Centrifugal pump impeller for cavitation and cavitation erosion experiments

Abstract

The centrifugal pump impeller used for the cavitation and cavitation erosion experiment comprises a plurality of front cover plates and a plurality of impeller rear cover plates and blade assemblies, the impeller rear cover plates and the blade assemblies are connected to form concentric circles, the front cover plates are arranged at the ends of the impeller rear cover plates and the blade assemblies, the front cover plates form a hollow cylinder, the front cover plates are made of transparent materials, and the front cover plates are made of transparent materials. The impeller rear cover plates and the blade assemblies distributed on the symmetrical positions of the concentric circles are made of the same material. The centrifugal pump impeller is mainly machined and assembled through various different materials, so that the cavitation erosion resistance of various different materials can be synchronously tested in the completely same cavitation erosion environment during hydraulic machinery cavitation erosion testing, the structure is simple, the consistency of the surface roughness of different materials can be guaranteed through part machining, and the cavitation erosion resistance of the centrifugal pump impeller is improved. Therefore, the problem that the cavitation erosion experiment precision is affected due to the fact that the surface of the integrated impeller is difficult to finish is solved.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic machinery testing, in particular to a centrifugal pump impeller used for cavitation erosion experiments. Background Art

[0002] Cavitation refers to the process when a liquid is transformed from a liquid phase into a vapor (cavitation bubble) under a low-pressure environment, and then further develops and finally collapses under a high-pressure environment. The collapse of cavitation bubbles is often accompanied by the generation of cavitation erosion. This is because when cavitation bubbles collapse near the wall, they will generate high-pressure waves and microjets with extremely strong impact force. When they repeatedly act on the surface of the material, they will cause material peeling, quality loss, fatigue failure and even fracture.

[0003] Centrifugal pumps are the most widely used pumps in liquid transportation, and cavitation is an inevitable physical phenomenon in the operation of centrifugal pumps. The cavitation damage closely related to it often causes the deterioration of the pump's boosting performance and a significant increase in vibration and noise, which greatly increases the maintenance cost and maintenance frequency of centrifugal pumps. It can be said that cavitation has become one of the main factors affecting the life of hydraulic components in centrifugal pumps and the reliability of the working system. Therefore, it is urgent to carry out cavitation erosion experiments in centrifugal pumps and to compare the tolerance of different materials in the cavitation environment of centrifugal pumps.

[0004] However, there are many difficulties in measuring cavitation and erosion experiments in centrifugal pumps. The flow channel in the pump is twisted, and the front and rear covers of the centrifugal pump are closed, which makes it difficult to clearly obtain the entire evolution process of cavitation and erosion of the materials in the pump during the experiment. Secondly, when comparing the cavitation resistance of different materials, it is often necessary to use impellers made of different materials to perform repetitive cavitation and erosion experiments. This puts extremely strict requirements on the repeatability of the cavitation experiment, and requires the same water quality, the same ambient temperature, the same cavitation bubble length and the cavitation test duration in several repeated experiments. However, the experimental equipment and systems required for centrifugal pump cavitation are relatively complex, and there are many uncontrollable factors in the experiment (water quality, water temperature, gas content), so it is difficult to ensure that different materials are subjected to cavitation loads of the same characteristics under the same cavitation environment. Therefore, how to ensure that different materials are subjected to cavitation loads with the same spatial and temporal distribution and the same duration has become a technical difficulty for researchers in the field of material testing.

[0005] Therefore, there is an urgent need for a centrifugal pump impeller for cavitation erosion experiments. Summary of the invention

[0006] The invention provides a centrifugal pump impeller for cavitation erosion experiment, so as to solve the technical problem that it is difficult to ensure completely the same cavitation working environment and material surface characteristics in the cavitation erosion experiment of hydraulic machinery.

[0007] The present invention provides a centrifugal pump impeller for cavitation and erosion experiments, comprising a plurality of front cover plates and a plurality of impeller rear cover plates and blade assemblies, wherein the impeller rear cover plates and blade assemblies are connected to form concentric circles, the ends of the impeller rear cover plates and blade assemblies are provided with the front cover plates, and the front cover plates form a hollow cylinder, the front cover plates are made of transparent material, and the impeller rear cover plates and blade assemblies distributed at symmetrical positions of the concentric circles are made of the same material.

