A scale-preventing jet mixing device and method

Abstract

This invention relates to the field of jet mixers, specifically to an anti-scaling jet mixing device and method, comprising a pre-rectifier section, a conical constriction nozzle, and a mixing throat connected sequentially along the axial direction; and a central injection assembly disposed inside an outer tube assembly. The pre-rectifier section is used to introduce a first fluid, and the central injection assembly is used to introduce a second fluid. The inner cross-section of the conical constriction nozzle gradually decreases along the flow direction, and the discharge end face of the central injection assembly extends to the junction of the conical constriction nozzle and the mixing throat, causing the first fluid to form an annular liquid sheath at the junction enveloping the second fluid flowing out from the discharge end face. The anti-scaling jet mixing method ensures that when the second fluid flows out from the central injection assembly, it is immediately subjected to radial compression by the first fluid, forcing it to form a core flow suspended in the center of the annular liquid sheath, preventing the second fluid from flowing back into the interior of the conical constriction nozzle and preventing direct contact between the unmixed second fluid and the mixing throat.

Description

Technical Field

[0001] This invention relates to the field of jet mixers, and more specifically to an anti-scaling jet mixing device and method. Background Technology

[0002] In industries such as nanomaterial preparation, new energy battery slurry production, fine chemicals and water treatment, there is a common need to disperse high-viscosity, easily agglomerated or thixotropic materials (second fluid) into low-viscosity carrier media (first fluid).

[0003] To achieve continuous production, the industry typically employs jet mixing technology, which uses a high-pressure first fluid to generate a high-speed jet, and then uses entrainment to draw in a second fluid and mix and transport it to downstream pipelines. However, in existing jet mixing devices, scaling and clogging have always been problems that restrict the long-term stable operation of the system.

[0004] Existing jet mixing devices typically fall into the following two categories:

[0005] The first type is the side-wall suction structure (such as the traditional Venturi jet pump). In this type of structure, the second fluid is drawn in through the side wall opening of the mixing chamber. Due to the wall adhesion effect, the second fluid adheres to the inner wall of the throat after entering the mixing chamber. Since the second fluid usually has high viscosity or strong adsorption, it is very easy to deposit and scale once it comes into contact with the wall, which leads to a reduction in the effective cross-sectional area of ​​the mixing channel.

[0006] The second type is the wall annular gap injection structure (such as a jet pump), see [reference] Figure 1 Such structures typically include an upstream slurry pipe, a downstream mixing pipe, and an outer casing at the junction of the two. When the first and second fluids cross the annular gap and enter the downstream mixing pipe, they are prone to backflow. When the second fluid is a high-viscosity slurry, it is very easy for the high-viscosity slurry to adhere to the inlet edge of the downstream mixing pipe. Over time, the second fluid accumulates and grows at the inlet of the downstream mixing pipe, eventually causing the annular gap to be blocked in the reverse direction. Summary of the Invention

[0007] The purpose of this invention is to provide an anti-scaling jet mixing device and method to solve the problem of scaling and clogging that easily occurs when the jet mixing device mixes high-viscosity slurry and low-viscosity carrier fluid due to backflow of high-viscosity slurry.

[0008] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0009] An anti-scaling jet mixing device includes: an outer tube assembly, comprising a pre-rectifier section, a conical constriction nozzle, and a mixing throat connected sequentially along the axial direction;

[0010] A central injection assembly is disposed inside the outer tube assembly;

[0011] The pre-rectifier section is used to introduce a first fluid, the central injection assembly is used to introduce a second fluid, the inner cross-section of the conical constricting nozzle gradually decreases along the flow direction, and the discharge end face of the central injection assembly extends to the junction of the conical constricting nozzle and the mixing throat, so that the first fluid entering through the pre-rectifier section is accelerated in the conical constricting nozzle and forms an annular liquid sheath at the junction that envelops the second fluid flowing out from the discharge end face; the ratio of the cross-sectional area occupied by the discharge end face of the central injection assembly to the internal flow cross-sectional area of ​​the mixing throat is 0.3~0.6; the angle between the inner wall surface of the conical constricting nozzle and the central axis is 10°~18°.

