EP3237760B1 - Diffuser for a centrifugal compressor - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a diffuser for a radial compressor. The term radial compressor in the following also includes so-called mixed-flow compressors with an axial inflow and a radial outflow of the compressor impeller. The scope of the present invention also extends to compressors with a purely radial or diagonal inflow or outflow of the compressor impeller. Furthermore, the present invention relates to a diffuser for a radial compressor, wherein the radial compressor can be used in a turbocharger, and wherein the turbocharger can have an axial turbine or a radial or a so-called mixed flow turbine.

STATE OF THE ART

Diffusers for use in radial compressors for turbocharger applications are known from the prior art. In a radial compressor, a fluid (eg air) is first drawn in axially via a compressor wheel upstream of the diffuser and accelerated and precompressed in the compressor wheel. Energy is supplied to the fluid in the form of pressure, temperature and kinetic energy. High flow velocities prevail at the outlet of the compressor wheel. The accelerated, compressed air leaves the compressor wheel tangentially in the direction of the diffuser. The kinetic energy of the accelerated air is converted into pressure in the diffuser. This is done by delaying the flow in the diffuser. The radial cross section of the diffuser is enlarged by radial expansion. This delays the fluid and builds up pressure. In order to achieve the highest possible pressure ratios in a turbocharger with a radial compressor, the diffusers used therein can be equipped with blading. An example of a bladed diffuser is shown in DE102008044505 , The diffusers with blading known from the prior art are generally designed as radial parallel-walled diffusers with blading, as for example in FIG US4131389 shown. In order to achieve a higher compressor efficiency for a given total pressure ratio, the flow in the diffuser can be decelerated more. This reduces the flow velocities in the spiral, which reduces the wall friction losses and improves the efficiency of the compressor stage. It is known from the prior art that the use of diffusers with radial side wall divergence allows a greater delay with the same overall length compared to parallel-walled diffusers.

However, the delay or pressure increase that can be achieved in the diffuser by means of a geometry variation for a given operating point is limited, since the delay is too great Flow instabilities due to boundary layer detachments in the diffuser comes. The limits of the stable operating range of the diffuser thus determine the position of the surge limit of the compressor in the compressor map. If a diffuser with side wall divergence is used instead of a parallel-walled diffuser - such a diffuser is for example in the WO 2012/116880 A1 and GB2041149 A described - although the efficiency increases with the same compressor pressure ratios, at the same time, however, for a given compressor pressure ratio the pump limit shifts to larger mass flows compared to the compressor with a parallel-walled diffuser. This effect is undesirable. This reduces the compressor map width and limits the usability of the compressor stage for applications in the turbocharger. One solution is to fluidly connect a diffuser channel section of a bladed diffuser to an annular channel via pressure equalization openings in order to enable pressure equalization between individual diffuser passages of the diffuser, which are formed by adjacent diffuser blades. However, with this solution using pressure equalization openings, the problem can arise that the ring channel and / or the individual pressure equalization openings become blocked, for example due to residues and deposits from a compressor cleaning or due to particles which are in oil-containing intake air. This has a negative impact on the surge limit of the compressor and, in extreme cases, can mean that a motor connected to the diffuser can no longer be operated.

SUMMARY OF THE INVENTION

The present invention has for its object to develop a bladed diffuser with radial side wall convergence for radial compressors in such a way that the efficiency compared to parallel-walled diffusers is improved and at the same time the flow in the diffuser is stabilized in order to improve the pumping behavior of the compressor. Another object of the present invention is to avoid or reduce premature boundary layer detachments on the diffuser vanes and on the side walls of the diffuser in individual diffuser passages due to excessive delays. Furthermore, it is a further object of the present invention to ensure that the function of the diffuser is not impaired even in the event of possible contamination due to deposits and residues from the intake air containing oil from the compressor.

The object is achieved by the features of independent claim 1.

In particular, the object is achieved by a diffuser for a radial compressor, the diffuser comprising a diffuser channel section which is formed by a first side wall and a second side wall, the first side wall and the second Sidewall are at least partially divergent from each other in the flow direction. Furthermore, the diffuser comprises a blade ring with a number of blades, the blades being arranged at least partially in the diffuser channel section, each of the blades having a pressure side and a suction side, and wherein

the pressure side and the suction side of each blade are delimited by a blade leading edge and by a blade leading edge of this blade. Furthermore, the diffuser comprises a number of pressure compensation openings, which are incorporated in at least one of the two side walls of the diffuser channel section, each of the number of pressure compensation openings being arranged between the pressure side of a blade and the suction side of the adjacent blade of the blade ring. Furthermore, the diffuser comprises a first ring channel, which is arranged behind the pressure compensation openings, the first ring channel being fluidically connected to the diffuser channel section via at least two of the pressure compensation openings, as a result of which a number of diffuser passages of the diffuser can be fluidly connected to one another, a region between two being used as the diffuser passage adjacent blades of the blade ring in the diffuser channel section is referred to, the number of pressure equalization openings which are incorporated in at least one of the two side walls of the diffuser channel section being arranged in a region of the respective side wall in which the first side wall and second side wall are arranged to be divergent to one another in the flow direction , In one embodiment of the present invention, the first ring channel can be connected to a pressure plenum via a connecting channel, as a result of which a fluid can flow from the pressure plenum into the first ring channel so that the first ring channel is flushed with the fluid.

