Gradual expansion rotary diffuser based on parametric modeling method and centrifugal compressor

Abstract

The invention provides a divergent rotary diffuser based on a parametric modeling method and a centrifugal compressor. The divergent rotary diffuser comprises an impeller section, a transition vaneless section, a diffuser blade section, a rotary section and a volute section. In the air inlet direction of the diffuser, the transition vaneless section is installed at the rear end of the diffuser impeller section in the radial direction of an outlet, the transition vaneless section is in clearance fit with a diffuser impeller, and the wheel disc side and the wheel cover side of the transition vaneless section are equal in width. After the diffuser blade section is installed on the transition vaneless section, an inlet of the diffuser blade section and an outlet of the transition vaneless section are the same in width. The wheel disc side of the diffuser blade section and the wheel disc side of the transition vaneless section are in the same radial direction, and an expansion angle exists between the wheel cover side of the diffuser blade section and the wheel cover side of the transition vaneless section. After the rotation section is installed on the transition vaneless section, the width of an inlet of the rotation section is the same as that of an outlet of the transition vaneless section. According to the technical scheme, radial installation of the centrifugal compressor diffuser can be reduced, and the modeling difficulty is further reduced by adopting a parametric modeling method.

Description

Technical Field

[0001] The invention belongs to the technical field of compressor design, and in particular relates to a gradually expanding rotary diffuser and a centrifugal compressor based on a parametric modeling method. Background Art

[0002] The centrifugal compressor is mainly composed of a rotor and a stator. The rotor is equipped with an impeller, and the stator includes a diffuser and a volute. When the impeller rotates, the gas is sucked into the impeller and accelerated, and then enters the diffuser, where the gas velocity decreases and the pressure increases. Finally, the gas is discharged from the compressor through the volute. The gas at the impeller outlet usually has large kinetic energy and velocity energy, and a diffuser is required to reduce the speed and increase the pressure of the gas. The blade diffuser guides the airflow through blades so that the gas flows in a predetermined direction. It can effectively control the flow direction of the airflow, reduce flow losses along the way, and improve efficiency. Under design conditions, the efficiency of a blade diffuser is usually about 3% to 5% higher than that of a bladeless diffuser.

[0003] At present, there are many types of diffusers. The diffuser type that reduces the radial size of the diffuser is mainly a conformal diffuser used in some special models. The research on this type of diffuser has not been proposed for a long time, and the research on it is still in the preliminary stage. The installation of conventional blade diffusers usually requires a larger radial installation position to install the blades and arrange the flow passage between the volute. In some installation scenarios with limited axial dimensions, it is difficult to achieve coordinated installation. In addition, the shape of the diffuser blades is usually a complex nonlinear surface, which makes it difficult to model the blades and flow passages and perform subsequent optimization work through a process-based modeling method.

[0004] Therefore, how to provide a gradually expanding rotary diffuser and centrifugal compressor based on parametric modeling methods, which can reduce the radial installation of the centrifugal compressor diffuser, and use parametric modeling methods to further reduce the modeling difficulty has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The embodiment of the present invention provides a gradually expanding rotary diffuser and a centrifugal compressor based on a parametric modeling method, which can reduce the radial installation of the centrifugal compressor diffuser and further reduce the modeling difficulty by using a parametric modeling method.

[0006] In one embodiment of the present invention, a gradually expanding rotary diffuser based on a parametric modeling method is provided, comprising: an impeller section, a transition bladeless section, a diffuser blade section, a rotary section, and a volute section;

[0007] Along the air inlet direction of the gradually expanding rotary diffuser, the transition bladeless section is installed at the rear end of the diffuser impeller section in the radial direction of the outlet, there is a clearance fit between the transition bladeless section and the diffuser impeller, and the wheel disc side and the wheel cover side of the transition bladeless section are of equal width;

[0008] The diffuser blade segment is installed behind the transition bladeless segment, and the inlet of the diffuser blade segment is the same width as the outlet of the transition bladeless segment;

[0009] The wheel disc side of the diffuser blade segment is maintained in the same radial direction as the wheel disc side of the transition bladeless segment, and the wheel cover side of the diffuser blade segment and the wheel cover side of the transition bladeless segment have an expansion angle;

[0010] The rotating section is installed after the transition bladeless section. The inlet of the rotating section has the same width as the outlet of the transition bladeless section. The rotating section rotates to the radial direction through two quarter circles and is connected to the volute section.