[0012] Furthermore, the central injection assembly includes a long straight injection tube, the root of which is fixedly connected to the rear end of the outer tube assembly, and the tube body of which is suspended axially through the interior of the pre-rectifier section and the conical constriction nozzle.

[0013] The second fluid enters axially from the tail end of the long straight injection tube.

[0014] Furthermore, the central injection assembly includes a central short nozzle located inside the conical constriction nozzle;

[0015] A plurality of radially distributed support rods are connected between the central short nozzle and the inner wall of the outer tube assembly, and the support rods are used to fix the central short nozzle.

[0016] The feed passage for the second fluid passes through the interior of at least one of the support rods and is introduced from the side wall of the outer tube assembly into the inner cavity of the central short nozzle.

[0017] Furthermore, a flow rectifier is provided at one end of the central short nozzle facing the direction of the first fluid flow. The outer surface of the flow rectifier is a rotationally symmetrical streamlined rotating body, and a curved flow guide channel is provided inside the flow rectifier.

[0018] The curved guide channel is configured to guide the second fluid from radial flow relative to the central short nozzle to axial flow. After passing through the interior of the support rod and entering the interior of the rectifier head, the second fluid enters the interior of the central short nozzle along the curved guide channel.

[0019] Furthermore, the cross-section of the support rod is teardrop-shaped or elliptical, and the major axis of the cross-section is parallel to the flow direction of the first fluid.

[0020] Furthermore, the end of the support rod away from the direction of the first fluid's flow is provided with a straight section parallel to the direction of the first fluid's flow, thereby making the support rod form the shape of a hollow guide vane. The straight section is used to rectify the first fluid.

[0021] Furthermore, the central injection assembly also includes an annular feed manifold sleeved outside the outer tube assembly, with one end of the internal channel of each support rod connected to the annular feed manifold and the other end converging into the inner cavity of the central short nozzle;

[0022] The second fluid is diverted through the annular feed manifold and simultaneously injected into the central short nozzle through multiple support rods.

[0023] Furthermore, the number of support rods is N, where N≥3;

[0024] The sum of the total cross-sectional areas of the internal channels of all the support rods is greater than or equal to the cross-sectional area of ​​the discharge end face of the central short nozzle.

[0025] Furthermore, the axial linear distance between the edge of the support rod facing the direction of the first fluid flow and the discharge end face of the central short nozzle is L, and the maximum cross-sectional thickness of the support rod is t, where L / t > 5.

[0026] An anti-scaling jet mixing method, applied to an anti-scaling jet mixing device, includes the following steps:

[0027] The first fluid is introduced into the pre-rectifier section of the outer tube assembly, so that the first fluid enters the conical constriction nozzle and generates a pressure gradient acceleration.

[0028] The second fluid is introduced into the central injection assembly and flows out from the discharge end face that extends to the junction of the conical constriction nozzle and the mixing throat.

[0029] The accelerated first fluid applies radial compression force to the outflowing second fluid at the interface, forming an annular liquid sheath that envelops the second fluid. This forces the second fluid to form a wick that is suspended in the center of the mixing throat and does not contact the pipe wall. The annular liquid sheath physically isolates the second fluid from the inner wall of the mixing throat until the fluid leaves the mixing throat and enters the downstream region.

[0030] Compared with the prior art, this application has the following advantages:

[0031] This invention increases the flow rate of the first fluid through a conical constriction nozzle, so that when the second fluid flows out from the center, it is immediately subjected to radial compression by the first fluid, forcing it to form a core flow suspended in the center of the annular liquid sheath. This prevents the backflow of the high-viscosity second fluid and prevents the second fluid from contacting the mixing throat before it is fully mixed with the first fluid. This avoids the formation of scale in the annular gap at the junction of the conical constriction nozzle and the mixing throat, and reduces the scale formation downstream of the mixing throat. Attached Figure Description

