Centrifugal compressor adopting wing-shaped blade diffuser

Abstract

The utility model provides a centrifugal compressor adopting a wing-shaped blade diffuser, relates to a centrifugal compressor, and solves the problems that the operation working condition range of the conventional centrifugal compressor adopting a multi-blade diffuser is sharply reduced, and a unit cannot meet the requirements of industries such as petroleum, chemical engineering and steel on the wide working condition range of the centrifugal compressor. And the normal operation of the centrifugal compressor is influenced due to mutual excitation between the blades and the impeller. According to the utility model, gas enters the centrifugal compressor from the gas inlet, the gas is acted by the impeller, and the gas discharged by the rear impeller enters the wing-shaped blade diffuser, so that the wing-shaped diffuser can reduce the loss of gas flow, ensures that the single-stage pressure ratio and the stage efficiency are improved, and does not influence the operation condition of the centrifugal compressor at the same time. The speed energy of gas can be fully converted into pressure energy, and therefore it is guaranteed that the centrifugal compressor achieves the effects of high efficiency and wide working conditions.

Description

Technical Field

[0001] The utility model relates to a centrifugal compressor, in particular to a centrifugal compressor adopting a wing-shaped blade diffuser. Background Art

[0002] Centrifugal compressors can convert the kinetic energy of high-speed gas movement into pressure energy. Gas enters the centrifugal compressor and passes through the diffuser in the centrifugal compressor. The impeller on the diffuser rotates at high speed, causing the gas to generate pressure due to the centrifugal force. Centrifugal compressors make full use of the higher flow velocity of gas when it flows out of the impeller to increase the gas pressure. Centrifugal compressors are widely used in the fields of petroleum, chemical industry, steel, etc. With the continuous development of centrifugal compressor technology, while ensuring the high performance and wide operating conditions of the compressor, new requirements are placed on it for small size and low energy consumption.

[0003] In the prior art, centrifugal compressors usually use a flow channel combination of an impeller and an ordinary blade diffuser, which can increase the single-stage pressure ratio, thereby improving the stage efficiency and meeting the requirements of small models. However, due to the narrowing of the flow channel of the multi-leaf diffuser, the gas flow through the multi-leaf diffuser is limited. Therefore, the operating range of the centrifugal compressor using the multi-leaf diffuser will be sharply reduced, and the unit cannot meet the requirements of the petroleum, chemical, steel and other industries for a wide range of centrifugal compressors, which seriously limits the application range of centrifugal compressors. In addition, ordinary multi-leaf diffusers may cause mutual excitation between the impeller and diffuser blades in special occasions, such as in flammable and explosive compression media, affecting the normal operation of the compressor. Utility Model Content

[0004] The purpose of the utility model is to solve the technical problems that the existing centrifugal compressors using multi-blade diffusers have a small operating range and cannot meet the requirements of the petroleum, chemical, steel and other industries for a wide operating range of centrifugal compressors, and there is mutual excitation between the blades and the impeller, which affects the normal operation of the centrifugal compressor. A centrifugal compressor using a wing-shaped blade diffuser is proposed.

[0005] In order to solve the above technical problems, the technical solutions provided by the utility model are as follows:

[0006] A centrifugal compressor using a wing-shaped blade diffuser comprises a casing, an air inlet and an air outlet arranged on the casing, a main shaft located inside the casing, a partition plate arranged on the casing, and a diffuser and an impeller located in a flow channel, and the special features thereof are:

[0007] The diffuser adopts an airfoil-shaped blade diffuser, including a diffuser ring and N airfoil-shaped blades arranged on the diffuser ring; the diffuser ring is arranged on a partition, the impeller is close to the inlet of the flow channel, and the N airfoil-shaped blades are located on a side of the diffuser ring facing the impeller;

[0008] The total area occupied by the N airfoil-shaped blades on the side of the diffuser ring accounts for 2% to 5% of the area of ​​the side of the diffuser ring;

[0009] The ratio of the inner diameter φc of the diffuser ring to the diameter φb of the circle where the center point of the leading edge of the wing-shaped blade is located is 0.8 to 0.9;

[0010] The ratio of the diameter φa of the circle where the center point of the trailing edge of the wing-shaped blade is located to the outer diameter φd of the diffuser ring is 0.7 to 0.8;

[0011] The sum of the center angles e° corresponding to the arc lines of the N airfoil-shaped blades, N*e°, accounts for 44% to 65% of the diffuser ring circular angle, and N is 7 to 11.