The core idea on which this embodiment is based is that in the case of a diffuser with side wall divergence, the bladed diffuser channel section of the diffuser has pressure compensation openings which are incorporated in at least one of the two side walls of the diffuser channel section, and the diffuser channel section of the diffuser being fluidly connected to a first ring channel and wherein the first ring channel can be connected to a pressure plenum via a connecting channel, whereby a fluid can flow from the pressure plenum into the first ring channel so that the first ring channel is flushed with the fluid.

This has the advantage that possible deposits and residues from coking caused by oil-containing suction air, which could clog the ring channel and the pressure compensation openings, via the fluid designed as a flushing medium, which flows from the plenum of pressure into the first ring channel in order to flush the ring channel with fluid. be flushed out of the ring channel and thus also out of the pressure compensation openings. In this way it can be prevented that the pressure compensation openings are closed by deposits and the volume of the ring channel is greatly reduced.

Another advantage of the present invention is that a pressure equalization can take place in the ring channel, which causes flow separation in the diffuser blades in the bladed diffuser channel section due to excessive flow delays counteracts and compensates for a flow separation.

Another advantage of the present invention is that the pressure equalization that takes place in the ring channel also results in a pressure equalization between the individual passages of the diffuser in the diffuser channel section, which in turn leads to a reduction in the uneven loading of individual diffuser passages in the diffuser channel section. A diffuser passage is defined as a space or a section between two adjacent diffuser blades. Uneven loads on individual diffuser passages in the diffuser channel section arise, for example, from asymmetries in the compressor housing and air intake port of the compressor and the resulting non-rotationally symmetrical pressure field in the outflow area of the diffuser, manufacturing and installation tolerances, and through transient flow effects. The pressure compensation makes it possible to compensate for instabilities in individual diffuser passages, by using the stability reserves of other, still stable, diffuser passages. As a result, the stable working area of the diffuser and the compressor is expanded as a whole until all diffuser passages come into the area of the unstable flow. The consequence of this is that the pump limit of the compressor shifts towards lower volume flows and the usable area of the compressor map increases.

In one embodiment of the present invention, the pressure plenum is connected to a fluid source, the fluid source being designed to provide fluid for the pressure plenum.

In one embodiment of the present invention, the fluid source is designed as a charge air cooler, the charge air cooler being designed to provide fluid, and the fluid being able to be introduced from the charge air cooler into the pressure plenum.

It should be noted here that the fluid from the charge air cooler, which is designed, for example, as a flushing medium, can also or additionally be used for cooling a compressor wheel of the radial compressor.

In one embodiment of the present invention, a filter system for cleaning the fluid is installed between the pressure plenum and the fluid source.

In one embodiment of the present invention, a turbocharger arrangement is provided which comprises a diffuser.

In one embodiment of the present invention, the first ring channel is incorporated in one of the two side walls of the diffuser channel section.

In one embodiment of the present invention, the pressure compensation openings are each designed as a bore and / or as a slot. Alternatively, however, a pressure compensation opening could also be formed from several individual bores or slots.

In one embodiment of the present invention, the orientation of each of the pressure equalization openings in the respective side wall of the diffuser channel section is determined by an angle of attack, which is defined as the angle of attack of the respective pressure equalization opening to the surface of this side wall facing the diffuser channel section.

In one embodiment of the present invention, the first ring channel is divided by separating means into a number of individual, sub-channel areas of the first ring channel that are separated from one another. In this way, pressure equalization between diffuser passages within a subchannel area can be limited locally.

In one embodiment of the present invention, each sub-channel region of the first ring channel comprises at least two pressure compensation openings. However, it should be noted in general that the pressure compensation openings do not have to be an integral part of the ring channel.

In one embodiment of the present invention, at least one second ring channel is incorporated in one of the side walls with pressure compensation openings in the diffuser channel section, as a result of which the diffuser passages of two non-adjacent blades of the blade ring can be fluidly connected to one another.

In one embodiment of the present invention, the first or second side wall of the diffuser channel section is designed as a diffuser plate, the number of pressure compensation openings and at least one ring channel being incorporated in the diffuser plate.

One embodiment of the present invention includes a radial compressor with a diffuser.