[0032] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0033] Figure 1 The volume distribution of the two fluids in the existing annular jet method is shown;

[0034] Figure 2 This is a front view of the first embodiment of the present invention;

[0035] Figure 3 for Figure 2 A cross-sectional view along the AA direction;

[0036] Figure 4 This is a front view of the second embodiment of the present invention;

[0037] Figure 5 for Figure 4 A cross-sectional view along the BB direction;

[0038] Figure 6 for Figure 4 A cross-sectional view along the CC direction;

[0039] Figure 7 This is a front view of the third embodiment of the present invention;

[0040] Figure 8 for Figure 7 A cross-sectional view along the DD direction;

[0041] Figure 9 for Figure 7 A cross-sectional view along the EE direction;

[0042] The labels in the diagram represent the following:

[0043] 1-Outer tube assembly; 11-Pre-rectifier section; 12-Conical converging nozzle; 13-Mixing throat;

[0044] 2-Center injection assembly; 21-Long straight injection tube; 22-Center short nozzle; 23-Support rod; 24-Annular feed manifold; 25-Rectifier head; 26-Bent flow guide channel; 27-Straight section. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] (Example 1)

[0047] See Figure 2 and Figure 3 This embodiment provides an anti-scaling jet mixing device.

[0048] like Figure 2 As shown, the anti-scaling jet mixing device mainly consists of an outer tube assembly 1 and a central injection assembly 2.

[0049] The outer pipe assembly 1 is sequentially connected to a pre-rectifier section 11, a conical constriction nozzle 12 and a mixing throat 13 along the flow direction of the first fluid.

[0050] The pre-rectifier section 11 is used to introduce a first fluid (usually a low-viscosity dynamic fluid), and its internal flow channel configuration is configured to homogenize the flow field of the first fluid; the inner cross-section of the conical constriction nozzle 12 gradually decreases along the flow direction to accelerate the first fluid; the mixing throat 13 is connected to the end of the conical constriction nozzle 12; the center injection assembly 2 is disposed inside the outer tube assembly 1 to introduce a second fluid (usually a high-viscosity slurry).

[0051] In this embodiment, in order to meet the preferred hydrodynamic performance, the angle between the inner wall surface of the conical constriction nozzle 12 and the central axis is set to 10°~18° to prevent fluid separation from generating backflow vortices.

[0052] like Figure 3 As shown, the central injection component 2 in this embodiment specifically includes a long straight injection tube 21.

[0053] The root of the long straight injection tube 21 is fixedly connected to the rear end of the outer tube assembly 1, and the tube body of the long straight injection tube 21 is suspended along the axial direction through the interior of the pre-rectifier section 11 and the conical shrink nozzle 12.

[0054] The end of the long straight injection tube 21 has a discharge end face that extends to the junction of the conical shrink nozzle 12 and the mixing throat 13.

[0055] The working principle of this embodiment is as follows: The first fluid enters through the pre-rectifier section 11. When it flows through the conical constriction nozzle 12, the flow velocity increases due to the contraction of the flow channel cross section, forming a high-speed annular flow field at the inlet of the mixing throat 13.

[0056] The second fluid enters axially from the tail end of the long straight injection tube 21 and flows out from the discharge end face.

[0057] Since the discharge end face is located at the above-mentioned junction, according to Bernoulli's principle, the high-speed flowing first fluid on the periphery forms a low static pressure zone (annular liquid sheath), which exerts radial compression and focusing effect on the second fluid in the center, causing the second fluid to be enveloped by the first fluid and form a core flow suspended in the center of the pipe.

[0058] This embodiment differs from the common "retractable" or "annular gap water injection" structures in the prior art. In this embodiment, the discharge end face of the central injection component 2 is extended to the junction of the conical shrinkage nozzle 12 and the mixing throat 13. With a specific cone angle, it is ensured that the first fluid is always in an accelerated state caused by the pressure gradient before reaching the mixing point.