[0012] The ratio of the diameter φb of the circle where the center point of the leading edge of the wing-shaped blade is located to the impeller diameter is 1.1-1.3, and the ratio of the blade width of the wing-shaped blade in the flow channel to the impeller diameter is 0.06-0.085.

[0013] Furthermore, the leading edge of the wing-shaped blade is an arc structure, and the trailing edge is a sharp-angle structure, and both sides of the sharp angle are straight.

[0014] Furthermore, the impeller includes a first-stage impeller, a second-stage impeller and a third-stage impeller which are arranged in sequence from the air inlet to the air outlet; the diffuser includes a first-stage diffuser, a second-stage diffuser and a third-stage diffuser which are arranged in sequence from the air inlet to the air outlet; the number of the partitions is three, and the first-stage diffuser, the second-stage diffuser and the third-stage diffuser are all installed on corresponding partitions.

[0015] Furthermore, it also includes two returners; one of which is arranged between the outlet of the first-stage diffuser and the second-stage impeller; and the other returner is arranged between the outlet of the second-stage diffuser and the inlet of the third-stage impeller;

[0016] The return flow device is connected to the airfoil-shaped blade diffuser via a bend; the outlet side of the three-stage diffuser is connected to the volute chamber of the centrifugal compressor.

[0017] Furthermore, a thrust bearing and a support bearing are provided on one end of the main shaft close to the air inlet, and a support bearing is provided on one end close to the air outlet.

[0018] Furthermore, the total area occupied by the airfoil-shaped blades on the side of the diffuser ring accounts for 4.24% of the area of ​​the side of the diffuser ring;

[0019] The ratio of the inner diameter φc of the diffuser ring to the diameter φb of the circle where the center point of the leading edge of the wing-shaped blade is located is 0.845;

[0020] The ratio of the diameter φa of the circle where the center point of the trailing edge of the wing-shaped blade is located to the outer diameter φd of the diffuser ring is 0.7094;

[0021] The sum of the center angles e° corresponding to the arc lines of N airfoil-shaped blades, N*e°, accounts for 44.53% of the diffuser ring angle, where N=11;

[0022] The ratio of the diameter φb of the circle where the center point of the leading edge of the blade of the wing-shaped blade diffuser is located to the impeller diameter is 1.2.

[0023] Compared with the prior art, the beneficial effects of the utility model are:

[0024] 1. The utility model discloses a centrifugal compressor using an airfoil-shaped blade diffuser. Gas enters the centrifugal compressor from an air inlet, and work is done on the gas through an impeller. The gas flowing out of the impeller enters the airfoil-shaped blade diffuser. The ratio of the diameter of the circle where the center point of the leading edge of the blade of the airfoil-shaped blade diffuser is located to the diameter of the impeller is 1 to 1.3, and the ratio of the blade width of the airfoil-shaped blade diffuser to the diameter of the impeller is 0.06 to 0.085. The blade angle and the number of blades on the airfoil-shaped blade diffuser are matched with the impeller located in front of the airfoil-shaped blade diffuser, so as to avoid mutual excitation between the impeller and the airfoil-shaped blade diffuser.

[0025] 2. The wing-shaped diffuser in the utility model can reduce the gas flow loss while ensuring the improvement of the single-stage pressure ratio and stage efficiency, and at the same time does not affect the operating conditions of the centrifugal compressor. It can fully convert the velocity energy of the gas into pressure energy, thereby ensuring that the centrifugal compressor achieves high efficiency and wide operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of a centrifugal compressor embodiment of the utility model using an airfoil-shaped blade diffuser;

[0027] Figure 2 The utility model is a structural schematic diagram of an airfoil-shaped blade diffuser of a centrifugal compressor embodiment using an airfoil-shaped blade diffuser.

[0028] Description of reference numerals:

[0029] 1-wing-shaped blade diffuser, 101-wing-shaped blade, 102-diffuser ring; 2-casing; 3-air inlet; 4-air outlet; 5-main shaft; 6-impeller; 7-curve; 8-returner; 9-partition; 10-thrust bearing; 11-support bearing. DETAILED DESCRIPTION

[0030] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0031] The utility model proposes a centrifugal compressor using a wing-shaped blade diffuser, such as Figure 1 As shown, it includes a casing 2, an air inlet 3 and an air outlet 4 arranged on the same side of the casing 2. The gas enters the compressor through the air inlet 3 and is discharged through the air outlet 4. A main shaft 5 is arranged inside the casing 2, and a thrust bearing 10 and a support bearing 11 are arranged on the end of the main shaft 5 close to the air inlet 3, and a support bearing 11 is arranged on the end close to the air outlet 4. The support bearing 11 is used for bearing weight, and the thrust bearing 10 is used for fixing the main shaft. From the air inlet 3 to the air outlet 4, a multi-stage impeller 6 and a wing-shaped blade diffuser 1 are arranged in sequence, and the 1-3 stage diffusers adopt the wing-shaped blade diffuser 1.

