Multistage leaf-shaped static mixer for mixing viscoelastic fluid and Newtonian fluid

Abstract

The invention belongs to the technical field of fluid mixing, and discloses a multi-stage leaf-shaped static mixer for mixing viscoelastic fluid and Newtonian fluid, and multi-stage mixing units which are sequentially connected end to end in the longitudinal direction are arranged between a fluid input channel and a fluid output channel; the fluid input channel is used for connecting the Newtonian fluid inlet and the viscoelastic fluid inlet, and the fluid output channel is used for leading out mixed liquid; the mixing unit is a flat shell composed of an upper surface, a lower surface, a first outer contour surface, a first inner contour surface, a second outer contour surface and a second inner contour surface, and an upstream confluence area, a shunting area and a downstream confluence area are sequentially formed between the first outer contour surface and the first inner contour surface and between the second outer contour surface and the second inner contour surface. According to the invention, the viscoelastic fluid can be rapidly mixed under the condition of low shear disturbance, so that the fluid forms secondary vortex and spiral flow along the main flow direction in the mixing area, and the mixing rate of the viscoelastic fluid and the Newtonian fluid is obviously improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fluid mixing, and particularly relates to a static mixer for mixing viscoelastic fluid and Newtonian fluid. BACKGROUND

[0002] Fluid mixing technology is a key unit operation in many industrial processes such as chemical industry, energy, pharmaceuticals, food processing and environmental engineering, and its goal is to achieve efficient and uniform mixing between different fluids with as low energy consumption as possible. According to whether there is a moving part, the mixing device can be divided into two categories: dynamic mixer and static mixer.

[0003] Dynamic mixers usually rely on rotating impellers or other mechanical components to generate macroscopic turbulence to achieve mixing, and have high mixing efficiency, but have complex structure, high energy consumption, high operation and maintenance cost, and are prone to problems such as seal failure, wear and vibration, and are not suitable for high-viscosity or long-time continuous operation occasions.

[0004] In contrast, static mixers do not contain moving parts and rely on the effects of splitting, converging, vortex and shearing generated when the fluid flows through the fixed geometry to achieve mixing, and have the advantages of simple structure, high reliability, easy maintenance and low energy consumption. Therefore, it is widely used in polymer solution preparation, oil and gas gathering and transportation, food processing and water treatment systems. However, traditional static mixers are mostly based on Newtonian fluids for research and design, and for viscoelastic fluids with complex rheological properties, the existing design has significant limitations.

[0005] Viscoelastic fluid is a kind of non-Newtonian fluid with both viscous and elastic properties, and typical representatives include polymer solutions, surfactant systems, gels and drag reducer solutions. The flow behavior of such fluids not only depends on viscosity, but also is affected by molecular chain structure and strain rate, and they are prone to special phenomena such as shear thinning, positive normal stress difference and elastic vortex in flow. These characteristics make the response mechanism of viscoelastic fluid in the mixing process completely different from that of Newtonian fluid: when the local shear rate is too high, the polymer chain will stretch and break, resulting in a decrease in drag reducer performance or even failure; if the mixer structure cannot effectively induce three-dimensional disturbance, the fluid may form "elastic slip" or "dead zone" along the main flow direction, causing uneven mixing; too strong turbulence or high pressure drop not only increases energy consumption, but also destroys the molecular structure of the fluid, making it difficult to balance mixing efficiency and fluid stability.

[0006] To solve the above problems, the existing static mixers (such as Kenics type, SMX type, etc.) can enhance the turbulence degree through blade rotation or staggered structure, but these designs are mostly for Newtonian fluid systems, which often produce local high shear zones when dealing with high molecular viscoelastic fluids, which is not conducive to maintaining the integrity of the fluid chain structure. In addition, blindly increasing the number of mixing units in pursuit of mixing efficiency will also cause a significant increase in pressure drop, leading to increased pumping power consumption and reduced overall system energy efficiency.

[0007] Therefore, there is an urgent need for a new type of static mixer that can achieve rapid mixing of viscoelastic fluids under low shear conditions while maintaining low pressure drop and energy consumption. The ideal device should form a multi-scale disturbance and secondary vortex flow field inside the mixing unit, allowing different components to achieve efficient dispersion and macroscopic mixing in a short distance while avoiding polymer chain rupture and energy loss. SUMMARY

[0008] The present application provides a multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids, which can achieve rapid mixing of viscoelastic fluids under low shear disturbance conditions by continuous structural design of the multi-stage mixing unit, allowing the fluid to form a secondary vortex and spiral flow along the main flow direction in the mixing zone, thereby significantly improving the mixing rate of viscoelastic fluids and Newtonian fluids.

