Self-priming tapered spin streamer for foam gel spraying

Abstract

The application provides a self-suction tapered spiral flow guide reinforced and shear-enhanced jet pipe for foam gel spraying, which comprises a circular pipe body, the circular pipe body comprising a smoothly connected tapered section, a throat and a diverging section; the inner wall of the tapered section is provided with a plurality of tapered spiral flow guide vanes which are uniformly distributed in the circumferential direction of the tapered section and are fixed to the inner wall of the tapered section in a spiral shape; the inner wall of the diverging section is provided with a plurality of long wedge shear ridges which are uniformly distributed in the circumferential direction of the diverging section and have a triangular pyramid structure; a self-suction hole is formed in the side wall of the diverging section at a position upstream of the long wedge shear ridges; the self-suction tapered spiral flow guide reinforced and shear-enhanced jet pipe can effectively avoid stagnation and accumulation of high-viscosity fluid in the boundary layer of the pipe wall, realize self-adaptive shear thinning and low-resistance high-efficiency conveying of non-Newtonian fluid, enhance premixing effect, foaming efficiency and fine, uniform and stable stability of foam, and avoid blockage of gel in the internal screw or screw core structure of a traditional jet pipe through non-axle-occupying spiral flow guide.

Description

Technical Field

[0001] This application relates to the field of fire-fighting equipment and multiphase flow mixing and spraying technology, and in particular to a self-priming, tapering, swirling, and shear-enhanced jet pipe for foam gel spraying. Background Technology

[0002] Currently, gel foam, as a novel and highly efficient fire extinguishing and protective material, has received widespread attention in recent years due to its excellent adhesion, thermal insulation and flame retardant properties, and oxygen asphyxiation barrier effect. It is used in fire suppression, lithium battery and new energy thermal runaway fire containment, and emergency response to hazardous chemical leaks. The application of gel foam typically requires rapid and uniform mixing and efficient foaming of the gas and liquid phases and the gel matrix to form a jet with high momentum, stable flow pattern, and ideal coverage.

[0003] There are two common types of guide tubes: one with a spiral screw or guide core with a central shaft inside the jet tube, and the other a straight-through or simply narrow-diameter guide tube. Gel foam fluids have extremely complex physicochemical properties, typically exhibiting high viscosity and non-Newtonian fluid behavior (such as significant shear-thinning characteristics). The first type of guide tube, with its solid mandrel and blades occupying the center of the flow channel, not only increases flow resistance but also makes the gel foam prone to agglomeration and blockage during pipeline transport. The second type of guide tube faces several technical bottlenecks when spraying such high-viscosity, non-Newtonian rheological fluids:

[0004] In straight-through or simple narrow-diameter structures, the fluid flow inside the pipe exhibits relatively uniform axial acceleration or disordered turbulence. High-viscosity gels cannot achieve effective pre-dispersion and accelerated impact before entering the throat, and tend to accumulate in the boundary layer of the pipe wall. This not only increases flow resistance but also leads to uneven mixing of the fluid at the center of the pipe and the wall surface.

[0005] The jetting pipeline usually relies on the local negative pressure at the throat for passive self-aspiration. Its converging and expanding sections are mostly smooth transitions. When processing high-viscosity gels, the simple axial acceleration in the smooth converging section can easily lead to a limited gas-liquid contact area.

[0006] During the gradual expansion (pressure) stage, the fluid faces a reverse pressure gradient due to the expansion of the channel cross-section. For high-viscosity non-Newtonian fluids, the reverse pressure gradient can easily lead to boundary layer separation, flow stagnation, or the formation of a disordered large-scale backflow zone. This not only severely depletes the kinetic energy of the jet (resulting in a decrease in jet outlet velocity and a shortening of the spray distance), but also prevents the intake air from undergoing deep microscale shear mixing with the gel matrix. Ultimately, this results in uneven foam size distribution, rapid liquid precipitation, and a low foaming ratio. Summary of the Invention

[0007] This application provides a self-priming, tapering, spiral-guided, and shear-enhanced jet tube for foam gel spraying, thereby at least partially addressing one of the technical problems in related technologies. The technical solution of this application is as follows:

[0008] This application provides a self-priming, tapered, spiral-guided, and shear-enhanced jet tube for foam gel spraying, comprising a circular tube body, wherein the circular tube body includes a tapered section, a throat, and a diffusing section that are smoothly connected sequentially along the fluid flow direction.

