X-shaped twisted impeller for liquid ring pump and liquid ring pump

Abstract

The invention relates to an X-shaped twisted impeller for a liquid ring pump, which comprises a hub, a plurality of X-shaped twisted blades are arranged on the hub, the blade profile of each X-shaped twisted blade is equally divided into six axial sections (a, b, c, d, e and f) with different radiuses from the hub to a rim, and the axial section a at the hub of each X-shaped twisted blade and the axial section f at the rim of each X-shaped twisted blade form an X-shaped structure. The blade inlet angle of each axial section at different radiuses is the same as the inlet relative liquid flow angle at the position of the axial section, and the blade inlet angle of each axial section is equal to the blade outlet angle. According to the technical scheme of the invention, the designed X-shaped twisted blade impeller can effectively reduce the impact loss of an air inlet and an air outlet and reduce flow separation by selecting proper blade molded lines and accurately controlling the twisting angles of the inlet and the outlet at different section positions of the blades, so that the hydraulic loss in the working process is reduced, and the service life of the impeller is prolonged. And the working stability and efficiency of the liquid ring pump are improved.

Description

Technical Field

[0001] The present invention relates to the field of fluid mechanical equipment, and particularly to an X-shaped twisted impeller for a liquid ring pump and a liquid ring pump. Background Art

[0002] A liquid ring pump is a fluid machine used to pump gas. It uses liquid as an intermediate medium for energy conversion. During the working process, the liquid plays roles such as energy transfer, sealing, and cooling. The impeller of the liquid ring pump is eccentrically installed in the housing. Under the action of the high-speed rotation of the impeller, a moving ring, i.e., a liquid ring, is formed on the inner wall of the housing. Its working process is as Figure 1 shown. The gas-liquid two-phase in the pump is approximately in a separated state, forming a zigzag gas-liquid interface, and a large number of small bubbles of different scales splash into the liquid ring. In the existing design of liquid ring pumps, the impeller blades all adopt cylindrical blades and axial suction methods. There is a large incidence angle at the impeller inlet in the suction area, which causes flow separation on the back of the blade inlet, generating a large impact loss and resulting in a decrease in the efficiency of the liquid ring pump. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related technologies.

[0004] To this end, the object of the present invention is to provide an X-shaped twisted impeller for a liquid ring pump and a liquid ring pump, which can reduce the flow impact caused when gas enters and exits the impeller, make the flow in the pump more stable, and thus improve the performance of the liquid ring pump.

[0005] To achieve the above object, a technical solution of the first aspect of the present invention provides an X-shaped twisted impeller for a liquid ring pump, including a hub, on which a plurality of X-shaped twisted blades are provided. On the blade profile of the X-shaped twisted blades, six axial sections (a, b, c, d, e, f) with different radii are equally divided from the hub to the rim. The blade inlet angle of each axial section is equal to the relative liquid flow angle of the inlet at the position of this axial section. The axial section a at the hub of the X-shaped twisted blade and the axial section f at the rim form an X-shaped structure.

[0006] In the above technical solution, preferably, the control parameters of the axial sections taken at different radii of the X-shaped twisted blades include the blade inlet angle, the blade outlet angle, and the impeller axial width B, and the blade inlet angle and the blade outlet angle are the same.

[0007] In the above technical solution, preferably, the relative liquid flow angle of the blade inlet at each axial section of the X-shaped twisted blade gradually decreases along the blade profile from the hub to the rim;

[0008] The circumferential velocity u of each axial section of the X-shaped twisted blade i (i = a, b,..., f) satisfies: ui = ωr i = 2πnr i , where ω is the impeller rotational speed and r i is the impeller radius at section i

[0009] The absolute velocity v1 of the suction port of each axial section of the X-shaped twisted blade satisfies: where Q1 is the volume flow rate of the gas pumped by the liquid ring pump flowing axially into the impeller, and A1 is the cross-sectional area of the suction port.

[0010] The inlet relative liquid flow angle α of the cross-section i (i = a, b,..., f) of the X-shaped twisted blade at a radius of r i satisfies: i1 That is That is

[0011] In the above technical solution, preferably, the axial sections at different radii of the X-shaped twisted blade are deflected by the same angle along the circumferential direction of the impeller.

[0012] In the above technical solution, preferably, the deflection angle of the axial section a at the hub of each X-shaped twisted blade along the circumferential direction of the impeller satisfies:

[0013] The deflection angle of the axial section f at the rim of the X-shaped twisted blade along the circumferential direction of the impeller satisfies: where B is the axial width of the impeller, and r a and r f are the radii of the axial section a and the axial section f respectively, and α a1 and α f1 are the inlet relative liquid flow angles of the axial section a and the axial section f.

