WO2024051608A1

WO2024051608A1 - Gas suction pipe of centrifugal compressor

Info

Publication number: WO2024051608A1
Application number: PCT/CN2023/116564
Authority: WO
Inventors: 汪洪丹; 苏秀平; 马小魁
Original assignee: 江森自控空调冷冻设备(无锡)有限公司; 江森自控泰科知识产权控股有限责任合伙公司
Priority date: 2022-09-05
Filing date: 2023-09-01
Publication date: 2024-03-14
Also published as: CN115419616A

Abstract

A gas suction pipe of a centrifugal compressor. A centrifugal compressor (120) is provided with a gas suction port (125), and the gas suction port (125) has a central axis; a gas suction pipe (150) introduces a fluid from an upstream component into the centrifugal compressor (120), and the fluid enters the gas suction pipe (150) in a direction substantially perpendicular to the central axis of the gas suction port (125). The gas suction pipe (150) comprises an imaginary middle cross-section, a downstream interface (226) connected to the centrifugal compressor (120), and an upstream interface (228) connected to the upstream component; the central axis of the gas suction port (125) of the centrifugal compressor (120) is located on the middle cross-section, and the gas suction pipe (150) has a shape of being symmetrical with respect to the middle cross-section; the inner contour of the downstream interface (226) is circular and the downstream interface (226) is connected to the gas suction port (125), and the inner contour of the upstream interface (228) comprises a first direction maximum spanning size D₁ located on the middle cross-section and a second direction maximum spanning size D₂ perpendicular to the middle cross-section, wherein D₁ is greater than D₂.

Description

Suction pipe of centrifugal compressor

Technical field

The present application relates to a suction pipe of a centrifugal compressor, and in particular to a suction pipe of a refrigeration centrifugal compressor mainly used in large chillers.

Background technique

The refrigeration centrifugal compressor used in large chillers rotates the refrigerant gas coming out of the evaporator through the high-speed rotation of the impeller in the centrifugal compressor, so that the refrigerant gas acquires high speed and is then transported to the condenser so that the refrigerant Perform refrigeration cycle. The elbow-shaped suction pipe of the centrifugal compressor connects the evaporator to the impeller of the centrifugal compressor, so that the refrigerant gas coming out of the evaporator enters the evaporator through the suction pipe. Since the suction pipe is curved, the flow direction of the refrigerant gas will be deflected when it enters the suction pipe from the evaporator and reaches the impeller of the centrifugal compressor. There is a pressure loss in the suction pipe of the prior art centrifugal compressor, thereby affecting the performance of the compressor.

Contents of the invention

According to a first aspect of the application, the application provides a suction pipe of a centrifugal compressor. The centrifugal compressor has a suction port. The suction port has a central axis. The suction pipe will come from upstream. The fluid of the component is introduced into the centrifugal compressor, and the fluid enters the suction pipe in a direction substantially perpendicular to the central axis of the suction port. The suction pipe includes an imaginary middle section, a downstream interface connected to the centrifugal compressor, and an upstream interface connected to the upstream component. The central axis of the suction port of the centrifugal compressor is located on the middle section, and the suction pipe has a symmetrical shape relative to the middle section. The inner contour of the downstream interface is circular and connected to the suction port. The inner contour of the upstream interface includes a first direction maximum span dimension D ₁ located on the mid-section, and includes a second direction maximum span dimension D ₂ perpendicular to the mid-section, wherein the first direction is the largest The span size D ₁ is larger than the maximum span size D ₂ in the second direction.

According to the suction pipe of the centrifugal compressor of the first aspect, the upstream member is cylindrical with an axis parallel to the central axis of the suction port and has a diameter D ₀ . The maximum spanning dimension D ₁ in the first direction and the maximum spanning dimension D ₂ in the second direction of the inner contour of the upstream interface satisfy: 0.55<D ₁ /D ₀ <0.7, D ₂ <0.5×D ₁ . The radius R ₆ of the inner contour of the downstream interface satisfies: 0.43<R _6max /D ₁ <0.57.

According to the suction pipe of the centrifugal compressor of the above-mentioned first aspect, the suction pipe has a centerline located on the middle section. The center line is a spline curve, and the center line satisfies the following formula: Among them, V ₁ , V ₂ , V ₃ , and V ₄ satisfy the following relationships: -7e7<V ₁ <-6e7,1100<V ₂ <1300,-2950<V ₃ <-2750,250<V ₄ <270.

According to the suction pipe of the centrifugal compressor of the first aspect, the suction pipe includes an inlet section, an outlet section and a transition section. The upstream interface is the end face of the inlet section. The inlet section includes a connection part and a guide part. The connection part connects the suction pipe to the upstream component. The inner contour of the guide part and the guide part are The connection line of the inner contour of the connecting portion intersects with the middle section at the inner intersection point and the outer intersection point. The downstream interface is the end face of the outlet section. The transition section connects the inlet section to the outlet section. The suction pipe includes a first cross-section passing through the inner and outer intersections and perpendicular to the middle section. Between the first cross section and the downstream interface, the cross section of the inner profile of the suction pipe at least on the inlet section and the transition section is an ellipse with the long axis located on the middle section. shape.

According to the suction pipe of the centrifugal compressor of the above first aspect, between the first cross section and the downstream interface, the cross section of the inner contour of the inlet section and the outlet section of the suction pipe is oriented toward the gradually decreases in the direction of the downstream interface.

According to the suction pipe of the centrifugal compressor of the first aspect, the cross-section of the inner contour of the transition section of the suction pipe first gradually increases and then gradually decreases in the direction toward the downstream interface.

