JP2013119801A - Supercharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercharger capable of avoiding such a problem that an air pressure supplied to an engine becomes too high.SOLUTION: A supercharger includes a turbine 11 to rotate a rotor with exhaust gas, and a compressor to compress the fluid after being taken in by rotation of the rotor, wherein the turbine 11 includes a turbine body 16 having stator blades 20 and rotor blades 21 and a diffuser 17 whereby the exhaust gas discharged from the turbine body 16 is exhausted upon recovery of the pressure. The diffuser 17 includes a separation means 31 to generate a separation in the flow of the exhaust gas having a swirling component in the opposite direction to the rotating direction of the rotor.

Description

  The present invention relates to a supercharger that supplies compressed air driven by exhaust gas guided from an internal combustion engine to the internal combustion engine.

  There is a supercharger that supplies compressed air to an air supply manifold that is attached to a marine diesel engine such as a low-speed two-cycle diesel engine and communicates with the inside of a cylinder liner (see, for example, Patent Document 1).

  By the way, it is desirable that the turbocharger used in the marine engine which is a diesel engine is highly efficient in order to send sufficient air to the engine in a state where the engine load is low and the turbine pressure ratio is low. In such a supercharger, when the load on the engine is high, the turbine pressure ratio is also high, so that a situation where the supply air pressure to the engine becomes too high is likely to occur. Therefore, a method of bypassing a part of the exhaust gas without passing through the turbine or a method of lowering the turbine pressure ratio by using the turbine nozzle as a variable mechanism may be used.

  However, the above method needs to control the valve and nozzle opening while monitoring the state quantity of the engine. Moreover, since it has a movable part, it becomes a factor of a cost increase or a reliability fall.

  As described above, there is a demand for a method of avoiding excessive engine supply air pressure on the turbine high pressure ratio side and high efficiency on the turbine low pressure ratio side without causing an increase in cost and a decrease in reliability. As a turbocharger that satisfies such a requirement and can significantly reduce the efficiency on the turbine high pressure ratio side, there is one having the shape of the stationary blade 101 and the moving blade 102 as shown in FIGS. 10 and 11.

  As shown in FIG. 10, the conventional turbocharger 100 has an absolute flow at the outlet of the turbine rotor blade in order to ensure performance on the turbine low pressure ratio side in the speed triangle composed of the absolute speed V1 and the relative speed V2. The stationary blade 101 and the moving blade 102 are selected so that is substantially in the axial flow direction. Here, it is generally known that a turbine has high performance under the same pressure ratio and the same flow rate condition under the condition that the rotor blade outlet flow is in the axial flow direction.

As shown in FIG. 11, the conventional turbocharger 100 performs the selection of the stationary blade 101 and the moving blade 102 as described above. It has a swirling flow in the direction opposite to the rotational direction.
In the conventional turbocharger 100, the turbine efficiency on the turbine high pressure ratio side is slightly reduced by the generation of the swirling flow as compared with the case of the axial outflow.

JP 2011-021497 A

  However, in the conventional supercharger 100, although the efficiency is lowered on the turbine high pressure ratio side due to the generation of the swirling flow, there is no effect to prevent the situation where the supply air pressure to the engine becomes too high.

  The present invention has been made to solve the above-described problems, and its purpose is to maintain the turbine efficiency as high as possible in a state where the turbine rotor blade outlet is substantially in the axial outflow, that is, in a state corresponding to engine low load. On the other hand, in a state where the turbine rotor blade outlet has a swirling flow opposite to the turbine rotation direction, that is, a state corresponding to a high engine load, it is possible to avoid the problem that the supply air pressure to the engine becomes too high. Is to provide a supercharger.

  A supercharger according to the present invention is a supercharger comprising: a turbine that rotationally drives a rotor with exhaust gas; and a compressor that compresses fluid sucked by the rotation of the rotor. A turbine body having blades and rotor blades, and a diffuser for recovering the pressure of exhaust gas exhausted from the turbine body and exhausting the diffuser, wherein the diffuser has a swirl component in a direction opposite to the rotational direction of the rotor. A stripping means for stripping the exhaust gas flow is provided.

  According to the above configuration, in the state where the turbine rotor blade outlet is almost in the axial outflow, that is, in the state corresponding to the engine low load, the turbine efficiency is maintained as high as possible, while the turbine rotor blade outlet is opposite to the turbine rotation direction. In a state where there is a swirl flow of the engine, that is, a state corresponding to a high engine load, the problem is that the supply air pressure to the engine becomes too high by causing separation at the diffuser at the turbine rotor blade outlet and greatly reducing the turbine efficiency. The effect that can be avoided.

