The present invention relates to a rotary machine single-suction intake device.
In the related art, in most cases, a centrifugal compressor adopts a single-suction intake device. In addition, an axial compressor such as a gas turbine also adopts the single-suction intake device.
The air which flows from the suction port 101a is introduced through the upstream duct 101 in a direction approximately orthogonal to a rotational axis RL, and the shape of the suction port 101a and the shape of the outlet portion 101b are approximately the same as each other (widths W and depths D on the suction port 101a side and the outlet portion 101b side are approximately constant).
In addition, the intake duct body section 102 is provided so as to surround a rotating shaft (not shown) on an outside in a radial direction of the rotating shaft, and includes a tubular channel 102a (hereinafter, referred to as a compressor-side channel) which is formed along an outer periphery of the rotating shaft on the compressor side.
Here, in the rotary machine single-suction intake device such as the centrifugal compressor or the axial compressor in the related art, when air is suctioned, although there is a difference in degree, there is always a difference between a flow speed on a forward direction side (a range indicated by A in
For example, in the case of the centrifugal compressor, as shown in
In addition, in the case of the axial compressor, as shown in
That is, since flows of air in the inlet of the compressor are asymmetrical due to effects of rotation of a rotor blade or an IGV inlet angle, as shown in
Since the flow distortion generates a peripheral direction distribution in the inlet of the rotary machine, there is a problem that variation in performance of the rotary machine occurs in the peripheral direction of the rotating shaft.
With respect to the problem, in PTL 1 below, a restriction member which covers an air intake port and partially blocks an air flow around the air intake port is provided to obtain a uniform air flow distribution over the entire air intake port. Moreover, PTL 2 below discloses a fluid machine in which a fitting part is attached to a cavity portion of a suction casing to uniformly introduce a fluid in a peripheral direction.
However, in the inventions disclosed in PTLs 1 and 2, there is a problem that separate members are required to be added.
From the above-described problem, an object of the present invention is to provide a rotary machine single-suction intake device in which asymmetry between the flow speed of a fluid flowing in a forward direction relative to a rotational direction of a rotating shaft of a compressor and a flow speed of a fluid flowing in an opposite direction relative thereto can be reduced using a simpler configuration.
In order to achieve the object, according to a first invention, there is provided a rotary machine single-suction intake device which includes an upstream side casing having a suction port opening in a direction which intersects a rotational axis of a rotary machine and a downstream side casing which is connected to the upstream side casing and through which a fluid passing through the inside of the upstream side casing is introduced to the rotary machine, in which a channel cross-sectional area on a forward direction side relative to a rotational direction of a rotating shaft is different from a channel cross-sectional area on an opposite direction side relative thereto so as to equalize a flow speed distribution of a fluid passing through the forward direction side relative to the rotational direction of the rotating shaft and a flow speed distribution of a fluid passing through the opposite direction side, according to a flow distortion trend of the fluid passing through the inside of the downstream side casing.
In addition, in the rotary machine single-suction intake device according to a second invention, in the rotary machine single-suction intake device according to the first invention, widths of the suction port on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft are different from each other.
Moreover, in the rotary machine single-suction intake device according to a third invention, in the rotary machine single-suction intake device according to the first invention, the downstream side casing includes a tubular channel which is formed on the rotary machine side, and channel cross-sectional areas of an inlet-side opening portion of the channel on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft are different from each other.
In addition, in the rotary machine single-suction intake device according to a fourth invention, in the rotary machine single-suction intake device according to the first invention, depths of the suction port on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft are different from each other.
According to the rotary machine single-suction intake device of the present invention, it is possible to reduce asymmetry between the flow speed of the fluid flowing in the forward direction relative to the rotational direction of the rotating shaft of the compressor and the flow speed of the fluid flowing in the opposite direction relative thereto using a simple configuration.
Hereinafter, an embodiment of a rotary machine single-suction intake device according to the present invention will be described.
The rotary machine single-suction intake device according to the present embodiment is a rotary machine single-suction intake device which includes an upstream side casing having a suction port opening in a direction which intersects a rotational axis of a rotary machine and a downstream side casing which is connected to the upstream side casing and through which a fluid passing through the inside of the upstream side casing is introduced to the rotary machine, and distributions in intake flow rates are biased to a forward direction side and an opposite direction side relative to a rotational direction of a rotating shaft by a single-suction intake device positioned on the upstream side of the rotary machine. Accordingly, effects of flow distortions generated by the rotation of the rotating shaft are cancelled off, and it is possible to obtain a uniform flow speed distribution in a peripheral direction in an inlet portion of the rotary machine.
A ratio of the intake flow rates between the forward direction side and the opposite direction side can be realized by changing a channel cross-sectional area of the single-suction intake device on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft.
Here, (density)×(speed)×(cross-sectional area)=constant is satisfied according to a flow conservation law, and since a speed is low in a case of a suction casing, the density ρ is approximately constant, and there is an inverse proportional relationship between the speed and the cross-sectional area.
