially encasing the central main flow duct, with a first sealing seat which is formed by a first compressor inlet sealing surface and a first hollow truncated cone sealing surface and in which first end position, the first compressor inlet sealing surface and the first hollow truncated cone sealing surface are in contact with one another, so that the central main flow duct is open and the coaxially enclosing bypass duct is closed, and with a second sealing seat, which is formed by a second compressor inlet sealing surface and a second Hollow truncated cone sealing surface is formed and in the second end position the second compressor inlet sealing surface and the second hollow truncated cone sealing surface are in contact with one another, so that the central main flow duct is closed and the coaxially enclosing secondary flow duct is open. The compressor inlet sealing surfaces are part of the compressor inlet and the hollow truncated cone sealing surfaces are part of the hollow truncated cone.

Flow guide elements are also provided in the bypass channel, which impart a twisting movement to the bypass flow. The flow elements extend at least partially spirally in the direction of flow of the compressor inflow in the bypass duct. The flow guide elements are formed with the inner lateral surface of the compressor inlet and/or with the outer lateral surface of the hollow truncated cone.

For stabilization under different operating conditions, the inflow is divided into a central main flow and a secondary flow coaxially encasing the central main flow, with the secondary flow being forced to twist. This provides a swirl flow that is uniform over the circumference of the compressor impeller, with the flow through the bypass duct not being influenced by the flow through the main flow duct in an advantageous manner according to the invention when the bypass duct is opened to the maximum. An axial displacement of the hollow truncated cone between the first end position and the second end position changes the proportions of the main flow and the secondary flow in the total flow, with only the main flow and no secondary flow flowing through the compressor inlet in the first end position, and only the secondary flow and no main flow flowing through the compressor inlet in the second end position . The axially displaceable hollow truncated cone can be displaced between the first end position and the second end position by means of an adjustment device. The hollow truncated cone is to be understood as a cone sleeve, with the inner diameter being constant or decreasing in the flow direction of the compressor inflow.

In a particularly advantageous manner, the first compressor inlet sealing surface is formed by the inner lateral surface of the compressor inlet or by a step reducing the inner diameter of the compressor inlet and the first hollow truncated cone sealing surface is formed by the outer lateral surface of the hollow truncated cone or by the hollow truncated cone top surface. An axial displacement from the second end position to the first end position of the hollow truncated cone reduces the distance from the outer lateral surface of the hollow truncated cone to the inner lateral surface of the compressor inlet and thus the available flow cross section of the secondary duct until they abut one another and thus close the secondary flow duct.

In a particularly advantageous manner, the second compressor inlet sealing surface is formed by an outer surface of a sealing element positioned centrally in the compressor inlet and the second hollow truncated cone sealing surface is formed by the inner lateral surface of the hollow truncated cone or by the base of the hollow truncated cone. The centrally positioned sealing element is to be understood as part of the compressor inlet. The centrally positioned sealing element is preferably designed as a cone and the second compressor inlet sealing surface is formed by an outer surface of the cone and the second hollow truncated cone sealing surface is formed by the inner lateral surface of the hollow truncated cone. In a particularly advantageous manner, a separate hollow truncated cone sealing seat is formed as part of the inner lateral surface of the hollow truncated cone, which then rests as a second hollow truncated cone sealing surface on the outer surface of the sealing element in the second end position.

The flow guide elements are designed as a recess in the form of a depression running spirally in the flow direction of the compressor inflow, in particular as a groove, notch or channel. The depth is constant. Alternatively, the depth varies over the course of the indentation in the flow direction of the compressor inflow, wherein the depth in the course of the indentation in the flow direction of the compressor inflow can in particular decrease to zero or increase from zero. In a particularly advantageous manner, the first sealing seat is formed in an area in which the depth of the depression is zero.

The flow guide elements are alternatively designed as an integral part in the form of an elevation running spirally in the flow direction of the compressor inflow, in particular as a baffle plate, rectangular or round integral part. The height is constant. Alternatively, the height is different in the course of the increase in the direction of flow of the compressor inflow, in which case the height can be reduced in particular as it falls to zero or can be increased as it rises from zero. In a particularly advantageous manner, the first sealing seat is formed in an area in which the elevation is zero.