[0008] The centrifugal pump impeller used for cavitation and erosion experiments, preferably, the impeller rear cover plate and blade assembly include a rear cover plate and blades, along the length direction of the blades, the rear cover plate is arranged on the blades, a mounting hole is provided between one side of the rear cover plate and the side edge of the blades, adjacent blades are connected by installing screws in the mounting holes, the front cover plate is installed at the end of the blades, and the front cover plate is abutted against the other side of the rear cover plate, and the tail of the blade is arc-shaped, so that adjacent front cover plates are connected to form a hollow cylinder, and adjacent blades are connected to form concentric circles.

[0009] The centrifugal pump impeller used for cavitation and erosion experiments, preferably, the rear cover plates distributed at the concentrically symmetrical positions are made of the same material.

[0010] In the centrifugal pump impeller used for cavitation and erosion experiments, preferably, the rear cover plate and the blades distributed at the concentrically symmetrical positions are made of the same material.

[0011] The centrifugal pump impeller used for cavitation erosion experiment, preferably, the front cover plate and the heads of the blades are both provided with drilling holes to realize the assembly of the front cover plate and the blades.

[0012] The centrifugal pump impeller used for cavitation erosion experiment, preferably, the number of the front cover plate, the impeller rear cover plate and the blade assembly is not less than 2 and is an even number.

[0013] In the centrifugal pump impeller used for cavitation and erosion experiments, preferably, the material of the front cover plate is transparent organic glass.

[0014] The beneficial effects are:

[0015] The present invention divides the integrated centrifugal pump impeller into different components, thereby making it possible to test the anti-cavitation performance of different materials under exactly the same cavitation environment, thereby avoiding errors in the experimental results caused by changes in environmental parameters and working conditions in the cavitation experiment, and improving the accuracy of related experiments.

[0016] The present invention can simultaneously carry out cavitation performance tests of different materials through the centrifugal pump impeller assembled with different materials, thereby reducing the time and economic cost of the experiment.

[0017] Compared with an integrated centrifugal pump impeller, the assembled impeller of the present invention is easier to achieve blade surface finishing, can ensure that the surface roughness of different materials is consistent, and is easier to later observe and compare the surface characteristics of different materials after being subjected to cavitation impact.

[0018] The invention has strong applicability, and blade components made of different materials are easy to disassemble and assemble, which is convenient for comparing the material quality loss after the cavitation test. It has a simple structure and is easy to manufacture. At the same time, a wide range of materials can be selected, and the number of impeller rear cover plate components can be adjusted to achieve the comparison of the cavitation resistance performance of 2, 4 or even more materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a front view of the impeller body in the embodiment of the present invention;

[0020] Figure 2 It is a rear view of the impeller body in the embodiment of the present invention;

[0021] Figure 3 An exploded view of the impeller rear cover and blade components in an embodiment of the present invention;

[0022] Figure 4 A three-dimensional diagram of a single rear cover plate and blade parts in an embodiment of the present invention;

[0023] In the figure:

[0024] 1-1, rear cover plate and blade group of the first impeller; 1-2, rear cover plate and blade group of the second impeller;

[0025] 2-1, rear cover plate and blade assembly of the third impeller; 2-2, rear cover plate and blade assembly of the fourth impeller;

[0026] 3-1, rear cover plate and blade assembly of the fifth impeller; 3-2, rear cover plate and blade assembly of the sixth impeller;