[0014] The technical solution of the second aspect of the present invention provides a liquid ring pump, including a housing and an impeller installed in the housing; the impeller adopts the X-shaped twisted impeller provided by any one of the technical solutions in the first aspect of the present invention; the suction and exhaust ports are arranged on opposite sides of the side cover of the liquid ring pump housing, the impinging angle of the axial suction process on the suction port side is 0, and the axial exhaust process on the opposite exhaust port side is a normal outlet.

[0015] Compared with the prior art, the advantages of the X-shaped twisted impeller and the liquid ring pump for the liquid ring pump provided by the present invention are as follows: By selecting a suitable blade profile and precisely controlling the inlet and outlet twist angles at different radius axial section positions on the blade profile, the designed "X"-shaped twisted blade impeller can effectively reduce the impact loss at the inlet and outlet, reduce the separation flow, thereby reducing the hydraulic loss during the working process and improving the working stability and efficiency of the liquid ring pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, wherein:

[0017] Figure 1 The working principle diagram of the liquid ring pump involved in the embodiment of the present invention is shown;

[0018] Figure 2 The three-dimensional structure diagram of the X-type twisted impeller involved in the embodiment of the present invention is shown;

[0019] Figure 3 The vertical plane diagram of the shaft of the X-type twisted impeller involved in the embodiment of the present invention is shown;

[0020] Figure 4 The structure diagram of the cylindrical blade involved in the embodiment of the present invention is shown;

[0021] Figure 5 The structure diagram of the X-type twisted blade involved in the embodiment of the present invention is shown;

[0022] Figure 6 The control parameter analysis diagram of the X-type twisted blade involved in the embodiment of the present invention is shown;

[0023] Figure 7 The modeling principle diagram of the X-type twisted impeller involved in the embodiment of the present invention is shown;

[0024] Wherein, Figures 1 to 7 The corresponding relationship between the reference numerals in the drawings and the component names is as follows:

[0025] 1, hub; 2, X-type twisted blade; 3, cross-section of cylindrical blade; 4, cross-section of X-type twisted blade; 5, suction port; 6, exhaust port. Detailed implementation manners

[0026] In order to more clearly understand the above objects, features and advantages of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0027] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the limitations of the specific embodiments disclosed below.

[0028] As Figures 1 to 7 shown, the X-type twisted impeller for a liquid ring pump according to an embodiment of the present invention includes a hub 1, and a plurality of X-type twisted blades 2 are arranged on the hub 1, that is, keeping the blade profile in the vertical plane of the blade unchanged (as Figure 3As shown in the figure, on the blade profile of the X-shaped twisted blade, six axial sections (a, b, …, f) with different radii are equally divided from the hub to the rim. The blade inlet angle of each section is equal to the relative liquid flow angle at this position. The axial section a at the hub of the X-shaped twisted blade 2 and the axial section f at the rim form an X-shaped structure.

[0029] The control parameters of the axial sections taken at different radii of the X-shaped twisted blade include the blade inlet angle, the blade outlet angle, and the impeller axial width B. The blade inlet angle and the blade outlet angle are the same.

[0030] The present invention takes into account the cylindrical blade 3 of the traditional liquid ring pump as shown in Figure 4 the figure. There is a large incidence angle in its axial air intake process. At the same time, the gas will cause a certain impact on the pump body during the axial exhaust process, which has an adverse effect on the flow inside the liquid ring pump. Therefore, a liquid ring pump with an X-shaped twisted blade 4 is proposed. The main control parameters of the X-shaped twisted blade 4 are the blade inlet and outlet angles, and their sizes are designed according to the relative liquid flow angle at the blade inlet. The relative liquid flow angle at the inlet gradually decreases along the blade profile from the impeller hub to the outer edge. The twist angle of the blade section decreases with the decrease of the relative liquid flow angle at the inlet. Therefore, the designed twisted blade is approximately in the shape of an "X", as shown in Figure 5 the figure.

[0031] In this embodiment, by selecting a suitable blade profile and precisely controlling the inlet and outlet twist angles at the axial section positions with different radii of the blade 2, the "X"-shaped twisted blade 2 impeller designed can effectively reduce the impact loss at the inlet and outlet, reduce the separation flow, thereby reducing the hydraulic loss during the working process and improving the working stability and efficiency of the liquid ring pump.

