Centrifugal compressor and turbocharger
阅读说明:本技术 离心压缩机及涡轮增压器 (Centrifugal compressor and turbocharger ) 是由 岩切健一郎 藤田豊 林良洋 于 2018-07-06 设计创作,主要内容包括:离心压缩机具备:叶轮;压缩机入口管,其将空气向叶轮引导;涡旋流路,其设置于叶轮的外周侧;旁通流路,其从涡旋流路经由分支口分支,绕过叶轮与压缩机入口管连接;旁通阀,其可开闭设置于旁通流路的阀口,分支口在沿着经过分支口的中心的分支口的法线N1观察时具有非圆形形状。(The centrifugal compressor comprises: an impeller; a compressor inlet duct that guides air toward the impeller; a scroll flow path provided on an outer peripheral side of the impeller; a bypass flow path that branches from the scroll flow path through a branch port and is connected to the compressor inlet pipe while bypassing the impeller; and a bypass valve which can open and close a valve port provided in the bypass flow path, wherein the branch port has a non-circular shape when viewed along a normal N1 to the branch port passing through the center of the branch port.)
1. A centrifugal compressor is provided with:
an impeller;
a compressor inlet duct that directs air toward the impeller;
a scroll flow path provided on an outer peripheral side of the impeller;
a bypass flow path that branches from the scroll flow path via a branch port and is connected to the compressor inlet pipe while bypassing the impeller;
a bypass valve that opens and closes a valve port provided in the bypass flow path;
the branch portal has a non-circular shape when viewed along a normal N1 of the branch portal passing through a center of the branch portal.
2. The centrifugal compressor of claim 1,
when a flow path cross section including the center of the branch port in the scroll flow path is denoted by G, a dimension T of the branch port in a flow direction F orthogonal to the flow path cross section G is smaller than a dimension L of the branch port in a direction H orthogonal to the flow direction F and the normal N1, respectively.
3. The centrifugal compressor according to claim 1 or 2,
the length of the branch port is larger than the caliber of the valve port, and the width of the branch port is smaller than the caliber of the valve port.
4. A centrifugal compressor according to any one of claims 1 to 3,
when the opening area of the valve port is set to S1 and the opening area of the branch port is set to S2,
satisfies 0.8S1 ≦ S2 ≦ 1.2S 1.
5. The centrifugal compressor according to any one of claims 1 to 4,
a width Te of the branch port at an end portion of the branch port in the radial direction of the impeller is smaller than a width Tc of the branch port at a central portion of the branch port in the radial direction of the impeller.
6. The centrifugal compressor according to any one of claims 1 to 5,
the center of the branch port is offset to the inside in the radial direction of the impeller with respect to the center of the valve port.
7. The centrifugal compressor according to any one of claims 1 to 6,
the longitudinal direction of the branch port is orthogonal to the flow direction orthogonal to the flow path cross section of the scroll flow path.
8. The centrifugal compressor according to any one of claims 1 to 7,
in a flow path cross section G including the center of the branch port of the scroll flow path, a vector representing the center position of the branch port with respect to the center position of the flow path cross section G is defined as P,
When a vector representing a flow direction perpendicular to the flow path section G is denoted by Q, an outer product of the vector P and the vector Q is denoted by R (═ P × Q), and a vector parallel to the longitudinal direction of the branch port is denoted by V,
one of an inner product V.R of the vector V and the vector R and an inner product V.Q of the vector V and the vector Q has a positive value, and the other has a negative value.
9. A turbocharger provided with:
the centrifugal compressor of any one of claims 1 to 8, and a turbine sharing a rotational axis with an impeller of the centrifugal compressor.
Technical Field
The present disclosure relates to a centrifugal compressor and a turbocharger.
Background
In a centrifugal compressor for a turbocharger, a bypass valve (also referred to as a bleed valve or a recirculation valve) may be provided at an outlet of the centrifugal compressor in order to avoid an excessive increase in discharge pressure of the compressor. In this configuration, when the discharge pressure of the compressor is excessive, the bypass valve is opened, and the discharge air of the compressor is returned to the inlet side of the compressor via the bypass flow path.
On the other hand, the provision of such a bypass flow path also leads to an increase in pressure loss. As shown in fig. 24, although a circulating flow is formed in the bypass flow passage by shearing with the main flow, when almost no flow flows from the main flow into the bypass flow passage, pressure loss hardly occurs. On the other hand, as shown in fig. 25 and 26, when a large amount of the flow from the main flow flows into the bypass flow path, the flow flowing into the bypass flow path may be swirled and may flow out to the main flow again. At this time, the swirling flow flowing out interferes with the main flow to generate a large pressure loss as shown in fig. 25. In this case, the compressor efficiency may be significantly reduced (sometimes 5% or more).