According to the suction pipe of the centrifugal compressor of the first aspect, the part of the suction pipe between the first cross section and the downstream interface is equally divided into five parts along the center line into four cross sections respectively. are the second cross-section, the third cross-section, the fourth cross-section and the fifth cross-section, wherein the fourth cross-section is the largest cross-section of the transition section. The angle α ₆ between the downstream interface and the first cross section satisfies: 80° ≤ _{α 6} ≤ 90°. The major axis radius R _1max and the minor axis radius R _1min of the first cross section respectively satisfy: R _1max =0.5×D ₁ , 0.9<R _1min /R _1max <0.95. The angle α ₂ between the second cross section and the first cross section and the major axis radius R _2max and the minor axis radius R _2min of the second cross section respectively satisfy: 0.1<α ₂ /α ₆ <0.15, 0.68<R _2max /D ₁ <0.78, 0.92<R _2min /R _2max <0.98. The angle α ₃ between the third cross section and the first cross section and the major axis radius R _3max and the minor axis radius R _3min of the third cross section respectively satisfy: 0.25<α ₃ /α ₆ <0.38, 0.6<R _3max /D ₁ <0.76, 0.8<R _3min /R _3max <0.9. The angle α ₄ between the fourth cross section and the first cross section and the major axis radius R _4max and the minor axis radius R _4min of the fourth cross section respectively satisfy: 0.45<α ₄ /α ₆ <0.6, 0.6<R _4max /D ₁ <0.74, 0.84<R _4min /R _4max <0.92. The angle α ₅ between the fifth cross section and the first cross section and the major axis radius R _5max and the minor axis radius R _5min of the fifth cross section respectively satisfy: 0.7<α ₅ /α ₆ <0.8, 0.45<R _5max /D ₁ <0.6, 0.98<R _5min /R _5max <1.05.

According to the suction pipe of the centrifugal compressor of the above first aspect, the cross section of the suction pipe in the transition section gradually decreases in the direction toward the downstream interface.

According to the suction pipe of the centrifugal compressor of the first aspect, the part of the suction pipe between the first cross section and the downstream interface is equally divided into five parts along the center line into four cross sections respectively. are the second cross-section, the third cross-section, the fourth cross-section and the fifth cross-section, wherein the fourth cross-section is the largest cross-section of the transition section. The angle α ₁₆ between the downstream interface and the first cross section satisfies: 80° ≤ α ₁₆ ≤ 90°. The major axis radius R _11min and the minor axis radius R _12min of the first cross section respectively satisfy: R11max=0.5×D ₁₁ , 0.9<R11min/R11max<0.95. The angle α ₁₂ between the second cross section and the first cross section and the major axis radius R12max and the minor axis radius R12min of the second cross section respectively satisfy: 0.1<α ₁₂ /α ₁₆ <0.15, 0.68<R12max/D11<0.78,0.92<R12min/R12max<0.98. The angle α ₁₃ between the third cross section and the first cross section and the major axis radius R13max and the minor axis radius R13min of the third cross section respectively satisfy: 0.25<α ₁₃ /α ₁₆ <0.38, 0.55<R13max/D11<0.7,0.8<R13min/R13max<0.9. The angle α14 between the fourth cross section and the first cross section and the major axis radius R14max and the minor axis radius R14min of the fourth cross section respectively satisfy: 0.45<α ₁₄ /α ₁₆ <0.6, 0.5<R14max /D11<0.6, 0.9<R14min/R14max<0.95. The angle α ₁₅ between the fifth cross section and the first cross section and the major axis radius R15max and the minor axis radius R15min of the fifth cross section respectively satisfy: 0.7<α ₁₅ /α ₁₆ <0.8, 0.45< R _15max /D ₁₁ <0.6, 0.98 <R _15min /R _15max <1.05.

According to a second aspect of the application, the application provides a centrifugal compressor, which includes the suction pipe according to the above-mentioned first aspect.

Description of the drawings

Figure 1A is a perspective view of a chiller using the suction pipe of the centrifugal compressor of the present application;

Figure 1B is a simplified left schematic diagram of the chiller shown in Figure 1A;

Figure 2A is a front perspective view of the first embodiment of the suction pipe of the centrifugal compressor of the present application;

Figure 2B is a rear perspective view of the suction pipe of the centrifugal compressor shown in Figure 2A;

Figure 2C is a front view of the inner profile of the suction pipe of the centrifugal compressor shown in Figure 2A;

Figure 2D is a left view of the inner profile of the suction pipe of the centrifugal compressor shown in Figure 2A;

Figure 2E is a schematic diagram of the first cross-section in Figure 2D;

Figure 2F is a schematic diagram of the second cross-section in Figure 2D;

Figure 2G is a schematic diagram of the third cross-section in Figure 2D;

Figure 2H is a schematic diagram of the fourth cross-section in Figure 2D;

Figure 2I is a schematic diagram of the fifth cross-section in Figure 2D;

Figure 2J is a schematic diagram of the inner outline of the downstream interface of the suction pipe for the centrifugal compressor shown in Figure 2A;

Figure 3A is a schematic diagram showing the fluid flow state of the suction pipe of a comparative example when in use;

Figure 3B is a schematic diagram showing the fluid flow state of the first embodiment of the suction pipe for a centrifugal compressor of the present application in use;

Figure 3C shows a velocity vector diagram in the suction pipe obtained by using the CFD method for the suction pipe of the comparative example shown in Figure 3A;

Figure 3D shows the velocity vector diagram in the suction pipe obtained by using the CFD method for the suction pipe of the present application shown in Figure 3B;

Figure 3E shows a velocity vector diagram at the downstream interface of the suction pipe obtained by using the CFD method for the suction pipe of the comparative example shown in Figure 3A;

Figure 3F shows the velocity vector diagram at the downstream interface of the suction pipe obtained by using the CFD method for the suction pipe of the present application shown in Figure 3B;

Figure 3G shows the vortex intensity diagram at the downstream interface of the suction pipe obtained by using the CFD method for the suction pipe of the comparative example shown in Figure 3A;

