A solid-liquid cyclone separator with a spiral groove drag reduction structure

Abstract

The present invention discloses a solid-liquid cyclone separator with a spiral groove drag reduction structure, which is provided with a cylindrical section, a conical section, an underflow pipe, an overflow pipe and a feed pipe, and is characterized in that: the inner wall surface of the cylinder of the cylindrical section is provided with a spiral bionic groove structure, the spiral groove is in a continuous placement mode and has a sawtooth shape, the continuous placement mode is composed of two sawtooth grooves, and the size of the sawtooth groove is determined by a dimensionless parameter h + and + Compared with the traditional cyclone separator, the present invention can reduce the surface resistance of the inner wall of the cylindrical section to the maximum extent, maximize the energy utilization rate, and obtain a better cyclone separation effect.

Description

Technical Field

[0001] The invention relates to the technical field of solid-liquid separation and sorting, in particular to a solid-liquid cyclone separator with a groove wall which has a simple structure, reduces the surface resistance of a cylindrical section and improves separation efficiency. Background Art

[0002] In nature, many animals have evolved a variety of drag-reducing structures to adapt to their living environment. This has long existed in high-speed swimming species such as fish, sharks, and dolphins. For example, sharks' "skin teeth," which are small grooves on the surface of tiny scales on their skin, have been proven to effectively reduce drag during swimming. NASA's Langley Research Center has found that the surface of tiny grooves downstream can effectively reduce wall friction resistance, breaking the concept that the smoother the surface, the less drag. The "FAST-SKIN" swimsuit developed by the Australian Speedo company, a swimsuit manufacturer, can reduce drag by 3%.

[0003] The cyclone separator is a process in which different phases are incompatible with each other and different centrifugal forces are generated to accelerate the sedimentation and separation of the heavy medium phase in the material. In essence, it is the process of the generation, development and disappearance of fluid vortex. In a semi-free vortex, the wall friction resistance and pressure difference resistance play a dominant role in the separation efficiency and energy consumption of the cyclone. The most important resistance is the wall friction resistance, which is generated by the interaction between the fluid and the solid surface. Therefore, the study of drag reduction structure is particularly important. Summary of the invention

[0004] In order to reduce the friction resistance of the inner wall of the cylindrical section, the purpose of the present invention is to provide a solid-liquid cyclone separator with a spiral groove drag reduction structure which has low cost, reduces surface resistance and has high separation efficiency.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A solid-liquid cyclone separator with a spiral groove drag reduction structure comprises a cylindrical section, a conical section, an underflow pipe, an overflow pipe and a feed pipe, wherein the cylindrical section is tangentially connected to the feed pipe, the lower end of the cylindrical section is connected to the conical section through a flange, the lower end of the conical section is connected to the underflow pipe, the overflow pipe is arranged in the middle of the upper end of the cylindrical section, the lower end of the overflow pipe extends into the cylindrical section, the upper end of the overflow pipe extends to the outside of the cylindrical section, the upper end of the overflow pipe is arranged with an overflow port, the inner wall surface of the cylinder of the cylindrical section is provided with a spiral bionic groove drag reduction structure, the groove drag reduction structure is in a continuous placement mode, the groove drag reduction structure is in a sawtooth shape, the continuous placement mode is composed of two spiral sawtooth grooves, and the size of the sawtooth groove is determined by a dimensionless parameter h + and +Function calculations show that the spiral groove structure can rationally utilize energy and improve separation efficiency;

[0007]

[0008]

[0009] Where: u τ is the wall friction velocity, m / s;

[0010] ν is the kinematic viscosity of the fluid, Pa·s.

[0011] Preferably, the inner wall surface of the cyclone is provided with two spiral sawtooth grooves with a pitch of 2 mm and a starting angle difference of 90°.

[0012] Preferably, the sawtooth groove starts at the lower part of the feed pipe and ends at the junction of the cylindrical section and the conical section.

