A porous array vortex-suppressing water port structure applied to a flow channel and a design method thereof

Abstract

The application discloses a porous array vortex-inhibiting water gap structure applied to a flow channel and a design method thereof, and belongs to the technical field of casting equipment. The porous array vortex-inhibiting water gap structure comprises a water outlet unit fixedly embedded at a water outlet position of the flow channel, and a plurality of porous arrays are arranged on a water outlet end surface of the water outlet unit. The porous array vortex-inhibiting water gap structure is composed of at least two water outlet through holes, and all the water outlet through holes are arranged in a central symmetry around a geometric center of the water outlet unit. The application can destroy the generation condition of the vortex, thereby reducing the slag entrapment and air suction, and improving the ingot quality.

Description

Technical Field

[0001] This invention relates to the field of metallurgical casting technology, specifically to a porous array vortex suppressor structure for use in flow channels and its design method. Background Technology

[0002] Vacuum induction melting (VIM) is a key piece of equipment for producing high-end materials such as high-temperature alloys and special steels. During the casting process, the sprue at the end of the molten steel flow channel (the sprue placement position is as follows)... Figure 1 As shown, the existing sprue structure is as follows: Figure 2 As shown, when the liquid flows out, it easily forms a strong vortex above the nozzle. This vortex will suck in fine particles of refractory material that have been eroded and detached above the nozzle, as well as scum on the surface of the liquid, resulting in defects such as non-metallic inclusions and slag inclusions in the final ingot, which seriously affects the quality of high-purity materials.

[0003] To suppress such vortices, existing technologies typically employ methods such as optimizing the pouring velocity curve, applying electromagnetic flow stabilization, or installing complex dams within the pouring channel. However, these methods generally suffer from problems such as high control difficulty, slow response, increased system complexity and cost, and their vortex suppression effect often decreases significantly in the low liquid level stage of the later pouring phase. Therefore, there is an urgent need for a simple and reliable solution that, starting from the geometry of the pouring outlet itself, can stably and effectively suppress vortices in a vacuum environment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a porous array vortex suppression nozzle structure and its design method for use in flow channels, which can disrupt the conditions for vortex generation, thereby reducing slag entrapment and air intake, and improving ingot quality.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows.

[0006] A porous array vortex suppressor structure and its design method for use in a flow channel include a water outlet unit fixedly embedded in the water outlet position of the flow channel, and a porous array is provided on the water outlet end face of the water outlet unit; the porous array consists of at least two water outlet through holes, and all water outlet through holes are arranged in a centrally symmetrical manner around the geometric center of the water outlet unit.

[0007] Preferably, the total cross-sectional area of ​​all the water outlet orifices matches the steel flow rate required for the predetermined process.

[0008] Preferably, the number of water outlet holes is four, which are arranged in a cross shape and close to the outer edge of the water outlet unit.

[0009] Preferably, the centers of the four water outlet holes are located on the same circumference and are evenly distributed.

[0010] A design method for a porous array vortex-suppressing nozzle structure applied to a flow channel includes the following steps: S1. Determine the structural constraint parameters of the water outlet unit, including the outer diameter D of the water outlet unit, the diameter d of a single water outlet through hole, and the required minimum safe wall thickness t; S2. Determine the upper limit constraint condition of the center distance S of each water outlet hole according to the structural constraint parameters: × [ (D / 2) - (d / 2) - t] S3. Under the premise of satisfying the above constraints, maximize the center distance S of the holes and arrange each water outlet hole in an allowable position close to the outer edge of the water outlet unit.

[0011] Preferably, the water outlet unit is an independent refractory material component whose shape matches the opening at the end of the flow channel, and the minimum safe wall thickness t is determined in step S1 based on the strength of the refractory material.

[0012] Preferably, in step S1, the diameter d of a single water outlet is determined based on the principle of "equal flow capacity", so that the total cross-sectional area of ​​all water outlets is equal to the cross-sectional area of ​​the traditional single-hole water outlet to be replaced.

[0013] Due to the adoption of the above technical solutions, the technical progress achieved by this invention is as follows.

[0014] This invention exhibits a significant vortex suppression effect: by disrupting the axisymmetry of the outlet confluence point through a porous array, the generation of stable vortices is fundamentally suppressed. Water simulation experiments demonstrate that this invention can delay the liquid level at which vortices begin to form in the flow channel from approximately 100 mm to 70 mm, and prevent vortices from forming a continuous flow, thereby significantly reducing the risk of slag entrapment at the end of the casting process.

[0015] This invention improves the purity of ingots: Production test data shows that, under the same initial molten steel conditions, the total number of internal inclusions and the number of inclusions in each size segment of the ingot cast using this invention are significantly lower than those of traditional single-hole nozzles, with the overall number of inclusions reduced by about 70%-80%, and the product quality is effectively improved.