In a particularly advantageous manner, the flow guide elements are formed with the inner lateral surface of the compressor inlet and with the outer lateral surface of the hollow truncated cone, wherein between the inner lateral surface of the compressor inlet and the outer lateral surface of the hollow truncated cone there is a flow guide element designed as an integral part with an opposite flow guide element designed as a recess cooperates, so that they engage with each other during the axial displacement of the hollow truncated cone from the second end position to the first end position. When the opposing and cooperating flow guide elements engage in one another, the continued axial displacement imparts a rotational movement to the hollow truncated cone, which corresponds to the pitch of the spiral flow guide elements.

The flow guide elements can in particular be designed spirally in such a way that they impart a twisting movement to the bypass flow in the bypass channel which corresponds to the direction of rotation of the compressor impeller, or impart a twisting movement to the bypass flow which corresponds to the opposite direction of rotation of the compressor impeller.

In an extremely advantageous manner, at least one inlet point for exhaust gas is provided in the compressor inlet in the area of the bypass duct in order to influence, in particular to promote, the generation of swirl in the bypass duct. Closing the bypass duct thus also closes the at least one introduction point. The at least one introduction point is in fluid communication with an exhaust gas feed designed as a ring channel, with the ring channel extending in the region of the flow guide elements. The ring channel can in particular intersect with the flow guide elements, so that there are several inlet points assigned to the flow guide elements. Alternatively, the inlet points can open out as a branch channel, starting from the ring channel in the area of the flow guide elements, into the bypass channel, with the branch channels being aligned with the course of the flow guide elements to support the generation of swirl.

example

• 1a: eine schematische Darstellung der verstellbareren Drallerzeugungseinrichtung 1 in einer ersten Endlage eines Hohlkegelstumpfes 2, und
• 1b: eine schematische Darstellung der verstellbaren Drallerzeugungseinrichtung 1 in einer zweiten Endlage des Hohlkegelstumpfes 2.

An embodiment of the adjustable swirl generation device 1 according to the invention for the compressor 2 is shown here as an example. In the accompanying figures shows:

• 1a : a schematic representation of the adjustable twist generation device 1 in a first end position of a hollow truncated cone 2, and
• 1b : a schematic representation of the adjustable twist generation device 1 in a second end position of the hollow truncated cone 2.

The exemplary embodiment of the adjustable swirl generation device 1 for compressors, shown in 1a and 1b , has a compressor inlet 3, the inner diameter of which decreases in the flow direction of the compressor inflow, which in the compressor inlet 3 is between the first end position, shown in 1a and the second end position, shown in 1b , axially displaceable hollow truncated cone 2, the outer diameter of which decreases in the flow direction of the compressor inflow, with a central main flow duct 5 passing through an inner lateral surface 4 of the hollow truncated cone 2 and a central main flow duct 5 coaxially enveloping through an outer lateral surface 6 of the hollow truncated cone 2 and an inner lateral surface 7 of the compressor inlet 3 Bypass channel 8 is formed.

The adjustable swirl generating device 1 also has a first sealing seat 9, which is formed by a first compressor inlet sealing surface 10 and a first hollow truncated cone sealing surface 11, with the first compressor inlet sealing surface 10 and the first hollow truncated cone sealing surface 11 being in contact with one another in the first end position, so that the main flow channel 5 is open and the bypass channel 8 is closed. The first compressor inlet sealing surface 10 is formed by the inner lateral surface 7 of the compressor inlet 3 and the first hollow truncated cone sealing surface 11 by the outer lateral surface 6 of the hollow truncated cone 2 .

The adjustable swirl generating device 1 also has a second sealing seat 12, which is formed by a second compressor inlet sealing surface 13 and a second hollow truncated cone sealing surface 14, and in the second end position the second compressor inlet sealing surface 13 and the second hollow truncated cone sealing surface 14 are in contact with one another, so that the main flow channel 5 closed and the bypass channel 8 is open.

The second compressor inlet sealing surface 13 is formed by an outer surface of a sealing element 19 positioned centrally in the compressor inlet 3 and the second hollow truncated cone sealing surface 14 by the inner lateral surface 8 of the hollow truncated cone 2 or a base surface of the hollow truncated cone 2 .