[0059] In contrast, if the concave structure in the prior art is used (i.e. the nozzle is located inside the mixing chamber), the external fluid will suddenly expand when it flows through the end of the nozzle, which will inevitably form a backflow stagnation zone behind the nozzle lip. This will cause the second fluid introduced through the central injection assembly 2 to flow back into the interior of the conical concave nozzle 12, thereby agglomerating in the gap between the conical concave nozzle 12 and the mixing throat 13, and eventually leading to scaling and blockage.

[0060] This embodiment eliminates the backflow stagnation zone and utilizes the annular liquid sheath formed by the first fluid to compress the second fluid into an extremely fine wick. Within the mixing throat 13, the second fluid is enveloped in the center of the annular liquid sheath as it passes through, achieving a "transport-only, non-contact" anti-scaling effect. The mixing process mainly occurs in the downstream region of the mixing throat 13.

[0061] Downstream of the mixing throat 13, on the one hand, the first fluid and the second fluid have basically mixed and formed a medium-viscosity slurry, which is not easy to adhere to the inner wall of the mixing throat 13; on the other hand, the mixing throat 13 has a large flow rate and is easy to replace, so even if there is a little scaling, it will not affect the overall working efficiency of the anti-scaling jet mixing device.

[0062] (Example 2)

[0063] See Figure 4 , Figure 5 and Figure 6 Based on Embodiment 1, this embodiment improves the structure and support form of the central injection component 2 to enhance structural rigidity and optimize the internal flow channel.

[0064] like Figure 5 and Figure 6 As shown, the central injection assembly 2 in this embodiment includes a central short nozzle 22.

[0065] The central short nozzle 22 is located inside the conical constricting nozzle 12, and its length is less than that of the long straight injection tube 21 in Example 1.

[0066] Several radially distributed support rods 23 are connected between the central short nozzle 22 and the inner wall of the outer tube assembly 1. The support rods 23 are used to fix the central short nozzle 22 to the center of the flow channel.

[0067] To reduce the flow resistance to the first fluid, the cross-section of the support rod 23 is teardrop-shaped or elliptical, and the major axis of the cross-section is parallel to the flow direction of the first fluid.

[0068] Regarding the feeding path, this embodiment adopts a side feeding method.

[0069] The feed passage of the second fluid passes through the interior of at least one of the support rods 23 and is introduced from the side wall of the outer tube assembly 1 into the inner cavity of the central short nozzle 22.

[0070] This structure transforms the central injection assembly 2 from a cantilever beam support to a spoke-type support, which can effectively suppress the vibration and jet eccentricity of the central injection assembly 2 caused by high-speed fluid impact.

[0071] Furthermore, in order to address the potential flow dead zone problem at corners during lateral feeding, such as... Figure 5 As shown, a rectifier head 25 is provided at one end of the central short nozzle 22 facing the direction of the first fluid flow.

[0072] The outer surface of the rectifier head 25 is a rotationally symmetric streamlined rotating body (e.g., bullet-shaped or hemispherical) to ensure the symmetry of the flow field of the external first fluid.

[0073] A curved guide channel 26 is provided inside the rectifier head 25. The curved guide channel 26 is configured to guide the second fluid from radial flow relative to the central short nozzle 22 to axial flow.

[0074] Specifically, after the second fluid passes through the interior of the support rod 23 and enters the interior of the rectifier head 25, it smoothly enters the interior of the central short nozzle 22 along the curved guide channel 26.

[0075] The curved flow channel 26 avoids local turbulence and material deposition caused by right-angle turns.

[0076] (Example 3)

[0077] See Figure 7 , Figure 8 and Figure 9 Based on Example 2, this embodiment further optimizes the support structure and introduces an annular feed manifold 24, making it suitable for high flow rates and conditions with extremely high requirements for flow field stability.

[0078] like Figure 7 As shown, in this embodiment, the support rod 23 is constructed as a hollow guide vane, and a straight section 27 parallel to the flow direction of the first fluid is provided at one end of the support rod 23 away from the incoming flow direction of the first fluid (i.e., the trailing edge).

[0079] The straight section 27 is used to force rectification of the first fluid passing through the blades and eliminate the swirling component.