Figure 3H shows the vortex intensity diagram at the downstream interface of the suction pipe obtained by using the CFD method for the suction pipe of the present application shown in Figure 3B;

Figure 4A is a front perspective view of the second embodiment of the suction pipe of the centrifugal compressor of the present application;

Figure 4B is a rear perspective view of the second embodiment of the suction pipe of the centrifugal compressor of the present application;

Figure 4C is a front view of the inner profile of the second embodiment of the suction pipe of the centrifugal compressor of the present application;

Figure 4D is a left view of the inner profile of the second embodiment of the suction pipe of the centrifugal compressor of the present application;

Figure 4E is a schematic diagram of the first cross-section in Figure 4D;

Figure 4F is a schematic diagram of the second cross-section in Figure 4D;

Figure 4G is a schematic diagram of the third cross-section in Figure 4D;

Figure 4H is a schematic diagram of the fourth cross-section in Figure 4D;

Figure 4I is a schematic diagram of the fifth cross-section in Figure 4D;

Figure 4J is a schematic diagram of the inner outline of the downstream interface of the suction pipe of the centrifugal compressor shown in Figure 4A.

Detailed ways

Various embodiments of the present application will be described below with reference to the accompanying drawings, which constitute a part of this specification. It should be understood that although terms referring to directions are used throughout this application, such as "front," "back," "upper," "lower," "left," "right," etc., to describe various example structural portions of the present application. and elements, but these terms are used herein for convenience of description only and are determined based on the example orientations shown in the drawings. Since the embodiments disclosed in the present application can be arranged in different directions, these terms indicating directions are for illustration only and should not be regarded as limiting.

The present application provides an improved suction pipe of a centrifugal compressor, which reduces the pressure loss of fluid in the suction pipe by changing the shape of the suction pipe.

1A and 1B show the overall structure of a chiller 100 using the suction pipe of the centrifugal compressor of the present application, wherein FIG. 1A is a perspective view of the chiller 100 and FIG. 1B is a simplified left view of the chiller 100 Schematic diagram. As shown in Figures 1A and 1B, the chiller 100 includes an evaporator 110, a centrifugal compressor 120, a condenser 130 and a throttling device (not shown in the figure) forming a refrigeration cycle. The centrifugal compressor 120 has a suction port 125, and the suction port 125 has a central axis X1. The evaporator 110 includes a substantially cylindrical body, the axis X2 of which is parallel to the central axis X1 of the suction port 125 of the centrifugal compressor 120, and the diameter of which is D ₀ . The chiller 100 also includes a suction pipe 150 connecting the evaporator 110 and the centrifugal compressor 120 . Evaporator 110 is an upstream component of centrifugal compressor 120 .

The refrigeration cycle of the chiller 100 includes four processes: compression process, condensation process, throttling process and evaporation process. During the compression process, the refrigerant gas coming out of the evaporator 110 first obtains a high speed through the high-speed rotation of the impeller of the centrifugal compressor 120, and then becomes high-temperature and high-pressure through the expansion and deceleration of the diffuser and the volute. Refrigerant gas. During the condensation process, the high-temperature and high-pressure refrigerant gas from the centrifugal compressor 120 enters the condenser 130 for condensation. The high-temperature and high-pressure refrigerant exchanges heat with the relatively low-temperature cooling water flowing through the condenser 130 and is condensed into liquid. During the throttling process, the high-pressure normal-temperature refrigerant liquid coming out of the condenser 130 passes through a throttling device (such as a throttling orifice plate) and becomes a low-temperature and low-pressure refrigerant liquid. During the evaporation process, the low-temperature and low-pressure refrigerant liquid coming out of the throttling device enters the evaporator 110. And performs heat exchange with the cooling water in the evaporator 110, so that the low-temperature and low-pressure refrigerant liquid evaporates into a normal-temperature and normal-pressure refrigerant gas. The suction pipe 150 introduces the refrigerant gas coming out of the evaporator 110 into the centrifugal compressor 120. During this process, since the axes of the evaporator 110 and the centrifugal compressor 120 are parallel to each other, the refrigerant needs to be changed through the suction pipe 150. According to the flow direction of the gas, the suction pipe 150 is generally in the shape of a curved tube. More specifically, the refrigerant gas coming out of the evaporator 110 enters the suction pipe 150 in a direction generally perpendicular to the axis of the compressor 120, and the refrigerant gas coming out of the suction pipe 150 needs to pass along the direction of the compressor. 120 axial direction into the compressor. Therefore, the suction pipe 150 deflects the flow direction of the air flow by approximately 90°.

Figures 2A-2J show the suction pipe 150 of the centrifugal compressor according to the first embodiment of the present application, wherein Figure 2A is a front perspective view of the suction pipe 150, and Figure 2B is a rear perspective view of the suction pipe 150 , Figure 2C is a front view of the inner profile of the suction pipe 150, Figure 2D is a left view of the inner profile of the suction pipe 150, Figures 2E-2I are schematic views of the first to fifth cross sections in Figure 2D, Figure 2J is a schematic diagram of the inner contour of the downstream interface of the suction pipe 150 . As shown in Figures 2A-2C, the suction pipe 150 has an imaginary middle section 250, which is coplanar with the axis of the centrifugal compressor, that is, the axis of the centrifugal compressor is located on the middle section 250. The suction pipe 150 has a tubular structure that is symmetrical with respect to the mid-section 250 .