[0009] The inner wall of the tapered section is provided with a plurality of tapered spiral guide vanes evenly distributed along the circumference of the tapered section, and the tapered spiral guide vanes are fixed to the inner wall of the tapered section in a spiral shape.

[0010] The inner wall of the expanding section is provided with a plurality of long wedge shear ridges evenly distributed along the circumference of the expanding section, and the long wedge shear ridges are in the form of a triangular pyramid structure.

[0011] At least one radial self-priming hole is provided on the sidewall of the expanding section at the upstream position of the long wedge shear ridge to connect to external gas.

[0012] In some implementations, the tapered spiral guide vanes are circumferentially symmetrically distributed along the axis of the circular tube body, and the spiral directions of the multiple tapered spiral guide vanes are consistent.

[0013] In some implementations, the pitch of the tapered spiral guide vane gradually decreases as the pipe diameter shrinks, and the rotation angle of the tapered spiral guide vane meets the following requirement: the rotation angle within every 8cm length is less than 120°.

[0014] In some implementations, the triangular pyramidal structure includes an inflow ramp that gently transitions toward the throat and two flow channel side ramps that transition toward the sidewall of the circular tube body. The intersection of the two flow channel side ramps forms a ridge line, and the two flow channel side ramps are symmetrically arranged.

[0015] In some implementations, the apex of the long wedge shear ridge is parallel to the axis of the circular tube body.

[0016] In some implementations, the inner wall of the tapering section is provided with five tapering spiral guide vanes, and the inner wall of the expanding section is provided with six long wedge shear ridges.

[0017] In some implementations, the inlet diameter D1 of the converging section, the minimum diameter D2 of the throat, and the outlet diameter D3 of the expanding section satisfy the following proportional relationship: D1:D2:D3=3.25:1:6.5.

[0018] In some implementations, the maximum radial protrusion height h of the long wedge shear ridge satisfies: 0.15 D2 ≤ h ≤ 0.3 D2.

[0019] In some implementations, the tapering section uses a tapering curve with gradually changing curvature for diameter reduction transition.

[0020] In some implementations, the inlet pipe diameter D1 is 26mm, the minimum pipe diameter D2 is 8mm, and the outlet pipe diameter D3 is 52mm; the total axial length of the circular pipe body is 250mm, and the diameter of the self-priming hole is 2.4mm.

[0021] This application has the following advantages and beneficial effects:

[0022] This application addresses the high viscosity and shear-thinning non-Newtonian fluid dynamics characteristics of gel fluids. By introducing multiple tapered, swirling guide vanes in the converging section, part of the axial kinetic energy of the fluid passing through the jet tube is converted into circumferential rotational kinetic energy. This can apply a strong circumferential shear force to the fluid. This active shearing action significantly reduces the apparent viscosity of the gel fluid before it enters the throat, alleviating flow resistance and effectively avoiding the stagnation and accumulation of high-viscosity fluids at the pipe wall boundary layer. It does not hinder the spraying of foam gel, thus achieving adaptive shear-thinning and low-resistance, high-efficiency transport of non-Newtonian fluids.

[0023] This application uses multiple tapered spiral guide vanes to streamline the fluid, causing the fluid to form an orderly spiral streamline bundle that tightens in three-dimensional space. This effectively increases the maximum flow velocity at the throat, thereby enhancing the static pressure drop at the self-priming orifice, creating a stronger negative pressure vacuum, and significantly improving the intake rate of air or other media and the gas-liquid mixing ratio.

[0024] This application utilizes the combined effects of helical shear and centrifugal force achieved by multiple tapered spiral guide vanes to ensure that the mainstream is spatially dispersed before entering the throat, effectively enhancing the turbulence intensity at the narrowed section. This allows the gel matrix to achieve highly efficient dispersion-based premixing the instant it comes into contact with the inhaled air at the throat, thereby constructing a high-intensity turbulent premixing field. This enhances the premixing effect, foaming efficiency, and the fineness, uniformity, and stability of the foam, laying an excellent foundation for foaming.