Disclosure of Invention
Problems to be solved by the invention
In order to solve such a problem of an increase in pressure loss, patent document 1 proposes forming a surface of a valve body of a bypass valve in a shape along an inner wall of a scroll passage of a compressor. With this configuration, an increase in pressure loss due to the flow flowing into the bypass flow path can be suppressed.
However, since general-purpose products are often used for the valve, the surface of the valve body needs to be formed into a special shape along the inner wall of the pipe using a special-purpose product, which increases the cost.
At least one embodiment of the present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a centrifugal compressor and a turbocharger capable of suppressing an increase in pressure loss while suppressing complication of the shape of a valve body of a bypass valve.
Means for solving the problems
(1) A control device according to at least one embodiment of the present invention includes:
an impeller;
a compressor inlet duct that directs air toward the impeller;
a scroll flow path provided on an outer peripheral side of the impeller;
a bypass flow path that branches from the scroll flow path via a branch port and is connected to the compressor inlet pipe while bypassing the impeller;
a bypass valve that opens and closes a valve port provided in the bypass flow path;
the branch port has a non-circular shape when viewed along a normal N1 of the branch port passing through a center of the branch port.
According to the configuration described in (1) above, by using the branch port having the noncircular shape when viewed along the normal line of the branch port, the flow entering the bypass flow path can be prevented from forming a vortex, as compared with the configuration of the related art using the branch port having the circular shape. This can suppress an increase in pressure loss caused by the vortex flow flowing out from the bypass flow passage to the vortex flow passage.
Further, as in the configuration described in patent document 1, even if the surface of the valve body of the bypass valve is not formed into a shape along the inner wall of the pipe, an increase in pressure loss can be suppressed. Therefore, the shape of the valve body of the bypass valve can be prevented from being complicated, and an increase in the pressure loss can be prevented while suppressing an increase in the cost.
In the configuration described in patent document 1, if the valve body of the bypass valve is provided along the inner wall of the scroll flow path, a space for installing the valve body and a space for moving the valve body are required to be provided at a position close to the scroll flow path in the bypass flow path, and a restriction is easily imposed on the layout of the bypass flow path that needs to be connected to the inlet of the compressor.
In contrast, according to the configuration of the above (1), since an increase in pressure loss can be suppressed without providing the valve body of the bypass valve along the inner wall of the scroll flow path, it is not necessary to provide a space for the valve body to move in the vicinity of the scroll flow path in the bypass flow path, and the degree of freedom in layout of the bypass flow path connected to the inlet of the compressor can be improved.
(2) In some embodiments, in the control device according to the above (1),
when a flow path cross section of the scroll flow path including the center of the branch port is denoted by G, a dimension T of the branch port in a flow direction F orthogonal to the flow path cross section G is smaller than a dimension L of the branch port in the flow direction F and a direction H orthogonal to the normal N1, respectively.
According to the control device described in the above (2), since the distance required for the flow of the scroll passage to pass through the branch port is shortened by making the dimension T smaller than the dimension L, the entrance of the flow into the bypass passage can be reduced. In addition, the flow entering the bypass flow path can be effectively prevented from forming a vortex.
(3) In some embodiments, in the control device according to the above (1) or (2),
the length of the branch port is larger than the caliber of the valve port, and the width of the branch port is smaller than the caliber of the valve port.
According to the control device described in the above (3), the flow entering the bypass flow path is effectively blocked from swirling, and an appropriate bypass flow rate at which the flow is bypassed by opening the bypass valve can be easily secured.
(4) In some embodiments, in the control device of any one of (1) to (3) above,
when the opening area of the valve port is set to S1 and the opening area of the branch port is set to S2,
satisfies 0.8S1 ≦ S2 ≦ 1.2S 1.
The opening area of the branch port is preferably small from the viewpoint of reducing the pressure loss associated with the installation of the bypass flow path as much as possible, but if the opening area of the branch port is too small, a sufficient bypass flow rate may not be secured when the bypass valve is opened to bypass the flow. In contrast, as described in (4) above, by making the opening area S2 of the branch port equal to the opening area S1 of the valve port so as to satisfy 0.8S1 ≦ S2 ≦ 1.2S1, it is possible to suppress the generation of swirl in the bypass flow path while securing a required bypass flow rate.
(5) In some embodiments, in the control device of any one of (1) to (4) above,
a width Te of the branch port at an end portion of the branch port in the radial direction of the impeller is smaller than a width Tc of the branch port at a central portion of the branch port in the radial direction of the impeller.