As still shown in FIGS. 2A-2C , the suction pipe 150 generally includes three parts connected in sequence, an inlet section 211 , a transition section 212 and an outlet section 213 . The inlet section 211 connects the suction pipe 150 and the evaporator 110, the outlet section 213 connects the suction pipe 150 and the compressor 120, and the transition section 212 connects the inlet section 211 and the outlet section 213. The refrigerant gas coming out of the evaporator 110 enters the inlet section 211 in a direction generally perpendicular to the central axis X1 of the suction port 125 of the compressor 120 and generally along the central axis X1 of the suction port 125 of the compressor 120 The direction of X1 enters the compressor 120 from the outlet section 213. Therefore, the flow direction of the refrigerant gas in the suction pipe 150 is substantially deflected by 90°. Among them, although the flow direction of the refrigerant gas is slightly deflected in the inlet section 211 and the outlet section 213, the deflection of the flow direction mainly occurs in the transition section 212. The end surface of the outlet section 213 connected to the suction port 125 of the compressor 120 is a downstream interface 226, which is generally annular and matches the shape of the suction port 125 of the compressor 120. Therefore, the inner contour of the downstream interface 226 is circular. The end surface connecting the inlet section 211 and the evaporator 110 is the upstream interface 228 .

The inlet section 211 includes an interconnected connecting portion 241 and a guiding portion 242. The guiding portion 242 is located downstream of the connecting portion 241. The connecting portion 241 is used to achieve a mechanical connection between the suction pipe 150 and the evaporator 110. The upstream interface 228 is formed by a connection 241 which forms the starting point of the fluid guide channel. It can be seen from FIGS. 2A-2D that the upstream part of the inlet section 211 (including a part of the connecting part 241 and the guide part 242 ) is in the shape of lugs located on opposite sides of the middle section 250 to connect with the cylindrical evaporator 110 to match the top. Therefore, the upstream interface 228 assumes an undulating shape.

Specifically, the inner contour of the upstream interface 228 includes an upstream inside endpoint 231 , an upstream outside endpoint 232 , an upstream left endpoint 233 and an upstream right endpoint 234 . The upstream inner endpoint 231 and the upstream outer endpoint 232 are located on the middle section 250, while the upstream left endpoint 233 and the upstream right endpoint 234 are respectively located on opposite sides of the middle section 250. In the direction perpendicular to the axis X2 of the evaporator 110 , the upstream inner endpoint 231 and the upstream outer endpoint 232 are located above the upstream left endpoint 233 and the upstream right endpoint 234 . The upstream inner endpoint 231 and the upstream outer endpoint 232 will be in contact with the top end of the cylindrical evaporator 110, while the upstream left endpoint 233 and the upstream right endpoint 234 will be in contact with the two opposite ends of the top end of the cylindrical evaporator 110. side junction.

On the inner contour of the intake pipe 150 , the connecting line between the guide portion 242 and the connecting portion 241 has a shape parallel to the upstream interface 228 . The connecting line between the guide portion 242 and the connecting portion 241 intersects the middle section 250 at the inner intersection point 245 and the outer intersection point 246 .

The distance between the upstream inner endpoint 231 and the upstream outer endpoint 232 is D ₁ , and the distance between the upstream left endpoint 233 and the upstream right endpoint 234 is D ₂ . The distance D ₁ between the upstream inner end point 231 and the upstream outer end point 232 is the maximum spanning dimension of the inner contour of the upstream interface 228 in the first direction on the mid-section 250 , and is also the inner contour of the upstream interface 228 along the evaporator 110 The maximum span size in the X2 direction of the axis. The distance between the upstream left endpoint 233 and the upstream right endpoint 234 is D ₂ , which is the second largest spanning dimension of the inner contour of the upstream interface 228 in the direction perpendicular to the mid-section 250 , and is also the inner contour of the upstream interface 228 in the direction perpendicular to the mid-section 250 . The maximum span size in the axis X2 direction of the evaporator 110. The area of the upstream interface 228 determines the local loss ΔP1 of the pressure of the refrigerant gas when entering the suction pipe 150 from the evaporator 110 .

Specifically, when the fluid enters the suction pipe 150 from the evaporator 110, there is a sudden contraction of the fluid flow area from large to small at the fluid interface between the cylinder of the evaporator 110 and the suction pipe 150. Therefore, during the suction There is a fluid pressure loss at the interface between the pipe 150 and the evaporator 110, that is, a local loss ΔP1, and the interface between the suction pipe 150 and the evaporator 110 (ie, the upstream interface 228) is perpendicular to the mid-section 250 and parallel to the centrifugal compressor. The size of the projected area A1 on the projection surface 265 of the central axis X1 of the air inlet 125 of the air inlet 120 directly determines the size of the local loss ΔP1. More specifically, the local loss ΔP1 of the suction pipe is: A ₁ is the projected area of the interface between the suction pipe 150 and the evaporator 110 (i.e., the upstream interface 228 ) on the projection surface 265 , A ₀ is the axial cross-sectional area of the evaporator 110 , and V ₁ is the average value in the suction pipe 150 Flow velocity, g is the acceleration due to gravity.

In order to reduce the local loss ΔP1, the larger the area A ₁ of the interface between the suction pipe 150 and the evaporator 110 (i.e. the upstream interface 228), the better. However, due to the limitation of the diameter of the evaporator barrel, the upstream left endpoint 233 and the upstream right side The distance between the end points 234 is D ₂ (that is, the maximum span size of the upstream interface 228 in the direction perpendicular to the axis of the evaporator 110 ) must satisfy D ₂ <0.5×D ₁ to meet the requirements of the cylinder strength of the evaporator 110 .

To this end, in the suction pipe according to the present application, the upstream interface 228 is set to: the distance D1 between the upstream inner end point 231 and the upstream outer end point 232 (ie, the first distance D1 of the inner contour of the upstream interface 228 located on the middle section 250 The directional maximum span dimension) is greater than the distance D ₂ between the upstream left endpoint 233 and the upstream right endpoint 234 (i.e., the second directional maximum span dimension of the inner contour of the upstream interface 228 in the direction perpendicular to the mid-section 250). Therefore, on the projection surface 265, the inner contour of the upstream interface 228 is projected into an elliptical shape, and the projected area A ₁ is A ₁ =pi×D ₁ ×D ₂ , where pi is the pi ratio.

