CN216589292U - Centrifugal compressor stage serial diffuser - Google Patents
Centrifugal compressor stage serial diffuser Download PDFInfo
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- CN216589292U CN216589292U CN202123170209.7U CN202123170209U CN216589292U CN 216589292 U CN216589292 U CN 216589292U CN 202123170209 U CN202123170209 U CN 202123170209U CN 216589292 U CN216589292 U CN 216589292U
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Abstract
The utility model relates to a centrifugal compressor stage serial diffuser which is sequentially provided with a diffuser radial front-row blade, a diffuser axial back-row main blade and a diffuser axial back-row splitter blade which are fixedly connected with a diffuser hub and a diffuser casing respectively along the airflow direction; the tail edge of a radial front row of blades of the diffuser extends to the bending section of the meridian flow channel, and the radial front row of blades of the diffuser is used for changing radial flow into axial flow in the bending section in advance; the tail edge of the radial front row of blades of the diffuser is close to the front edge of the axial rear row of main blades of the diffuser, and a flow channel gap is arranged between the tail edge of the radial front row of blades of the diffuser and the front edge of the axial rear row of main blades of the diffuser; the utility model obviously inhibits the backflow at the outlet casing of the centrifugal impeller, and the flow field is more uniform.
Description
Technical Field
The utility model belongs to the field of a micro-turbojet centrifugal compressor, and particularly relates to a diffuser structure of a compressor.
Background
The stationary elements of a multistage centrifugal compressor have a great influence on the overall aerodynamic performance. With the continuous and intensive research on the centrifugal compressor, researchers find that when a static element is not properly designed, the flow loss is large, and sometimes the total pressure recovery coefficient of a diffuser of the centrifugal compressor is even 0.85. Further improvements in the performance of centrifugal compressor stages require that flow losses in the stationary elements be minimized, and therefore the design and optimization of stationary component passages is also one of the issues that have been the focus of research to improve the aerodynamic performance of centrifugal compressors.
The conventional micro-turbojet centrifugal compressor stage diffuser is generally configured in such a way that a radial diffuser and an axial diffuser are separately arranged, flow separation and the like exist behind a blunt trailing edge of the radial diffuser, and if the axial diffuser is not ideal in design, the flow loss is usually large.
The conventional centrifugal compressor stage radial diffuser and the conventional centrifugal compressor stage axial diffuser of the small turbojet engine are two-dimensional blades, and the blade profiles at the upper end wall and the lower end wall are basically the same. The radial diffuser is generally wedge-shaped, and the axial diffuser is generally constrained by the axial size, so that the torsion of the airflow is large, and the difference of the inlet angle and the outlet angle is large. Therefore, flow separation and the like often exist behind the radial diffuser, flow in the passage of the axial diffuser is very complex, and the flow separation, the large velocity gradient and the like can generate adverse effects on the flow field. In addition, the traditional centrifugal compressor stage has the conditions that the flow separation at the impeller outlet casing is large, the radial direction of the meridian flow channel is converted into the radial direction of the axial section, the curvature radius is small, and the direction is severe. Both of these conditions can result in a centrifugal compressor stage with a low efficiency.
Disclosure of Invention
The utility model aims to avoid the defects of the prior art and provide a serial diffuser of a centrifugal compressor stage, which obviously inhibits the flow separation at the outlet casing of a centrifugal impeller, has more uniform flow field and reduces the loss.
In order to achieve the purpose, the utility model adopts the technical scheme that: a centrifugal compressor stage serial diffuser comprises a diffuser casing and an axial section casing which are sequentially connected in the air inlet direction of the diffuser, and further comprises a diffuser hub and an axial section hub which is connected behind the diffuser hub; the diffuser casing and the diffuser hub are matched to form a diffuser meridian flow channel, and a diffuser radial front row blade, a diffuser axial rear row main blade and a diffuser axial rear row splitter blade which are respectively fixedly connected with the diffuser hub and the diffuser casing are sequentially arranged in the meridian flow channel along the airflow direction;
the tail edge of the radial front row of blades of the diffuser extends to the curved section of the meridian flow channel, and the radial front row of blades of the diffuser is used for changing radial flow into axial flow in the curved section in advance; the tail edge of the radial front row of blades of the diffuser is close to the front edge of the axial rear row of main blades of the diffuser, and a flow channel gap is arranged between the tail edge of the radial front row of blades of the diffuser and the front edge of the axial rear row of main blades of the diffuser;
the diffuser radial front-row blades are uniformly distributed on the circumferential surface of the diffuser hub, and the diffuser axial back-row main blades and the diffuser axial back-row splitter blades are alternately and uniformly distributed on the axial circumferential surface of the diffuser hub.