[0011] Furthermore, the gradually expanding rotary diffuser comprises:

[0012] The inlet and outlet of the transition bladeless section are designed with equal width; the impeller outlet airflow of the gradually expanding rotary diffuser is in a high-speed state, and the transition bladeless section performs preliminary rectification on the impeller outlet airflow, reduces the airflow angle of the fluid entering the diffuser blade section, and reduces separation and loss.

[0013] Furthermore, the gradually expanding rotary diffuser comprises:

[0014] The value of R3 / R2 is 1.1-1.2, and the value of b2 / b1 is 1.02-1.05;

[0015] Among them, R2 is the impeller radius, R3 is the leading edge radius of the diffuser blade, b1 is the impeller outlet width, and b2 is the diffuser inlet width.

[0016] Furthermore, the wheel cover side of the diffuser blade segment adopts an equal-angle gradual expansion design to increase the flow area of ​​the fluid through the expansion angle; wherein the R4 / R3 value is 1.3-1.9, and the α1 value is 1°-25°;

[0017] Furthermore, the blade profile of the diffuser blade segment is spliced ​​by parameterized arcs, and along the tangent direction of the blade height, the trailing edge L3 of the blade is determined by a circle with a given origin as the center and R4 as the radius; the leading edge boundary of the blade is determined by a circle with a given origin as the center and R3 as the radius; the pressure surface curve L1 is determined by the center radius value of the given Ra circle for constructing the pressure surface; the pressure surface curve L2 is determined by the center radius value of the given Rb circle for constructing the pressure surface; and the leading edge L4 is constructed by constructing a tangent circle given the leading edge radius value and keeping it connected with L1, L2 and the leading edge boundary.

[0018] Furthermore, the gradually diverging rotary diffuser completes the entire blade height section profile of the diffuser blade segment, and is stretched along the hub surface toward the wheel cover side in its meridian direction to complete the three-dimensional modeling of the entire blade.

[0019] Furthermore, the turning section adopts an equal-width turning design. By adjusting the r1 turning section cover side radius and the r2 turning section hub side radius, the width of the reflow section is kept the same as the blade section outlet width of the gradually expanding turning diffuser, which is used to smoothly guide the 90° turn of the airflow into the volute section and reduce the radial dimension.

[0020] In yet another embodiment of the present invention, a centrifugal compressor is provided, wherein the centrifugal compressor comprises a gradually expanding rotary diffuser based on a parametric modeling method as described in any one of the above.

[0021] The beneficial effects brought by the present invention are as follows:

[0022] It can be seen from the above scheme that the embodiment of the present invention provides a gradually expanding rotary diffuser and a centrifugal compressor based on a parametric modeling method, including: an impeller section, a transition bladeless section, a diffuser blade section, a rotary section and a volute section. Along the air inlet direction of the gradually expanding rotary diffuser, the transition bladeless section is installed at the rear end of the radial direction of the outlet of the diffuser impeller section, there is a clearance fit between the transition bladeless section and the diffuser impeller, and the wheel disc side and the wheel cover side of the transition bladeless section are the same width; the diffuser blade section is installed after the transition bladeless section, and the inlet of the diffuser blade section is the same width as the outlet of the transition bladeless section; the wheel disc side of the diffuser blade section maintains the same radial direction as the wheel disc side of the transition bladeless section, and there is an expansion angle between the wheel cover side of the diffuser blade section and the wheel cover side of the transition bladeless section; the rotary section is installed after the transition bladeless section, and the inlet of the rotary section is the same width as the outlet of the transition bladeless section. The technical scheme of the present invention can reduce the radial installation of the centrifugal compressor diffuser, and adopt the parametric modeling method to further reduce the modeling difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of a gradually expanding rotary diffuser based on a parametric modeling method according to an embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram showing a parameterized blade profile of a gradually diverging rotary diffuser based on a parameterized modeling method according to an embodiment of the present invention;