[0025] This application sets multiple triangular pyramidal long wedge shear ridges in the gradually expanding section. When the high-speed gas-liquid mixture climbs along the gentle slope of the long wedge shear ridges and slides to both sides, the flow is forced to undergo localized controlled separation. A pair of counter-rotating longitudinal conical vortices are symmetrically induced on both sides of the long wedge shear ridges. These longitudinal conical vortices penetrate into the mainstream, constructing a local high shear stress field and a high turbulent kinetic energy dissipation zone. This continuously breaks up the large air bubbles that are drawn in into micron-sized microbubbles and prevents secondary aggregation of gel particles. It significantly improves the liquid separation stability and foaming uniformity of the gel foam, realizes active control of boundary layer separation under the reverse pressure gradient, and constructs a double-vortex transverse strong shear field. It can enhance shear stretching and secondary vortices in the foam gel. Enhanced shear can refine the foaming of the foam gel, breaking large air bubbles into fine air bubbles of uniform size step by step, and simultaneously achieving enhanced premixing, increased foaming ratio, and enhanced foam stability.

[0026] The tapered swirling guide vanes and long wedge shear ridges of this application primarily form guides on the inner wall of the jet tube, which helps prevent blockage of high-density, high-viscosity liquids such as foam gels. Through the smooth curvature of the tapered section, the gradual pitch of the tapered swirling guide vanes, and the symmetrical, gentle slope design of the long wedge shear ridges, this application geometrically ensures that while the multiphase flow experiences strong disturbance and shearing, it significantly reduces useless local pressure loss. The highly coordinated overall flow channel structure results in uniform flow velocity, concentrated spray momentum, long range, and wide coverage of the gel foam sprayed from the outlet. Simultaneously, the non-axial swirling guides avoid blockage of the gel in the screw or core structure inside the traditional jet tube.

[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0028] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0029] Figure 1 A schematic diagram of the wireframe structure of a self-priming tapered spiral guiding and shear-enhancing jet pipe for spraying foam gel, provided for an embodiment of this application.

[0030] Figure 2 Left view of a self-priming tapered spiral flow-enhancing and shear-enhancing jet pipe for foam gel spraying, provided as an embodiment of this application;

[0031] Figure 3 A partial cross-sectional view of a self-priming, tapering, spiral-guided, and shear-enhanced jet pipe for spraying foam gel, provided as an embodiment of this application.

[0032] Figure 4 A simulation diagram (contour lines) showing the maximum flow velocity at the throat, provided as an example of this application.

[0033] Figure 5 A diagram (contour lines) showing the turbulence intensity and the resulting swirl vector arrow at the location of the tapered swirling guide vane, as provided in an example of this application.

[0034] Figure 6 A simulation diagram (contour lines) of the turbulence intensity of a long wedge shear ridge provided as an example of this application.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1-Jet tube inlet, 2-Gradually contracting spiral guide vane, 3-Reduced diameter section, 4-Self-priming hole, 5-Long wedge shear ridge, 6-Jet tube outlet. Detailed Implementation

[0037] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0038] To address the technical challenges of existing technologies for spraying high-viscosity, non-Newtonian rheological gel foams, such as large disordered collision resistance in the inlet converging section, limited flow velocity and weak self-absorption capacity in the throat, easy fluid separation due to adverse pressure gradient in the expanding section, insufficient microscale shearing of the gas-liquid two-phase system, and uneven foaming, this application provides a self-absorbing, converging, swirling flow-guiding and shear-enhancing jet tube for spraying foam gels. This tube features a reasonable structure, low resistance, large self-absorption negative pressure, strong micro-vortex shearing, and stable spraying.

[0039] The following description, with reference to the accompanying drawings, describes an embodiment of the self-priming, tapering, spiral-guided, and shear-enhanced jet tube for spraying foam gel.