Further, the flow passage gap is a gap between a trailing edge pressure surface of the radial front row of blades of the diffuser and a leading edge suction surface of the axial rear row of main blades of the diffuser.
Furthermore, the diffuser axial back row main blades and the adjacent diffuser axial back row splitter blades are a group of diffuser axial back row blades, and an airflow channel formed by the group of diffuser axial back row blades is used for reducing an included angle between airflow and the axial direction; the number of the groups of the blades in the axial back row of the diffuser is the same as that of the blades in the radial front row of the diffuser.
Furthermore, the diffuser casing and the axial section casing, the diffuser hub and the axial section hub form the meridian flow channel, and the meridian flow channel is a composite curve formed by matching a straight line and a Bezier curve; the casing at the axial section of the inlet of the meridian flow passage has a casing contraction section which contracts 1.5-2.5mm towards the direction of the diffuser hub, and the backflow at the diffuser inlet casing is obviously inhibited.
Furthermore, an air inlet channel hub and a diffuser hub are sequentially arranged in the air inlet direction of the diffuser, a centrifugal impeller disc hub is arranged between the air inlet channel hub and the diffuser hub, centrifugal impeller main blades and centrifugal impeller splitter blades are alternately arranged on the windward circumferential surface of the centrifugal impeller disc hub, and the centrifugal impeller disc hub and the centrifugal impeller main blades jointly form a centrifugal impeller and work and rotate at a constant speed;
diffuser air inlet direction is last, still connects gradually and is equipped with intake duct machine casket, centrifugal impeller machine casket, intake duct wheel hub and centrifugal impeller dish wheel hub set up intake duct machine casket and centrifugal impeller machine casket in.
Furthermore, the main blades of the centrifugal impeller and the splitter blades of the centrifugal impeller are uniformly distributed in the circumferential direction.
The utility model has the beneficial effects that: the centrifugal compressor stage serial diffuser provided by the utility model reduces the speed and expands the airflow, and simultaneously changes the airflow flowing direction in the radial section and the axial section successively, thereby changing the condition that most of the turning function of the traditional scheme is borne by the axial diffuser, reducing the load of the second row (axial section) of the serial diffuser, leading the load to be closer to the axial direction, greatly reducing the backflow and the speed gradient in the channel of the axial section, reducing the loss under the condition of giving the requirement of the axial air outlet angle, converting the meridian channel from the radial direction to the axial section with increased curvature radius, relieving the problem of violent turning, and obviously inhibiting the flow separation at the outlet of the centrifugal impeller by the contraction section (14) of the casing at the outlet of the impeller; the advantages are verified by the steady CFD calculation, and the practical loss reduction and the efficiency improvement can be completely realized.
Drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a meridian plane sectional structural schematic of the present invention;
FIG. 3 is a schematic view of a diffuser of the present invention at 50% blade height streamlines;
FIG. 4 is a schematic view of a meridian plane flow line of the present invention;
in the figure: 1. diffuser radial front row blades; 2. the diffuser is axially arranged at the back of the main blade; 3. the diffuser is axially arranged with splitter blades at the back row; 4. a centrifugal impeller main blade; 5. a centrifugal impeller splitter blade; 6. an inlet hub; 7. a centrifugal impeller disc hub; 8. a diffuser hub; 9. an axial segment hub; 10. an air inlet casing; 11. a centrifugal impeller casing; 12. a diffuser casing; 13. an axial section casing, 14 and a casing contraction section.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the utility model.
Example 1: as shown in fig. 1-4, a centrifugal compressor stage serial diffuser comprises a diffuser casing 12 and an axial section casing 13 which are sequentially connected in the air inlet direction of the diffuser, and further comprises a diffuser hub 8 and an axial section hub 9 which is connected behind the diffuser hub 8; the diffuser casing 12 and the diffuser hub 8 are matched to form a diffuser meridian flow channel, the diffuser casing 12, the axial section casing 13, the diffuser hub 8 and the axial section hub 9 form a meridian flow channel, and the meridian flow channel is a composite curve formed by matching a straight line and a Bessel curve; in the meridian flow passage, a diffuser radial front row blade 1, a diffuser axial rear row main blade 2 and a diffuser axial rear row splitter blade 3 which are respectively fixedly connected with a diffuser hub 8 and a diffuser casing 12 are sequentially arranged along the airflow direction; the casing 13 at the inlet of the meridian flow passage has a casing contraction section 14 which contracts 1.5-2.5mm towards the diffuser hub 8, so that backflow at the diffuser inlet casing is remarkably inhibited.
