TWO-STAGE CAVITATION GENERATOR FOR ORGANIC WASTEWATER TREATMENT

Abstract

The present disclosure provides a two-stage cavitation generator for organic wastewater treatment, including a shrouded impeller, a stator, and a rotor. The shrouded impeller includes a front cover plate, blades, and a rear cover plate. Several blades are evenly distributed between the front cover plate and the rear cover plate. A working surface of the blade is an arc surface, and a back of the blade protrudes locally, so that a flow channel between the back of the blade and a working surface of its adjacent blade is narrowed locally, forming a throat structure. An outlet of the shrouded impeller is provided with the stator and the rotor, and the stator is located at an outer edge of the front cover plate and fixed on an inner wall of a volute. The rotor is mounted on the rear cover plate.

Claims

1. A two-stage cavitation generator for organic wastewater treatment, comprising a shrouded impeller, a stator, and a rotor, wherein the shrouded impeller comprises a front cover plate, several blades, and a rear cover plate, the several blades are evenly distributed between the front cover plate and the rear cover plate, a working surface of each of the blades is an arc surface, and a back of each of the blades protrudes locally, so that a flow channel between the back of each of the blades and the working surface of an adjacent one of the blades is narrowed locally, forming a throat structure; an outlet of the shrouded impeller is provided with the stator and the rotor, and the stator is located at an outer edge of the front cover plate and fixed on an inner wall of a volute; the rotor is mounted on the rear cover plate, a gap is provided between the stator and the rotor, and blind holes are respectively provided on the stator and rotor on both sides of the gap, for performing secondary cavitation.

2. The two-stage cavitation generator for organic wastewater treatment according to claim 1, wherein a top of a protrusion on the back of each of the blades is an arc surface in an axial direction, with a radius of R.sub.3=0.1-0.3b, wherein b is a width of the outlet of the shrouded impeller.

3. The two-stage cavitation generator for organic wastewater treatment according to claim 1, wherein the throat structure is positioned at ?=R.sub.1/R.sub.2=0.45-0.75, wherein R.sub.2 is a linear distance from a center of the protrusion on the back of each of the blades to an axis of rotation in a radial plane of the shrouded impeller; and R.sub.1 is a radius of the outlet of the shrouded impeller.

4. The two-stage cavitation generator for organic wastewater treatment according to claim 1, wherein a width of the throat structure is W.sub.1=0.25-0.55b, and the width W.sub.1 of the throat structure is defined as a vertical distance from a tip of the protrusion on the back of each of the blades to the working surface of the adjacent one of the blades in the radial plane of the shrouded impeller.

5. The two-stage cavitation generator for organic wastewater treatment according to claim 1, wherein a width of the gap formed between the stator and the rotor is W.sub.2=0.2-1.b, wherein b is the width of the outlet of the shrouded impeller.

6. The two-stage cavitation generator for organic wastewater treatment according to claim 1, wherein the stator and the rotor on the both sides of the gap are each provided with an annular protrusion, an effective thickness of the annular protrusion in a radial direction is H.sub.2=0.9-1.2b, and the several blind holes are evenly distributed on the annular protrusion in a circumferential direction.

7. The two-stage cavitation generator for organic wastewater treatment according to claim 6, wherein the blind holes are each formed by smoothly connecting a cylindrical hole and a hemispherical hole, a height of the cylindrical hole is H.sub.1=0.1-0.4b, and a radius of the hemispherical hole is R.sub.4=0.2-0.6b.

8. The two-stage cavitation generator for organic wastewater treatment according to claim 6, wherein a quantity of the blind holes is Z.sub.2=3-5 Z.sub.1, wherein Z.sub.1 is a quantity of the blades.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to provide a clearer explanation of the embodiments of the present disclosure or the technical solutions in the prior art, a brief introduction will be given to the accompanying drawings required in the description of the embodiments or prior art. The accompanying drawings in the following description are some embodiments of the present disclosure. For those of ordinary skill in the art, it is evident that other accompanying drawings can be obtained according to these drawings without any creative efforts.

[0021] FIG. 1 is a schematic structural diagram of a two-stage cavitation generator according to the present disclosure.

[0022] FIG. 2 is a cross-sectional diagram of a two-stage cavitation generator according to the present disclosure.