[0032] The impeller 6 is close to the inlet of the flow channel, the diffuser ring (102) of the airfoil-shaped blade diffuser 1 is fixed on the partition (9), and N airfoil-shaped blades (101) are located on the side of the diffuser ring (102) facing the impeller (6). The impeller 6 rotates at a high speed, and the gas generates kinetic energy through the impeller 6 and then enters the airfoil-shaped blade diffuser 1 located in the diffuser flow channel. The airfoil-shaped blade diffuser 1 converts the kinetic energy of the impeller 6 into pressure energy. The area of ​​the wing-shaped blade 101 of the wing-shaped blade diffuser 1 accounts for 4.24% of the side area of ​​the diffuser ring 102; the ratio of the inner circle diameter φc of the diffuser ring 102 to the diameter φb of the circle where the center point of the leading edge of the wing-shaped blade 101 is located is 0.845; the ratio of the diameter φa of the circle where the center point of the trailing edge of the wing-shaped blade 101 is located to the outer circle diameter φd of the diffuser ring 102 is 0.7094; the sum N*e° of the center angles e° corresponding to the arcs of N wing-shaped blades 101 accounts for 44.53% of the circular angle of the diffuser ring 102, N=11; the ratio of the diameter φb of the circle where the center point of the leading edge of the blade of the wing-shaped blade diffuser 1 is located to the diameter of the impeller 6 is 1.2, and the ratio of the blade width of the wing-shaped blade diffuser 1 to the impeller diameter is 0.06-0.085. By limiting the position, size and number of the blades of the airfoil-shaped blade diffuser 1, the efficiency of the gas passing through the airfoil-shaped blade diffuser 1 is improved while the gas flow is not restricted, and the centrifugal compressor can maintain a wider operating condition. The blades of the airfoil-shaped blade diffuser 1 are matched with the impeller 6 to avoid mutual excitation between the impeller and the airfoil-shaped blade diffuser.

[0033] In this embodiment, the impeller 6 and the airfoil-shaped blade diffuser 1 are provided with three stages in total. The impeller (6) includes a first-stage impeller, a second-stage impeller and a third-stage impeller arranged in sequence from the air inlet (3) to the air outlet (4); the diffuser includes a first-stage diffuser, a second-stage diffuser and a third-stage diffuser arranged in sequence from the air inlet (3) to the air outlet (4); the number of the baffles is three, and the first-stage diffuser, the second-stage diffuser and the third-stage diffuser are all installed on the corresponding baffles (9). A return flow device 8 is provided on the outlet side of the first-stage diffuser and the second-stage diffuser. In a multi-stage centrifugal compressor, the gas must turn to enter the next stage, so there is a bend 7 structure between the return flow device 8 and the airfoil-shaped blade diffuser 1. The outlet side of the third-stage diffuser leads directly to the volute. The gas enters from the air inlet of the centrifugal compressor and first enters the impeller 6 in front of the first-stage diffuser. The gas rotates at high speed following the impeller 6, and is thus subjected to the centrifugal force. The gas flows in the impeller 6 with pressure diffusion, and the pressure will also be increased. The gas flowing out of the impeller 6 has a high flow velocity, and then enters the first-stage diffuser. The first-stage diffuser converts the velocity energy of the gas into pressure energy, thereby completing the diffusion of the gas. The gas flowing out of the first-stage diffuser enters the bend 7 and turns, and then enters the reflow device 8. The reflow device 8 allows the gas to enter the impeller 6 in front of the secondary diffuser evenly in the required direction, and is diffused again through the secondary diffuser. The gas flowing out of the secondary diffuser enters the bend 7 and the reflow device 8 again, enters the impeller 6 in front of the tertiary diffuser in the required direction, and flows into the tertiary diffuser for diffusion again. The gas flowing out of the tertiary diffuser is collected in the volute chamber and finally discharged from the outlet 4.