BRIEF DESCRIPTION OF THE DRAWINGS

• Fig. 1 zeigt einen Diffusor mit Beschaufelung für einen Radialverdichter gemäss einer ersten Ausführungsform der vorliegenden Erfindung;
• Fig. 2 zeigt einen Teilausschnitt eines Diffusors mit Beschaufelung für einen Radialverdichter gemäss einer zweiten Ausführungsform der vorliegenden Erfindung;
• Fig. 3 zeigt eine Diffusorplatte mit Druckausgleichsöffnungen und mit einer Anzahl voneinander abgetrennter Teilkanalbereiche gemäss einer dritten Ausführungsform der vorliegenden Erfindung;
• Fig. 4 zeigt eine Diffusorplatte mit Druckausgleichsöffnungen und mit einer Anzahl voneinander abgetrennter Teilkanalbereiche gemäss einer vierten Ausführungsform der vorliegenden Erfindung;
• Fig. 5 zeigt eine Diffusorplatte mit Druckausgleichsöffnungen und einer Verbindung von nicht benachbarten Diffusorpassagen gemäss einer fünften Ausführungsform der vorliegenden Erfindung;
• Fig. 6 zeigt einen Ausschnitt einer Diffusorplatte mit Beispielen für mögliche Ausrichtungen von Druckausgleichsöffnungen zwischen benachbarten Schaufeln in einer Diffusorpassage;
• Fig. 7 zeigt ein Beispiel für eine Ausrichtung einer Druckausgleichsöffnung in einer Diffusorplatte;
• Fig. 8 zeigt einen beschaufelten Diffusor für einen Radialverdichter mit Ringkanal und Druckplenum für einen Radialverdichter zur Anwendung in einer Turboladeranordnung gemäss einer sechsten Ausführungsform der vorliegenden Erfindung;
• Fig. 9 zeigt in einer alternativen schematischen Abbildung einen beschaufelten Diffusor mit Ringkanal und Druckplenum für einen Radialverdichter gemäss einer siebten Ausführungsform der vorliegenden Erfindung.

The invention is described below using exemplary embodiments which are explained in more detail with reference to drawings. Here show:

• Fig. 1 shows a diffuser with blading for a radial compressor according to a first embodiment of the present invention;
• Fig. 2 shows a partial section of a diffuser with blading for a radial compressor according to a second embodiment of the present invention;
• Fig. 3 shows a diffuser plate with pressure equalization openings and with a number of separated subchannel areas according to a third embodiment of the present invention;
• Fig. 4 shows a diffuser plate with pressure equalization openings and with a number of separated sub-channel areas according to a fourth embodiment of the present invention;
• Fig. 5 shows a diffuser plate with pressure equalization openings and a connection of non-adjacent diffuser passages according to a fifth embodiment of the present invention;
• Fig. 6 shows a section of a diffuser plate with examples of possible orientations of pressure equalization openings between adjacent blades in a diffuser passage;
• Fig. 7 shows an example of an alignment of a pressure compensation opening in a diffuser plate;
• Fig. 8 shows a bladed diffuser for a radial compressor with an annular channel and pressure plenum for a radial compressor for use in a turbocharger arrangement according to a sixth embodiment of the present invention;
• Fig. 9 shows an alternative schematic illustration of a bladed diffuser with ring channel and pressure plenum for a radial compressor according to a seventh embodiment of the present invention.

In the following description, identical reference numerals are used for identical and identically functioning parts.

DETAILED DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a diffuser 1 with blading for a radial compressor 100 according to a first embodiment of the present invention. The diffuser 1 comprises a diffuser channel section 2, which is formed by a first side wall 3 and a second side wall 4. The diffuser channel section 2 extends from the compressor wheel until it enters the compressor spiral (not shown). The first side wall 3 and the second side wall 4 are at least partially divergent from one another in the flow direction. The diffuser 1 comprises in the Figure 1 a blade ring 5 with a number of individual blades 6, 6 ', the blades 6, 6' being at least partially arranged in the diffuser channel section 2. This means that in the diffuser 1 there can be both bladed and non-bladed areas within the diffuser channel section 2. In the embodiment of the Figure 1 a number of pressure compensation openings 7, 7 'are incorporated in the second side wall 4, wherein in the side view of the Figure 1 only one pressure compensation opening 7, 7 'is shown. The second side wall 4 of the diffuser 1 is in the embodiment of FIG Figure 1 on a side facing a turbine wheel (not shown), the turbine wheel being part of a turbocharger arrangement (not shown) which also includes the radial compressor 100. The diffuser 1 comprises a first ring channel 10, which is arranged behind or after the pressure compensation openings 7, 7 '. The first ring channel 10 is designed as an essentially annular continuous channel, which can also be referred to as an open channel. The pressure equalization takes place over the entire circumference of the open channel. The pressure equalization ensures that the flow between the diffuser passages in the diffuser channel section 2 is stabilized by using stability reserves from adjacent or non-adjacent diffuser passages to stabilize the flow in individual diffuser passages that are already operated in the unstable area. A space or an area or a section between two adjacent diffuser blades is referred to as a diffuser passage.