  Moreover, the supercharger which concerns on this invention WHEREIN: It is preferable that the said peeling means is provided in the inner peripheral side of the said diffuser, and has the fin distribute | arranged along the axial direction.

  According to the said structure, peeling generate | occur | produces in the installation position of the fin inside a turbine blade exit diffuser, and can cause a significant turbine performance fall.

  Moreover, the supercharger which concerns on this invention WHEREIN: The said peeling means is good also as a guide means to guide the flow of the outer peripheral side of the said diffuser to a rotation direction reverse direction.

  According to the above configuration, in order to guide the flow on the outer peripheral side of the turbine rotor blade outlet diffuser in the direction opposite to the rotational direction, the guide means of the peeling means reliably peels the exhaust gas and causes a significant decrease in turbine performance. Can do.

  The guide means is preferably a hole that inclines in the direction opposite to the rotation direction from the inner peripheral side toward the outer peripheral side and discharges the flow to the outer peripheral side.

  According to the above configuration, since the guide means is a hole that inclines in the direction opposite to the rotation direction and discharges the flow to the outer peripheral side, it can be formed much more easily than when another member is additionally processed.

  The guide means may be a groove formed in a spiral shape in the direction opposite to the rotation direction from the inner peripheral side toward the outer peripheral side.

  According to the above configuration, when the exhaust gas flowing out from the turbine rotor blade has a swirling flow in the direction opposite to the turbine rotation direction, the exhaust gas actively enters the groove by its centrifugal force. The exhaust gas flows out toward the outlet of the turbine rotor blade outlet diffuser through the groove, causing a significant decrease in turbine performance and avoiding the problem that the supply air pressure to the engine becomes too high.

  The turbocharger according to the present invention maintains the turbine efficiency as high as possible in a state where the turbine rotor blade outlet is substantially in an axial outflow, that is, in a state corresponding to a low engine load. In a swirl flow in the direction opposite to the rotation direction, that is, in a state corresponding to a high engine load, the supply air pressure to the engine is greatly reduced by causing separation at the diffuser at the turbine rotor blade outlet to greatly reduce the turbine efficiency. This has the effect of avoiding problems that become too high.

It is a longitudinal cross-sectional view of the supercharger of 1st Embodiment which concerns on this invention. It is a longitudinal cross-sectional view around the diffuser of the supercharger of 1st Embodiment which concerns on this invention. It is the sectional view on the AA line of FIG. It is a longitudinal cross-sectional view around the diffuser of the supercharger of 2nd Embodiment which concerns on this invention. It is the BB sectional view taken on the line of FIG. It is a longitudinal cross-sectional view around the diffuser of the supercharger of 3rd Embodiment which concerns on this invention. It is the external appearance perspective view which looked at the inner surface of the flow guide from the exit side of the diffuser of FIG. It is a longitudinal cross-sectional view around the diffuser of the supercharger of 4th Embodiment which concerns on this invention. It is CC sectional view taken on the line of FIG. It is a typical sectional view of a moving blade and a stationary blade on the turbine low pressure ratio side of a conventional turbocharger. It is a typical sectional view of a moving blade and a stationary blade on the turbine high pressure ratio side of a conventional turbocharger.

Hereinafter, a plurality of superchargers according to embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the supercharger 10 of 1st Embodiment which concerns on this invention is comprised mainly from the turbine 11 and the compressor 12, and is mounted in marine diesel engines, such as a low speed 2 cycle diesel engine, for example. Has been.
The turbine 11 includes a turbine housing 13 having an exhaust gas inlet passage 14 and an exhaust gas outlet passage 15, and a turbine body 16. The turbine housing 13 has a turbine blade outlet diffuser (diffuser) 17, and the turbine blade outlet diffuser 17 has a flow guide 19 facing the hub-side casing wall 18.

The inlet passage 14 is connected to the downstream side of an exhaust manifold (not shown). The outlet passage 15 is connected to a pipe connected to the atmosphere such as a chimney (not shown).
The turbine 11 has a stationary blade 20 and a turbine blade 21 that is a moving blade in a turbine body 16. The stationary blade 20 is attached to a portion of the turbine housing 13 that communicates with the inlet passage 14 and the outlet passage 15.
The turbine rotor blade 21 is an axial flow type, and is attached to a portion communicating with the inlet passage 14 and the outlet passage 15 close to the stationary blade 20.
The turbine rotor blade 21 has a disk 22 integrally coupled to a compressor impeller 24 made of an aluminum alloy via a turbine rotor shaft 23.