[0040] like Figures 1 to 3 As shown in the embodiment of this application, a self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for spraying foam gel is provided. The jet pipe includes a circular tube body, which comprises a tapered section, a throat, and a diverging section smoothly connected sequentially along the fluid flow direction. The tapered section has a jet pipe inlet 1 at its end, and the diverging section has a jet pipe outlet 6 at its end. The inlet diameter of the tapered section is D1. The throat includes a narrowing section 3 with a minimum diameter of D2. The outlet diameter of the diverging section is D3, satisfying D1 > D2. <D3。

[0041] The inner wall of the tapered section is provided with multiple tapered swirling guide vanes 2 evenly distributed along the circumference of the tapered section. The tapered swirling guide vanes 2 are helically fixed to the inner wall of the tapered section. By providing multiple tapered swirling guide vanes 2 on the inner wall of the tapered section, part of the axial kinetic energy of the fluid is converted into circumferential kinetic energy rotating around the axis of the jet tube. During the accelerated contraction of the fluid, a strong shear swirling flow is generated, which can effectively reduce the apparent viscosity and circumferential pre-dispersion of the gel fluid.

[0042] The inner wall of the expanding section is provided with multiple long wedge shear ridges 5 evenly distributed along the circumference of the expanding section. The long wedge shear ridges 5 have a triangular pyramidal structure. Multiple long wedge shear ridges 5 with a triangular pyramidal structure are provided on the inner wall of the expanding section.

[0043] In the expansion section, due to the increased pipe diameter and decreased flow velocity, conventional structures are prone to fluid separation due to adverse pressure gradients, resulting in large-scale dead zones. This application utilizes multiple circumferentially distributed triangular pyramidal long wedge shear ridges 5 as boundary layer disturbances. These ridges disrupt the wall-attached boundary layer during fluid decompression and deceleration, inducing longitudinal and counter-rotating vortex pairs to perform microscale secondary shearing on the fluid. Furthermore, the multiple long wedge shear ridges 5 enhance shear stretching and secondary vortices within the foam gel. This enhanced shearing refines the foam gel's foaming process, progressively breaking large bubbles into uniformly sized fine bubbles, simultaneously achieving enhanced premixing, increased foaming ratio, and improved foam stability.

[0044] At least one radial self-priming hole 4 is provided on the sidewall of the diffuser section upstream of the long wedge shear ridge 5 to connect to external gas. As an example, the self-priming hole 4 is a radial through hole, located axially near the output end of the throat and forward of the long wedge shear ridge 4 in the flow direction. The self-priming hole 4, located upstream of the long wedge shear ridge 5 on the sidewall of the diffuser section, utilizes the negative pressure generated at the throat and the front of the diffuser section to draw the medium into the pipe, allowing the drawn-in medium to initially converge with the mainstream before entering the strong shear zone formed by the long wedge shear ridge 5.

[0045] In some embodiments, the tapered spiral guide vanes 2 are symmetrically distributed circumferentially along the axis of the circular tube body, and the spiral directions of the multiple tapered spiral guide vanes 2 are consistent. The pitch of the tapered spiral guide vanes 2 gradually decreases as the tube diameter shrinks. The rotation angle of the tapered spiral guide vanes 2 meets the following requirement: the rotation angle within every 8 cm length is less than 120°.

[0046] This allows the fluid to achieve a continuously increasing rotational angular velocity while accelerating smoothly.

[0047] In some embodiments, the triangular pyramidal structure includes an inflow ramp that gently transitions toward the throat and two flow channel side ramps that transition toward the sidewall of the circular tube body. The intersection of the two flow channel side ramps forms a ridge line, and the two flow channel side ramps are symmetrically arranged.

[0048] Thus, the long wedge shear ridge with symmetrical structure ensures that the multiphase flow is subjected to strong disturbance shear while greatly reducing useless local pressure loss.

[0049] In some embodiments, the apex of the long wedge shear ridge 5 is parallel to the axis of the circular tube body.

[0050] Compared to the inclined top ridge line, the parallel design allows the long wedge shear ridge to generate only axial pure shear, without circumferential induced velocity, which helps maintain spray consistency and avoid centrifugal stratification.

[0051] In some embodiments, the inner wall of the tapering section is provided with five tapering spiral guide vanes 2, and the inner wall of the expanding section is provided with six long wedge shear ridges 5.

[0052] In some embodiments, the inlet diameter D1 of the converging section, the minimum diameter D2 of the throat, and the outlet diameter D3 of the expanding section satisfy the following proportional relationship: D1:D2:D3=3.25:1:6.5.

[0053] A diameter reduction that meets this ratio helps increase flow rate and prevents blockage of the foam gel pipeline due to excessive diameter reduction. Setting the outlet expansion ratio helps the foam gel to foam quickly and achieve large-area spray coverage.