The first ring channel 10 can be integrated as a component of the side wall 3, 4 directly into one or both of the side walls 3, 4, provided that it is ensured that the ring channel 10 is always installed behind the pressure compensation openings 7, 7 '. However, an embodiment would also be possible in which an annular channel is installed in each of the side walls 3, 4 and is fluidically connected to the diffuser channel section 2 via pressure compensation openings 7, 7 '(not shown).

In the embodiment of the Figure 1 the first ring channel 10 is incorporated in a third side wall 15, the third side wall 15 being arranged behind or after the second side wall 4 of the diffuser channel section 2 and the pressure equalization openings 7, 7 'being incorporated in the second side wall 4. The third side wall 15 can also be designed as a so-called partition, which is arranged between the compressor side and the turbine side of a turbocharger arrangement.

However, the ring channel 10 and thus also the pressure compensation openings 7, 7 'could also be a component of the second side wall 4 or the first side wall 3 of the diffuser channel section 2 (not shown), so that the third side wall 15 would be omitted. The pressure compensation openings 7, 7 'and the first ring channel 10 would then be incorporated in a one-piece component, one surface of this component forming the first side wall 3 or the second side wall 4. In this embodiment too, however, the ring channel 10 would be arranged behind the pressure equalization openings 7, 7 ', so that it is ensured that the ring channel 10 is fluidly connected to the diffuser channel section 2 via the pressure equalization openings 7, and thereby at the same time it is achieved that the number the flow cross sections of the diffuser 1 are fluidly connected to one another. In the embodiment of the Figure 1 it makes sense that the ring channel 10 is fluidly connected to the diffuser channel section 2 via at least two of the pressure compensation openings 7, 7 '. Each of the pressure equalization openings 7, 7 ', which are incorporated in at least one of the two side walls 3, 4 of the diffuser channel section 2, are arranged in all embodiments of the invention in a region of the respective side wall 3, 4, in which the first side wall 3 and second side wall 4 are arranged divergent to each other in the flow direction.

The pressure compensation openings 7, 7 'can each be designed as a bore and / or as a slot. As an alternative, however, a pressure equalization opening could also be composed of a plurality of openings, that is to say for example of a plurality of individual bores or slots or a combination of both shapes. However, another form of the pressure compensation opening in the diffuser 1 could also be realized. In the Figure 1 the pressure compensation openings 7, 7 'are also arranged in the bladed diffuser channel section 2 of the diffuser 1. This has the advantage that flow separations in this area - the bladed diffuser area - are compensated for due to excessive delays. As an alternative or in addition, the pressure compensation openings 7, 7 'could, however, also be arranged in a non-bladed diffuser channel section 2, which means that a number of individual pressure compensation openings 7, 7' are incorporated in at least one of the two side walls 3, 4 and in this area of the Diffuser channel section 2, which is formed by the two side walls 3, 4, no diffuser blades 6, 6 'are arranged. In the embodiment of the Figure 1 The radial compressor 100 with the diffuser 1 according to the invention also comprises a compressor wheel 40, a compressor housing 42 and a bearing housing 44. However, additional or further components of the compressor are not shown in the figure for reasons of clarity. Figure 2 shows a profile view of a partial section of a diffuser 1 with blading for a radial compressor 100 according to a second embodiment of the present invention. The Figure 2 shows a diffuser 1 which in the diffuser channel section 2 has a number of diffuser blades 6, 6 'of the blade ring 5 (not completely in FIG Figure 2 shown). In the view of the Figure 2 only the second side wall 4 of the diffuser 1 is shown. In the second side wall 4 pressure equalization openings 7, 7 'are incorporated, in which Figure 2 only one pressure equalization opening is shown in the profile view. An annular channel 10 is arranged in the side wall 4 directly behind the pressure compensation opening 7, 7 '. The ring channel 10 is thus in the embodiment shown Figure 2 Part of the second side wall 4. The ring channel 10 enables pressure equalization between individual diffuser blades 6, 6 ', which are at least partially arranged within the side wall divergent diffuser channel section 2. A flow separation on the individual diffuser blades 6, 6 ′ of the blade ring 5 of the diffuser 1 can thereby be compensated for. Flow separations occur when the pump limit of the diffuser 1 is approached initially in individual heavily loaded diffuser passages, that is to say in areas of two adjacent diffuser blades 6, 6 ', which are loaded unevenly due to asymmetries, such as in the compressor housing. The illustrated pressure compensation opening 7, 7 'of Figure 2 connects the first ring channel 10 to the flow cross sections of the diffuser 1.

The second side wall 4 of the diffuser 1 is in the in Figure 2 The illustrated embodiment of the diffuser 1 is part of a diffuser plate 12. The diffuser plate 12 comprises the individual pressure compensation openings 7, 7 'and the first ring channel 10, the first ring channel 10 being arranged behind the pressure compensation openings 7, 7'.