According to the control device described in the above (5), the diffuser outlet flow flowing out from the diffuser of the centrifugal compressor to the scroll flow path is made to flow easily along the inner wall surface of the scroll flow path, which is the outer side in the radial direction of the impeller. Therefore, it is desirable to reduce the width Te of the end portion from the viewpoint of suppressing the inflow of the diffuser outlet flow to the branch port from the end portion on the outer side in the radial direction of the impeller where the diffuser outlet flow easily flows into the branch port. On the other hand, since the bypass flow path must be eventually smoothly connected to the circular shape of the valve port, the width of the center portion of the branch port needs to be increased to some extent. Therefore, as described above, by making the width Te of the outer end portion smaller than the width Tc of the central portion, the bypass flow path can be smoothly connected to the valve port while suppressing the inflow of the diffuser outlet to the branch port.
(6) In some embodiments, in the control device of any one of (1) to (5) above,
the center of the branch port is offset to the inside in the radial direction of the impeller with respect to the center of the valve port.
As described above, the diffuser outlet flow easily flows into the radially outer end portion of the impeller of the branch port. Therefore, as described in (6) above, by offsetting the center of the branch port inward in the radial direction of the impeller with respect to the center of the valve port, the diffuser exit flow flows along the inner wall surface of the scroll flow path and it becomes difficult to flow from the branch port into the bypass flow path, and an increase in pressure loss can be suppressed.
(7) In some embodiments, in the control device of any one of (1) to (6) above,
the longitudinal direction of the branch port is orthogonal to the flow direction orthogonal to the flow path cross section of the scroll flow path.
According to the control device described in (7) above, the distance required for the flow of the scroll flow path to pass through the branch port is shortened, and therefore, the flow can be prevented from entering the bypass flow path. In addition, the flow entering the bypass flow path can be effectively prevented from forming a vortex.
(8) In some embodiments, in the control device of any one of (1) to (7) above,
in a flow path cross section G including the center of the branch port of the scroll flow path, a vector representing the center position of the branch port with respect to the center position of the flow path cross section G is represented by P, a vector representing a flow direction orthogonal to the flow path cross section G is represented by Q, an outer product of the vector P and the vector Q is represented by R (═ P × Q), and a vector parallel to the longitudinal direction of the branch port is represented by V,
one of an inner product V.R of the vector V and the vector R and an inner product V.Q of the vector V and the vector Q has a positive value, and the other has a negative value.
According to the control device described in (8) above, the angle formed by the flow direction of the swirling flow of the scroll passage and the longitudinal direction of the branch port at the position of the branch port can be increased as compared with the case where both the inner products V · E and V · Q of the branch port have positive values and the case where both the inner products V · E and V · Q have negative values, and therefore, the inflow of the swirling flows of the branch port and the scroll passage into the branch port can be effectively suppressed.
(9) A turbocharger according to at least one embodiment of the present invention includes:
the centrifugal compressor according to any one of (1) to (8) above, wherein the turbine shares a rotation shaft with an impeller of the centrifugal compressor.
The control device according to the above (9), which is provided with the centrifugal compressor according to any one of the above (1) to (8), can suppress an increase in pressure loss while suppressing an increase in cost by suppressing complication of the shape of the valve body of the bypass valve.
Effects of the invention
According to at least one embodiment of the present invention, there are provided a centrifugal compressor and a turbocharger capable of suppressing increase in pressure loss while suppressing complication of the shape of a valve body of a bypass valve.
Drawings
Fig. 1 is a partial sectional view showing a schematic structure of a turbocharger 2 according to an embodiment.
Fig. 2 is a partially enlarged view of the centrifugal compressor 4 shown in fig. 1.
Fig. 3A is a perspective view schematically showing the shape of the
Fig. 3B is a diagram showing the shape of the
Fig. 3C is a diagram for explaining the flow direction F of the
Fig. 4A is a perspective view schematically showing the shape of a branch port 20c according to the related art.
Fig. 4B is a diagram showing the shape of the branch port 20c and the shape of the
Fig. 5 is a diagram for explaining the shape of the
Fig. 6 is a diagram showing another example of the shape of the
Fig. 7 is a diagram showing another example of the shape of the
Fig. 8 is a diagram showing another example of the shape of the
Fig. 9 is a diagram for explaining the diffuser outlet flow D.
Fig. 10 is a diagram showing another example of the shape of the
Fig. 11 is a diagram showing another example of the shape of the
Fig. 12 is a diagram showing another example of the shape of the
Fig. 13 is a diagram showing another example of the shape of the
Fig. 14 is a diagram showing another example of the shape of the
Fig. 15 is a diagram for explaining an effect obtained by shifting the center O1 of the
Fig. 16 is a diagram for explaining the definition of a vector used in the explanation of some embodiments.
Fig. 17 is a diagram showing the shape of the
Fig. 18 is a diagram showing the shape of the
Fig. 19 is a diagram showing the shape of the
Fig. 20 is a diagram showing the shape of the
Fig. 21 is a diagram showing the shape of the
Fig. 22 is a diagram showing the shape of the
Fig. 23 is a diagram showing the shape of the
Fig. 24 is a diagram showing a circulation flow in the bypass flow path along with the inflow of the flow from the spiral flow path to the bypass flow path.