[0016] This invention is highly practical in engineering: the structure is an independent embedded unit, making modification and replacement convenient. Its design method is based on clear geometric and strength constraints, allowing for the determination of optimal hole positions through simple calculations. The logic is clear, making it easy to implement and promote on existing production lines without adding extra control systems or operating costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram showing the existing water inlet placement locations; Figure 2 This is a schematic diagram of the existing water inlet structure; Figure 3 This is a schematic diagram of the structure of the present invention.

[0018] Among them: 1. Water outlet unit, 2. Water outlet through hole. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] A porous array vortex suppressor structure applied to flow channels, combined with Figure 3 As shown, it includes a water outlet unit 1 that is fixedly embedded in the water outlet position of the flow channel. The water outlet unit 1 is an independent refractory material component whose shape matches the opening at the end of the flow channel. It is fixedly embedded in the predetermined water outlet position of the flow channel, replacing the traditional single-hole water outlet brick.

[0021] The water outlet end face of the water outlet unit 1 is provided with a porous array. The porous array consists of at least two water outlet through holes 2, and all water outlet through holes 2 are arranged in a centrally symmetrical manner around the geometric center of the water outlet unit 1.

[0022] The total cross-sectional area of ​​all water outlet holes 2 is matched with the steel flow rate required by the predetermined process, that is, following the principle of "equal flow capacity". Its total cross-sectional area is equal to the cross-sectional area of ​​the original single-hole water outlet that is replaced, thereby ensuring that the steel flow rate of the casting process remains stable.

[0023] As a preferred embodiment, there are four water outlet holes 2, which are arranged in a cross shape and close to the outer edge of the water outlet unit 1. The centers of the four water outlet holes 2 are located on the same circumference and are evenly distributed. This layout can provide optimal flow symmetry in a limited space and prevent flow deviation.

[0024] A design method for a porous array vortex-suppressing nozzle structure applied to a flow channel includes the following steps: S1. Determine the structural constraint parameters.

[0025] The structural constraint parameters of water outlet unit 1 are determined, including: The outer diameter D of the water outlet unit is determined by the size of the opening at the end of the flow channel; The diameter d of a single water outlet is determined based on the principle of "equal flow capacity", even if the total cross-sectional area of ​​all water outlets 2 is equal to the cross-sectional area of ​​the traditional single-hole water outlet that needs to be replaced. The required minimum safe wall thickness t is determined based on the strength of the refractory material to ensure the structural integrity of the water outlet unit 1.

[0026] S2. Determine the upper limit constraint condition for the hole center distance.

[0027] The upper limit constraint condition for the center distance S of each water outlet hole 2 is determined based on the structural constraint parameters: × [ (D / 2) - (d / 2) - t] The physical meaning of this formula is to ensure that the minimum safe wall thickness requirement is met between each through hole and between the through hole and the outer edge of the unit within the finite circular area of ​​the water outlet unit end face, so as to prevent structural failure.

[0028] S3. Maximize the center distance of the holes.

[0029] Under the premise of satisfying the above constraints, the center distance S of the holes is maximized, and each water outlet hole 2 is arranged in an allowable position close to the outer edge of the water outlet unit 1. This allows the multiple jets to achieve maximum separation on the outlet plane, creating favorable initial conditions for subsequent flow disturbances.

[0030] (1) Water simulation experiment verification: To determine whether the optimized nozzle could reduce vortices, a water simulation method was first used for verification. A flow channel model was made using a transparent material (such as plexiglass), with water as the simulation medium, and high-speed camera technology was used to observe the flow pattern, vortex formation, and slag entrainment tendency.

[0031] Experimental results show that: When using the original single-hole nozzle, vortices begin to form when the liquid level drops to 100mm during the pouring process, and develop into a through-hole shape when the liquid level drops to 95mm.

[0032] When using the multi-hole array vortex suppressor nozzle (four-hole cross-shaped layout) of the present invention, vortices begin to form when the liquid level drops to 70mm during the pouring process, and disappear when the liquid level drops to 40mm. The vortex does not form a through-type vortex, but only a rudimentary vortex shape.

[0033] Water simulation experiments demonstrate that the porous array vortex suppressor of this invention can effectively suppress the generation of vortices.

[0034] (2) Production experiment verification: To determine the practical benefits of this invention in production, a comparative experiment was conducted with two furnaces. One furnace used the original nozzle, while the other used the multi-hole nozzle optimized by this invention. Samples were taken from the molten steel to be poured and from the head and tail of the finished ingots for analysis.

[0035] The inclusion data from the original sprue are shown in Table 1 below: Table 1. Data on inclusions from the original sprue.

[0036] The inclusion data of the sprue after optimization using the present invention are shown in Table 2 below: Table 2. Data on inclusions in the sprue after optimization using the present invention.