For example, in an example of a flow speed distribution in a single-suction intake device which is applied to an axial compressor of the related art shown in
In order to average the flow rates, if the ratio between the channel cross-sectional area on the forward direction side and the channel cross-sectional area on the opposite direction side is set to 96:104 so as to be an inverse number of the flow speed ratio, the flow distortion is alleviated, and a vertically symmetrical flow is achieved.
Hereinafter, a specific example of the rotary machine single-suction intake device according to the present invention will be described in detail according to Examples. In addition, the present invention is not limited to the following Examples, and various modifications may be applied within a scope which does not depart from the gist of the present invention.
A rotary machine single-suction intake device according to Example 1 of the present invention will be described with reference to
As shown in
The rotary machine single-suction intake device according to the present Example adopts an upstream duct (upstream side casing) 111 shown in
As shown in
More specifically, while a depth at an end portion on a forward direction side (a side which is positioned further forward than the center in the width direction W) A relative to the rotational direction of the rotating shaft 50 is the length D, a depth at an end portion on an opposite direction side (in the present Example, a side which is positioned further backward than the center in the width direction W) B relative to the rotational direction of the rotating shaft is a length D+d (d>0) and is longer than the depth at the end portion on the forward direction side A. In short, in the present Example, the suction port 111a has a trapezoidal shape in which the end portion on the forward direction side A is a short side and the end portion on the opposite direction side B is a long side, and the channel cross-sectional areas on the forward direction side A and the opposite direction side B are different from each other.
Here, as shown in
For example, if the ratio between the flow speed distribution on the forward direction side and the flow speed distribution on the opposite direction side shown in
That is, the length d is represented by the following Expression (1) from SA:SB=(2D+3d/2)×W/4:(2D+d/2)×W/4=96:104.
d≈0.17D (1)
In order to set the ratio SA:SB between the area SA of the trapezoid of the forward direction side A and the area SB of the trapezoid on the opposite direction side B to 96:104, the length d may be approximately 17% of the depth D of the end portion on the forward direction side A.
According to the intake duct of the rotary machine according to the above-described present Example, since the shape of the suction port 111a is set such that the channel cross-sectional area SB on the opposite direction side B is larger than the channel cross-sectional area SA of the forward direction side A, an inflow speed of air on the opposite direction side B in the suction port 111a of the upstream duct 111 can be accelerated as shown in
Moreover, in the present Example, as shown in
Moreover, in the shape of the suction port 101a of the upstream duct 101, all surfaces may be flat surfaces as shown in
In addition, in the present Example, the example is shown in which the length d is set such that the ratio between the area SA of the trapezoid on the forward direction side A and the area SB of the trapezoid on the opposite direction side B satisfies SA:SB=96:104. However, the ratio SA SB between the area SA of the trapezoid on the forward direction side A and the area SB of the trapezoid on the opposite direction side B may be appropriately set according to the flow rate distribution of the rotary machine single-suction intake device which is applied to the present invention.
In addition, in the present Example, the example is shown in which the length d≈0.17D is satisfied. However, the length d may be any length as long as the length d is within a range of 0<d<0.35D
Moreover, in the present Example, the example is shown in which the present invention is applied to the axial compressor of the gas turbine. However, it is needless to say that the present invention can be also applied to a centrifugal compressor. This is similarly applied to the following Examples 2 and 3.
A rotary machine single-suction intake device according to Example 2 of the present invention will be described with reference to
The rotary machine single-suction intake device according to the present Example adopts an intake duct body section (downstream side casing) 112 shown in
As shown in
More specifically, while the channel inner diameter-side wall surface 112b has a shape (a perfect circular shape having a radius RA in a sectional view) similar to the shape of the related art on the forward direction side A, an upstream side of the compressor-side channel 112a on the opposite direction side B has an elliptical arc shape in a sectional view (an elliptical arc shape in which a long diameter in a sectional view is the length RA which is the same as that of the related art and a short diameter is the length RB (RB<RA)), a downstream side (inlet side of the compressor 30) of the compressor-side channel 112a has a perfect circular shape in a sectional view similarity to the related art, and the channel cross-sectional areas on the upstream side of the compressor-side channel 112a on the forward direction side A and the opposite direction side B are different from each other.
Here, a size relation between the channel cross-sectional areas on the forward direction side A and the opposite direction side B of the compressor-side channel 112a on the upstream side of the compressor-side channel 112a is set according to the flow speed distribution of the intake duct of the related art. That is, SA:SB=b:a is satisfied such that the ratio SA SB between the channel cross-sectional area SA on the forward direction side A and the channel cross-sectional area SB on the opposite direction side B becomes an inverse number of the ratio a:b between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in
For example, if the ratio between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in
That is, in a case where RA is 0.70R, the length RB is represented by the following Expression (2) from SA:SB=π(R2−RA2):π(R2−RARB)=96:104.
RB≈0.92RA (2)
Accordingly, in the case where RA is 0.70R, in order to set the ratio SA:SB between the channel cross-sectional area SA on the forward direction side A and the channel cross-sectional area SB on the opposite direction side B to 96:104, the short diameter RB of the channel inner diameter-side wall surface 112b on the opposite direction side B may be approximately 92% of the radius (the long diameter of the channel inner diameter-side wall surface 112b on the opposite direction side B) RA on the forward direction side A.