By making the above settings for the upstream interface 228, this application can minimize the local loss ΔP1 while meeting the cylinder strength requirements of the evaporator 110, because by increasing the distance of the upstream interface 228 along the axis X2 of the evaporator 110 The maximum spanning dimension D ₁ in the direction can increase the area A 1 of the upstream interface 228 , thereby effectively reducing the local loss ΔP 1 .

According to some embodiments of the present application, the distance between the upstream inner endpoint 231 and the upstream outer endpoint 232 (the first direction maximum spanning dimension) D ₁ and the distance between the upstream left endpoint 233 and the upstream right endpoint 234 (the second The maximum span size in the direction) D ₂ satisfies: 0.55<D ₁ /D ₀ <0.7, D ₂ <0.5×D ₁ . The radius R ₆ of the inner contour of the downstream interface 226 satisfies: 0.43<R ₆ /D ₁ <0.57.

Since the inner contour of the upstream interface 228 is projected onto the projection surface 265 as an ellipse, while the inner contour of the downstream interface 226 is circular, the cross section of the portion of the suction pipe 150 between the upstream interface 228 and the downstream interface 226 Gradually change from oval to round.

The suction pipe 150 has a center line 270 located on the middle section 250, and the centers of the cross sections of the suction pipe 150 are located on the center line 270. The center line 270 is a spline curve that satisfies the following formula: Among them, V ₁ , V ₂ , V ₃ , V ₄ satisfy the following relationships:

-7e7<V ₁ <-6e7,1100<V ₂ <1300,-2950<V ₃ <-2750,250<V ₄ <270.

Among them, the coordinate system involved in the above formula takes the bottom end of the center line 270 (that is, the intersection point of the center line 270 and the projection plane 265) O ₀ as the origin of the coordinate system, and is parallel to the center of the suction port 125 of the centrifugal compressor 120 The direction of the axis X1 is the X-axis direction, and the direction perpendicular to the central axis X1 of the suction port 125 of the centrifugal compressor 120 is the Y-axis direction, as shown in FIG. 2D .

As shown in FIG. 2D , the suction pipe 150 has a first cross section 251 that passes through the inner intersection point 245 and the outer intersection point 246 and is perpendicular to the middle section 250 , with its center O ₁ located on the center line 270 . That is to say, the first cross section 251 is parallel to the projection plane 265 . Between the first cross section 251 of the suction pipe 150 and the downstream interface 226, the cross section of the inner contour of the suction pipe 150 at least on the inlet section 211 and the transition section 212 is an ellipse with the long axis located on the middle section 250, And the cross-sections of the inner contours of the inlet section 211 and the outlet section 213 gradually decrease in the direction toward the downstream interface 226, and then The cross-section of the inner contour of the transition section 212 first gradually increases and then decreases in the direction toward the downstream interface 226 . That is to say, the suction pipe 150 forms a bulge-like shape on the transition section 212 .

As an example, the above-mentioned suction pipe 150 is described by discrete multiple cross-sectional dimensions. As shown in FIG. 2D , the portion of the suction pipe 150 located between the first cross section 251 and the downstream interface 226 is divided into five equal parts along the center line 270 and the four cross sections are respectively the second cross section 252 and the third cross section. Section 253, the fourth cross section 254 and the fifth cross section 255, the centers of these cross sections are all on the center line 270, are O ₂ , O ₃ , O ₄ and O ₅ respectively. The fourth cross-section 254 is the largest cross-section of the transition section 212 . The first cross-section 251 and the downstream interface 226, as well as the dimensional characteristics of each of the above cross-sections are as follows.

The angle α ₆ between the downstream interface 226 and the first cross section 251 and the radius R ₆ of the downstream interface 226 satisfy:

80°≤α ₆ ≤90°, 0.43<R ₆ /D ₁ <0.57.

The major axis radius R1max and the minor axis radius R1min of the first cross section 251 respectively satisfy: R _1max =0.5×D ₁ , 0.9<R _1min /R _1max <0.95.

The angle α ₂ between the second cross section 252 and the first cross section 251 and the major axis radius R _2max and the minor axis radius R _2min of the second cross section 252 respectively satisfy: 0.1<α ₂ /α ₆ <0.15, 0.68<R _2max /D ₁ <0.78, 0.92<R _2min /R _2max <0.98.

The angle α ₃ between the third cross section 253 and the first cross section 251 and the major axis radius R _3max and the minor axis radius R _3min of the third cross section 253 respectively satisfy: 0.25<α ₃ /α ₆ <0.38, 0.6<R _3max /D ₁ <0.76, 0.8<R _3min /R _3max <0.9.

The angle α ₄ between the fourth cross section 254 and the first cross section 251 and the major axis radius R _4max and the minor axis radius R _4min of the fourth cross section 254 respectively satisfy: 0.45<α ₄ /α ₆ <0.6, 0.6<R _4max /D ₁ <0.74, 0.84<R _4min /R _4max <0.92.

The angle α ₅ between the fifth cross section 255 and the first cross section 251 and the major axis radius R _5max and the minor axis radius R _5min of the fifth cross section 255 respectively satisfy: 0.7<α ₅ /α ₆ <0.8, 0.45<R _5max /D ₁ <0.6, 0.98<R _5min /R _5max <1.05.

It can be seen that the first to fourth cross-sections are all ellipses with the long axis located on the middle section 250, and the short axis of the fifth cross-section 255 can be larger than the long axis, equal to the long axis, or equal to the long axis. Short, therefore, fifth cross-section 255 may be circular.

By forming each of the above cross-sections, the upstream interface 228, the downstream interface 226, and the centerline 270, the inner contour of the suction duct 150 is formed, and then by adding a wall of a specific thickness, the suction duct 150 is formed.

