Micro flow cavitation venturi

Abstract

The application discloses a micro flow cavitation venturi, which adopts a two-section structure and is composed of an inlet section and an outlet section through vacuum electron beam welding; and the flow channel of the cavitation venturi is sequentially composed of an inlet converging section, an inlet round corner section, a throat straight section, a throat chamfer section and an outlet expansion section. The cavitation venturi effectively solves the problems that the production and processing of the micro flow cavitation venturi is extremely difficult due to the too small throat diameter, and the inner surface size and surface smoothness are difficult to guarantee, realizes the accurate control of the micro flow of the fluid medium in the spacecraft, and has the advantages of simple structure, convenient production and processing, low cost, high precision and the like.

Description

Technical Field

[0001] This invention relates to a low-flow-rate cavitation venturi tube, belonging to the field of aerospace technology. Background Technology

[0002] A cavitation venturi tube is a component used to control the flow rate of liquids. Its internal structure is characterized by initial convergence followed by expansion. During operation, a stable cavitation zone forms after the throat section, ensuring that the flow rate remains constant within a certain range, unaffected by the outlet pressure, while maintaining a constant inlet pressure. Furthermore, it suppresses the back transmission of pulsating pressure, maintaining system stability. Currently, cavitation venturi tubes are used in many fields to control the flow rate of fluid media, and their application is particularly widespread in the aerospace industry.

[0003] Currently, in aerospace applications, standard-shaped cavitation venturi tubes are typically single-section, one-piece structures with a minimum throat diameter of Φ1.5mm. However, to achieve precise control of fluid flow rate, micro-flow cavitation venturi tubes are often required, such as those for water with a constant flow rate of less than 2g / s. In this case, the throat diameter of the cavitation venturi tube will be less than Φ0.2mm. The extremely small throat diameter makes the manufacturing and processing of micro-flow cavitation venturi tubes extremely difficult, and it is challenging to guarantee both internal dimensions and surface finish. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a micro-flow cavitation venturi tube. Through an innovative two-section structural design, it effectively solves the problem that the micro-flow cavitation venturi tube is extremely difficult to manufacture due to its small throat diameter, and that it is difficult to guarantee the internal dimensions and surface finish. This enables precise control of the micro-flow of fluid media in spacecraft.

[0005] The technical solution of the present invention is: a micro-flow cavitation venturi tube, which adopts a two-section structure, consisting of an inlet section and an outlet section welded together by vacuum electron beam; wherein, the inlet section includes an inlet converging section, an inlet rounded section, a throat straight section and a throat chamfered section welded together in sequence, and the outlet section includes an outlet expanding section; the overall flow channel from the inlet to the outlet consists of an inlet converging section, an inlet rounded section, a throat straight section, a throat chamfered section and an outlet expanding section in sequence.

[0006] Both the straight section and the chamfered section of the throat are machined by drilling.

[0007] The export expansion section is processed using a slow wire EDM method.

[0008] Both the entrance convergence section and the entrance rounded corner section are machined by turning.

[0009] The inlet converging section is a conical structure that gradually narrows along the liquid inflow direction, with a convergence angle α of the inlet converging section. i =30°~60°; the outlet expansion section is a conical structure that gradually expands along the liquid outflow direction, and the expansion angle α of the outlet expansion section is 30°~60°. o =6°~10°.

[0010] The inlet rounded corner section is an arc-shaped structure that gradually narrows along the liquid inflow direction, with a rounded corner radius R of 0.3mm to 1mm.

[0011] The straight section of the throat is a cylindrical structure with a diameter D. t ≤0.2mm; the length of the straight segment at the throat, L=(1~4)D t .

[0012] The beveled throat section is a tapered structure that gradually expands along the direction of liquid outflow, with a cone angle β = 90° to 15°.

[0013] The outlet diameter of the chamfered throat section is the same as the inlet diameter D of the outlet expansion section. e ≥0.35mm.

[0014] The inlet diameter of the inlet convergence section and the outlet diameter of the outlet expansion section are the same as the corresponding pipe diameters of the cavitation venturi inlet and outlet.

[0015] The aforementioned low-flow-rate cavitation venturi tube specifically refers to a cavitation venturi tube with a water flow rate of less than 2 g / s.

[0016] The micro-flow cavitation venturi tube is made of 1Cr18Ni9Ti stainless steel.

[0017] The surface finish of all internal surfaces of the micro-flow cavitation venturi tube is Ra≤0.8μm.

[0018] The advantages of this invention compared to the prior art are:

[0019] (1) The cavitation venturi tube of the present invention has an innovative two-section structural design, and the throat diameter can be less than Φ0.2mm, while the throat diameter of the most standard cavitation venturi tube is currently Φ1.5mm.

[0020] (2) Based on the two-section structure, the cavitation venturi tube of the present invention is processed by precision drilling and slow wire cutting, which can ensure the requirements of inner surface size and surface finish Ra≤0.8μm when the throat diameter Φ0.2mm is less than 0.2mm;

[0021] (3) The cavitation venturi tube of the present invention has been tested by single-path test and system test. The water flow deviation is less than 5% in both steady state and pulse working modes, which shows excellent performance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the micro-flow cavitation venturi tube design scheme described in this invention;

[0023] Figure 2 This is a magnified view of a local structure of a cavitation venturi tube with a small flow rate. Detailed Implementation

[0024] The micro-flow cavitation venturi tube of this invention is suitable for precise control of micro-flow rates in spacecraft where the constant water flow rate is less than 2 g / s. Specific implementation methods are as follows:

[0025] like Figure 1 As shown, the low-flow cavitation venturi tube adopts a two-section structure, consisting of an inlet section and an outlet section. The flow channel from the inlet to the outlet consists of an inlet converging section 1, an inlet rounded corner section 2, a straight throat section 3, a chamfered throat section 4, and an outlet expanding section 5. The inlet section includes the inlet converging section 1, the inlet rounded corner section 2, the straight throat section 3, and the chamfered throat section 4, which are welded together sequentially. The outlet section includes the outlet expanding section 5.