The compressor 12 accommodates a compressor impeller 24 in a compressor housing 25 and has an impeller diffuser 26.
The compressor housing 25 has a working fluid inlet 27 and an outlet scroll 28, and the turbine rotor shaft 23 is rotatable by two radial bearings 29 and a thrust bearing 30 that receives an axial thrust load. I support it.

As shown in FIG. 2, the supercharger 10 is provided with a peeling means 31 on the flow guide 19 on the outer peripheral side of the turbine rotor blade outlet diffuser 17 in the turbine 11.
The peeling means 31 has a plurality of gas peeling through holes 32 as guide means, and these gas peeling through holes 32 communicate with the inside of the turbine rotor blade outlet diffuser 17 and the outside of the flow guide 19 on the outer peripheral side. Yes. The gas peeling through hole 32 can be formed by a drill or the like.
As shown in FIG. 3, the gas separation through-hole 32 has an outer periphery from the inner peripheral side in order to smoothly receive the flow when the swirling flow opposite to the turbine rotational direction D flows out of the turbine rotor blade 21. It is inclined toward the side by an angle θ1 with respect to the radial direction.

Next, the operation of the supercharger 10 will be described.
When the marine diesel engine is driven, positive pressure exhaust gas flows through the exhaust manifold, and the exhaust gas passes through the inlet passage 14 and is statically expanded by the stationary blade 20 to generate an axial exhaust gas flow. .
Then, the turbine rotor blade 21 is rotationally driven by the exhaust gas flow, and the exhaust gas that has driven the turbine rotor blade 21 is discharged to the outside from the outlet passage 15.
The rotation of the turbine blade 21 rotates the compressor impeller 24 through the turbine rotor shaft 23, and the air sucked through the working fluid inlet 27 of the compressor housing 25 is pressurized by the compressor impeller 24. .
The air pressurized by the compressor impeller 24 is supplied into the intake manifold of the marine diesel engine through the impeller diffuser 26 and the outlet scroll 28.

At this time, when the engine is in a low load state, the outflow flow from the turbine rotor blade 21 is substantially in the axial direction. The exhaust gas only leaks into the turbine rotor blade outlet diffuser 17 and does not significantly affect the performance.
On the other hand, when the engine is in a high load state, the outflow flow of the exhaust gas from the turbine rotor blade 21 has a swirling flow opposite to the turbine rotation direction D, so that the gas separation through hole 32 has an inlet inside the flow guide 19. In the portion, the dynamic pressure at the inlet of the gas separation through-hole 32 increases due to the swirl component of the flow.
Therefore, an exhaust gas flow from the inner side of the flow guide 19 toward the outer side of the flow guide 19 is generated as the dynamic pressure at the inlet of the gas separation through hole 32 increases.
Thereby, the flow of the exhaust gas inside the turbine rotor blade outlet diffuser 17 is drawn toward the flow guide 19 side, and the exhaust gas is discharged to the outer peripheral side through the gas separation through hole 32.
Accordingly, the turbine rotor blade outlet diffuser 17 separates the exhaust gas on the hub-side casing wall 18 side, thereby greatly suppressing the turbine performance.
That is, the supercharger 10 maintains the efficiency of the turbine 11 as high as possible when the engine is under a low load, while actively causing separation at the turbine blade outlet diffuser 17 when the engine is under a high load. The efficiency of the turbine 11 can be suppressed.

As described above, according to the turbocharger 10 of the first embodiment, the efficiency of the turbine 11 is maintained as high as possible in a state where the turbine rotor blade outlet is substantially in the axial outflow, that is, a state corresponding to a low engine load. To do.
Further, according to the supercharger 10, in a state where the turbine blade outlet is in a swirling flow opposite to the turbine rotation direction D, that is, in a state corresponding to a high engine load, the turbine blade outlet diffuser 17 at the turbine blade outlet. The peeling means 31 causes peeling.
And according to the supercharger 10, when the peeling means 31 peels in the turbine blade exit diffuser 17 of a turbine blade exit, the efficiency of the turbine 11 is suppressed.
Therefore, according to the supercharger 10, the problem that the supply air pressure to the engine becomes too high can be avoided.

  Further, according to the supercharger 10, the gas separation through-hole 32 of the separation means 31 reliably separates the exhaust gas in order to guide the flow on the outer peripheral side of the turbine rotor blade outlet diffuser 17 in the reverse direction of the rotation direction. Turbine performance can be suppressed.

  And according to the supercharger 10, since the gas peeling through-hole 32 is a hole which inclines in the reverse direction of the rotation direction and discharges the flow to the outer peripheral side, it is far more than the case where additional members are additionally processed. Can be easily formed.