[0009] In order to achieve the above-mentioned application purposes, the present application is implemented by the following technical solutions:

[0010] The present application provides a multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids, comprising a fluid input channel and a fluid output channel; a multi-stage mixing unit is connected between the fluid input channel and the fluid output channel, and the multi-stage mixing unit is connected in sequence along the longitudinal direction of the multi-stage leaf-shaped static mixer;

[0011] The upstream end of the first-stage mixing unit is connected to one end of the fluid input channel, and the other end of the fluid input channel is connected to a Newtonian fluid inlet and a viscoelastic fluid inlet; the downstream end of the last-stage mixing unit is connected to one end of the fluid output channel, and the other end of the fluid output channel is used to guide out the mixed liquid;

[0012] The mixing unit is a flat shell composed of an upper surface, a lower surface, a first outer contour surface, a first inner contour surface, a second outer contour surface, and a second inner contour surface; the first outer contour surface and the second outer contour surface are asymmetrically staggered on both sides of the mixing unit; the first inner contour surface is located inside the first outer contour surface, and the second inner contour surface is located inside the second outer contour surface;

[0013] The first outer profile surface and the second outer profile surface each comprise an upstream planar section and a downstream curved section, and the upstream planar section and the downstream curved section are smoothly connected; the upstream planar section is gradually inclined from the inner side to the outer side, and the downstream curved section is curved back from the outer side to the inner side;

[0014] The first inner profile surface and the second inner profile surface each comprise an upstream angular front edge and a downstream curved rear edge, and the upstream angular front edge and the downstream curved rear edge form a closed ring surface;

[0015] The first outer profile surface and the first inner profile surface, and the second outer profile surface and the second inner profile surface, are sequentially formed with an upstream merging zone, a separating zone and a downstream merging zone from the upstream direction to the downstream direction; for each mixing unit: the downstream merging zone between the first outer profile surface and the first inner profile surface overlaps with the upstream merging zone between the second outer profile surface and the second inner profile surface; for two adjacent mixing units: the downstream merging zone between the second outer profile surface and the second inner profile surface of the upstream mixing unit overlaps with the upstream merging zone between the first outer profile surface and the first inner profile surface of the downstream mixing unit.

[0016] Further, the fluid input channel and the fluid output channel are opposite in position in the longitudinal direction of the multi-stage vane-shaped static mixer.

[0017] Preferably, the number of the mixing units is 2-12.

[0018] Further, the flat shell refers to the vertical distance between the upper surface and the lower surface of the mixing unit being less than the longitudinal length of the mixing unit.

[0019] Further, the first outer profile surface, the first inner profile surface, the second outer profile surface and the second inner profile surface are connected with the upper surface and are connected with the lower surface.

[0020] Further, the first outer profile surface is closer to the fluid input channel than the second outer profile surface, and further, the second outer profile surface is closer to the fluid output channel than the first outer profile surface.

[0021] Preferably, the end of the upstream planar section of the first outer profile surface and the second outer profile surface is staggered in the longitudinal direction, and the downstream curved section of the first outer profile surface and the second outer profile surface is staggered in the longitudinal direction by an equal distance, which is 13-63mm.

[0022] Preferably, the inclination angle of the upstream planar section gradually inclined from the inner side to the outer side is 10°-25°.

[0023] Further, for the two adjacent stages of the mixing units: the end of the downstream curved section of the first outer profile surface of the upper stage of the mixing units is connected with the end of the upstream planar section of the first outer profile surface of the lower stage of the mixing units; the end of the downstream curved section of the second outer profile surface of the upper stage of the mixing units is connected with the end of the upstream planar section of the second outer profile surface of the lower stage of the mixing units.

[0024] Further, the ends of the upstream planar sections of the first outer profile surface and the second outer profile surface of the first stage of the mixing units are used for connecting the fluid input channel.

[0025] Further, the ends of the downstream curved sections of the first outer profile surface and the second outer profile surface of the last stage of the mixing units are used for connecting the fluid output channel.

[0026] Further, the first inner profile surface of the two adjacent stages of the mixing units has a spacing therebetween, and the second inner profile surface of the two adjacent stages of the mixing units has a spacing therebetween.

[0027] Further, the Newtonian fluid inlet, the viscoelastic fluid inlet, the fluid input channel and the fluid output channel are all rectangular in cross section.