[0054] In some embodiments, the maximum radial protrusion height h of the long wedge shear ridge 5 satisfies: 0.15 D2 ≤ h ≤ 0.3 D2.

[0055] This allows for further optimization of the three gain effects: shear thinning, bubble refinement, and anti-clogging.

[0056] In some embodiments, the tapering section uses a tapering curve with gradually changing curvature for the diameter reduction transition.

[0057] This reduces inlet impact loss and local resistance caused by sudden changes in flow direction when the fluid enters the converging section.

[0058] As an example, the inlet pipe diameter D1 is 26mm, the minimum pipe diameter D2 is 8mm, and the outlet pipe diameter D3 is 52mm; the total axial length of the circular pipe body is 250mm, and the diameter of the self-priming hole 4 is 2.4mm.

[0059] Traditional smooth tapering sections tend to generate high pressure at the center due to disordered streamline collisions, hindering fluid acceleration. In contrast, this application uses multiple tapering, swirling guide vanes to streamline the fluid, creating an ordered helical streamline bundle that tightens in three-dimensional space. The performance of the jet tube in this application was verified through CFD (Computational Fluid Dynamics) simulation. The CFD simulation results show that:

[0060] After the foam gel passes through multiple tapered spiral guide vanes, as... Figure 4 As shown, the maximum flow velocity at the throat is significantly increased to 287.1 m / s. This substantial increase in velocity directly enhances the static pressure drop at the self-priming orifice, creating a stronger negative pressure vacuum and significantly improving the intake rate of air or other media and the gas-liquid mixing ratio. Through the combined effect of helical strong shear and centrifugal force achieved by multiple tapered swirling guide vanes, the mainstream is spatially dispersed to a deep extent before entering the throat. Figure 5 The image shows the turbulence intensity and the resulting swirling vector arrow at the swirling guide with tapered swirling guide vanes. It is evident that the turbulence intensity at the swirling guide is significantly increased. This powerful microscale turbulent pulsation allows for highly efficient dispersion-based premixing of the gel matrix the instant it comes into contact with the inhaled air at the throat. Figure 6 As shown, the turbulence intensity at the shear ridge of the long wedge is also significantly improved.

[0061] The jet tube of this application addresses the high viscosity and shear-thinning non-Newtonian fluid dynamics characteristics of gel fluids. By introducing multiple tapered, swirling guide vanes in the converging section, it converts part of the axial kinetic energy of the fluid passing through the jet tube into circumferential rotational kinetic energy. This generates a strong circumferential shear force on the fluid, significantly reducing its apparent viscosity before the gel fluid enters the throat. This reduces flow resistance and effectively avoids the stagnation and accumulation of high-viscosity fluids at the tube wall boundary layer, thus not hindering the spraying of foam gel. This achieves adaptive shear-thinning and low-resistance, high-efficiency transport of non-Newtonian fluids. Simultaneously, the multiple tapered, swirling guide vanes streamline the fluid, creating an ordered helical streamline bundle. Tightening in three-dimensional space effectively increases the maximum flow velocity at the throat, thereby enhancing the static pressure drop at the self-priming orifice and creating a stronger negative pressure vacuum. This significantly improves the intake rate of air or other media and the gas-liquid mixing ratio. Furthermore, the combined effect of strong spiral shear and centrifugal force achieved through multiple tapered spiral guide vanes ensures that the mainstream is spatially dispersed before entering the throat, effectively increasing the turbulence intensity at the narrowed section. This allows the gel matrix to achieve highly efficient dispersion-based premixing the instant it comes into contact with the intake air at the throat, thus constructing a high-intensity turbulent premixing field. This enhances the premixing effect, foaming efficiency, and the fineness, uniformity, and stability of the foam, laying an excellent foundation for foaming. This application sets multiple triangular pyramidal long wedge shear ridges in the gradually expanding section. When the high-speed gas-liquid mixture climbs along the gentle slope of the long wedge shear ridges and slides to both sides, the flow is forced to undergo localized controlled separation. A pair of counter-rotating longitudinal conical vortices are symmetrically induced on both sides of the long wedge shear ridges. These longitudinal conical vortices penetrate into the mainstream, constructing a local high shear stress field and a high turbulent kinetic energy dissipation zone. This continuously breaks up the large air bubbles that are drawn in into micron-sized microbubbles and prevents secondary aggregation of gel particles. It significantly improves the liquid separation stability and foaming uniformity of the gel foam, realizes active control of boundary layer separation under the reverse pressure gradient, and constructs a double-vortex transverse strong shear field. It can enhance shear stretching and secondary vortices in the foam gel. Enhanced shear can refine the foaming of the foam gel, breaking large air bubbles into fine air bubbles of uniform size step by step, and simultaneously achieving enhanced premixing, increased foaming ratio, and enhanced foam stability. The tapered swirling guide vanes and long wedge shear ridges of this application primarily form guides on the inner wall of the jet tube, which helps prevent blockage of high-density, high-viscosity liquids such as foam gels. Through the smooth curvature of the tapered section, the gradually changing pitch of the tapered swirling guide vanes, and the symmetrical, gentle slope design of the long wedge shear ridges, this application geometrically ensures that while the multiphase flow experiences strong disturbance and shearing, it significantly reduces useless local pressure loss. The highly coordinated overall flow channel structure results in uniform flow velocity, concentrated spray momentum, long range, and wide coverage of the gel foam sprayed from the outlet. The jet tube of this application is mainly suitable for spraying high-viscosity liquids such as gels.