[0032] In order to reduce the hydraulic loss caused by the backflow and impact at the inlet and outlet under the axial suction and exhaust working conditions of the liquid ring pump, the present invention designs a liquid ring pump with an X-shaped twisted blade. The design principle is as follows: keep the blade profile of the impeller unchanged in the vertical plane of the shaft, as shown in Figure 3 the figure. The absolute velocity v1 of the gas at the suction port and the circumferential velocity u can be calculated from the gas intake and structural parameters of the liquid ring pump. i , combined with the inlet velocity triangle as shown in Figure 4 the figure, the relative liquid flow angle α i1 value is obtained. Control the blade inlet angle and outlet angle of each section of the X-shaped twisted blade to be equal to the relative liquid flow angle (α i1 = γ i1 = γ i2 ), then the incidence angle at the suction port can be made 0, and the axial exhaust process is a normal outlet, thereby reducing the flow impact caused by the gas entering and leaving the impeller, making the flow inside the pump more stable, and achieving the purpose of improving the performance of the liquid ring pump.

[0033] In this embodiment, the blade inlet angle of each cross-section of the blade is equal to the inlet liquid flow angle (α a1 =γ a1 、α b1 =γ b1 …α f1 =γ f1 ); the blade inlet angles of the axial cross-sections a, b, …, f are equal to the blade outlet angles (i.e., γ a1 =γ a2 、γ b1 =γ b2 …γ f1 =γ f2 ); the blade solid is obtained by scanning along the original blade profile from the axial cross-section a at the hub to the axial cross-section f at the rim.

[0034] In the above embodiment, preferably, the relative liquid flow angle of the blade inlet at each axial cross-section at different radii of the X-shaped twisted blade gradually decreases along the blade profile from the hub to the rim;

[0035] The circumferential velocity u i (i = a, b, …, f) of each axial cross-section of the X-shaped twisted blade satisfies: u i =ωr i =2πnr i , where ω is the impeller rotational speed and r i is the impeller radius at the i cross-section;

[0036] The absolute velocity v1 of the suction port of each axial cross-section of the X-shaped twisted blade satisfies: where Q1 is the volume flow rate of the gas pumped by the liquid ring pump flowing axially into the impeller and A1 is the suction port cross-sectional area.

[0037] The relative liquid flow angle α i of the inlet of the axial cross-section i (i = a, b, …, f) of the X-shaped twisted blade at a radius of r i1 satisfies: That is

[0038] In the above embodiment, preferably, each cross-section at different radii of the X-shaped twisted blade is deflected by the same angle along the circumferential direction of the impeller.

[0039] In the above embodiment, preferably, the deflection angle of the axial cross-section a at the hub of the X-shaped twisted blade along the circumferential direction of the impeller satisfies:

[0040] The deflection angle of the axial cross-section f at the rim of the X-shaped twisted blade along the circumferential direction of the impeller satisfies: where B is the axial width of the impeller, r a 、r fis the blade radius of the axial sections a and f, α a1 and α f1 are the inlet relative liquid flow angles of the axial sections a and f.

[0041] To enable the designed blades of the liquid ring pump to achieve good hydraulic performance, according to blade design theory, the impeller blades need to ensure that the blade profiles are consistent in each axial vertical plane along the axial direction (z-axis direction), and the twist angles are equal on each axial vertical plane. The following combines Figure 7 to prove that the designed X-type twisted blades meet the requirements.

[0042] As Figure 7 shown, the designed X-type twisted blades have a certain deflection along the circumferential direction of the impeller in each circumferential development plane. The deflection angles of the axial section a and the axial section f are marked as ∠1 and ∠2 in the figure respectively.

[0043] Proof:

[0044]

[0045] ∴ ∠1 = ∠2.

[0046] That is, the deflection angles of the section a and the section f in the circumferential direction are equal in magnitude. Therefore, the twist angles are equal and the blade profiles are consistent on each axial vertical plane. The three-dimensional entity of the X-type twisted blade for the liquid ring pump is as Figure 2 .

[0047] As Figures 1 to 7 shown, the liquid ring pump according to another embodiment of the present invention includes a housing and an impeller installed in the housing; the impeller includes a hub 1, and a plurality of X-type twisted blades 2 are arranged on the hub 1. The blade profiles of the X-type twisted blades are equally divided into 6 axial sections (a, b,..., f) with different radii from the hub to the rim. The inlet angle of each section blade is the same as the inlet relative liquid flow angle at the position of this section. An air inlet 5, an air outlet 6 and a liquid replenishing port are arranged on the opposite sides (i.e., both sides) of the side cover of the housing (as Figure 1 shown). The attack angle during the axial air intake process on the air inlet side is 0, and the axial exhaust process on the exhaust port side opposite to the air inlet is a normal outlet.