[0037] Comparing the data in Tables 1 and 2, it can be seen that, under the premise that the cleanliness level of the molten steel is similar before casting, the ingots cast using the multi-hole water outlet unit of this invention have significantly lower total inclusions and large inclusions at each sampling point at the head and tail compared to ingots cast using a traditional single-hole nozzle. This proves that this invention can effectively suppress vortex slag entrapment and significantly improve the purity of the ingots.

[0038] The working principle of this invention is as follows: In a traditional single-orifice nozzle structure, molten steel forms a single "sink" flow field above the outlet, which is highly axisymmetric. According to fluid mechanics theory, axisymmetric converging flows are prone to forming stable suction vortices when the liquid level is low. These vortices, like funnels, draw scum and air from the liquid surface into the molten steel, leading to inclusion defects in the ingot.

[0039] The core of this invention lies in its innovative porous, discretized outlet structure, which, within a strictly limited installation space, maximizes the disruption of the axisymmetry of the molten steel converging flow at the outlet, thereby fundamentally suppressing the generation of stable vortices. Specifically, this invention decomposes a single large-sized outlet into multiple (n≥2) centrally symmetrically distributed small-sized outlet orifices, thus decomposing the single "sink point" flow field into multiple dispersed "sub-sink point" flow fields. This decomposition itself effectively disrupts the flow field axisymmetry required to generate large-scale stable vortices.

[0040] Building upon this foundation, the key design method for addressing spatial constraints: The key innovation of this invention lies in its design logic closely adhering to the rigid constraint of the physical installation boundary. Through an "equal flow capacity" design, the total steel throughput remains constant. By employing an optimization strategy of "maximizing the center-to-center distance of the orifices," each water outlet orifice is positioned as close as possible to the allowable location of the outer edge of the water outlet unit. This allows for maximum separation of the multiple jets on the outlet plane. The convergence and shearing of the outflows from each small orifice downstream further dissipates the flow energy into small-scale turbulence, thereby preventing the formation of a through-flow suction funnel.

[0041] Furthermore, the four through holes are symmetrically distributed in a cross shape, providing optimal flow symmetry within a limited space, preventing flow deviation, and ensuring uniform outflow of each jet. Even with a small center-to-center distance S due to installation space constraints, the multiple symmetrically distributed holes can still effectively suppress vortex generation, delaying the vortex-generating liquid level height from approximately 100 mm to 70 mm, and preventing vortices from penetrating.

[0042] In summary, this invention starts from the geometry of the casting outlet itself and destroys the conditions for vortex generation at the source through porous discretization design, thus achieving a stable and effective vortex suppression effect.

Claims

1. A porous array vortex-suppressing nozzle structure applied to a flow channel, characterized in that: It includes a water outlet unit (1) that is fixedly embedded in the water outlet position of the flow channel. The water outlet end face of the water outlet unit (1) is provided with a multi-hole array. The multi-hole array consists of at least two water outlet through holes (2), and all water outlet through holes (2) are arranged in a centrally symmetrical manner around the geometric center of the water outlet unit (1).

2. The porous array vortex suppressor structure for use in flow channels according to claim 1, characterized in that: The total cross-sectional area of ​​all the water outlet holes (2) is matched with the steel flow rate required by the predetermined process.

3. The porous array vortex suppressor structure for use in flow channels according to claim 1, characterized in that: The number of water outlet holes (2) is four, and they are arranged in a cross shape and close to the outer edge of the water outlet unit (1).

4. The porous array vortex suppressor structure for use in a flow channel according to claim 3, characterized in that: The centers of the four water outlet holes (2) are located on the same circumference and are evenly distributed.

5. A design method for a porous array vortex-suppressing nozzle structure applied to a flow channel as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Determine the structural constraint parameters of the water outlet unit (1), including the outer diameter D of the water outlet unit, the diameter d of a single water outlet hole, and the required minimum safe wall thickness t; S2. Determine the upper limit constraint condition of the center distance S of each water outlet hole (2) according to the structural constraint parameters: × [ (D / 2) - (d / 2) - t] S3. Under the premise of satisfying the above constraints, maximize the center distance S of the holes and arrange each water outlet hole (2) in an allowable position close to the outer edge of the water outlet unit (1).

6. The design method for a porous array vortex-suppressing nozzle structure applied to a flow channel according to claim 5, characterized in that: The water outlet unit (1) is an independent refractory material component whose shape matches the opening at the end of the flow channel. In step S1, the minimum safe wall thickness t is determined according to the strength of the refractory material.

7. The design method for a porous array vortex-suppressing nozzle structure applied to a flow channel according to claim 5, characterized in that: In step S1, the diameter d of a single water outlet is determined based on the principle of "equal flow capacity", so that the total cross-sectional area of ​​all water outlets (2) is equal to the cross-sectional area of ​​the traditional single-hole water outlet to be replaced.

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