An air inlet channel hub 6 and a diffuser hub 8 are sequentially arranged in the air inlet direction of the diffuser, a centrifugal impeller disc hub 7 is arranged between the air inlet channel hub 6 and the diffuser hub 8, centrifugal impeller main blades 4 and centrifugal impeller splitter blades 5 are alternately arranged on the windward circumferential surface of the centrifugal impeller disc hub 7, and the centrifugal impeller disc hub 7, the centrifugal impeller main blades 4 and the centrifugal impeller splitter blades 5 jointly form a centrifugal impeller which rotates at a constant speed; the main blades 4 of the centrifugal impeller and the splitter blades 5 of the centrifugal impeller are uniformly distributed in the circumferential direction; in the air inlet direction of the diffuser, an air inlet casing 10 and a centrifugal impeller casing 11 are sequentially connected, and an air inlet hub 6 and a centrifugal impeller disc hub 7 are arranged in the air inlet casing 10 and the centrifugal impeller casing 11;
the tail edge of the radial front row of blades 1 of the diffuser extends to the bending section of the meridian flow channel, and the radial front row of blades 1 of the diffuser is used for changing radial flow into axial flow in the bending section in advance; a flow channel gap is arranged between the trailing edge of the radial front-row blades 1 of the diffuser and the leading edge of the axial rear-row main blades 2 of the diffuser, and the flow channel gap is a gap between the trailing edge pressure surface of the radial front-row blades 1 of the diffuser and the leading edge suction surface of the axial rear-row main blades 2 of the diffuser; the flow passage gap enables high-energy fluid on the pressure surface of the radial front-row blades 1 of the diffuser to blow to the suction surface of the axial back-row main blades 2 of the diffuser, which is easy to separate, after being accelerated, so that the separation of the suction surface of the axial back-row main blades 2 of the diffuser is inhibited or delayed;
the radial front row blades 1 of the diffuser are uniformly distributed on the circumferential surface of the hub 8 of the diffuser, and the axial back row main blades 2 and the axial back row splitter blades 3 of the diffuser are alternately and uniformly distributed on the axial circumferential surface of the hub 8 of the diffuser; the diffuser axial back row main blades 2 and the adjacent diffuser axial back row splitter blades 3 are a group of diffuser axial back row blades, and an airflow channel formed by the group of diffuser axial back row blades is used for reducing the included angle between airflow and the axial direction; the number of the groups of the blades in the axial back row of the diffuser is the same as that of the blades 1 in the radial front row of the diffuser.
The working process of the utility model is as follows: when the centrifugal compressor works, a centrifugal impeller consisting of a centrifugal impeller main blade 4, a centrifugal impeller splitter blade 5 and a centrifugal impeller disc hub 7 rotates at a high speed, and due to the action of the high speed of rotation, gas in a gas flow channel formed by adjacent blades is thrown out of the centrifugal impeller and enters a rear structure along the radial direction. The air in the impeller is thrown out, and the air at the inlet of the impeller is sucked into the airflow channel of the centrifugal impeller under the action of pressure. The air at the front end of the centrifugal impeller flows at a high speed, and the pressure is reduced, so that the air in the air inlet formed by the air inlet hub 6 and the air inlet casing 10 flows into the centrifugal impeller, and the outside air flows into the air inlet.
After being thrown out of the centrifugal impeller, gas sequentially enters a diffuser radial front-row blade 1 and a diffuser axial rear-row blade of a diffuser along a certain angle with the radial direction, the radial front-row blade 1 of the diffuser enables the gas flow to be in advance in a bent section to change radial flow in a meridian plane into axial flow in the meridian plane, meanwhile, the speed is reduced and the pressure is increased, the axial rear-row blade of the diffuser enables the gas flow to be closer to the Z axis to change the direction of the gas flow, and finally the gas flow enters a subsequent combustion chamber and other parts.
As shown in fig. 3 and 4, at the gap between the front radial row of blades 1 of the diffuser and the rear axial row of blades of the diffuser, the rear axial row of blades of the diffuser limits the development of the low-speed region of the fluid on the suction surface of the front radial row of blades 1 of the diffuser, the backflow is significantly reduced, and the meridional average flow chart can show that the flow field of the diffuser is very uniform.