[0062] In the foregoing descriptions of the embodiments, the terms "some embodiments," "examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0064] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A self-priming, tapering, spiral-guided, and shear-enhanced jet pipe for spraying foam gel, characterized in that, The tube body includes a circular tube body, which comprises a tapering section, a throat, and a dilating section that are smoothly connected sequentially along the fluid flow direction. The inner wall of the tapered section is provided with a plurality of tapered spiral guide vanes evenly distributed along the circumference of the tapered section, and the tapered spiral guide vanes are fixed to the inner wall of the tapered section in a spiral shape. The inner wall of the expanding section is provided with a plurality of long wedge shear ridges evenly distributed along the circumference of the expanding section, and the long wedge shear ridges are in the form of a triangular pyramid structure. At least one radial self-priming hole is provided on the sidewall of the expanding section at the upstream position of the long wedge shear ridge to connect to external gas.

2. The self-priming, tapering, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 1, characterized in that, The tapered spiral guide vanes are symmetrically distributed circumferentially at equal angles along the axis of the circular tube body, and the spiral directions of the multiple tapered spiral guide vanes are consistent.

3. The self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 1, characterized in that, The pitch of the tapered spiral guide vane gradually decreases as the pipe diameter shrinks, and the rotation angle of the tapered spiral guide vane meets the following requirement: the rotation angle within every 8cm length is less than 120°.

4. The self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 1, characterized in that, The triangular pyramidal structure includes a flow-facing slope that gently transitions towards the throat and two flow-channel side slopes that transition towards the sidewall of the circular tube body. The intersection of the two flow-channel side slopes forms a ridge line, and the two flow-channel side slopes are symmetrically arranged.

5. A self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 4, characterized in that, The apex of the long wedge shear ridge is parallel to the axis of the circular tube body.

6. The self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 1, characterized in that, The inner wall of the tapering section is provided with five tapering spiral guide vanes, and the inner wall of the expanding section is provided with six long wedge shear ridges.

7. A self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 1, characterized in that, The inlet pipe diameter D1 of the converging section, the minimum pipe diameter D2 of the throat, and the outlet pipe diameter D3 of the expanding section satisfy the following proportional relationship: D1:D2:D3=3.25:1:6.

5.

8. A self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 7, characterized in that, The maximum radial protrusion height h of the long wedge shear ridge satisfies: 0.15 D2 ≤ h ≤ 0.3 D2.

9. A self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 1, characterized in that, The tapering section uses a tapering curve with gradually changing curvature for the diameter reduction transition.

10. A self-priming, tapered, spiral-guided, and shear-enhanced jet pipe for foam gel spraying according to claim 7, characterized in that, The inlet pipe diameter D1 is 26mm, the minimum pipe diameter D2 is 8mm, and the outlet pipe diameter D3 is 52mm; the total axial length of the circular pipe body is 250mm, and the diameter of the self-priming hole is 2.4mm.

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