[0027] 4. Front cover; 5. Blades; 6. Rear cover; 7. Mounting hole; 8. Hollow cylinder. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "head", "tail", "one side" and "the other side" indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", "fourth", "fifth", and "sixth" are used to define components, only for the convenience of distinguishing the above components, and unless otherwise stated, the above terms have no special meaning and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "setting" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] The present invention provides a centrifugal pump impeller for cavitation and erosion experiments, comprising a plurality of front cover plates and a plurality of impeller rear cover plates and blade assemblies, wherein the impeller rear cover plates and blade assemblies are connected to form concentric circles, the ends of the impeller rear cover plates and blade assemblies are provided with the front cover plates, and the front cover plates form a hollow cylinder, the front cover plates are made of transparent material, and the impeller rear cover plates and blade assemblies distributed at symmetrical positions of the concentric circles are made of the same material. The present invention mainly assembles a centrifugal pump impeller through processing of a plurality of different materials, and thus can ensure the simultaneous testing of the cavitation resistance of a plurality of different materials under exactly the same cavitation environment during the hydraulic mechanical cavitation and erosion test. In addition, the present invention has a simple structure, and can ensure the consistency of the surface roughness of different materials through the processing of parts and components, thereby avoiding the problem that the surface of the integrated impeller is difficult to finely process, thereby affecting the accuracy of the cavitation experiment.

[0032] The entire technical process is explained in detail below using a centrifugal pump impeller used for cavitation erosion experiments as an example.

[0033] Example 1

[0034] like Figures 1 to 3As shown, a centrifugal pump impeller for cavitation erosion experiment includes 6 front cover plates and 6 impeller rear cover plates and blade assemblies, the first impeller rear cover plate and blade group 1-1, the second impeller rear cover plate and blade group 1-2, the third impeller rear cover plate and blade group 2-1, the fourth impeller rear cover plate and blade group 2-2, the fifth impeller rear cover plate and blade group 3-1, and the sixth impeller rear cover plate and blade group 3-2 are sequentially connected to form concentric circles, the first impeller rear cover plate and blade group 1-1, the second impeller rear cover plate and blade group 1-2, the third impeller rear cover plate and blade group 2-1, the fourth impeller rear cover plate and blade group 2-2, the fifth impeller rear cover plate and blade group 3-1, and the sixth impeller rear cover plate and blade group 3-2 are sequentially connected to form concentric circles. The ends of the impeller rear cover plate and blade group 3-1 and the sixth impeller rear cover plate and blade group 3-2 are respectively provided with front cover plates 4, and the front cover plate 4 forms a hollow cylinder 8. The front cover plate 4 is made of transparent material. The two impeller rear cover plates and blade assemblies distributed at the symmetrical positions of the concentric circles are made of the same material, that is, the first impeller rear cover plate and blade group 1-1 are made of the same material as the second impeller rear cover plate and blade group 1-2, the third impeller rear cover plate and blade group 2-1 are made of the same material as the fourth impeller rear cover plate and blade group 2-2, and the fifth impeller rear cover plate and blade group 3-1 are made of the same material as the sixth impeller rear cover plate and blade group 3-2.

[0035] The front cover plate 4 is made of transparent organic glass, so as to facilitate the photographing of the cavitation structure inside the impeller by a high-speed camera.

[0036] like Figure 4 As shown, the first impeller rear cover plate and blade group 1-1, the second impeller rear cover plate and blade group 1-2, the third impeller rear cover plate and blade group 2-1, the fourth impeller rear cover plate and blade group 2-2, the fifth impeller rear cover plate and blade group 3-1, and the sixth impeller rear cover plate and blade group 3-2 respectively include a rear cover plate 6 and a blade 5. Along the length direction of the blade 5, the rear cover plate 6 is arranged on the blade 5, and a mounting hole 7 is provided between one side of the rear cover plate 6 and the side edge of the blade 5. Screws are installed in the mounting hole 7 to connect adjacent blades 5. The front cover plate 4 is installed at the end of the blade 5, and the front cover plate 4 is abutted against the other side of the rear cover plate 6. The tail of the blade 5 is arc-shaped to connect adjacent front cover plates 4 to form a hollow cylinder 8, that is, the impeller blade is in the form of a cylindrical blade, so that the cavity characteristics in the three-dimensional space of the impeller can be accurately captured from the axial position of the impeller in the high-speed photography experiment, and adjacent blades 5 are connected to form concentric circles.