Figure 3 shows a top view of a diffuser 1. The diffuser 1 comprises a diffuser plate 12. The diffuser plate 12 comprises a number of pressure compensation openings 7, 7 ', each of which fluidly connects the flow cross sections of the diffuser 1 to a first ring channel 10. The first ring channel 10 is arranged behind the pressure compensation openings 7, 7 '. The first ring channel 10 is, as in the Figure 3 shown, designed as a so-called continuous annulus. The first ring channel 10 can, as already in the Figure 1 and the Figure 2 illustrated, either be integrated directly into the diffuser plate 12, or alternatively, can be incorporated into a separate wall, the separate wall being arranged behind the diffuser plate 12. Each of the pressure equalization openings 7, 7 'in Figure 3 The diffuser plate 12 shown is arranged between two adjacent blades 6, 6 '. Each of the blades 6, 6 ′ comprises a pressure side 22 and a suction side 23, the pressure side 22 and the suction side 23 of each blade 6, 6 ′ from a blade leading edge 8 and from a blade leading edge 8 'of this blade 6, 6' are limited. For example, the blade 6 ′ in FIG Figure 3 a blade leading edge 8 and a blade leading edge 8 ', which respectively limit the pressure side 22 and the suction side 23 of this blade 6'. Each of the number of pressure equalization openings 7, 7 'is arranged between the pressure side 22 of one blade 6 and the suction side 23 of the adjacent blade 6' of the blade ring 5. For example, the one in the Figure 3 arranged in the diffuser passage between the blade 6 and the blade 6 'pressure equalization opening 7 such that it is arranged between the pressure side 22 of the blade 6 and the suction side 23 of the adjacent blade 6' of the blade ring 5.

The individual pressure equalization openings 7, 7 'are in the Figure 3 formed as slots. Alternatively, the individual pressure compensation openings 7, 7 'can each be designed as a bore and / or slot. However, it would also be conceivable to provide a plurality of bores or slots, which then each form a pressure compensation opening 7, 7 '.

In the illustrated embodiment of the diffuser 1 Figure 3 the first ring channel 10 is divided by separating means 13 into a number of individual subchannel regions 11, 11 'which are separated from one another. In the embodiment shown, two diffuser passages are assigned to each of the sub-channel regions 11, 11 ′ of the first ring channel 10. However, it should be clarified that the pressure compensation openings 7, 7 'are not an integral part of the first ring channel 10. The subdivision of the first ring channel 10 into individual sub-channel areas ensures that pressure equalization takes place only between adjacent blades 6, 6 'of a sub-channel area 11, 11'. In this way, the pressure equalization between blades within a sub-channel area can be limited locally. So-called closed subchannel areas result from the individual subchannel areas. A pressure equalization takes place in the Figure 3 embodiment no longer takes place over the complete first ring channel 10, as is the case in the embodiments of FIG Figure 1 and the Figure 2 is the case with a continuous ring channel. The separating means 13 can be designed, for example, as partitions. The individual partition walls 13 are located on the side of the diffuser 1 facing away from the flow. The subdivision of the first ring channel 10 into individual subchannel regions that are independent of one another in terms of flow technology can contribute to increased stability and an improvement in the efficiency of the diffuser 1. The individual subchannel areas 11, 11 'within the first ring channel 10 can be produced, for example, by so-called additive manufacturing methods. Alternatively, it would also be possible to divide the first ring channel 10 into individual sub-channel regions 11, 11 'by abutment on an adjacent component, such as a bearing housing of the radial compressor 100 (not shown).

Figure 4 shows a top view of a further embodiment of the diffuser 1 according to the invention. Figure 4 shows the diffuser plate 12 of the diffuser 1. In the diffuser plate 12, a number of pressure compensation openings 7, 7 ', 7 "are incorporated, each of which fluidly connects the narrowest flow cross sections of the diffuser 1 with the ring channel 10, the first ring channel 10 behind the pressure compensation openings 7, 7 ', 7 "is arranged. The in the Figure 4 The illustrated embodiment of the diffuser 1 differs from that in FIG Figure 3 Embodiment shown in that each of the individual subchannel regions 11, 11 'comprises three pressure compensation openings 7, 7', 7 "with the three blades 6, 6 ', 6". For the sake of a better overview is in the Figure 4 only the partial channel region 11 of the first ring channel 10 is provided with corresponding reference numerals. As an alternative, designs can also be implemented in which, by appropriate separation, more than three blades divide a partial channel area of the first ring channel 10. It would also be conceivable that there are sub-channel areas within the first ring channel 10, each of which comprises a different number of blades, for example a sub-channel area which extends over two blades and a sub-channel area which comprises three blades. In the embodiment of the Figure 4 is also exemplified by the direction vector 52 of the main flow direction of the fluid in a diffuser passage, which is formed by the blade 6 and the blade 6 '.