Fig. 25 is a diagram for explaining a state in which a swirl flow flowing out from the bypass flow path interferes with the main flow to cause pressure loss.
Fig. 26 is a diagram for explaining a state in which a swirl flow flowing out from the bypass flow path interferes with the main flow to cause pressure loss.
Detailed Description
Hereinafter, some embodiments of the present invention will be described with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention to these, and are merely illustrative examples.
For example, the expressions indicating relative or absolute arrangements such as "a certain direction", "along a certain direction", "parallel", "orthogonal", "central", "concentric" or "coaxial" indicate not only arrangements in a strict sense but also states of relative displacement with a tolerance or an angle and a distance to the extent that the same function can be obtained.
For example, the expressions indicating "the same", "equal", and "uniform" are equivalent to each other, and not only are the expressions indicating the equivalent to each other strictly, but also the expressions indicating the difference in tolerance or the degree of obtaining the same function.
For example, the expression "a shape such as a square shape or a cylindrical shape" means not only a shape such as a square shape or a cylindrical shape in a strict geometrical sense but also a shape including a concave-convex portion, a chamfered portion, and the like within a range in which the same effect can be obtained.
On the other hand, the expression "having", "equipped", "provided", "including", or "containing" is not an exclusive expression that excludes the presence of other constituent elements.
Fig. 1 is a partial sectional view showing a schematic structure of a turbocharger 2 according to an embodiment. Fig. 2 is a partially enlarged view of the centrifugal compressor 4 shown in fig. 1.
As shown in fig. 1, the turbocharger 2 includes: a centrifugal compressor 4; a turbine 12 comprising a turbine rotor 10 sharing a rotation axis 8 with the
The centrifugal compressor 4 includes: an
Fig. 3A is a perspective view schematically showing the shape of the
In some embodiments, for example as shown in fig. 3B, the
Thus, by using the
In the configuration described in patent document 1, if the valve body of the bypass valve is provided along the inner wall of the scroll flow path, it is necessary to provide an installation space of the valve body and a space in which the valve body moves at a position close to the scroll flow path in the bypass flow path, and restrictions are likely to be imposed on the layout of the bypass flow path connected to the inlet of the compressor.
In contrast, according to the configuration of the above embodiment, since an increase in pressure loss can be suppressed without providing the valve body 24 of the bypass valve 18 along the inner wall of the
Fig. 5 is a diagram for explaining the shape of the
In some embodiments, as shown in fig. 5 to 8, for example, the
By making the dimension T smaller than the dimension L in this way, the distance required for the flow of the
In some embodiments, as shown in fig. 5 to 8, for example, the length of the branch port 20 (dimension L in direction H in the illustrated exemplary embodiment) is greater than the aperture R of the
This effectively prevents the flow entering the
In some embodiments, for example, as shown in fig. 3A, when the opening area of the
The opening area of the
In some embodiments, for example, as shown in fig. 5 to 7, the width Te of the
As shown in fig. 9, the diffuser outlet flow D flowing out from the
In some embodiments, for example as shown in fig. 8, the width T of the
According to this configuration, the increase in pressure loss associated with the installation of the
In some embodiments, for example as shown in fig. 5-8, the length direction of the
According to this configuration, the distance required for the flow of the
In the embodiments shown in fig. 5 to 8, the configuration in which the center O1 of the
In some embodiments, for example as shown in fig. 10-14, the center O1 of the
The
As described with reference to fig. 9, the diffuser outlet flow D easily flows into the
Next, other embodiments will be described. The actual flow flowing through the
Fig. 16 is a diagram for explaining definitions of vectors used in the following description of the respective embodiments. First, as shown in fig. 16, in a flow path cross section G including the center O1 of the
Fig. 17 is a diagram showing the shape of the
In some embodiments, for example, as shown in fig. 17-21, the
According to this configuration, compared to a case where the
In the embodiment in which the
In the embodiment shown in fig. 17 to 21, the embodiment in which the center O1 of the
The present invention is not limited to the above-described embodiments, and includes embodiments in which modifications are added to the above-described embodiments and embodiments in which these embodiments are appropriately combined.
For example, the shape of the
Description of the reference numerals
2 turbo charger
4 centrifugal compressor
6 impeller
8 rotating shaft
10 turbine rotor
12 turbine
14 swirl flow path
16 bypass flow path
18 bypass valve
19 actuator
20 branch port
22 valve port
24 valve core
25 seat surface
26 end of the tube
28 center part
30 diffuser
32 inner wall surface
34 outer end
36 inner end
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