[0028] The present application has the following beneficial effects:

[0029] The present application adopts effective design of the structure of the mixing units, forms specific flow path directions, and can generate multi-directional flow field separation and recombination effects in the pipe, thereby significantly improving the mixing efficiency of the viscoelastic fluid and the Newtonian fluid. The device is particularly suitable for rapid mixing of viscoelastic systems such as polymer drag reducer and surfactant solution, and can realize high-uniformity mixing under low energy consumption conditions, and provides a new solution for fluid blending in oil and gas gathering and fine chemical processes. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the overall schematic diagram of the multi-stage vane-shaped static mixer provided by the embodiment of the present application;

[0031] Figure 2 is the structural schematic diagram of the mixing unit provided by the embodiment of the present application;

[0032] Figure 3 is the numerical simulation result diagram of the viscoelastic fluid mixing uniformity of the embodiment of the present application;

[0033] Figure 4 is the pressure nephogram of the viscoelastic fluid mixing of the embodiment of the present application;

[0034] Figure 5 is the flow path diagram of the fluid in the multi-stage vane-shaped static mixer provided by the embodiment of the present application.

[0035] In the above figure: 1-mixing unit; 11-upper surface; 12-lower surface; 13-first outer contour surface; 14-first inner contour surface; 15-second outer contour surface; 16-second inner contour surface; 2-Newtonian fluid inlet; 3-viscoelastic fluid inlet; 4-fluid input channel; 5-fluid output channel. Detailed Implementation

[0036] To further understand the invention's content, features, and effects, the following embodiments are provided, along with detailed descriptions in conjunction with the accompanying drawings:

[0037] Figure 1 This is an overall schematic diagram of the multi-stage airfoil static mixer provided in an embodiment of the present invention. The multi-stage airfoil static mixer includes multiple mixing units 1 connected end-to-end along the longitudinal direction. The multiple mixing units 1 are integrally formed into a multi-stage series structure, continuously forming a multi-scale perturbation flow field along the mainstream direction. Figure 1 An embodiment consisting of eight mixing units 1 is shown, but more or fewer mixing units 1 can be provided as needed. Typically, the number of mixing units 1 in a multi-stage leaf-shaped static mixer is 2-12.

[0038] In this invention, "longitudinal" refers to the general direction of fluid flow, that is, along the length of the entire multi-stage bladed static mixer. For example, Figure 1 The term "vertical" should be understood as the horizontal direction of the drawing plane. Correspondingly, "horizontal" refers to the direction perpendicular to the "vertical," that is, along the width of the entire multi-stage leaf-shaped static mixer. For example, Figure 1 The term "horizontal" should be understood as the direction perpendicular to the drawing plane.

[0039] In this invention, "upstream" refers to the direction in which fluid flows in, while "downstream" is the opposite, referring to the direction in which fluid flows out. For adjacent mixing units 1, the upper-level mixing unit 1 is the mixing unit 1 located upstream, and the lower-level mixing unit 1 is the adjacent mixing unit 1 located downstream.

[0040] The multi-stage blade-shaped static mixer also includes a fluid input channel 4. One end of the fluid input channel 4 is connected to the upstream end of the first-stage mixing unit 1, which is connected end to end in sequence. The other end is connected to both the Newtonian fluid inlet 2 and the viscoelastic fluid inlet 3. Fluid can enter the fluid input channel 4 through the Newtonian fluid inlet 2 and the viscoelastic fluid inlet 3, thereby entering the multiple mixing units 1 for sequential mixing.

[0041] The multi-stage blade static mixer also includes a fluid output channel 5. One end of the fluid output channel 5 is connected to the downstream end of the last stage mixing unit 1 connected in sequence, and the other end is used to output the liquid mixed in the multi-stage blade static mixer for the next stage of processing or use.

[0042] The fluid input channel 4 and the fluid output channel 5 are positioned opposite each other in the longitudinal direction of the multi-stage blade static mixer, and the longitudinal channel between the fluid input channel 4 and the fluid output channel 5 is regarded as the main channel of the multi-stage blade static mixer.

[0043] In this invention, "outer side" refers to the direction away from the main flow channel of the multi-stage blade static mixer, and "inner side" refers to the direction close to the main flow channel of the multi-stage blade static mixer.