Figure 5 shows a further embodiment of the diffuser 1 according to the invention with a diffuser plate 12 of the diffuser 1 in plan view. The diffuser plate 12 shown in this embodiment Figure 5 is in principle with that in the Figure 3 illustrated embodiment of the diffuser 1 identical. The embodiment of the Figure 5 differs from the embodiment of Figure 3 only in that in the diffuser plate 12 Figure 5 in addition to a first ring channel 10, a second ring channel 20 is provided. The second ring channel 20 in the diffuser plate 12 has the task of fluidly connecting the diffuser passages from non-adjacent blades. In the embodiment of the Figure 5 The ring channel 20 connects the blades of the partial channel area 11 with the blades of the partial channel area 11 ". In this way, pressure equalization can be realized between non-adjacent blades, which are each located in different partial channel areas of the diffuser plate 1. The second ring channel 20 can be in the diffuser plate 12 into which the first ring channel 10 is also worked in. Alternatively, the second ring channel 20 can be worked into a separate wall which is arranged behind the diffuser plate 12 if the diffuser plate 12 has pressure equalization openings of the side walls 3, 4 with pressure compensation openings 7, 7 'of the diffuser channel section 2 or in the third side wall 15, which is located behind one of the side walls 3, 4 with pressure compensation openings 7, 7'. In this way, for example, two diffuser passages can be fluidically mite inander connect, the two diffuser passages are not arranged directly next to each other and adjacent. Based on Figure 5 Illustrated, this means that, for example, a diffuser passage, which comprises the pressure compensation opening 7, is fluidly connected to a diffuser passage, which comprises the pressure compensation opening 7 ″. In this way, pressure compensation between blades or diffuser passages from non-adjacent subchannel regions can take place Application can also be incorporated in the diffuser 1 more than two ring channels.

Fig. 6 shows a section of a diffuser plate 12 with examples of possible alignments of pressure compensation openings in a diffuser passage between two adjacent blades 6, 6 '. The embodiment of the Figure 6 differs from the embodiments of FIG Figures 3 . 4 and 5 only in that the in Figure 6 pressure equalization openings 7-1 and 7-2 shown as examples within a diffuser passage of two adjacent diffuser blades 6, 6 'can each have different orientations with respect to the diffuser plate 12 or positions. Each of the blades 6, 6 'of the Figure 6 each comprises a pressure side 22 and a suction side 23. The pressure side 22 and the suction side 23 of each blade 6, 6 'are delimited by a blade leading edge 8 and a blade leading edge 8' of the respective blade 6, 6 '. In the Figure 6 the pressure compensation opening 7-1 located in the diffuser passage between the blade 6 and the blade 6 'is arranged or aligned such that, for example, the pressure compensation opening 7-1 between the pressure side 22 of the blade 6 and the suction side 23 of the adjacent blade 6' of the blade ring 5 is arranged. The same applies to the arrangement of the Figure 6 shown pressure equalization opening 7-2.

In the embodiment of the Figure 6 there is a pressure equalization opening in the diffuser passage between the mutually adjacent diffuser blades 6, 6 ′, that is to say either the pressure equalization opening 7-1 or the pressure equalization opening 7-2. However, it would also be possible for a plurality of pressure compensation openings to be arranged within a diffuser passage, the position and the position of the plurality of pressure compensation openings within the diffuser passage being able to differ from one another.

Fig. 7 shows an example of an orientation or a possible position of a pressure compensation opening 7, 7 'within a diffuser plate 12 and with respect to the main flow direction 52 of the fluid in the diffuser channel section 2. In the Figure 7 the diffuser channel section is formed by the side wall 3 and the side wall 4, the side wall 4 being a component of the diffuser plate 12. The pressure equalization opening 7, 7 'is in the embodiment of the Figure 7 incorporated in the diffuser plate 12 and is connected to the first ring channel 10. For illustration, see the Figure 7 additionally shows the direction of flow of the fluid in the diffuser channel section 2, which is represented by a vector 52. The orientation of the in the Figure 7 shown pressure equalization opening 7, 7 ', which is incorporated in the side wall 4 of the diffuser channel section 2, is determined by an angle of attack 54, which is defined as the angle of attack 54 of the pressure compensation opening 7, 7' to the surface of the side wall 4 facing the diffuser channel section 2. The angle of attack 54 in the embodiment of FIG Figure 7 can preferably be in a range between greater than 0 degrees and approximately less than 180 degrees in order to reduce fluid losses in the diffuser channel section 2.