[0034] The utility model can be applied to product design and technical solutions in large-scale air separation fields, propane dehydrogenation product gas, nitrogen oxide compressors and multi-shaft compressors and other large-flow engineering application fields.

Claims

1. A centrifugal compressor using an airfoil-shaped blade diffuser, comprising a casing (2), an air inlet (3) and an air outlet (4) arranged on the casing (2), a main shaft (5) located inside the casing (2), a partition (9) arranged on the casing (2), and a diffuser and an impeller (6) located in a flow channel, characterized in that: The diffuser adopts an airfoil-shaped blade diffuser (1), comprising a diffuser ring (102) and N airfoil-shaped blades (101) arranged on the diffuser ring (102); the diffuser ring (102) is arranged on a partition plate (9), the impeller (6) is close to the inlet of the flow channel, and the N airfoil-shaped blades (101) are located on a side of the diffuser ring (102) facing the impeller (6); The total area occupied by the N airfoil-shaped blades (101) on the side of the diffuser ring (102) accounts for 2% to 5% of the area of ​​the side of the diffuser ring (102); The ratio of the inner diameter φc of the diffuser ring (102) to the diameter φb of the circle where the center point of the leading edge of the wing-shaped blade (101) is located is 0.8 to 0.9; The ratio of the diameter φa of the circle where the center point of the trailing edge of the wing-shaped blade (101) is located to the outer diameter φd of the diffuser ring (102) is 0.7 to 0.8; The sum N*e° of the center angles e° corresponding to the arc lines of the N airfoil-shaped blades (101) accounts for 44% to 65% of the circular angle of the diffuser ring (102), and N is 7 to 11; The ratio of the diameter φb of the circle where the front edge center point of the wing-shaped blade (101) is located to the diameter of the impeller (6) is 1.1 to 1.3, and the ratio of the blade width of the wing-shaped blade (101) in the flow channel to the impeller diameter is 0.06 to 0.

085.

2. A centrifugal compressor using an airfoil-shaped blade diffuser according to claim 1, characterized in that: The leading edge of the wing-shaped blade (101) is an arc structure, and the trailing edge is a sharp-angle structure, with both sides of the sharp angle being straight.

3. A centrifugal compressor using an airfoil-shaped blade diffuser according to claim 1 or 2, characterized in that: The impeller (6) comprises a first-stage impeller, a second-stage impeller and a third-stage impeller which are arranged in sequence from the air inlet (3) to the air outlet (4); the diffuser comprises a first-stage diffuser, a second-stage diffuser and a third-stage diffuser which are arranged in sequence from the air inlet (3) to the air outlet (4); the number of the partitions is three, and the first-stage diffuser, the second-stage diffuser and the third-stage diffuser are all installed on the corresponding partitions (9).

4. A centrifugal compressor using an airfoil-shaped blade diffuser according to claim 3, characterized in that: It also includes two returners (8); one of the returners (8) is arranged between the first-stage diffuser outlet and the second-stage impeller; and the other returner (8) is arranged between the second-stage diffuser outlet and the third-stage impeller; The return flow device (8) is connected to the airfoil-shaped blade diffuser (1) via a bend (7); the outlet side of the three-stage diffuser is connected to the volute of the centrifugal compressor.

5. A centrifugal compressor using an airfoil-shaped blade diffuser according to any one of claims 1 to 4, characterized in that: A thrust bearing (10) and a support bearing (11) are provided on one end of the main shaft (5) close to the air inlet (3), and a support bearing (11) is provided on the other end close to the air outlet (4).

6. A centrifugal compressor using an airfoil-shaped blade diffuser according to claim 5, characterized in that: The total area occupied by the wing-shaped blades (101) on the side of the diffuser ring (102) accounts for 4.24% of the area of ​​the side of the diffuser ring (102); The ratio of the inner diameter φc of the diffuser ring (102) to the diameter φb of the circle where the center point of the leading edge of the wing-shaped blade (101) is located is 0.845; The ratio of the diameter φa of the circle where the center point of the trailing edge of the wing-shaped blade (101) is located to the outer diameter φd of the diffuser ring (102) is 0.7094; The sum N*e° of the center angles e° corresponding to the arc lines of the N airfoil-shaped blades (101) accounts for 44.53% of the circular angle of the diffuser ring (102), wherein N=11; The ratio of the diameter φb of the circle where the center point of the leading edge of the blade of the wing-shaped blade diffuser (1) is located to the diameter of the impeller (6) is 1.2.

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