FIG. 3A is a schematic diagram showing the fluid flow state of the suction pipe 310 of a comparative example in use. FIG. 3B is a schematic diagram showing the fluid flow state of the suction pipe 150 in use according to the first embodiment of the present application. As shown in FIG. 3A , in a comparative example, the suction pipe 310 is in the shape of a circular tube as a whole, and the inlet section 311 of the suction pipe 310 is a straight pipe section perpendicular to the evaporator 320 . Due to the sudden change in the interface area between the evaporator 320 and the suction pipe 310, the refrigerant gas will have a local pressure loss ΔP ₁ when entering the suction pipe 310 from the evaporator 320. Moreover, the refrigerant gas will produce gas in the straight-tube inlet section 311. The pressure loss ΔP ₂ occurs because when the fluid enters the suction pipe 310 from the evaporator 320, the flow direction will deflect greatly, and the fluid will generate flow separation and vortices in places where the flow deflection is large. In addition, the refrigerant gas has a pressure loss ΔP ₃ in the transition section 312 of the suction pipe 310 . This is due to the large deflection of the fluid in the transition section 312 , and the deflection of the fluid steering causes the velocity distribution in the transition section 312 of the suction pipe. Inhomogeneity leads to aggravation of internal friction in the main flow, causing front and back collisions of fluid microclusters to increase turbulence in the main flow, thereby causing pressure and energy losses. The refrigerant gas also has a pressure loss ΔP ₄ in the outlet section 313 of the suction pipe 310. This is because there is a local high-speed zone near the inside of the suction pipe, which increases the internal friction of the fluid and causes pressure loss.

As shown in FIG. 3B , the suction pipe 150 according to the first embodiment of the present application can greatly reduce the pressure losses ΔP ₁ , ΔP ₂ , ΔP ₃ and ΔP ₄ existing in the above comparative example. The reasons for reducing the local pressure loss ΔP ₁ have been detailed previously and will not be repeated here. The suction pipe 150 of the present application can also reduce the pressure loss ΔP ₂ of the inlet section, because the cross-section of the inlet section 211 of the suction pipe 150 of the present application gradually decreases, thus reducing the flow of fluid from the evaporator 320 into the suction section. The magnitude of flow direction deflection in trachea 310. The suction pipe 150 of the present application can also reduce the pressure loss ΔP ₃ in the transition section, because the cross-section of the transition section 212 first increases and then decreases, which can reduce the uneven speed distribution caused by the deflection of the steering. The suction pipe 150 of the present application can also reduce the pressure loss ΔP ₄ in the outlet section, because the process of first increasing and then decreasing the cross-section of the transition section 212 reduces the flow velocity in the local high-speed zone inside the suction pipe of the outlet section 313.

3C and 3D respectively show the suction pipe 310 of the comparative example shown in FIG. 3A and the suction pipe 150 of the present application shown in FIG. 3B obtained using the CFD (computational fluid dynamics) method. Speed vector illustration. It can be seen from the CFD simulation results that the suction pipe 310 of the comparative example shown in Figure 3A has two turbulent vortex areas (darker areas in the picture) on the left and right sides of the bottom of the suction pipe, while the suction pipe 310 shown in Figure 3B The left and right sides of the bottom of the suction pipe 150 of this application basically eliminate turbulent vortices, which can effectively reduce pressure loss. As shown in Table 1 below, the pressure loss of the suction pipe 150 of the present application shown in FIG. 3B is 17% lower than that of the suction pipe 310 of the comparative example shown in FIG. 3A.

3E and 3F respectively show the suction pipe downstream obtained by using the CFD (computational fluid dynamics) method for the suction pipe 310 of the comparative example shown in FIG. 3A and the suction pipe 150 of the present application shown in FIG. 3B. The velocity vector diagram at the interface (i.e., the compressor inlet); Figures 3G and 3H respectively show the use of the suction pipe 310 of the comparative example shown in Figure 3A and the suction pipe 150 of the present application shown in Figure 3B The vortex intensity diagram at the downstream interface of the suction pipe (i.e., the compressor inlet) obtained by the CFD (Computational Fluid Dynamics) method. The velocity distribution at the downstream interface of the suction pipe (i.e., the compressor inlet) has a great influence on the performance of the compressor. The more uniform the velocity distribution at the compressor inlet, the higher the efficiency of the compressor. The impact of the suction pipe on the performance of the compressor can be judged by the vortex intensity at the interface between the suction pipe and the compressor. Generally speaking, the smaller the vortex intensity, the better the compressor efficiency. As can be seen from Figures 3E-3H, this application The downstream interface of the suction pipe 150 (i.e. the compressor inlet mouth), the velocity distribution is more uniform, and the vortex intensity is significantly reduced (the darker the color, the higher the flow speed and the greater the vortex intensity). In addition, it can be seen from Table 1 that the vortex intensity of the suction pipe 150 of the present application is 74% lower than that of the existing suction pipe, which can greatly improve the inlet conditions of the compressor and enhance the performance of the compressor.

Figures 4A-4D show the suction pipe 450 of the centrifugal compressor according to the second embodiment of the present application, wherein Figure 4A is a front perspective view of the suction pipe 450, and Figure 4B is a rear perspective view of the suction pipe 450 , Figure 4C is a front view of the inner profile of the suction pipe 450, Figure 4D is a left view of the inner profile of the suction pipe 450, Figures 4E-4I are schematic views of the first to fifth cross-sections in Figure 4D, Figure 4J is a schematic diagram of the inner contour of the downstream interface of the suction pipe 450. The main difference between the suction pipe 450 of the second embodiment shown in FIGS. 4A-4J and the suction pipe 150 of the first embodiment shown in FIGS. 2A-2J lies in the transition section of the suction pipe 150 of the first embodiment. The cross section of the inner contour 612 first gradually increases and then gradually decreases. However, the cross section of the inner contour 612 of the transition section 612 of the suction pipe 450 of the second embodiment does not have an increasing portion, but toward the downstream interface 626 direction gradually decreases. That is, the cross section of the inner contour of the suction pipe 450 of the second embodiment gradually decreases in the direction from the first cross section 651 (centered at O ₁₁ ) to the downstream interface 626 . As shown in Table 1 below, the suction pipe 450 of the second embodiment, like the suction pipe 150 of the first embodiment, can reduce the pressure loss, the static pressure loss in the suction pipe and the pressure loss at the downstream interface of the suction pipe. Vortex intensity.