Fig. 8 shows a schematic illustration of a turbocharger arrangement 150 with a bladed diffuser 2. In the embodiment of FIG Figure 8 The turbocharger arrangement 150 comprises a diffuser 2, which is fluidly connected to a first ring channel 10 via pressure compensation openings 7, 7 '(not shown). The diffuser 2 is connected to a compressor wheel 101, the compressor wheel 101 being driven by a turbine 151 via a shaft 153. The diffuser 2 and the compressor wheel 101 are components of a radial compressor 100. The first ring channel 10 is connected via a connecting channel 30 to a pressure plenum 31, which is also referred to as a ring channel plenum. A fluid is fed into the pressure plenum 31 as a flushing agent or as a flushing medium, which fluid is preferably designed as flushing air and which, however, can also or additionally be used for cooling. The fluid in the embodiment of the Figure 8 is provided by a fluid source 35. This fluid source 35, which can also be referred to as a pressure source, can preferably be designed as a charge air cooler. The charge air cooler is supplied with compressed air by the radial compressor 100 and cools the compressed air of the radial compressor 100 down to a certain temperature before it is supplied to an engine (not shown). The fluid from the charge air cooler, which is designed as a flushing agent, is then fed to the pressure plenum 31. The pressure plenum 31 is in the embodiment shown Figure 8 additionally connected to the compressor wheel 101 via a channel 154, so that part of the flushing agent from the charge air cooler 35 can also be used to cool the compressor wheel 101. In this way, compressor wheel cooling can be implemented. The first ring channel 10 is flushed with the flushing agent from the fluid source 35, the flushing agent being storable in the pressure plenum 31. The connecting channel 30 is preferably designed as a bore with a defined diameter. However, the connecting channel 30 does not necessarily have to be designed as a bore with a specific diameter D, but can also be designed as an angular or otherwise shaped passage. Alternatively, the connection channel 30 can also be formed from a number of individual passages. The geometric configuration of the connecting channel 30 is important in this respect, since it determines the pressure with which the detergent is passed through the connecting channel 30 into the first ring channel 10. The amount of pressure in the first ring channel 10 should be minimally higher than a pressure which is formed in the diffuser channel section 2, so that Intended pressure equalization in the first ring channel 10 is not impaired. In addition, it should be avoided that there is a massive blowout of air from the first ring channel 10 into the diffuser channel section 2. The geometric configuration of the connecting channel 30 thus allows the pressure with which the washing-up liquid in the connecting channel 30 is transported to the first ring channel 10 to be set. The flushing agent conveyed into the first ring channel 10 with a specific, set pressure ensures that the first ring channel 10 is flushed with flushing agent. The flushing prevents contamination of the first ring channel 10 and clogging of the pressure equalization openings 7, 7 ', 7 ", 7"''by deposits of oil-containing particles, such as the air from the diffuser channel section 2, so that the flushing medium with a defined pressure can be introduced into the first ring channel 10, a defined pressure should be formed in the fluid source 35 and in the pressure plenum 31, which is greater in amount than a pressure in the first ring channel 10 and a pressure in the diffuser 2. The pressure in the The amount of the fluid source 35 should be greater than a pressure in the pressure plenum 31 and a pressure in the ring channel 10 and a pressure in the diffuser channel section 2. The fluid source 35 can also be designed as a compressed air network, in which case the fluid source 35 can also consist of a plurality of fluid sources which provide fluid for the pressure plenum 31. Additionally, in the embodiment of the Figure 8 and Figure 9 a filter system 39 can be provided, which is installed between the pressure plenum 31 and the fluid source 35 in order to clean the detergent or fluid. In general, it can also be provided that the fluid from the fluid source 35 can be used to rinse a second ring channel in addition to the first ring channel 10 if a corresponding connection is established between the pressure plenum 31 and the second ring channel (not shown).

Fig. 9 shows a diffuser 2 with blading and pressure plenum 31 for a radial compressor. The embodiment of the Figure 9 differs from the embodiment of Figure 1 in that the first ring channel 10 is connected to a pressure plenum 31 via a connecting channel 30. As already for the embodiment of the Figure 8 explained, a fluid under pressure is introduced from the pressure plenum 31, which is connected to the fluid source 35, via the connecting channel 30 into the first ring channel 10. This has the effect that the first ring channel 10 is flushed with the flushing agent designed as a fluid from the fluid source 35 in order to loosen or close deposits and particle residues in the ring channel 10 and in the pressure compensation openings 7, 7 ', 7 ", 7"' prevent. Another difference from the embodiment of the Figure 1 consists in that a compressor wheel cooling for cooling the compressor wheel 101 is additionally realized by the fluid from the pressure plenum 31 being conducted via a connecting channel 154 to the compressor wheel 101.