[0013] Preferably, the cross-section of the flow-through surface of the spiral groove on the inner wall is sawtooth-shaped, and a single sawtooth is an equilateral triangle with a side length of 1 mm.

[0014] Specifically, the flow surface of the cylindrical segment is composed of a first groove and a second groove placed continuously. The direction of the groove is the streamline direction during the design working condition. The starting angles of the first groove and the second groove differ by 90°. The cross-sections of the first and second grooves are the same sawtooth structure. The groove spacing s is 1 mm, the height is 0.877 mm, and the angle α is 60°.

[0015] Taking the feed pipe speed of 6m / s as an example, the height and width of the groove are calculated according to the dimensionless parameter h + and + Function to calculate.

[0016] Compared with the existing cyclone, the present invention has the following advantages:

[0017] The present invention sets a groove drag reduction structure on the flow surface of the cylindrical section of the solid-liquid cyclone separator. The cross section of the groove is sawtooth-shaped and is placed in a continuous manner, which can effectively reduce the surface resistance of the inner wall of the cylindrical section, thereby improving energy utilization and separation efficiency. Since the height and width of the groove are smaller than the overall cyclone separator, the working principle of the cyclone separator and the range of the semi-free vortex zone and the forced vortex zone are not changed, and the original separation performance of the cyclone separator is maintained; the groove on the surface of the cylindrical section is simple to process and low in cost, which can reduce the surface roughness of the inner wall of the cylindrical section, and can meet the requirements of a solid-liquid cyclone separator for separation of various particle size ranges. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0019] Figure 1 It is a schematic diagram of the working principle of a solid-liquid cyclone separator with a spiral groove drag reduction structure;

[0020] Figure 2 It is a cross-sectional schematic diagram of a solid-liquid cyclone separator with a spiral groove drag reduction structure;

[0021] Figure 3 Schematic diagram of the flow cross section of the groove drag reduction structure.

[0022] Among them: 1. Overflow pipe; 2. Feed pipe; 3. Cylindrical section; 4. Conical section; 5. Underflow pipe; 6. Inner vortex; 7. Outer vortex. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making innovative changes are within the scope of protection of this application.

[0024] The present invention discloses a solid-liquid cyclone separator with a spiral groove drag reduction structure, comprising a cylindrical section 3, a conical section 4, an underflow pipe 5, an overflow pipe 1, a feed pipe 2, an inner cyclone 6 and an outer cyclone 7, wherein the cylindrical section 3 is tangentially connected to the feed pipe 2, the lower end of the cylindrical section 3 is connected to the conical section 4 through a flange, the lower end of the conical section 4 is connected to the underflow pipe 5, the outer cyclone 7 flows out through the underflow pipe 5, the overflow pipe 1 is provided at the middle of the upper end of the cylindrical section 3, and the overflow pipe 1 is provided at the bottom of the cylindrical section 3. The lower end of the pipe 1 extends into the cylindrical section 3, the upper end of the overflow pipe 1 extends to the outside of the cylindrical section 3, the upper end of the overflow pipe 1 is provided with an overflow port, the inner vortex 6 flows out through the overflow pipe 1, and the inner wall surface of the cylinder of the cylindrical section 3 is provided with a spiral bionic groove drag reduction structure, the groove drag reduction structure is a continuous placement method, the groove drag reduction structure is a sawtooth shape, the continuous placement method is composed of two spiral sawtooth grooves, and the size of the sawtooth groove is determined by the dimensionless parameter h + and + Function calculations show that the spiral groove structure can rationally utilize energy and improve separation efficiency;

[0025]

[0026]

[0027] Where: u τ is the wall friction velocity, m / s;

[0028] ν is the kinematic viscosity of the fluid, Pa·s.