[0023] FIG. 3 is a three-dimensional diagram of a shrouded impeller of a two-stage cavitation generator according to the present disclosure, with a front cover plate being hidden in the figure.

[0024] FIG. 4 is a cross-sectional diagram of a shrouded impeller of a two-stage cavitation generator according to the present disclosure.

[0025] FIG. 5 is a detailed diagram of a throat of a two-stage cavitation generator according to the present disclosure.

[0026] FIG. 6 is a three-dimensional diagram of a stator of a two-stage cavitation generator according to the present disclosure.

[0027] FIG. 7 is a cross-sectional diagram of a stator of a two-stage cavitation generator according to the present disclosure.

[0028] FIG. 8 is a three-dimensional diagram of a rotor of a two-stage cavitation generator according to the present disclosure.

[0029] FIG. 9 is a cross-sectional diagram of a rotor of a two-stage cavitation generator according to the present disclosure.

[0030] FIG. 10 is a detailed diagram of a blind hole of a two-stage cavitation generator according to the present disclosure.

[0031] In the drawings: [0032] 1Impeller; 2Stator; 3Rotor; 1aFront cover plate; 1bBlade; 1cRear cover plate; SThroat; 2aFirst blind hole; 3aSecond blind hole.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present disclosure will be further explained with reference to the accompanying drawings and specific embodiments, but the protection scope of the present disclosure is not limited to this.

[0034] The embodiments of the present disclosure are described in detail below, examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present disclosure, but should not be understood as limiting the present disclosure.

[0035] In the description of the present disclosure, it should be understood that orientation or position relationships indicated by terms center, longitudinal. transverse. length, width. thickness. up. down. axial, radial, vertical. horizontal. inner. outer. and the like are based on orientation or position relationships shown in the accompanying drawings, only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the apparatus or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present disclosure. In addition, terms first and second are only used for the purpose of description and should not be understood as indicating or implying relative importance or implying the quantity of technical features indicated. Therefore, features limited by first and second may explicitly or implicitly include one or more of the features. In the description of the present disclosure. a plurality of means two or more, unless otherwise specifically defined.

[0036] In the present disclosure, unless otherwise clearly defined and limited, terms mount, connect. connection. fix. and other terms should be understood in a broad sense, for example, there may be a fixed connection, a detachable connection, or an integrated connection; there may be a mechanical connection or an electrical connection; there may be a direct connection, indirect connection through an intermediate medium, or an internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood based on specific circumstances.

[0037] As shown in FIG. 1. FIG. 2, and FIG. 3, a two-stage cavitation generator for organic wastewater treatment according to the present disclosure includes a shrouded impeller 1, a stator 2, and a rotor 3. The shrouded impeller 1 includes a front cover plate 1a, blades 1b, and a rear cover plate 1c. Six blades 1b are evenly distributed between the front cover plate 1a and the rear cover plate 1c. A working surface of the blade 1b is an arc surface, and a back of the blade 1b protrudes locally, so that a flow channel between the back of the blade 1b and a working surface of its adjacent blade 1b is narrowed locally, forming a throat structure s. A quantity of the throats s is n=6. An outlet of the shrouded impeller is provided with the stator 2 and the rotor 3. The stator 2 is located at an outer edge of the front cover plate 1a, and the stator 2 is fixed on an inner wall of a volute. The rotor 3 is mounted on the rear cover plate 1c, and a gap is provided between the stator 2 and the rotor 3. A first blind hole 2a and a second blind hole 3a are respectively provided on the stator 2 and the rotor 3 on both sides of the gap, for performing secondary cavitation.

[0038] As can be seen with reference to FIG. 2, FIG. 6, and FIG. 8, the stator 2 and rotor 3 are both circular rings with an L-shaped section. The L-shaped circular ring stator 2 is in clearance fit with the outer edge of the front cover plate 1a, and the L-shaped circular ring rotor 3 is mounted on the rear cover plate 1c. A gap is provided between the L-shaped circular ring stator 2 and the L-shaped circular ring rotor 3. A width of the gap is W.sub.2=0.2-1.0b, where b is a width of the outlet of the shrouded impeller 1.