LIST OF REFERENCES

1

diffuser

2

Diffuser duct section

3

First side wall

4

Second side wall

5

blade ring

6, 6 ', 6 ", 6' ''

Shovel of the shovel ring

7, 7 ', 7 ", 7' '', 7-1, 7-2

Pressure equalization port

8th

Blade leading edge of a blade

8th'

Blade leading edge of a blade

10

First ring channel

11, 11 ', 11 "

Subchannel area

12

diffuser plate

13

release agent

15

Side wall

20

Second ring channel

22

Pressure side of a diffuser blade

23

Intake side of a diffuser blade

30

connecting channel

31

Delivery plenum

35

fluid source

39

filter system

40

compressor

42

Compressor housing (turbine side)

44

bearing housing

52

Direction vector of the main flow direction of the fluid in the diffuser channel section

54

angle of attack

100

centrifugal compressors

101

compressor

150

turbocharger assembly

151

turbine

153

wave

154

Verdichterradkühlungleitung

Claims (14)

1. Diffuser for a radial compressor (100), comprising:

   a diffusor duct portion (2) which is formed by a first side wall (3) and a second side wall (4), wherein the first side wall (3) and the second side wall (4) are arranged so as to diverge at least partially from one another in the direction of flow,

   a blade ring (5) having a number of blades (6, 6'), wherein the blades (6, 6') are arranged at least partially in the diffusor duct portion (2), wherein each of the blades (6, 6') has a pressure side (22) and a suction side (23), and wherein the pressure side (22) and the suction side (23) of each blade (6, 6') are delimited by a blade leading edge (8) and by a blade trailing edge (8') of said blade (6, 6'),

   a number of pressure equalizing openings (7, 7') which are incorporated in at least one of the two side walls (3, 4) of the diffuser duct portion (2), wherein each of the number of pressure equalizing openings (7, 7') is arranged between the pressure side (22) of one blade (6) and the suction side (23) of the adjacent blade (6') of the blade ring (5),

   a first annular duct (10), which is arranged behind the pressure equalizing openings (7, 7'), wherein the first annular duct (10) is fluidically connected to the diffuser duct portion (2) via at least two of the pressure equalizing openings (7, 7'), with the result that a number of diffuser passages of the diffuser (1) are fluidically connectable together, wherein a region between two adjacent blades (6, 6') of the blade ring (5) in the diffuser duct portion (2) is denoted diffuser passage, and wherein the diffuser is characterized in that

   the number of pressure equalizing openings (7, 7') which are incorporated in at least one of the two side walls (3, 4) of the diffuser duct portion (2) are arranged in a region of the respective side wall (3, 4) in which the first side wall (3) and second side wall (4) are arranged so as to diverge at least partially from one another in the direction of flow.
2. Diffuser according to Claim 1, wherein the first annular duct (10) is incorporated in one of the two side walls (3, 4) of the diffuser duct portion (2).
3. Diffuser according to either of the preceding claims, wherein the pressure equalizing openings (7, 7') are each configured as a bore and/or as a slot.
4. Diffuser according to one of the preceding claims, wherein the orientation of each of the pressure equalizing openings (7, 7') in the respective side wall (3, 4) of the diffuser duct portion (2) is determined by a setting angle (54) which is defined as the setting angle (54) of the respective pressure equalizing opening (7, 7') to that face of this side wall (3, 4) that faces the diffuser duct portion (2).
5. Diffuser according to one of the preceding claims, wherein the first annular duct (10) is subdivided by separating means (13) into a number of individual, mutually separate duct subregions (11, 11') of the first annular duct (10).
6. Diffuser according to Claim 5, wherein each duct subregion (11, 11') of the first annular duct (10) comprises at least two pressure equalizing openings (7, 7').
7. Diffuser according to one of the preceding claims, wherein at least one second annular duct (20) is incorporated in one of the side walls (3, 4) with pressure equalizing openings (7, 7') of the diffuser duct portion (2), with the result that the diffuser passages of two nonadjacent blades (6, 6") of the blade ring (5) are fluidically connectable together.
8. Diffuser according to one of the preceding claims, wherein the first or second side wall (3, 4) of the diffuser duct portion (2) is configured as a diffuser plate (12), wherein the number of pressure equalizing openings (7, 7') and at least one annular duct (10, 20) are incorporated in the diffuser plate (12).
9. Diffuser according to Claim 1, wherein the first annular duct (10) is connectable to a pressure plenum (31) via a connecting duct (30), with the result that a fluid can flow from the pressure plenum (31) into the first annular duct (10) in order that the first annular duct (10) is flushed with the fluid.
10. Diffuser according to Claim 9, wherein the pressure plenum (31) is connected to a fluid source (35), wherein the fluid source (35) is configured to provide fluid for the pressure plenum (31).
11. Diffuser according to Claim 10, wherein the fluid source (35) is configured as a charge air cooler, wherein the charge air cooler is configured to provide fluid and wherein the fluid is introducible into the pressure plenum (31) from the charge air cooler.
12. Diffuser according to one of Claims 10 to 11, wherein a filter system (39) for cleaning the fluid is installed between the pressure plenum (31) and the fluid source (35).
13. radial compressor (100) having a diffuser (1) according to one of Claims 1 to 12.
14. Turbocharger arrangement (150) comprising a radial compressor according to Claim 13.

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