According to the intake duct of the rotary machine according to the above-described present Example, in the upstream side of the compressor-side channel 112a, since the channel cross-sectional area SB on the opposite direction side B of the compressor-side channel 112a is larger than the channel cross-sectional area SA on the forward direction side A, similarly to the above-described Example 1, the inflow speed of the air on the opposite direction side B can be accelerated, and as shown in
Moreover, in the present Example, the example is shown in which the diameter of the channel inner diameter-side wall surface 112b on the opposite direction side B is larger than that of the related art. However, the present invention is not limited to the above-described Example, and for example, the diameter of the channel outer diameter-side wall surface 112c on the forward direction side A may be larger than that of the related art, or the diameter of the channel inner diameter-side wall surface 112b on the opposite direction side B may be larger than that of the related art and the diameter of the channel outer diameter-side wall surface 112c on the forward direction side A may be larger than that of the related art.
Moreover, the present Example may be combined with the above-described Example 1.
In addition, in the present Example, the example is shown in which the short diameter RB is set such that the ratio between the channel cross-sectional area SA on the forward direction side A and the channel cross-sectional area SB on the opposite direction side B satisfies SA:SB=96:104. However, the ratio SA:SB between the area SA of the trapezoid on the forward direction side A and the area SB of the trapezoid on the opposite direction side B may be appropriately set according to the flow rate distribution of the rotary machine single-suction intake device which is applied to the present invention.
In addition, in the present Example, the example is shown in which the ratio between the long diameter RA and the short diameter RB of the channel inner diameter-side wall surface 112b on the opposite direction side B satisfies RB/RA≈0.92. However, the ratio between the long diameter RA and the short diameter RB may be any ratio as long as it is within a range of 0.8≤RB/RA<1.
A rotary machine single-suction intake device according to Example 3 of the present invention will be described with reference to
The rotary machine single-suction intake device according to the present Example adopts an upstream duct (upstream side casing) 121 shown in
As shown in
More specifically, in the suction port 121a side, in the shape on the forward direction side A of the upstream duct 121, a width WA on the side A which is positioned further forward than a center W0 (hereinafter, referred to as a center W0 in a width direction) of the outlet portion 121b in the width direction and a width WB on the side B which is positioned further backward than the center W0 in the width direction are different from each other, and the channel cross-sectional areas on the forward direction side A and the opposite direction side B are different from each other.
Here, in the present Example, the size relation between the width WA of the suction port 121a on the side A which is positioned further forward than the center W0 in the width direction and the width WB of the suction port 121a on the side B which is positioned further backward than the center W0 in the width direction is set according to the flow speed distribution of the intake duct of the related art. That is, WA:WB=b:a is satisfied such that the ratio WA:WB between the width WA of the suction port 121a on the forward direction side A and the width WB of the suction port 121a on the opposite direction side B becomes an inverse number of the ratio a:b between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in
For example, if the ratio between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in
That is, the width WA is represented by the following Expression (3).
WA≈0.92WB (3)
Accordingly, the width WA of the suction port 121a on the forward direction side A may be approximately 92% of the width WB of the suction port 121a on the opposite direction side B.
In addition, as shown in
Even in this case, the size relation between the width WA of the suction port 131a on the side A which is positioned further forward than the center W0 in the width direction and the width WB of the suction port 131a on the side B which is positioned further backward than the center W0 in the width direction is set according to the flow speed distribution of the intake duct of the related art.
For example, if the ratio between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in
That is, the width WB is represented by the following Expression (4).
WB≈1.08WA (4)
Accordingly, in the example shown in
According to the intake duct of the rotary machine according to the above-described present Example, in the suction port 121a or the suction port 131a, the channel cross-sectional area SB on the opposite direction side B is larger than the channel cross-sectional area SA on the forward direction side A and the intake flow rate on the opposite direction side B is greater than the intake flow rate on the forward direction side A. Accordingly, the inflow speed of the air on the opposite direction side B can be accelerated, and as shown in
Moreover, in the present Example, the example is shown in which the widths are set such that the ratio between the width WA of the suction port 121a on the forward direction side A and the width WB of the suction port 121a on the opposite direction side B satisfies WA:WB=96:104. However, the ratio between the width WA of the suction port 121a on the forward direction side A and the width WB of the suction port 121a on the opposite direction side B may be appropriately set according to the flow rate distribution of the rotary machine single-suction intake device to which the present invention is applied.
For example, in the present Example, the example is shown in which the width WA≈0.92WB is satisfied. However, in a case where it is assumed that the maximum difference between the flow speed distribution on the forward direction side and the flow speed distribution on the opposite direction side shown in
The present invention is appropriately applied to a rotary machine single-suction intake device.
Number | Date | Country | Kind |
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2014-250614 | Dec 2014 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/066658 | 6/10/2015 | WO | 00 |