Non-clogging two-phase flow semi-open type sewage pump impeller and design method thereof

Abstract

The invention relates to a non-clogging two-phase flow semi-open type sewage pump impeller and a design method of the impeller, the non-clogging two-phase flow semi-open type sewage pump impeller comprises an impeller body, and 2-4 blades are arranged on the impeller body; when the number of the blades is small, wrap angles are increased, inlet edges of the blades are of blade sweepback structures, and back blades are arranged on the back face of the impeller body; the area change between the impeller inlet area and the impeller outlet area is uniformly and progressively increased; the impeller body, the blades and the back blades are integrally formed. By means of the innovative impeller design, accumulation and blockage of solids and impurities in the pump are effectively avoided, and therefore continuous and stable operation of the sewage pump is guaranteed. According to the design of the impeller, the hydrodynamic characteristics are optimized, the impact of bubbles on parts in the pump is reduced, the anti-cavitation capacity of the sewage pump is remarkably improved, and the service life of the pump is prolonged. Various solid-liquid mixtures can be smoothly treated, meanwhile, energy loss is reduced, and the overall working efficiency is improved.

Description

Technical Field

[0001] The present invention relates to a sewage pump impeller and a design method for the impeller, and in particular to a non-clogging two-phase flow semi-open sewage pump impeller with good impeller flow performance, good cavitation performance and stable comprehensive performance and a design method for the impeller. Background Art

[0002] Sewage pumps are generally used in municipal sewage, industrial wastewater treatment, mine drainage and other fields. The medium they transport mainly contains solid-liquid mixed fluids containing multiple complex components such as solid particles, fiber materials, sludge, etc. The traditional sewage pump impeller design, limited by its narrow flow channel structure, often encounters blockage problems frequently, and requires frequent shutdown maintenance, which seriously affects the operating efficiency and increases the maintenance cost; and the non-clogging impeller design on the current market has shown certain advantages in anti-clogging performance, but unfortunately, they are faced with problems such as low efficiency and insufficient anti-cavitation ability. With the increasingly stringent requirements of all sectors of society for energy conservation and environmental protection, and the significant increase in the working conditions of handling media such as high-concentration particles and long-fiber impurities, the existing sewage pump design faces challenges in balancing anti-clogging performance, improving work efficiency and ensuring long-term stable operation reliability. More importantly, the current design schemes mostly rely on traditional experience and lack an in-depth understanding and systematic application of the interaction mechanism between solid and liquid phases, which directly leads to the unstable dynamic performance of the pump and makes it difficult to meet the complex and changing application requirements. Therefore, exploring a new sewage pump design that can effectively prevent blockage while taking into account efficient operation and long-term reliability has become a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the above problems, the main purpose of the present invention is to provide a non-clogging two-phase flow semi-open sewage pump impeller with good impeller flow performance, good cavitation performance and stable comprehensive performance, and a design method for the impeller.

[0004] The present invention solves the above technical problems through the following scheme: a non-clogging two-phase flow semi-open sewage pump impeller, the non-clogging two-phase flow semi-open sewage pump impeller comprises: an impeller body, on which 2-4 blades are arranged; when the number of blades is small, the wrap angle is increased, the inlet edge of the blade is a blade swept structure, and a back blade is arranged on the back of the impeller body; the area change between the impeller inlet area F1 and the impeller outlet area F2 is uniformly increased; the impeller body, the blades and the back blades are integrally formed.

[0005] The back blades can reduce the airflow separation on the back of the main blades, improve the stability of fluid flow, and prevent turbulence and vibration; the back blades can balance the axial force, reduce the load on the main blades, reduce wear, and extend the service life.

[0006] In a specific implementation example of the present invention, the area change between the impeller inlet area F1 and the impeller outlet area F2 is uniformly increased, and

[0007] In a specific implementation example of the present invention, the streamline radius R1 of the impeller front cover is greater than or equal to 25 mm.

[0008] In a specific implementation example of the present invention, the back blades include 5 to 12 blades.

[0009] In a specific implementation example of the present invention, when the pump body outlet diameter is 32-250 mm (including 250 mm) and the number of blades is 2, the wrap angle φ is 160°-230°.

[0010] In a specific implementation example of the present invention, when the pump body outlet diameter is 250-500 mm (excluding 250 mm) and the number of blades is 3, the wrap angle φ is 150°-210°.

[0011] In a specific implementation example of the present invention, when the pump body outlet diameter is greater than 500 mm and the number of blades is 3 or 4, the wrap angle φ is set at 120°-180°.