[0025] In the figure, 1 is the impeller section, 2 is the transition bladeless section, 3 is the diffuser blade section, 4 is the rotary section, and 5 is the volute section. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] At present, the blade diffuser has obvious advantages over the bladeless diffuser in terms of performance, but it currently has the following disadvantages:

[0028] In order to achieve higher efficiency and supercharging effect, the installation of the diffuser usually requires a larger radial installation position to install the blades and arrange the flow passage between the diffuser and the volute. In some installation scenarios with limited axial dimensions, it is difficult to achieve coordinated installation.

[0029] The shape of diffuser blades is usually a complex nonlinear surface, which makes it difficult to model and subsequently optimize the blades and flow channels through a process-based modeling method.

[0030] The embodiment of the present invention adopts a gradually expanding rotary diffuser based on a parametric modeling method, which can reduce the radial installation of the centrifugal compressor diffuser, and adopts a parametric modeling method to reduce the modeling difficulty.

[0031] like Figure 1 and Figure 2 As shown, Figure 1 A schematic structural diagram of a gradually expanding rotary diffuser based on a parametric modeling method according to an embodiment of the present invention is shown; Figure 2 A schematic diagram of blade profile parameterization of a gradually diverging rotary diffuser based on a parametric modeling method according to an embodiment of the present invention is shown.

[0032] Figure 1 In the invention, a gradually expanding rotary diffuser based on a parametric modeling method comprises: an impeller section 1, a transition bladeless section 2, a diffuser blade section 3, a rotary section 4 and a volute section 5.

[0033] Along the air inlet direction of the gradually expanding rotary diffuser, the transition bladeless section is installed at the rear end of the diffuser impeller section in the radial direction of the outlet, there is a clearance fit between the transition bladeless section and the diffuser impeller, and the wheel disc side and the wheel cover side of the transition bladeless section are of equal width;

[0034] The diffuser blade segment is installed behind the transition bladeless segment, and the inlet of the diffuser blade segment is the same width as the outlet of the transition bladeless segment;

[0035] The wheel disc side of the diffuser blade segment is maintained in the same radial direction as the wheel disc side of the transition bladeless segment, and the wheel cover side of the diffuser blade segment and the wheel cover side of the transition bladeless segment have an expansion angle;

[0036] The rotating section is installed after the transition bladeless section. The inlet of the rotating section has the same width as the outlet of the transition bladeless section. The rotating section rotates to the radial direction through two quarter circles and is connected to the volute section.

[0037] In an embodiment of the present invention, a gradually expanding and rotating diffuser blade structure first increases the diffusion efficiency and reduces the radial size by gradually expanding the diffuser blades and adjusting the airflow direction of the rotating section. Next, a parametric modeling method for the flow channel and blade profile of this type of diffuser is given, and the three-dimensional modeling and adjustment of the diffuser flow channel can be completed through control points.

[0038] In an embodiment of the present invention, the gradually expanding rotary diffuser comprises:

[0039] The inlet and outlet of the transition bladeless section are designed with equal width; the impeller outlet airflow of the gradually expanding rotary diffuser is in a high-speed state, and the transition bladeless section performs preliminary rectification on the impeller outlet airflow, reduces the airflow angle of the fluid entering the diffuser blade section, and reduces separation and loss.

[0040] In one embodiment of the present invention, the gradually expanding rotary diffuser comprises:

[0041] The value of R3 / R2 is 1.1-1.2, and the value of b2 / b1 is 1.02-1.05;

[0042] Among them, R2 is the impeller radius, R3 is the leading edge radius of the diffuser blade, b1 is the impeller outlet width, and b2 is the diffuser inlet width.