[0080] To eliminate the influence of the trailing wake behind the blade on the stability of the annular liquid sheath, this embodiment limits the geometric parameters: the axial straight distance between the edge of the support rod 23 facing the direction of the first fluid flow and the discharge end face of the central short nozzle 22 is L, and the maximum cross-sectional thickness of the support rod 23 is t, where L and t satisfy the relationship: L / t>5.

[0081] This parameter setting ensures that the first fluid has enough distance to heal its wake after flowing over the blade.

[0082] For high-flow-rate feeding requirements, such as Figure 8 As shown, the central injection assembly 2 also includes an annular feed manifold 24 sleeved outside the outer tube assembly 1.

[0083] The number of support rods 23 is N (in this embodiment, N≥3, for example, 9).

[0084] One end of the internal channel of each support rod 23 is connected to the annular feed manifold 24, and the other end converges to the inner cavity of the central short nozzle 22 (specifically, converges to the curved guide channel 26 in the rectifier head 25).

[0085] The second fluid is diverted through the annular feed manifold 24 and simultaneously injected into the central short nozzle 22 through multiple support rods 23.

[0086] To ensure flow matching and prevent negative pressure or cavitation inside the central short nozzle 22, the sum of the total cross-sectional areas of the internal channels of all support rods 23 is configured to be greater than or equal to the cross-sectional area of ​​the discharge end face of the central short nozzle 22.

[0087] like Figure 9 As shown, in order to ensure that the formed annular liquid sheath has sufficient thickness and stability, in this embodiment, the ratio of the cross-sectional area occupied by the discharge end face of the control center injection component 2 to the internal flow cross-sectional area of ​​the mixing throat 13 is 0.3~0.6.

[0088] In this embodiment, uniform feeding of the second fluid is achieved through the annular feed manifold 24, deep rectification of the first fluid is achieved through the multi-blade array, and smooth transition of internal streamlines is achieved through the curved guide channel 26 in the rectifier head 25. While achieving anti-fouling, the operating stability and applicable flow range of the mixing device are significantly improved.

[0089] (Application of Examples 1, 2, and 3)

[0090] The anti-scaling jet mixing devices of the above embodiments are typically integrated into the mixing system.

[0091] In actual operation, the first fluid, as the carrier fluid, is transported to the pre-rectifier section 11 by a high-pressure pump; the second fluid, as the core material, is transported to the central injection component 2 by a metering pump.

[0092] When the mixing system is started, the first fluid preferentially establishes an annular liquid sheath; then the second fluid is injected into the center of the annular liquid sheath to form a core flow.

[0093] Utilizing the hydraulic focusing effect, the second fluid is enveloped by the first fluid to form a core-shell structure before entering the mixing throat 13. This prevents the second fluid from flowing back into the pre-rectifier section 11 and the conical constriction nozzle 12, and the mixing is completed inside or downstream of the mixing throat 13. This avoids direct contact between the second fluid and the inner wall of the device, thus solving the scaling problem.

[0094] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A scale-preventing jet mixing device, characterized in that, include: The outer tube assembly (1) includes a front rectifier section (11), a conical converging nozzle (12), and a mixing throat (13) connected sequentially along the axial direction. The central injection assembly (2) is disposed inside the outer tube assembly (1); The pre-rectifier section (11) is used to introduce the first fluid, the central injection assembly (2) is used to introduce the second fluid, the inner cross-section of the conical constriction nozzle (12) gradually decreases along the flow direction, and the discharge end face of the central injection assembly (2) extends to the junction of the conical constriction nozzle (12) and the mixing throat (13), so that the first fluid entering through the pre-rectifier section (11) is accelerated in the conical constriction nozzle (12) and forms an annular liquid sheath at the junction that wraps the second fluid flowing out from the discharge end face; the ratio of the cross-sectional area occupied by the discharge end face of the central injection assembly (2) to the internal flow cross-sectional area of ​​the mixing throat (13) is 0.3~0.6; the angle between the inner wall surface of the conical constriction nozzle (12) and the central axis is 10°~18°.