[0012] A design method for a non-clogging two-phase flow semi-open sewage pump impeller, the design method comprising the following steps:

[0013] Step 1: Determine the design flow rate Q, design head H, speed n, and the medium to be transported; in order to ensure good passing performance and better anti-cavitation performance, the impeller is designed with a small number of blades Z and a large inlet, so the area of ​​the impeller flow channel needs extra attention. This method is applicable to the specific speed n s =70-280, the value is obtained as follows:

[0014] (1) Determine the impeller inlet diameter:

[0015]

[0016] The value range of k0 is 4.6-5.5; the range of 4.6-5.5 includes 4.6 and 5.5;

[0017] (2) Determine the impeller outlet diameter and outlet width:

[0018]

[0019] The above values ​​of 9.4-11.5 include 9.4 and 11.5; the smaller the specific speed, the larger the coefficient;

[0020]

[0021] The above 1.8-2.4 includes 1.8 and 3.0. The smaller value is used for small pumps and the larger value is used for large pumps.

[0022] In the above formula:

[0023] D j ——Impeller inlet diameter, (mm)

[0024] Q——Pump flow rate, (m 3 / s)

[0025] k0——coefficient

[0026] n——Pump speed, (r / min)

[0027] D2——impeller outlet diameter, (m)

[0028] n s ——Specific speed of the pump, where

[0029] H——head of the pump at design point, (m);

[0030] Step 2: Determine the exit placement angle

[0031] In order to ensure that the overall sewage pump does not exceed the power, it is necessary to ensure that the head drop trend is steeper; the outlet angle is generally selected between 13°-22°;

[0032] Step 3: Draw the streamlines of the front and rear covers:

[0033] R1 is the streamline radius of the impeller front cover, and R2 is the streamline radius of the impeller rear cover. In order to ensure that the sewage pump has a better passing performance, R1 is usually slightly larger, usually not less than 25mm.

[0034] Step 4: Correct the impeller inlet and outlet areas:

[0035] After the impeller inlet and outlet diameters and the impeller outlet width are designed, the impeller inlet area F1 and the impeller outlet area F2 can be obtained. If the area change from F1 to F2 is uniformly increasing, and Then you can proceed to the next step. If it does not meet the requirements, you need to modify step one until it meets the requirements.

[0036] Step 5: Determine the wrap angle, number of blades and blade inlet edge curve:

[0037] The number of impeller blades is determined according to the pump body outlet diameter, generally 2-4 blades. When determining the wrap angle, it is necessary to comprehensively consider the blade extrusion and surface friction. When there are fewer blades, the wrap angle should be appropriately increased. The relevant value parameters are as follows:

[0038] When the pump body outlet diameter is 32-250mm (including 250mm) and the number of blades is 2, the wrap angle φ is 160°-230°.

[0039] When the pump body outlet diameter is 250-500mm (excluding 250mm) and the number of blades is 3, the wrap angle φ is 150°-210°.

[0040] When the pump body outlet diameter is greater than 500mm and the number of blades is 3 or 4, the wrap angle φ is 120°-180°.

[0041] In a specific implementation example of the present invention, a swept-back blade design is adopted.

[0042] The positive progress of the present invention is that the non-clogging two-phase flow semi-open sewage pump impeller and the design method of the impeller provided by the present invention have the following advantages compared with the common similar technologies:

[0043] (1) Significantly improved anti-clogging performance: When traditional sewage pumps process solid-liquid mixed fluids containing complex components such as solid particles, fiber materials and sludge, they are often blocked due to improper impeller design. The present invention effectively avoids the accumulation and blockage of these solids and impurities in the pump through innovative impeller design, thereby ensuring the continuous and stable operation of the sewage pump.

[0044] (2) Enhanced anti-cavitation capability: When conveying media containing bubbles, conventional sewage pumps are prone to cavitation, which not only affects the performance of the pump but may also damage the pump body. The impeller design of the present invention optimizes the fluid dynamics, reduces the impact of bubbles on the internal components of the pump, significantly improves the anti-cavitation capability of the sewage pump, and extends the service life of the pump.

[0045] (3) Improved flowability and efficiency: Through sophisticated flow channel design and optimized impeller structure, the sewage pump of the present invention exhibits better flowability when conveying complex fluids, and can smoothly handle various solid-liquid mixtures, while reducing energy loss and improving overall work efficiency. This not only reduces energy consumption, but also improves the economic efficiency of pump operation.