[0044] Figure 2 This is a schematic diagram of the structure of the hybrid unit 1 provided in an embodiment of the present invention. Figure 2 As shown, the mixing unit 1 is a flat shell integrally formed from an upper surface 11, a lower surface 12, a first outer contour surface 13, a first inner contour surface 14, a second outer contour surface 15, and a second inner contour surface 16. The term "flat shell" refers to a shell where the vertical distance between the upper and lower surfaces of the mixing unit 1 is relatively small compared to the longitudinal length of the mixing unit 1; generally, the longitudinal length of the mixing unit 1 is 2 to 5 times the vertical distance between the upper and lower surfaces. The first outer contour surface 13, the first inner contour surface 14, the second outer contour surface 15, and the second inner contour surface 16 are all connected to the upper surface 11 and the lower surface 12.

[0045] The first outer contour surface 13 and the second outer contour surface 15 have roughly the same shape, both including an upstream planar section and a downstream arcuate section, with a smooth transition between the upstream planar section and the downstream arcuate section forming a semi-closed annular surface. The upstream planar section gradually slopes from the inside to the outside, while the downstream arcuate section curves back from the outside to the inside. The angle of inclination of the upstream planar section from the inside to the outside (the angle between the upstream planar section and the longitudinal channel of the multi-stage blade-shaped static mixer) is 10° to 25°, preferably 15°.

[0046] For two adjacent mixing units 1: the downstream arc section end of the first outer contour surface 13 of the upper mixing unit 1 is connected to the end of the upstream planar section of the first outer contour surface 13 of the lower mixing unit 1; the downstream arc section end of the second outer contour surface 15 of the upper mixing unit 1 is connected to the end of the upstream planar section of the second outer contour surface 15 of the lower mixing unit 1. The upstream planar sections of the first outer contour surface 13 and the second outer contour surface 15 of the first mixing unit 1 are used to connect to the fluid input channel 4. The downstream arc section ends of the first outer contour surface 13 and the second outer contour surface 15 of the last mixing unit 1 are used to connect to the fluid output channel 5.

[0047] The first outer contour surface 13 and the second outer contour surface 15 are asymmetrically staggered on both sides of the mixing unit 1 (i.e., the main flow channel of the multi-stage blade-shaped static mixer). The first outer contour surface 13 is closer to the fluid input channel 4 than the second outer contour surface 15, and the second outer contour surface 15 is closer to the fluid output channel 5 than the first outer contour surface 13. The ends of the upstream planar sections of the first outer contour surface 13 and the second outer contour surface 15 are staggered longitudinally by a distance of 13~63mm, preferably 33mm. Similarly, the ends of the downstream arcuate sections of the first outer contour surface 13 and the second outer contour surface 15 are staggered longitudinally by a distance of 13~63mm, preferably 33mm.

[0048] The first inner contour surface 14 and the second inner contour surface 16 have approximately the same shape, both including an upstream angular leading edge and a downstream arcuate trailing edge, which together form a closed torus. There are gaps between the first inner contour surfaces 14 of adjacent mixing units 1 and between the second inner contour surfaces 16 of adjacent mixing units 1. The upstream angular leading edge is used to divide the fluid into two sub-flows, and the downstream arcuate trailing edge is used to re-merge the two sub-flows and enhance the disturbance.

[0049] The first inner contour surface 14 is inside the first outer contour surface 13, and the section of the first inner contour surface 14 facing the first outer contour surface 13 is generally parallel to the first outer contour surface 13, so that the flow channel width between the first inner contour surface 14 and the first outer contour surface 13 is as uniform as possible. The second inner contour surface 16 is inside the second outer contour surface 15, and the section of the second inner contour surface 16 facing the second outer contour surface 15 is generally parallel to the second outer contour surface 15, so that the flow channel width between the second inner contour surface 16 and the second outer contour surface 15 is as uniform as possible.

[0050] Due to the aforementioned shape design of the first outer contour surface 13, the first inner contour surface 14, the second outer contour surface 15, and the second inner contour surface 16, an upstream confluence area, a diversion area, and a downstream confluence area are formed sequentially from upstream to downstream between the first outer contour surface 13 and the first inner contour surface 14, and between the second outer contour surface 15 and the second inner contour surface 16, respectively. For each mixing unit 1: the downstream confluence area between the first outer contour surface 13 and the first inner contour surface 14 overlaps with the upstream confluence area between the second outer contour surface 15 and the second inner contour surface 16. For two adjacent mixing units 1: the downstream confluence area between the second outer contour surface 15 and the second inner contour surface 16 of the previous mixing unit 1 overlaps with the upstream confluence area between the first outer contour surface 13 and the first inner contour surface 14 of the next mixing unit 1.