2. The anti-scaling jet mixing device according to claim 1, characterized in that, The central injection assembly (2) includes a long straight injection tube (21), the root of which is fixedly connected to the rear end of the outer tube assembly (1), and the tube body of the long straight injection tube (21) is suspended along the axial direction through the interior of the pre-rectifier section (11) and the conical shrink nozzle (12). The second fluid enters axially from the tail of the long straight injection tube (21).

3. The anti-scaling jet mixing device according to claim 1, characterized in that, The central injection assembly (2) includes a central short nozzle (22) located inside the conical constriction nozzle (12); A plurality of radially distributed support rods (23) are connected between the central short nozzle (22) and the inner wall of the outer tube assembly (1), and the support rods (23) are used to fix the central short nozzle (22). The feed passage of the second fluid passes through the interior of at least one of the support rods (23) and is introduced from the side wall of the outer tube assembly (1) into the cavity of the central short nozzle (22).

4. The anti-scaling jet mixing device according to claim 3, characterized in that, The central short nozzle (22) is provided with a flow rectifier (25) at one end facing the direction of the first fluid. The outer surface of the flow rectifier (25) is a streamlined rotating body with rotational symmetry, and the interior of the flow rectifier (25) is provided with a curved guide channel (26). The curved guide channel (26) is configured to guide the second fluid from radial flow relative to the central short nozzle (22) to axial flow. After the second fluid passes through the interior of the support rod (23) and enters the interior of the rectifier head (25), it enters the interior of the central short nozzle (22) along the curved guide channel (26).

5. The anti-scaling jet mixing device according to claim 3, characterized in that, The cross-section of the support rod (23) is teardrop-shaped or elliptical, and the long axis of the cross-section is parallel to the flow direction of the first fluid.

6. The anti-scaling jet mixing device according to claim 5, characterized in that, The support rod (23) has a straight section (27) parallel to the flow direction of the first fluid at one end away from the flow direction of the first fluid, so that the support rod (23) forms the shape of a hollow guide vane, and the straight section (27) is used to rectify the first fluid.

7. The anti-scaling jet mixing device according to claim 6, characterized in that, The central injection assembly (2) also includes an annular feed manifold (24) sleeved outside the outer tube assembly (1), with one end of the internal channel of each support rod (23) connected to the annular feed manifold (24) and the other end converging into the inner cavity of the central short nozzle (22); The second fluid is diverted via the annular feed manifold (24) and simultaneously injected into the central short nozzle (22) through multiple support rods (23).

8. The anti-scaling jet mixing device according to claim 6, characterized in that, The number of support rods (23) is N, where N≥3; The sum of the total cross-sectional areas of the internal channels of all the support rods (23) is greater than or equal to the cross-sectional area of ​​the discharge end face of the central short nozzle (22).

9. The anti-scaling jet mixing device according to claim 8, characterized in that, The axial straight distance between the edge of the support rod (23) facing the direction of the first fluid flow and the discharge end face of the central short nozzle (22) is L, and the maximum cross-sectional thickness of the support rod (23) is t, where L / t > 5.

10. A method for mixing anti-scaling jets, characterized in that, The anti-scaling jet mixing device according to any one of claims 1-9 includes the following steps: The first fluid is introduced into the pre-rectifier section (11) of the outer tube assembly (1), so that the first fluid enters the conical constriction nozzle (12) and generates a pressure gradient acceleration; The second fluid is introduced into the central injection assembly (2) and flows out from the discharge end face that extends to the junction of the conical constriction nozzle (12) and the mixing throat (13); The accelerated first fluid applies radial compression force to the outflowing second fluid at the junction, forming an annular liquid sheath that envelops the second fluid. This forces the second fluid to form a core flow that is suspended in the center of the mixing throat (13) and does not contact the pipe wall. The annular liquid sheath physically isolates the second fluid from the inner wall of the mixing throat (13) until the fluid leaves the mixing throat (13) and enters the downstream area.

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