[0046] (4) Easy maintenance: Due to the semi-open design, the sewage pump of the present invention is easier to maintain and clean than a fully enclosed impeller, which reduces maintenance costs and time and improves the availability and reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is one of the overall structural schematic diagrams of the present invention (the front side of the line diagram).

[0048] Figure 2 This is the second schematic diagram of the overall structure of the present invention (the front side of the effect diagram).

[0049] Figure 3 This is the third schematic diagram of the overall structure of the present invention (the back of the effect diagram).

[0050] Figure 4 This is the fourth schematic diagram of the overall structure of the present invention (drawing the streamlines of the front and rear cover plates).

[0051] Figure 5 This is the fifth schematic diagram of the overall structure of the present invention (drawing the streamlines of the front and rear cover plates).

[0052] Figure 6 It is a comparison diagram of the inlet edge of the present invention and the common technology.

[0053] Figure 7 It is a comparison chart of the flow channel area of ​​the present invention and the common technology.

[0054] The following are the names corresponding to the labels in the present invention:

[0055] Impeller body 1, blades 2, blade swept structure 3, back blades 4. DETAILED DESCRIPTION

[0056] Preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to illustrate the technical solutions of the present invention in detail.

[0057] Figure 1 This is one of the overall structural schematic diagrams of the present invention (front side of the line diagram), Figure 2 This is the second schematic diagram of the overall structure of the present invention (front view of the effect diagram). Figure 3 The third schematic diagram of the overall structure of the present invention (the back of the effect diagram) is shown in FIG. Figure 1-3 The present invention proposes a non-clogging two-phase flow semi-open sewage pump impeller, which includes: an impeller body 1, on which 2-4 blades 2 are arranged; when the number of blades 2 is small, the wrap angle is increased, the inlet edge of the blade 2 is a blade swept structure 3, and a back blade 4 is arranged on the back of the impeller body 1; the impeller body 1, the blade 2 and the back blade 4 are integrally formed.

[0058] The back blades include 5-12 pieces. The back blades can reduce the airflow separation on the back of the main blades, improve the stability of fluid flow, and prevent turbulence and vibration. The back blades can balance the axial force, reduce the load of the main blades, reduce wear, and extend the service life.

[0059] The inlet edge of the blade 2 is a blade swept structure 3, see Figure 6 , A in the figure is a blade with a swept-back structure, and B in the figure (the dotted line) is the structure in the current common technology.

[0060] The present invention proposes a non-clogging two-phase flow semi-open sewage pump impeller design method, and the non-clogging two-phase flow semi-open sewage pump impeller design method mainly comprises the following steps:

[0061] Step 1: Determine the design flow rate Q, design head H, speed n, and the medium to be transported; in order to ensure good passing performance and better anti-cavitation performance, the impeller is designed with a small number of blades Z and a large inlet, so the area of ​​the impeller flow channel needs extra attention. This method is applicable to the specific speed n s =70-280, the value is obtained as follows:

[0062] (1) Determine the impeller inlet diameter

[0063]

[0064] The value range of k0 is 4.6-5.5; the range of 4.6-5.5 includes 4.6 and 5.5;

[0065] (2) Determine the impeller outlet diameter and outlet width

[0066]

[0067] The above values ​​of 9.4-11.5 include 9.4 and 11.5; the smaller the specific speed, the larger the coefficient;

[0068]

[0069] The above 1.8-2.4 includes 1.8 and 3.0. The smaller value is used for small pumps and the larger value is used for large pumps.

[0070] In the above formula:

[0071] D j ——Impeller inlet diameter, (mm)

[0072] Q——Pump flow rate, (m 3 / s)

[0073] k0——coefficient

[0074] n——Pump speed, (r / min)

[0075] D2——impeller outlet diameter, (m)

[0076] n s ——Specific speed of the pump, where

[0077] H——head at design point of pump, (m)

[0078] Step 2: Determine the exit placement angle

[0079] In order to ensure that the overall sewage pump does not exceed the power, it is necessary to ensure that the head drop trend is steeper. The outlet angle is generally selected between 13°-22°.

[0080] Step 3: Draw the front and rear cover streamlines

[0081] like Figure 4 As shown, R1 is the streamline radius of the impeller front cover, and R2 is the streamline radius of the impeller rear cover. In order to ensure that the sewage pump has a better passing performance, R1 is usually slightly larger, usually not less than 25mm, and R2 is slightly smaller, generally determined according to the flow area, to ensure its passing performance.