[0051] In a preferred embodiment, the Newtonian fluid inlet 2, the viscoelastic fluid inlet 3, the fluid input channel 4, and the fluid output channel 5 are all rectangular in cross-sections to fit the flat shell shape of the mixing unit 1.

[0052] Numerical simulations of the mixing of viscoelastic and Newtonian fluids were performed using the multi-stage leaf-shaped static mixer of this embodiment. Figures 3-5 The results are the corresponding simulation results. Figure 3 The dimensionless concentration distribution contour map is obtained from the numerical simulation of the viscoelastic fluid mixing process in this multi-stage blade-shaped static mixer, used to qualitatively describe the mixing uniformity of the viscoelastic fluid. From Figure 3 It can be seen that after the viscoelastic fluid and Newtonian fluid enter the main channel, the fluid has broken away from the initial phase separation state due to the action of mixing unit 1. The concentration begins to show the characteristics of mutual penetration and interweaving between multiple regions. As the longitudinal distance increases, the gradient of high and low concentration regions decays rapidly, and the uniformity of the concentration field continues to improve. Before the fluid output channel 5, the concentration distribution is close to uniform across the entire region. This indicates that the mixing element effectively promotes the interface renewal and mass transfer of viscoelastic fluid and Newtonian fluid, and significantly enhances the convective mixing process. Figure 4 This is a pressure contour plot from the numerical simulation of the static mixer, used to describe the pressure changes within the static mixer. From... Figure 4 It can be seen that the pressure drops significantly when the fluid passes through each mixing unit 1. This is because the structure of the mixing element causes the fluid to undergo complex flows such as segmentation, rotation, and collision, which exacerbates energy dissipation. It also shows that the mixing unit is the key to enhancing mixing. Figure 5 The velocity vector diagram from the numerical simulation of this static mixer represents the flow path of the fluid within it. Figure 5 It can be seen that when the fluid passes through mixing unit 1, high-speed flow occurs near the longitudinal axis of the mixer, causing some fluid in this area to separate or swirl up, further promoting the recirculation of the subsequent flow, and generating a large-scale reverse-rotating vortex, which promotes the mixing of the fluid.

[0053] The coefficient of variation (COV) of the multi-stage blade static mixer of the present invention is calculated by calculating the concentration at a monitoring point at section A, 40 mm from the port of fluid output channel 5, using the following formula:

[0054] ;

[0055] Where i is the index of the region selected on section A (i=1,2,3…n), and n is the total number of regions i. For a fully mixed dimensionless concentration, is the concentration in region i, and μ is the average concentration across the entire cross-section.

[0056] A smaller COV indicates better mixing uniformity. When the coefficient of variation (COV) at the monitoring point at section A is less than 0.05, the mixture can be considered completely mixed. In engineering, when the COV value is less than 0.1, it can be considered to have reached a homogeneous state. Pressure drop refers to the pressure loss of fluid flowing through a static mixer. It reflects the energy loss and flow resistance generated by the multi-stage blade static mixer. The pressure drop of this device is calculated by the difference between the average pressure at section B, which is 78 mm away from the Newtonian fluid inlet 2, and the average pressure at section A. Newtonian fluid and viscoelastic fluid (2000 PPM PEO solution) are injected into the multi-stage blade static mixer of this invention through Newtonian fluid inlet 2 and viscoelastic fluid inlet 3, respectively. Preferably, they flow in at a velocity of 0.25 m / s. The COV at the monitoring point at section A is calculated to be 0.04. At the same time, the pressure drop between section A and section B is 1423.94 Pa, obtained by the above calculation method. This indicates that the multi-stage blade static mixer can achieve a good fluid mixing effect without causing excessive pressure drop.

[0057] As can be seen, by optimizing the structure of mixing unit 1, this invention enables the viscoelastic fluid to generate sufficient flow field disturbance and secondary vortices under low shear conditions, thereby achieving efficient mixing without damaging the molecular chain structure at a relatively low pressure drop. The multi-stage blade-shaped static mixer of this invention has a simple structure, good mixing uniformity, and low energy consumption. It is particularly suitable for pipeline mixing of polymer systems containing polymer drag-reducing agents, surfactant solutions, etc., and can be used in fields such as chemical engineering, oil and gas gathering and transportation, and drag-reducing agent preparation.

[0058] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many specific modifications under the guidance of the present invention without departing from the spirit and scope of the claims, and these modifications all fall within the scope of protection of the present invention.