The centrifugal compressor stage with the structure can obviously improve the efficiency, the pressure ratio and the like of the centrifugal compressor stage. The centrifugal compressor stage with the structure is used for a small turbojet engine, so that the rated rotating speed can be reduced under the condition of ensuring that the thrust does not change much, and the stable work of the bearing is facilitated. And because the efficiency of the air compressor is greatly improved, the range of the aircraft is increased and the consumption rate of fuel is saved under the condition of carrying fuel oil with the same quality.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (6)
1. A centrifugal compressor stage serial diffuser is characterized by comprising a diffuser casing (12) and an axial section casing (13) which are sequentially connected in the air inlet direction of the diffuser, and further comprising a diffuser hub (8) and an axial section hub (9) which is connected behind the diffuser hub (8); the radial diffuser radial front row blades (1), the axial diffuser rear row main blades (2) and the axial diffuser rear row splitter blades (3) which are fixedly connected with the diffuser hub (8) and the diffuser casing (12) respectively are sequentially arranged in the radial flow channel along the airflow direction;
the tail edge of the radial front row of blades (1) of the diffuser extends to the curved section of the meridian flow channel, and the radial front row of blades (1) of the diffuser are used for changing radial flow into axial flow in the curved section in advance; a flow channel gap is arranged between the tail edge of the front radial row blade (1) of the diffuser and the front edge of the rear axial row main blade (2) of the diffuser, and the flow channel gap enables high-energy fluid on the pressure surface of the front radial row blade (1) of the diffuser to be blown to a suction surface, easy to separate, of the rear axial row main blade (2) of the diffuser after being accelerated, so that the separation of the suction surface of the rear axial row main blade (2) of the diffuser is inhibited or delayed;
the radial front row blades (1) of the diffuser are uniformly distributed on the circumferential surface of the diffuser hub (8), and the axial back row main blades (2) and the axial back row splitter blades (3) of the diffuser are alternately and uniformly distributed on the axial circumferential surface of the diffuser hub (8).
2. The centrifugal compressor stage diffuser according to claim 1, wherein the flow path gap is a gap between a trailing edge pressure surface of a radially front row of blades (1) of the diffuser and a leading edge suction surface of an axially rear row of main blades (2) of the diffuser.
3. The centrifugal compressor stage diffuser in series according to claim 1, wherein the diffuser axial trailing row main blades (2) and the adjacent diffuser axial trailing row splitter blades (3) are a set of diffuser axial trailing row blades, and the set of diffuser axial trailing row blades form an airflow passage for reducing an included angle between an airflow and an axial direction; the number of the groups of the blades in the axial back row of the diffuser is the same as that of the blades (1) in the radial front row of the diffuser.
4. The centrifugal compressor stage diffuser according to claim 1, wherein the diffuser casing (12), the axial section casing (13), the diffuser hub (8) and the axial section hub (9) form the meridian flow path, and the meridian flow path is a compound curve formed by matching a straight line and a Bezier curve; the diffuser casing (12) at the inlet of the meridian flow path has a casing convergent section (14) convergent towards the diffuser hub (8) by 1.5-2.5mm, significantly suppressing flow separation at the diffuser inlet casing.
5. The centrifugal compressor stage serial diffuser according to any one of claims 1 to 4, wherein an air inlet channel hub (6) and a diffuser hub (8) are sequentially arranged in an air inlet direction of the diffuser, a centrifugal impeller disk hub (7) is arranged between the air inlet channel hub (6) and the diffuser hub (8), centrifugal impeller main blades (4) and centrifugal impeller splitter blades (5) are alternately arranged on a windward circumferential surface of the centrifugal impeller disk hub (7), and the centrifugal impeller disk hub (7), the centrifugal impeller main blades (4) and the centrifugal impeller splitter blades (5) jointly form a centrifugal impeller and rotate at a constant speed;
diffuser air inlet direction is last, still connects gradually and is equipped with intake duct machine casket (10), centrifugal impeller machine casket (11), intake duct wheel hub (6) and centrifugal impeller dish wheel hub (7) set up intake duct machine casket (10) and centrifugal impeller machine casket (11) in.
6. The centrifugal compressor stage diffuser according to claim 5, wherein the centrifugal impeller main blades (4) and the centrifugal impeller splitter blades (5) are circumferentially equispaced.
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| CN202123170209.7U CN216589292U (en) | 2021-12-16 | 2021-12-16 | Centrifugal compressor stage serial diffuser |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115962153A (en) * | 2023-03-17 | 2023-04-14 | 潍柴动力股份有限公司 | Compressor and engine with narrowed runner width at noon of transition section |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115962153A (en) * | 2023-03-17 | 2023-04-14 | 潍柴动力股份有限公司 | Compressor and engine with narrowed runner width at noon of transition section |
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