Also provided in the bypass channel 8 are flow guide elements 15, 16 which extend spirally in the flow direction of the compressor inflow and impart a twisting movement to the bypass flow. The flow guide elements 15, 16 are formed with the inner lateral surface 7 of the compressor inlet 3 as an integral part 15 and with the outer lateral surface 6 of the hollow truncated cone 2 as a recess 16, so that between the inner lateral surface 7 of the compressor inlet 3 and the outer lateral surface 6 of the hollow truncated cone 2 there is in each case a molded part 15 trained flow guide element 15, 16 with an opposite lie lowing, formed as a recess 16 flow guide element 15, 16 cooperates. During the axial displacement of the hollow truncated cone 2 from the second end position to the first end position, the projection 15 and the recess 16 increasingly engage in one another.

In the compressor inlet 3 8 inlet points 17 are provided for exhaust gas in the area of the bypass duct. An exhaust gas feed 18 designed as a ring duct is arranged in the compressor inlet 3 in the region of the flow guide elements 15, 16, with the inlet points 17 opening into the bypass duct 8 as a branch duct between the projections 15.

Reference List

1

twist generating device

2

hollow truncated cone

3

compressor inlet

4

inner lateral surface

5

main flow channel

6

outer surface

7

inner lateral surface

8th

bypass channel

9

first sealing seat

10

first compressor inlet sealing surface

11

first hollow truncated cone sealing surface

12

second sealing seat

13

second compressor inlet sealing surface

14

second hollow truncated cone sealing surface

15

molding

16

recess

17

discharge point

18

exhaust gas supply

19

sealing element

Claims (6)

Adjustable swirl generating device (1) for compressors with a compressor inlet (3) whose inner diameter decreases in the flow direction of the compressor inflow, a hollow truncated cone (2) which can be displaced axially in the compressor inlet (3) between a first end position and a second end position, the outer diameter of which decreases in the flow direction of the compressor inflow, with a central main flow channel (5) passing through an inner lateral surface (4) of the hollow truncated cone (2) and through an outer lateral surface (6) of the hollow truncated cone (2) and an inner lateral surface (7) of the compressor inlet (3) a secondary flow channel (8) coaxially encasing the central main flow channel (5) is formed, with at least one flow guide element (15, 16) in the bypass duct (8), a first sealing seat (9), which is formed by a first compressor inlet sealing surface (10) and a first hollow truncated cone sealing surface (11) and in the first end position the first compressor inlet sealing surface (10 ) and the first hollow truncated cone sealing surface (11) are in contact with one another, so that the central main flow duct (5) is opened and the coaxially enclosing secondary flow duct (8) is closed, a second sealing seat (12) which is separated by a second compressor inlet sealing surface (13) and a second hollow truncated cone sealing surface (14) is formed and in the second end position the second compressor inlet sealing surface (13) and the second hollow truncated cone sealing surface (14) are in contact with one another, so that the central main flow duct (5) is closed and the coaxially enclosing secondary flow duct (8) is open . Adjustable swirl generating device (1) for compressors Claim 1 , characterized in that at least one inlet point (17) for exhaust gas is provided in the compressor inlet (3) in the area of the bypass duct (8). Adjustable swirl generating device (1) for compressors according to one of the preceding patent claims, characterized in that the flow elements (15, 16) extend at least partially spirally in the direction of flow of the compressor inflow in the bypass duct (8) and are connected to the inner surface (7) of the compressor inlet (3) and/or are formed with the outer lateral surface (6) of the hollow truncated cone (2). Adjustable swirl generating device (1) for compressors according to one of the preceding claims, characterized in that the flow guide elements (15, 16) are designed as recesses (16) in the form of a depression running spirally in the flow direction of the compressor inflow. Adjustable swirl generating device (1) for compressors according to one of the preceding claims, characterized in that the flow guide elements (15, 16) are designed as a molding (15) in the form of an elevation running spirally in the flow direction of the compressor inflow. Adjustable swirl generating device (1) for compressors according to one of the preceding claims, characterized in that the Flow guide elements (15, 16) are formed with the inner lateral surface (7) of the compressor inlet (3) and with the outer lateral surface (6) of the hollow truncated cone (2), with between the inner lateral surface (7) of the compressor inlet (3) and the outer lateral surface (6) of the hollow truncated cone (2), a flow guide element (15, 16) designed as an integral part (15) interacts with an opposite flow guide element (15, 16) designed as a recess (16), so that the latter, during the axial displacement of the hollow truncated cone (2) from of the second end position to the first end position interlock.

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