[0043] In one embodiment of the present invention, the shroud side of the diffuser blade segment adopts an equal-angle gradual expansion design to increase the flow area of ​​the fluid through the expansion angle; wherein the R4 / R3 value is 1.3-1.9, and the α1 value is 1°-25°;

[0044] In the embodiment of the present invention, the flow area of ​​the fluid is increased by the expansion angle, so that the speed reduction and pressure increase of the fluid are achieved with a smaller radial size.

[0045] In one embodiment of the present invention, the blade profile of the diffuser blade segment is spliced ​​by parameterized arcs, and along the tangent direction of the blade height, the trailing edge L3 of the blade is determined by a circle with a given origin as the center and R4 as the radius; the leading edge boundary of the blade is determined by a circle with a given origin as the center and R3 as the radius; the pressure surface curve L1 is determined by the center radius value of the given Ra circle for constructing the pressure surface; the pressure surface curve L2 is determined by the center radius value of the given Rb circle for constructing the pressure surface; and the leading edge L4 is constructed by constructing a tangent circle given the leading edge radius value and keeping it connected with L1, L2 and the leading edge boundary.

[0046] In one embodiment of the present invention, the gradually diverging rotary diffuser completes the entire blade height section profile of the diffuser blade segment, and is stretched along the hub surface toward the wheel cover side in its meridian direction to complete the three-dimensional modeling of the entire blade.

[0047] In one embodiment of the present invention, the turning section adopts an equal-width turning design. By adjusting the r1 turning section cover side radius and the r2 turning section hub side radius, the width of the reflow section is kept the same as the outlet width of the blade section of the gradually expanding turning diffuser, which is used to smoothly guide the 90° turn of the airflow into the volute section and reduce the radial dimension.

[0048] In the embodiment of the present invention, the bladeless transition section, the diffuser blade section, and the rotary section are integrated to ensure the continuity of the airflow channel, improve the steady flow performance of the diffuser channel, and suppress the flow separation phenomenon to a certain extent. At the same time, the gradually expanding blade structure can also effectively reduce the radial size of the diffuser, ensuring a compact structure and small flow loss.

[0049] In addition, the diffuser blade shape can adapt to high Mach number inflow, and at the same time has good diffusion pressure without flow separation. Finally, the blade is modeled by parametric modeling, and the modeling parameters are simplified to reduce the modeling difficulty. In summary, this patent proposes an efficient diffuser structure with good flow stability, compact structure and simple modeling method, which can improve the performance of the diffuser and reduce the radial size.

[0050] In yet another embodiment of the present invention, a centrifugal compressor is provided, wherein the centrifugal compressor comprises a gradually expanding rotary diffuser based on a parametric modeling method as described in any one of the above.

[0051] In an embodiment of the present invention, a gradually expanding and reversing diffuser and a centrifugal compressor based on a parametric modeling method include: an impeller section, a transition bladeless section, a diffuser blade section, a reversing section, and a volute section. Along the air inlet direction of the gradually expanding and reversing diffuser, the transition bladeless section is installed at the rear end of the outlet radial direction of the diffuser impeller section, there is a clearance fit between the transition bladeless section and the diffuser impeller, and the wheel disc side and the wheel cover side of the transition bladeless section are the same width; the diffuser blade section is installed after the transition bladeless section, and the inlet of the diffuser blade section is the same width as the outlet of the transition bladeless section; the wheel disc side of the diffuser blade section maintains the same radial direction as the wheel disc side of the transition bladeless section, and there is an expansion angle between the wheel cover side of the diffuser blade section and the wheel cover side of the transition bladeless section; the reversing section is installed after the transition bladeless section, and the inlet of the reversing section is the same width as the outlet of the transition bladeless section.

[0052] The technical solution of the present invention can reduce the radial installation of the centrifugal compressor diffuser and further reduce the difficulty of modeling by adopting the parametric modeling method.