Claims

1. A multi-stage blade-shaped static mixer for mixing viscoelastic and Newtonian fluids, comprising a fluid inlet channel and a fluid outlet channel; characterized in that, A multi-stage mixing unit is connected between the fluid input channel and the fluid output channel, and the multi-stage mixing unit is connected end to end along the longitudinal direction of the multi-stage leaf-shaped static mixer. The upstream end of the first-stage mixing unit is connected to one end of the fluid input channel, and the other end of the fluid input channel is connected to a Newtonian fluid inlet and a viscoelastic fluid inlet; the downstream end of the last-stage mixing unit is connected to one end of the fluid output channel, and the other end of the fluid output channel is used to discharge the mixed liquid. The hybrid unit is a flat shell composed of an upper surface, a lower surface, a first outer contour surface, a first inner contour surface, a second outer contour surface, and a second inner contour surface; the first outer contour surface and the second outer contour surface are asymmetrically staggered on both sides of the hybrid unit; the first inner contour surface is located inside the first outer contour surface, and the second inner contour surface is located inside the second outer contour surface. Both the first outer contour surface and the second outer contour surface include an upstream planar segment and a downstream arcuate segment, and the upstream planar segment and the downstream arcuate segment have a smooth transition; the upstream planar segment gradually slopes from the inside to the outside, and the downstream arcuate segment curves back from the outside to the inside; Both the first inner contour surface and the second inner contour surface include an upstream angular leading edge and a downstream arcuate trailing edge, and the upstream angular leading edge and the downstream arcuate trailing edge form a closed torus. An upstream confluence region, a diversion region, and a downstream confluence region are formed sequentially from upstream to downstream between the first outer contour surface and the first inner contour surface, and between the second outer contour surface and the second inner contour surface, respectively. For each mixing unit: the downstream confluence region between the first outer contour surface and the first inner contour surface overlaps with the upstream confluence region between the second outer contour surface and the second inner contour surface. For two adjacent mixing units: the downstream confluence region between the second outer contour surface and the second inner contour surface of the previous mixing unit overlaps with the upstream confluence region between the first outer contour surface and the first inner contour surface of the next mixing unit.

2. The multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids according to claim 1, characterized in that, The fluid input channel and the fluid output channel are positioned opposite each other in the longitudinal direction of the multi-stage blade-shaped static mixer.

3. A multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids according to claim 1, characterized in that, The number of the mixing units is 2-12; the flat shell refers to the vertical distance between the upper and lower surfaces of the mixing unit being less than the longitudinal length of the mixing unit.

4. A multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids according to claim 1, characterized in that, The first outer contour surface, the first inner contour surface, the second outer contour surface, and the second inner contour surface are all connected to the upper surface and to the lower surface.

5. A multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids according to claim 1, characterized in that, The first outer contour surface is closer to the fluid input channel than the second outer contour surface, and the second outer contour surface is closer to the fluid output channel than the first outer contour surface.

6. A multi-stage leaf-shaped static mixer for mixing viscoelastic and Newtonian fluids according to claim 1, characterized in that, The longitudinal offset distance between the ends of the upstream planar sections of the first and second outer contour surfaces and the longitudinal offset distance between the downstream arc sections of the first and second outer contour surfaces are equal, both ranging from 13 to 63 mm.

7. A multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids according to claim 1, characterized in that, The upstream plane section gradually slopes from the inside to the outside at an angle of 10° to 25°.

8. A multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids according to claim 1, characterized in that, For two adjacent mixing units: the downstream arc section end of the first outer contour surface of the previous mixing unit is connected to the end of the upstream planar section of the first outer contour surface of the next mixing unit; the downstream arc section end of the second outer contour surface of the previous mixing unit is connected to the end of the upstream planar section of the second outer contour surface of the next mixing unit; the upstream planar sections of the first and second outer contour surfaces of the first mixing unit are used to connect the fluid input channel; the downstream arc section ends of the first and second outer contour surfaces of the last mixing unit are used to connect the fluid output channel.

9. A multi-stage leaf-shaped static mixer for mixing viscoelastic fluids and Newtonian fluids according to claim 1, characterized in that, There is a spacing between the first inner contour surfaces of two adjacent levels of the hybrid unit and between the second inner contour surfaces of two adjacent levels of the hybrid unit.

10. A multi-stage leaf-shaped static mixer for mixing viscoelastic and Newtonian fluids according to claim 1, characterized in that, The Newtonian fluid inlet, the viscoelastic fluid inlet, the fluid input channel, and the fluid output channel all have rectangular cross-sections.

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