(Second Embodiment)
Next, a supercharger according to a second embodiment of the present invention will be described.
In the following embodiments, components that are the same as those in the first embodiment described above or components that are functionally similar are denoted by the same or corresponding reference numerals in the drawings, and the description thereof is simplified or omitted. To do.

As shown in FIG. 4, the supercharger 40 according to the second embodiment of the present invention is provided with a peeling means 41 in the flow guide 19 on the outer peripheral side of the turbine rotor blade outlet diffuser 17.
The peeling means 41 has a plurality of through slits 42 which are guide means, and these through slits 42 communicate with the inside of the turbine rotor blade outlet diffuser 17 and the outside of the flow guide 19 on the outer peripheral side.
As shown in FIG. 5, the through slit 42 extends from the inner peripheral side to the outer peripheral side in order to smoothly receive the flow when the swirling flow opposite to the turbine rotation direction D flows out of the turbine rotor blade 21. Inclined toward the radial direction by an angle θ2.

Next, the operation of the supercharger 40 will be described.
When the engine is in a low load state, the outflow flow from the turbine rotor blade 21 is substantially in the axial direction, so the through slit 42 hardly functions or a small amount of exhaust gas is generated from the outside of the flow guide 19 in the turbine motion. It only leaks into the blade outlet diffuser 17 and does not significantly affect the performance.
On the other hand, when the engine is in a high load state, the outflow flow of the exhaust gas from the turbine rotor blades 21 has a swirling flow opposite to the turbine rotation direction D, and thus the passage flow rate of the through slit 42 increases.
Therefore, as the dynamic pressure at the inlet of the through slit 42 increases, an exhaust gas flow from the inside of the flow guide 19 toward the outside of the flow guide 19 is generated.
As a result, the flow of the exhaust gas inside the turbine rotor blade outlet diffuser 17 is drawn toward the flow guide 19 side, and the exhaust gas is discharged to the outer peripheral side through the through slit 42.
Therefore, the turbine rotor blade outlet diffuser 17 separates the exhaust gas on the hub side casing wall 18 side to suppress the turbine performance.
That is, the supercharger 10 maintains the efficiency of the turbine 11 as high as possible when the engine is under a low load, while actively causing separation at the turbine blade outlet diffuser 17 when the engine is under a high load. The efficiency of the turbine 11 can be suppressed.

According to the supercharger 40 of the second embodiment, the efficiency of the turbine 11 is maintained as high as possible when the guide means engine is in a low load state, while separation occurs in the turbine blade outlet diffuser 17 when the engine is in a high load state. Is actively generated to greatly reduce the efficiency of the turbine 11.
Therefore, according to the supercharger 40, the problem that the supply air pressure to the engine becomes too high can be avoided.

(Third embodiment)
Next, a supercharger according to a third embodiment of the present invention will be described.
As shown in FIG. 6, the supercharger 50 according to the third embodiment of the present invention is provided with a peeling means 51 in the flow guide 19 on the outer peripheral side of the turbine rotor blade outlet diffuser 17.
The peeling means 51 has a plurality of grooves 52 which are guide means formed in a spiral shape opposite to the rotation direction around the turbine rotor blade 21 in the flow direction of the inner peripheral surface of the flow guide 19.
FIG. 7 is a developed view of the flow guide 19 in FIG. 6 in the circumferential direction. The groove 52 has an inclination angle θ3 in the range of 10 degrees to 30 degrees with respect to the axial direction E, and has a predetermined length dimension and depth dimension.

Next, the operation of the supercharger 50 will be described.
When the outflow flow from the turbine rotor blade 21 is substantially in the axial direction, the groove 52 hardly functions or a small amount of exhaust gas flows backward from the outlet side of the flow guide 19 toward the turbine rotor blade along the groove. This will not affect the performance.
On the other hand, when the exhaust gas outlet flow from the turbine rotor blade 21 has a swirling flow opposite to the turbine rotation direction D, the exhaust gas actively enters the groove 52 by its centrifugal force, It flows out toward the outlet of the blade outlet diffuser 17.
Thereby, the flow of the exhaust gas inside the turbine blade outlet diffuser 17 is drawn toward the flow guide 19 side.
Therefore, the turbine rotor blade outlet diffuser 17 separates the exhaust gas on the hub-side casing wall 18 side, causing a significant decrease in turbine performance.