[0039] As shown in FIG. 4 and FIG. 5, a top of the protrusion on the back of the blade 1b is an arc surface in an axial direction, with a radius of R.sub.3=0.1-0.3b, where b is the width of the outlet of the shrouded impeller 1. The throat structure s is positioned at ?=R.sub.1/R.sub.2=0.45-0.75, where R.sub.2 is a linear distance from a center of the circular protrusion on the back of the blade 1b to an axis of rotation in a radial plane of the shrouded impeller 1; and R.sub.1 is a radius of the outlet of the shrouded impeller 1. A width of the throat structure s W.sub.1=0.25-0.55b, and the width W.sub.1 of the throat structure s is defined as a vertical distance from a tip of the circular protrusion on the back of the blade 1b to the working surface of the adjacent blade 1b in the radial plane of the shrouded impeller 1.

[0040] As shown in FIG. 7 and FIG. 9, the stator 2 and the rotor 3 on both sides of the gap are each provided with an annular protrusion. An effective thickness of the annular protrusion in a radial direction is H.sub.2=0.9-1.2b. The stator 2 has several first blind holes 2a evenly distributed on the annular protrusion in a circumferential direction. The rotor 3 has several second blind holes 3a evenly distributed on the annular protrusion in the circumferential direction. The structures of the first blind hole 2a and the second blind hole 3a are the same. Taking the first blind hole 2a as an example, as shown in FIG. 10, the first blind hole 2a is formed by smoothly connecting a cylindrical hole and a hemispherical hole. A height of the cylindrical hole is H.sub.1=0.1-0.4b, and a radius of the hemispherical hole is R.sub.3=0.2-0.6b. A quantity of the first blind holes 2a is Z.sub.2=3-5Z.sub.1, where Z.sub.1 is a quantity of the blades 1b.

Working Principle:

[0041] As a fluid conveying apparatus, a pump ignores a depth of a buried pipe when used, and its inlet pressure is approximately one atmospheric pressure. At this time, cavitation is not expected to occur because it may affect a conveying efficiency. Therefore, in practical applications, the pump may basically not undergo cavitation at the inlet pressure of one atmospheric pressure. The two-stage cavitation generator according to the present disclosure is a modification of a traditional pump so as to utilize energy released by its cavitation collapse. By using specific cavitation generating units, such as blind holes and throat structures, a local pressure inside the cavitation generator may be reduced to below a saturated vapor pressure at the inlet pressure of one atmospheric pressure, thereby causing cavitation. This also avoids the pressure reduction operation required to achieve cavitation, and cavitation occurring at one atmospheric pressure is also a goal of the design. The two-stage cavitation generator provided by the present disclosure has three forms of cavitation, namely contraction cavitation, vortex cavitation, and shear cavitation. The impeller increases kinetic energy and pressure energy of a fluid by doing work on it, thereby conveying the fluid to a higher position. Before reaching the throat s, the fluid already has a certain velocity. When the fluid passes through the throat s, due to the reduction of a flow area, a fluid velocity increases sharply. As can be seen from the Bernoulli's principle, a downstream pressure of the throat drops suddenly, and when the pressure drops below the saturated vapor pressure, cavitation occurs. The process belongs to contraction cavitation, and the cavitation at this position is primary cavitation. Subsequently, due to the continued increase of the kinetic energy and pressure energy of the fluid by the blades, cavitation bubbles gradually collapse inside the impeller to release energy. When the fluid passes through the narrow gap between the stator and the rotor at the outlet of the impeller, the flow velocity is already high. The fluid enters the blind hole and then flows out, forming a vortex inside the blind hole. When a pressure at a center of the vortex drops below the saturated vapor pressure, cavitation occurs. In addition, due to periodic alignment and staggering of the blind holes between the stator and the rotor, the shear effect under the action may also lead to cavitation. Therefore, there are vortex cavitation and shear cavitation between the stator and the rotor, which belong to secondary cavitation. Subsequently, cavitation bubbles gradually collapse in a high-pressure region and releases energy again.

[0042] It should be understood that although this specification is described according to various embodiments, it does not necessarily include an independent technical solution for each embodiment. This description of the specification is only for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in the various embodiments can also be appropriately combined to form other implementations understandable by those skilled in the art.

[0043] The series of detailed explanations listed above are only specific explanations for the feasible embodiments of the present disclosure, and are not intended to limit the scope of protection of the present disclosure. Any equivalent embodiments or modifications made without departing from the spirit of the present disclosure should be included in the scope of protection of the present disclosure.