Same as the first embodiment, the distance between the upstream inner endpoint 631 and the upstream outer endpoint 632 of the suction pipe 450 of the second embodiment (the maximum spanning dimension in the first direction) D ₁₁ and the upstream left endpoint 633 and the upstream right side The distance D ₁₂ between the end points 634 (the maximum spanning dimension in the second direction) satisfies: 0.55<D ₁₁ /D ₀ <0.7, D ₁₂ <0.5×D ₁₁ . The radius R ₁₆ of the inner contour of the downstream interface 626 satisfies: 0.43<R ₁₆ /D ₁₁ <0.57. where D ₀ is the diameter of the evaporator in the upstream component.

As an example, the above-mentioned suction pipe 450 is described by discrete multiple cross-sectional dimensions. As shown in FIG. 2D , the portion of the suction pipe 450 located between the first cross section 651 and the downstream interface 626 is divided into five equal parts along the center line 670 and the four cross sections are respectively the second cross section 652 and the third cross section. Section 653, the fourth cross section 654 and the fifth cross section 655, the centers of these cross sections are all on the center line 670, are O ₁₂ , O ₁₃ , O ₁₄ and O ₁₅ respectively. The fourth cross-section 654 is the largest cross-section of the transition section 612 . The first cross-section 651 and the downstream interface 626, as well as the dimensional characteristics of each of the above cross-sections are as follows.

The angle α ₁₆ between the downstream interface 626 and the first cross section 651 and the radius R ₁₆ of the downstream interface 626 satisfy:

80°≤α ₁₆ ≤90°, 0.43<R ₁₆ /D ₁₁ <0.57.

The major axis radius R _11max and the minor axis radius R _12min of the first cross section 651 respectively satisfy: R _11max =0.5×D ₁₁ , 0.9<R _11min /R _11max <0.95.

The angle α 12 between the second cross section 652 and the first cross section ₆₅₁ and the major axis radius R _12max and the minor axis radius R _12min of the second cross section 652 respectively satisfy: 0.1<α ₁₂ /α ₁₆ <0.15, 0.68<R _12max /D ₁₁ <0.78, 0.92<R _12min /R _12max <0.98.

The angle α ₁₃ between the third cross section 653 and the first cross section 651 and the major axis radius R _13max and the minor axis radius R _13min of the third cross section 653 respectively satisfy: 0.25<α ₁₃ /α ₁₆ <0.38, 0.55<R _13max /D ₁₁ <0.7, 0.8<R _13min /R _13max <0.9.

The angle α ₁₄ between the fourth cross section 654 and the first cross section 651 and the major axis radius R _14max and the minor axis radius R _14min of the fourth cross section 654 respectively satisfy: 0.45<α ₁₄ /α ₁₆ <0.6, 0.5<R _14max /D ₁₁ <0.6, 0.9<R _14min /R _14max <0.95.

The angle α 15 between the fifth cross section 655 and the first cross section ₆₅₁ and the major axis radius R _15max and the minor axis radius R _15min of the fifth cross section 655 respectively satisfy: 0.7<α ₁₅ /α ₁₆ <0.8, 0.45<R _15max /D ₁₁ <0.6, 0.98<R _15min /R _15max <1.05.

Table 1 below shows a performance comparison table of the suction pipes of the two embodiments of the present application and the suction pipe of the comparative example in terms of static pressure loss and vortex intensity.

Table 1 Comparison of suction pipe performance

Although the present disclosure has been described in connection with the examples of embodiments outlined above, various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or not, will become apparent to those of at least ordinary skill in the art. It may be obvious whether it is now or can be foreseen in the near future. In addition, the technical effects and/or technical problems described in this specification are illustrative rather than restrictive; therefore, the disclosure in this specification may be used to solve other technical problems and have other technical effects. Accordingly, the examples of embodiments of the present disclosure set forth above are intended to be illustrative and not restrictive. Various changes may be made without departing from the spirit or scope of the disclosure. Accordingly, the present disclosure is intended to include all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.

Claims

A suction pipe of a centrifugal compressor. The centrifugal compressor has a suction port. The suction port has a central axis. The suction pipe introduces fluid from an upstream component into the centrifugal compressor. The fluid enters the suction pipe in a direction substantially perpendicular to the central axis of the suction port, and the suction pipe includes:

An imaginary middle section, the central axis of the suction port of the centrifugal compressor is located on the middle section, and the suction pipe has a symmetrical shape relative to the middle section;

A downstream interface connected to the centrifugal compressor, the inner contour of the downstream interface is circular and connected to the suction port; and

an upstream interface connected to the upstream component;

It is characterized in that: the inner contour of the upstream interface includes a maximum spanning dimension D 1 in the first direction located on the mid-section, and includes a maximum spanning dimension D 2 in a second direction perpendicular to the mid-section, wherein, the The maximum span dimension D 1 in the first direction is larger than the maximum span dimension D 2 in the second direction.
The suction pipe of a centrifugal compressor according to claim 1, characterized in that:

The upstream component is cylindrical with an axis parallel to the central axis of the suction port, and has a diameter D 0 ;

Wherein, the maximum spanning dimension D 1 in the first direction and the maximum spanning dimension D 2 in the second direction of the inner contour of the upstream interface satisfy: 0.55<D 1 /D 0 <0.7, D 2 <0.5×D 1 ;