[0037] The rear cover plates 6 distributed at the symmetrical positions of the concentric circles are made of the same material to balance the radial force of the impeller.

[0038] The rear cover plate 6 and the blades 5 distributed at the symmetrical positions of the concentric circles are made of the same material to balance the radial force of the impeller.

[0039] The front cover plate 4 and the heads of the blades 5 are both provided with drilling holes to realize the assembly of the front cover plate 4 and the blades 5 .

[0040] When the present invention is in working state, the mainstream flows in from the impeller inlet, the static pressure at the impeller inlet is reduced, and then the water flow forms a low-pressure vacuum zone with approximately uniform distribution in this area, and then the cavitation nuclei carried in the water flow expand to form cavitation bubbles under the action of low pressure. At the same time, due to the gradual expansion of the axial cross section, the flow field pressure rises rapidly, and the cavitation bubbles formed in the low-pressure area are transported by the mainstream to the downstream high-pressure area and quickly collapse, resulting in a cavitation effect. Due to the structural feature of uniform distribution of the impeller, the above-mentioned cavitation effect is approximately uniformly distributed in the circumferential direction. Therefore, the material sample on the blade is subjected to cavitation loads with nearly the same time-space characteristics and strength characteristics, thereby ensuring that different materials are tested for their anti-cavitation performance under the same hydraulic cavitation conditions.

[0041] Example 2

[0042] The difference from the first embodiment is that the number of the front cover plate 4 and the impeller rear cover plate and the blade assembly is 4, and the impeller rear cover plate and the blade assembly are made of 2 kinds of materials.

[0043] Example 3

[0044] The difference from the first embodiment is that the number of the front cover plate 4 and the impeller rear cover plate and the blade assembly is two, and the material of the impeller rear cover plate and the blade assembly is one.

[0045] Example 4

[0046] The difference from the first embodiment is that the number of the front cover plates 4 and the impeller rear cover plates and blade assemblies is 8, and the impeller rear cover plates and blade assemblies are made of 4 kinds of materials.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A centrifugal pump impeller for cavitation erosion experiment, characterized in that: It includes multiple front cover plates and multiple impeller rear cover plates and blade assemblies, the impeller rear cover plates and blade assemblies are connected to form concentric circles, the front cover plates are provided at the ends of the impeller rear cover plates and blade assemblies, and the front cover plates form a hollow cylinder, the front cover plates are made of transparent material, and the impeller rear cover plates and blade assemblies distributed at symmetrical positions on the concentric circles are made of the same material.

2. The centrifugal pump impeller for cavitation erosion experiment according to claim 1, characterized in that: The impeller rear cover plate and blade assembly include a rear cover plate and a blade. The rear cover plate is arranged on the blade along the length direction of the blade. A mounting hole is provided between one side of the rear cover plate and the side edge of the blade. Adjacent blades are connected by installing screws in the mounting hole. The front cover plate is installed at the end of the blade, and the front cover plate abuts against the other side of the rear cover plate. The tail of the blade is arc-shaped, so that adjacent front cover plates are connected to form a hollow cylinder, and adjacent blades are connected to form concentric circles.

3. The centrifugal pump impeller for cavitation erosion experiment according to claim 2, characterized in that: The rear cover plates distributed at symmetrical positions of the concentric circles are made of the same material.

4. The centrifugal pump impeller for cavitation erosion experiment according to claim 3, characterized in that: The rear cover plate and the blades distributed at symmetrical positions of the concentric circles are made of the same material.

5. The centrifugal pump impeller for cavitation erosion experiment according to claim 3 or 4, characterized in that: The front cover plate and the heads of the blades are both provided with drilling holes to realize the assembly of the front cover plate and the blades.

6. The centrifugal pump impeller for cavitation erosion experiment according to claim 5, characterized in that: The number of the front cover plate, the impeller rear cover plate and the blade assembly is not less than 2 and is an even number.

7. The centrifugal pump impeller for cavitation erosion experiment according to claim 6, characterized in that: The material of the front cover plate is transparent organic glass.

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