According to the supercharger 50 of the third embodiment, when the outflow flow of the exhaust gas from the turbine rotor blade 21 has a swirling flow opposite to the turbine rotation direction D, the exhaust gas is positively generated by its centrifugal force. Thus, it enters the groove 52.
Then, according to the supercharger 50, the exhaust gas flows out toward the outlet of the turbine blade outlet diffuser 17 through the groove 52, and the flow of the exhaust gas inside the turbine blade outlet diffuser 17 is directed to the flow guide 19 side. Draw.
Therefore, according to the supercharger 50, the turbine rotor blade outlet diffuser 17 peels off the exhaust gas on the hub side casing wall 18 side, causing a significant decrease in turbine performance, and the supply air pressure to the engine becomes too high. Can be avoided.

(Fourth embodiment)
Next, a supercharger according to a fourth embodiment of the present invention will be described.
As shown in FIG. 8, the turbocharger 60 of the fourth embodiment according to the present invention is provided with a peeling means 61 on the hub-side casing wall 18 of the turbine rotor blade outlet diffuser 17.
The peeling means 61 has a plurality of fins 62 that are guide means along the axial direction.
As shown in FIG. 9, the fin 62 has a height dimension L1 in a range of 1/10 to 1/2 of the height dimension of the turbine rotor blade 21, and has a predetermined length dimension and thickness dimension. .

Next, the operation of the supercharger 60 will be described.
When the engine is in a low load state, the outflow flow from the turbine rotor blades 21 is substantially in the axial direction, so the fins 62 hardly function and do not greatly affect the performance.
On the other hand, when the engine is in a high load state, the exhaust gas outflow flow from the turbine rotor blade 21 has a swirl flow opposite to the turbine rotation direction D, and therefore has an angle of attack with respect to the fins 62. The flow collides.
Therefore, separation occurs at the installation position of the fin 62 inside the turbine rotor blade outlet diffuser 17 to suppress the turbine performance.

According to the turbocharger 60 of the fourth embodiment, when the outflow flow of the exhaust gas from the turbine blade 21 has a swirling flow opposite to the turbine rotation direction D, the angle of attack with respect to the fins 62 is provided. The currents collide.
According to the supercharger 60, separation occurs at the installation position of the fins 62 inside the turbine rotor blade outlet diffuser 17, which causes a significant decrease in turbine performance.
Therefore, according to the supercharger 60, the turbine rotor blade outlet diffuser 17 peels off the exhaust gas on the hub side casing wall 18 side to suppress the turbine performance, and the problem that the supply air pressure to the engine becomes too high can be avoided. .

  In addition, the supercharger of this invention is not limited to each embodiment mentioned above, A suitable deformation | transformation, improvement, etc. are possible.

As described above, according to the supercharger of the present invention, the problem that the supply air pressure to the engine becomes too high can be avoided.
As a result, the efficiency of marine diesel engines such as diesel engines can be improved. It can be said that the industrial applicability of the present invention is great.

DESCRIPTION OF SYMBOLS 10 Supercharger 11 Turbine 12 Compressor 16 Turbine main body 17 Turbine blade exit diffuser (diffuser)
20 Stator blade 21 Turbine blade (roof blade)
23 Turbine rotor shaft (rotor)
31 Peeling means 32 Gas peeling through hole (hole) (guide means)
40 Supercharger 41 Peeling means 42 Through slit (guide means)
50 Supercharger 51 Peeling means 52 Groove (guide means)
60 Supercharger 61 Peeling means 62 Fin (guide means)

Claims (5)

A turbine that rotationally drives the rotor with exhaust gas;
A compressor that compresses fluid sucked by rotation of the rotor, and a supercharger comprising:
The turbine includes a turbine body having a stationary blade and a moving blade;
A diffuser for recovering the pressure of the exhaust gas discharged from the turbine body and exhausting it,
The turbocharger according to claim 1, wherein the diffuser includes a separation unit that causes separation in a flow of exhaust gas having a swirling component in a direction opposite to a rotation direction of the rotor.   2. The supercharger according to claim 1, wherein the peeling unit includes fins provided on an inner peripheral side of the diffuser and arranged along an axial direction. 3.   3. The supercharger according to claim 1, wherein the peeling unit includes a guide unit that guides the flow on the outer peripheral side of the diffuser in the direction opposite to the rotation direction. 4.   The said guide means is a hole which inclines in the rotation direction reverse direction from the inner peripheral side to the outer peripheral side and discharges the flow to the outer peripheral side. The turbocharger described in the paragraph.   4. The supercharger according to claim 3, wherein the guide means is a groove formed in a spiral shape in the direction opposite to the rotation direction from the inner peripheral side toward the outer peripheral side.

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