[0026] The entire micro-flow cavitation venturi tube is made of 1Cr18Ni9Ti stainless steel. Through an innovative two-section structural design, the straight throat section and the chamfered throat section are processed by precision drilling. The outlet expansion section also has relatively sufficient wire threading space and is processed by slow wire cutting. The inlet convergence section and the inlet rounded corner section are processed by turning. After the inlet section and the outlet section are processed separately, they are connected by vacuum electron beam welding.

[0027] After the liquid passes through the inlet converging section and the inlet rounded section of the cavitation venturi tube, the pressure decreases, and a stable cavitation zone is formed in local locations at the straight section of the throat, the chamfered section of the throat, and the expansion section of the outlet, thereby achieving precise control of minute flow rates.

[0028] like Figure 2 As shown, the inlet diameter of the converging section and the outlet diameter of the expanding section of the venturi tube with low flow rate cavitation are D, respectively. i and D o D i and D o The connecting pipe diameters corresponding to the inlet and outlet of the cavitation Venturi tube are the same; the inlet converging section is a tapered structure that gradually narrows along the liquid inflow direction, and the convergence angle α of the inlet converging section is... i =30°~60°; the outlet expansion section is a conical structure that gradually expands along the liquid outflow direction, and the expansion angle α of the outlet expansion section is 30°~60°. o=6°~10°; the inlet rounded corner section is an arc-shaped structure that gradually narrows along the liquid inflow direction, with a rounded corner R = 0.3mm~1mm; the throat straight section is a cylindrical structure with a diameter D. t Based on parameters such as inlet pressure, flow rate, and flow coefficient, D is calculated for the micro-flow cavitation venturi tube of this invention. t ≤0.2mm; the length of the straight segment at the throat, L=(1~4)D t The throat chamfered section is a tapered structure that gradually expands along the liquid outflow direction, with a cone angle β of 90° to 150°; the outlet diameter of the throat chamfered section, i.e., the inlet diameter of the outlet expansion section, is D. e To ensure sufficient threading space in the export expansion section, slow wire EDM is used for processing, requiring D... e ≥0.35mm; the surface finish of all internal surfaces of the cavitation venturi tube must be Ra≤0.8μm.

[0029] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention based on the above-disclosed technical content without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A low-flow-rate cavitation venturi tube, characterized in that, It adopts a two-section structure, consisting of an inlet section and an outlet section welded together by vacuum electron beam. The inlet section includes an inlet converging section, an inlet rounded corner section, a straight throat section, and a chamfered throat section welded together in sequence, while the outlet section includes an outlet expanding section. The overall flow channel, from inlet to outlet, consists of an inlet converging section, an inlet rounded corner section, a straight throat section, a chamfered throat section, and an outlet expanding section in sequence. The outlet expansion section is processed using a slow wire EDM method; The straight segment of the throat has a cylindrical structure with a diameter of... ; length of the straight segment of the throat ; The beveled throat section is a tapered structure that gradually expands along the liquid outflow direction, with a cone angle of... ; The outlet diameter of the chamfered throat section is the same as the inlet diameter of the outlet expansion section. .

2. The micro-flow cavitation venturi tube according to claim 1, characterized in that, Both the straight section and the chamfered section of the throat are machined by drilling.

3. The micro-flow cavitation venturi tube according to claim 1, characterized in that, Both the entrance convergence section and the entrance rounded corner section are machined by turning.

4. The micro-flow cavitation venturi tube according to claim 1, characterized in that, The inlet converging section is a tapered structure that gradually narrows along the liquid inflow direction, and the convergence angle of the inlet converging section is... The outlet expansion section is a conical structure that gradually expands along the liquid outflow direction, and the expansion angle of the outlet expansion section is... .

5. A micro-flow cavitation venturi tube according to claim 1, characterized in that, The inlet rounded corner section is an arc-shaped structure that gradually narrows along the liquid inflow direction. .

6. A micro-flow cavitation venturi tube according to any one of claims 1-5, characterized in that, The inlet diameter of the inlet convergence section and the outlet diameter of the outlet expansion section are the same as the corresponding pipe diameters of the cavitation venturi inlet and outlet.

7. A micro-flow cavitation venturi tube according to any one of claims 1-5, characterized in that, The aforementioned low-flow-rate cavitation venturi tube specifically refers to a cavitation venturi tube with a water flow rate of less than 2 g / s.

8. A micro-flow cavitation venturi tube according to any one of claims 1-5, characterized in that, The micro-flow cavitation venturi tube is made of 1Cr18Ni9Ti stainless steel.

9. A micro-flow cavitation venturi tube according to any one of claims 1-5, characterized in that, The surface finish of all internal surfaces of the micro-flow cavitation venturi tube is high. .

Images