And wherein, the radius R 6 of the inner contour of the downstream interface satisfies: 0.43<R 6max /D 1 <0.57.
The suction pipe of a centrifugal compressor according to claim 2, characterized in that:

The suction pipe has a centerline located on the mid-section;

Wherein, the center line is a spline curve, and the center line satisfies the following formula: Among them, V 1 , V 2 , V 3 , V 4 satisfy the following relationships:
-7e7<V 1 <-6e7,1100<V 2 <1300,-2950<V 3 <-2750,250<V 4 <270.
The suction pipe of a centrifugal compressor according to claim 3, characterized in that: the suction pipe includes:

Inlet section, the upstream interface is the end surface of the inlet section, the inlet section includes a connection part and a guide part, the connection part connects the suction pipe and the upstream component, the inner part of the guide part A connecting line between the contour and the inner contour of the connecting portion intersects the mid-section at an inner intersection point and an outer intersection point;

Exit section, the downstream interface is the end face of the outlet section;

a transition section that connects the inlet section and the outlet section;

Wherein, the suction pipe includes a first cross-section, the first cross-section passes through the inner intersection point and the outer intersection point and is perpendicular to the middle section; and

Wherein, between the first cross-section and the downstream interface, the cross-section of the inner profile of the suction pipe at least on the inlet section and the transition section is such that the long axis is located on the middle section oval shape.
The suction pipe of a centrifugal compressor according to claim 4, characterized in that:

Wherein, between the first cross-section and the downstream interface, the cross-sections of the inner contours of the inlet section and the outlet section of the suction pipe gradually decrease in a direction toward the downstream interface.
The suction pipe of a centrifugal compressor according to claim 5, characterized in that:

The cross-section of the inner contour of the suction pipe in the transition section first gradually increases and then gradually decreases in the direction toward the downstream interface.
The suction pipe of a centrifugal compressor according to claim 6, characterized in that:

The part of the suction pipe between the first cross section and the downstream interface is divided into five equal parts along the center line and the four cross sections are respectively the second cross section, the third cross section and the fourth cross section. cross-section and a fifth cross-section, wherein the fourth cross-section is the largest cross-section of the transition section;

Wherein, the angle α 6 between the downstream interface and the first cross section satisfies:
80°≤α 6 ≤90°;

Wherein, the major axis radius R 1max and the minor axis radius R 1min of the first cross section respectively satisfy:
R 1max =0.5×D 1 , 0.9<R 1min /R 1max <0.95;

Wherein, the angle α 2 between the second cross section and the first cross section and the major axis radius R 2max and the minor axis radius R 2min of the second cross section respectively satisfy:
0.1<α 2 /α 6 <0.15, 0.68<R 2max /D 1 <0.78, 0.92<R 2min /R 2max <0.98;

Wherein, the angle α 3 between the third cross section and the first cross section and the major axis radius R 3max and the minor axis radius R 3min of the third cross section respectively satisfy:
0.25<α 3 /α 6 <0.38, 0.6<R 3max /D 1 <0.76, 0.8<R 3min /R 3max <0.9;

Wherein, the angle α 4 between the fourth cross section and the first cross section and the major axis radius R 4max and the minor axis radius R 4min of the fourth cross section respectively satisfy:
0.45<α 4 /α 6 <0.6, 0.6<R 4max /D 1 <0.74, 0.84<R 4min /R 4max <0.92;

Wherein, the angle α 5 between the fifth cross section and the first cross section and the major axis radius R 5max and the minor axis radius R 5min of the fifth cross section respectively satisfy:
0.7<α 5 /α 6 <0.8, 0.45<R 5max /D 1 <0.6, 0.98<R 5min /R 5max <1.05.
The suction pipe of a centrifugal compressor according to claim 5, characterized in that:

The cross-section of the suction pipe in the transition section gradually decreases in the direction toward the downstream interface.
The suction pipe of a centrifugal compressor according to claim 8, characterized in that:

The part of the suction pipe between the first cross section and the downstream interface is divided into five equal parts along the center line and the four cross sections are respectively the second cross section, the third cross section and the fourth cross section. cross-section and a fifth cross-section, wherein the fourth cross-section is the largest cross-section of the transition section;

Wherein, the angle α 16 between the downstream interface and the first cross section satisfies:
80°≤α 16 ≤90°;

Wherein, the major axis radius R 11min and the minor axis radius R 12min of the first cross section respectively satisfy:
R 11max =0.5×D 11 , 0.9<R 11min /R 11max <0.95;

Wherein, the angle α 12 between the second cross section and the first cross section and the major axis radius R 12max and the minor axis radius R 12min of the second cross section respectively satisfy:
0.1<α 12 /α 16 <0.15, 0.68<R 12max /D 11 <0.78, 0.92<R 12min /R 12max <0.98;

Wherein, the angle α 13 between the third cross section and the first cross section and the major axis radius R 13max and the minor axis radius R 13min of the third cross section respectively satisfy:
0.25<α 13 /α 16 <0.38, 0.55<R 13max /D 11 <0.7, 0.8<R 13min /R 13max <0.9;

Wherein, the angle α 14 between the fourth cross section and the first cross section and the major axis radius R 14max and the minor axis radius R 14min of the fourth cross section respectively satisfy:
0.45<α 14 /α 16 <0.6, 0.5<R 14max /D 11 <0.6, 0.9<R 14min /R 14max <0.95;

Wherein, the angle α 15 between the fifth cross section and the first cross section and the major axis radius R 15max and the minor axis radius R 15min of the fifth cross section respectively satisfy:
0.7<α 15 /α 16 <0.8, 0.45<R 15max /D 11 <0.6, 0.98<R 15min /R 15max <1.05.
A centrifugal compressor, characterized in that: the centrifugal compressor includes the suction pipe according to any one of claims 1-9.