[0053] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A gradually expanding rotary diffuser based on a parametric modeling method, characterized in that: The gradually expanding rotary diffuser comprises: an impeller section, a transition bladeless section, a diffuser blade section, a rotary section and a volute section; Along the air inlet direction of the gradually expanding rotary diffuser, the transition bladeless section is installed at the rear end of the diffuser impeller section in the radial direction of the outlet, there is a clearance fit between the transition bladeless section and the diffuser impeller, and the wheel disc side and the wheel cover side of the transition bladeless section are of equal width; The diffuser blade segment is installed behind the transition bladeless segment, and the inlet of the diffuser blade segment is the same width as the outlet of the transition bladeless segment; The wheel disc side of the diffuser blade segment is maintained in the same radial direction as the wheel disc side of the transition bladeless segment, and the wheel cover side of the diffuser blade segment and the wheel cover side of the transition bladeless segment have an expansion angle; The rotating section is installed after the transition bladeless section. The inlet of the rotating section has the same width as the outlet of the transition bladeless section. The rotating section rotates to the radial direction through two quarter circles and is connected to the volute section.

2. The gradually expanding rotary diffuser based on the parametric modeling method according to claim 1, characterized in that: The gradually expanding rotary diffuser comprises: The inlet and outlet of the transition bladeless section are designed with equal width; the impeller outlet airflow of the gradually expanding rotary diffuser is in a high-speed state, and the transition bladeless section performs preliminary rectification on the impeller outlet airflow, reduces the airflow angle of the fluid entering the diffuser blade section, and reduces separation and loss.

3. The gradually expanding rotary diffuser based on the parametric modeling method according to claim 2, characterized in that: The gradually expanding rotary diffuser comprises: The value of R3 / R2 is 1.1-1.2, and the value of b2 / b1 is 1.02-1.05; Among them, R2 is the impeller radius, R3 is the leading edge radius of the diffuser blade, b1 is the impeller outlet width, and b2 is the diffuser inlet width.

4. The gradually expanding rotary diffuser based on the parametric modeling method according to claim 1, characterized in that: The wheel cover side of the diffuser blade segment adopts an equal-angle gradual expansion design to increase the flow area of ​​the fluid through the expansion angle; wherein the R4 / R3 value is 1.3-1.9, and the α1 value is 1°-25°.

5. The gradually expanding rotary diffuser based on the parametric modeling method according to claim 1, characterized in that: The blade profile of the diffuser blade segment is spliced ​​by parameterized arcs. Along the tangent direction of the blade height, the trailing edge L3 of the blade is determined by a circle with a given origin as the center and R4 as the radius; the leading edge boundary of the blade is determined by a circle with a given origin as the center and R3 as the radius; the pressure surface curve L1 is determined by the center radius value of the Ra circle for constructing the pressure surface; the pressure surface curve L2 is determined by the center radius value of the Rb circle for constructing the pressure surface; and the leading edge L4 is constructed by constructing a tangent circle given the leading edge radius value and keeping it connected with L1, L2 and the leading edge boundary.

6. The gradually expanding rotary diffuser based on the parametric modeling method according to claim 5, characterized in that: The gradually expanding rotary diffuser completes the entire blade height section blade profile of the diffuser blade segment, and is stretched along the hub surface toward the wheel cover side in its meridian direction to complete the three-dimensional modeling of the entire blade.

7. The gradually expanding rotary diffuser based on the parametric modeling method according to claim 1, characterized in that: The rotating section adopts an equal-width rotating design. By adjusting the r1 rotating section cover side radius and the r2 rotating section hub side radius, the width of the reflow section is kept the same as the blade section outlet width of the gradually expanding rotating diffuser, which is used to smoothly guide the 90° turn of the airflow into the volute section and reduce the radial dimension.

8. A centrifugal compressor, characterized in that: The centrifugal compressor comprises a gradually diverging rotary diffuser based on a parametric modeling method as described in any one of claims 1 to 7.

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