[0082] Step 4: Correct the impeller inlet and outlet areas

[0083] After the impeller inlet and outlet diameters and the impeller outlet width are designed, the impeller inlet area F1 and the impeller outlet area F2 can be obtained. If the area change from F1 to F2 is uniformly increasing, and Then you can proceed to the next step. If it does not meet the requirements, you need to modify step one until it meets the requirements.

[0084] Step 5: Determine the wrap angle, number of blades, and blade inlet edge curve

[0085] The number of impeller blades is determined according to the pump body outlet diameter, generally 2-4 blades. When determining the wrap angle, it is necessary to comprehensively consider the blade extrusion and surface friction. When there are fewer blades, the wrap angle should be appropriately increased. The relevant value parameters are as follows:

[0086] Pump outlet diameter 32-250 250-500 ＞500 Number of blades Z (pieces) 2 3 3 or 4 Wrap angle φ(°) 160-230 150-210 120-180

[0087] In order to improve the flow characteristics, avoid dirt entanglement, and improve the anti-cavitation performance, the present invention adopts a swept blade design.

[0088] The following is a specific implementation example: In the specific implementation example of the present invention, the design flow rate is 350m 3 / h, the design head is 38m, the speed is 1475r / min, the hub diameter is 76mm, and the pump outlet diameter is 150mm. The calculated specific speed is 110.

[0089] Step 1:

[0090] (1) Determine the impeller inlet diameter

[0091] Take 220mm

[0092] (2) Determine the impeller outlet diameter and outlet width Take 440mm

[0093] Take 36mm

[0094] Step 2: Determine the outlet placement angle β2

[0095] The outlet placement angle β2 of this design is 20°.

[0096] Step 3: Draw the front and rear cover streamlines

[0097] According to the relevant parameters of step 1, the front and rear cover streamlines of this case are determined, such as Figure 5 shown.

[0098] Step 4: Correct the impeller inlet and outlet areas:

[0099] The impeller inlet and outlet areas are checked, and the area changes are shown in the figure below. The outlet area F2 / inlet area F1 of this scheme is F2 / F1=1.48, which meets the relevant design requirements, and the area changes are uniform and increasing.

[0100] Step 4: Determine the wrap angle, number of blades and blade inlet edge curve:

[0101] The outlet diameter of this scheme is 250mm. According to Table 1, the number of blades is 2, the blade wrap angle is 220°, and the inlet edge curve is shown in the figure below.

[0102] (1) Parameter comparison

[0103]

[0104]

[0105] (2) Comparison of axial sections (see Figure 7 ): From the axial section, the flow channel area of ​​this scheme (line C in the figure) is obviously larger than that of the existing scheme (line D in the figure). The impeller of the sewage pump of this scheme is not easy to be blocked and has good passability.

[0106] (3) Comparison of blade inlet edge shape: The blade inlet edge shape of this solution is designed with a swept blade, which can improve flow characteristics, avoid dirt entanglement, and improve anti-cavitation performance.

[0107] The anti-clogging performance of the present invention is significantly improved: when traditional sewage pumps process solid-liquid mixed fluids containing complex components such as solid particles, fiber materials and sludge, they are often blocked due to improper impeller design. The present invention effectively avoids the accumulation and blockage of these solids and impurities in the pump through innovative impeller design, thereby ensuring the continuous and stable operation of the sewage pump.

[0108] The present invention has strong anti-cavitation ability: when conveying a medium containing bubbles, conventional sewage pumps are prone to cavitation, which not only affects the performance of the pump, but may also damage the pump body. The impeller design of the present invention optimizes the fluid dynamics characteristics, reduces the impact of bubbles on the internal components of the pump, significantly improves the anti-cavitation ability of the sewage pump, and prolongs the service life of the pump.

[0109] The present invention improves the passability and efficiency: through the fine flow channel design and optimized impeller structure, the sewage pump of the present invention shows better passability when conveying complex fluids, can smoothly handle various solid-liquid mixtures, and at the same time reduces energy loss and improves the overall working efficiency. This not only reduces energy consumption, but also improves the economical operation of the pump.

[0110] The present invention is easy to maintain: due to the semi-open design, compared with a fully enclosed impeller, the sewage pump of the present invention is simpler to maintain and clean, reduces maintenance costs and time, and improves the availability and reliability of the equipment.

[0111] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected, and the scope of the present invention to be protected is defined by the attached claims and their equivalents.