[0048] Compared with the prior art, the advantages of the X-type twisted impeller and the liquid ring pump for the liquid ring pump provided by the present invention are as follows: By selecting a suitable blade profile and precisely controlling the inlet and outlet twist angles at the axial section positions with different radii of the blade, the designed "X"-type twisted blade impeller can effectively reduce the impact loss at the inlet and outlet, reduce the separation flow, thereby reducing the hydraulic loss during the working process, and improving the working stability and efficiency of the liquid ring pump.

[0049] By means of theoretical analysis and numerical simulation to compare the internal flow field and hydraulic performance of cylindrical blades and X-shaped twisted blades, it is found that there is a large angle of attack during the air intake process of cylindrical blades, and a flow separation vortex is likely to occur on the back of the blade in the air intake area. While the design of the "X"-shaped twisted blade can make the inlet angle of attack zero, effectively reducing the impact loss and flow separation phenomenon on the back of the blade. In addition, during the exhaust process of cylindrical blades, the gas flow velocity direction will cause a certain impact on the pump body, while the outlet of the "X"-shaped twisted blade is a normal outlet with small gas energy loss. Therefore, the X-shaped twisted impeller can effectively reduce the hydraulic loss during the working process, improving the working stability and efficiency of the liquid ring pump.

[0050] In the present invention, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "connected to", "fixed" and other terms should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0052] In the description of this specification, the descriptions of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0053] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An X-shaped twisted impeller for a liquid ring pump, comprising a hub, characterized in that: The hub is provided with a plurality of X-shaped twisted blades, and the blade profile of the X-shaped twisted blade is equally divided into 6 axial sections (a, b, c, d, e, f) with different radii from the hub to the rim, and the blade inlet angle of each axial section is equal to the inlet relative liquid flow angle at the position of the axial section, and the axial section a at the hub of the X-shaped twisted blade and the axial section f at the rim form an X-shaped structure.

2. The X-shaped twisted impeller of the liquid ring pump according to claim 1, characterized in that: The control parameters of the axial cross section taken at different radii of the X-shaped twisted blade include the blade inlet angle, the blade outlet angle and the impeller axial width B, and the blade inlet angle is the same as the blade outlet angle.

3. The X-shaped twisted impeller of a liquid ring pump according to claim 1 or 2, characterized in that: The relative liquid flow angle of the blade inlet of each axial section at different radii of the X-shaped twisted blade gradually decreases along the blade profile from the hub to the rim; The circumferential speed u of each axial section of the X-shaped twisted blade i (i=a, b, ..., f) satisfies: u i =ωr i =2πnr i , where ω is the impeller speed, r i is the impeller radius at section i; The absolute velocity v1 of the air inlet of the X-shaped twisted blade satisfies: Among them, the volume flow rate of the gas pumped by the liquid ring pump flowing into the impeller along the axial direction is Q1, and the cross-sectional area of ​​the suction port is A1; The X-shaped twisted blade has a radius of r i The relative flow angle α of the inlet of the section i (i = a, b, ..., f) at i1 satisfy: Right now 4. The X-shaped twisted impeller of the liquid ring pump according to claim 3, characterized in that: Each cross section at different radii of the X-shaped twisted blade is deflected at the same angle along the circumference of the impeller.

5. The X-shaped twisted impeller of the liquid ring pump according to claim 4, characterized in that: The deflection angle of the axial section a at the hub of each X-shaped twisted blade along the impeller circumference satisfies: The deflection angle of the axial section f at the wheel edge of the X-shaped twisted blade along the circumference of the impeller satisfies: Where B is the axial width of the impeller, r a 、r f is the blade radius of the axial section a, f, α a1 , α f1 is the relative liquid flow angle at the inlet of the axial sections a and f.

6. A liquid ring pump adopts axial suction and exhaust mode, characterized in that: The impeller adopts an X-shaped twisted impeller as described in any one of claims 1-5; suction and exhaust ports are arranged on the opposite sides of the side cover of the liquid ring pump housing, the axial suction process angle on the suction port side is 0, and the axial exhaust process on the exhaust port side opposite thereto is a normal outlet.

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