Claims

1. A non-clogging two-phase flow semi-open sewage pump impeller, characterized in that: The non-clogging two-phase flow semi-open sewage pump impeller comprises: an impeller body, on which 2-4 blades are arranged; when the number of blades is small, the wrap angle is increased, The inlet edge of the blade is a swept-back blade structure, and the back of the impeller body is provided with a back blade; The area change between the impeller inlet area F1 and the impeller outlet area F2 is uniformly increasing; The impeller body, blades and back blades are integrally formed.

2. The non-clogging two-phase flow semi-open sewage pump impeller according to claim 1 is characterized in that: The area change between the impeller inlet area F1 and the impeller outlet area F2 is uniformly increasing, and 3. The non-clogging two-phase flow semi-open sewage pump impeller according to claim 1 is characterized in that: The impeller front cover streamline radius R1 is greater than or equal to 25mm.

4. The non-clogging two-phase flow semi-open sewage pump impeller according to claim 1 is characterized in that: The back blades consist of 5-12 pieces.

5. The non-clogging two-phase flow semi-open sewage pump impeller according to any one of claims 1 to 4, characterized in that: When the pump body outlet diameter is 32-250mm (including 250mm) and the number of blades is 2, the wrap angle φ is 160°-230°.

6. The non-clogging two-phase flow semi-open sewage pump impeller according to any one of claims 1 to 4, characterized in that: When the pump body outlet diameter is 250-500mm (excluding 250mm) and the number of blades is 3, the wrap angle φ is 150°-210°.

7. The non-clogging two-phase flow semi-open sewage pump impeller according to any one of claims 1 to 4, characterized in that: When the pump body outlet diameter is greater than 500mm and the number of blades is 3 or 4, the wrap angle φ is 120°-180°.

8. A design method for a non-clogging two-phase flow semi-open sewage pump impeller according to claims 1-7, characterized in that: The design method includes the following steps: Step 1: Determine the design flow rate Q, design head H, speed n, and the medium to be transported; in order to ensure good passing performance and better anti-cavitation performance, the impeller is designed with a small number of blades Z and a large inlet, so the area of ​​the impeller flow channel needs extra attention. This method is applicable to the specific speed n s =70-280, the value is obtained as follows: (1) Determine the impeller inlet diameter: The value range of k0 is 4.6-5.5; the range of 4.6-5.5 includes 4.6 and 5.5; (2) Determine the impeller outlet diameter and outlet width: The above values ​​of 9.4-11.5 include 9.4 and 11.5; the smaller the specific speed, the larger the coefficient; The above 1.8-2.4 includes 1.8 and 3.

0. The smaller value is used for small pumps and the larger value is used for large pumps. In the above formula: D j ——Impeller inlet diameter, (mm) Q——Pump flow rate, (m 3 / s) k0——coefficient n——Pump speed, (r / min) D2——impeller outlet diameter, (m) n s ——Specific speed of the pump, where H——head of the pump at design point, (m); Step 2: Determine the exit placement angle In order to ensure that the overall sewage pump does not exceed the power, it is necessary to ensure that the head drop trend is steeper; the outlet angle is generally selected between 13°-22°; Step 3: Draw the streamlines of the front and rear covers: R1 is the streamline radius of the impeller front cover, and R2 is the streamline radius of the impeller rear cover. In order to ensure that the sewage pump has a better passing performance, R1 is usually slightly larger, usually not less than 25mm; Step 4: Correct the impeller inlet and outlet areas: After the impeller inlet and outlet diameters and the impeller outlet width are designed, the impeller inlet area F1 and the impeller outlet area F2 can be obtained. If the area change from F1 to F2 is uniformly increasing, and Then you can proceed to the next step. If it does not meet the requirements, you need to modify step 1 until it meets the requirements; Step 5: Determine the wrap angle, number of blades and blade inlet edge curve: The number of impeller blades is determined according to the pump body outlet diameter, generally 2-4 blades. When determining the wrap angle, it is necessary to comprehensively consider the blade displacement and surface friction. When there are fewer blades, the wrap angle should be appropriately increased. The relevant value parameters are as follows: When the pump body outlet diameter is 32-250mm (including 250mm) and the number of blades is 2, the wrap angle φ is 160°-230°; When the pump body outlet diameter is 250-500mm (excluding 250mm) and the number of blades is 3, the wrap angle φ is 150°-210°; When the pump body outlet diameter is greater than 500mm and the number of blades is 3 or 4, the wrap angle φ is 120°-180°.

9. The design method of the non-clogging two-phase flow semi-open sewage pump impeller according to claim 8 is characterized by: It adopts a swept-blade design.

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