[0029] First, determine the size of the cylindrical section of the cyclone separator; according to the size of the cylindrical section, further determine the cone angle, overflow pipe insertion length, overflow port diameter, underflow port diameter and housing section height, and determine the number of inlets and area size according to actual working conditions. Then determine the shape of the groove, such as height h, spacing s, angle α. The specific technical solution is as follows:

[0030] 1. Determine the size of the cylindrical section of the cyclone separator. In the process of selecting the diameter of the cyclone, a larger diameter range is usually selected. The diameter can be preliminarily calculated based on the production capacity and separation particle size, and then a similar standard diameter can be selected from its technical performance table. The diameter of the cyclone is calculated according to the empirical formula:

[0031]

[0032] Where: D is the diameter of the column, mm;

[0033] δ is the particle density, kg / m 3 ;

[0034] ΔPm is the inlet pressure, Pa;

[0035] d m is the separation particle size, μm;

[0036] μ m is the viscosity of the mixture, Pa·s;

[0037] ρ m is the density of the mixture, kg / m 3 .

[0038] 2. Cone angle: The cone angle of the cyclone determines the length of the cone and is directly proportional to the separation time of the material in the cyclone.

[0039] 3. Overflow pipe insertion length. The overflow pipe insertion depth is directly related to the short-circuit flow. Choosing the right depth will reduce the coarse particle size in the overflow product and the fine particle size in the underflow product. It can also extend the separation time and reduce the short-circuit flow, minimizing the phenomenon of overflow coarseness. Generally speaking, for a standard hydrocyclone, the overflow pipe insertion depth is:

[0040] h0=(0.50~0.80)D

[0041] Where: h0 is the overflow pipe insertion depth, mm.

[0042] 4. Overflow port diameter. For the overflow pipe diameter of the hydrocyclone, the diameter directly affects the production capacity, separation particle size, separation efficiency and product concentration. Generally speaking, the overflow pipe diameter is positively correlated with the production capacity, separation particle size and sedimentation concentration, but the separation efficiency decreases with the increase of the diameter. Generally speaking, for a standard hydrocyclone, the overflow pipe diameter is:

[0043] d0=(0.07~0.30)D

[0044] Where: d0 is the overflow diameter, mm.

[0045] 5. Diameter of underflow port. The underflow pipe 5 in the solid-liquid separation cyclone is a component that is very easy to wear. Its diameter has the most significant impact on the separation efficiency. If the diameter is too small, clogging will occur. A large diameter improves the separation efficiency to a certain extent, but a part of the material will be discharged directly through the underflow pipe 5 without separation. Usually, in practical applications, the underflow pipe diameter should be smaller than the overflow pipe diameter. Generally speaking, for a standard cyclone, the underflow pipe diameter is:

[0046] d u =(0.07~0.20)D

[0047] Where: d u is the bottom flow outlet diameter, mm.

[0048] 6. Height of cylindrical section. For a hydrocyclone, if the height of the cylindrical section is increased, the separation time of the mixed fluid in the hydrocyclone will be increased, the separation efficiency will be improved, but it will also increase unnecessary energy loss to a certain extent. Generally speaking, for a standard hydrocyclone, the height of the cylindrical section is:

[0049] H=(0.5~1.0)D

[0050] Where: H is the height of the cylindrical section, mm.

[0051] 7. The number of inlets is positively correlated with the stability of the internal flow field, but too many inlets will have higher requirements on the application site. Here, a single inlet is selected and the inlet width is consistent with the width of the fluid channel; the rectangular inlet can generate a large angular momentum when the material enters, which is conducive to the stability of the flow field. Practice shows that the best cyclone inlet diameter is divided into standard cyclones:

[0052] Based on the above empirical formula, the cylindrical section diameter of the solid-liquid cyclone separator selected in the present invention is 50 mm, the cone angle is 15°, the overflow pipe insertion depth is 36 mm, the overflow port diameter is 15 mm, the underflow port diameter is 8 mm, the cylindrical section height is 72 mm, and the single inlet area is 96 mm. 2 .

[0053] 8. Groove size. Although the physical spacing corresponding to the maximum drag reduction of grooves of different shapes is different, in general, the dimensionless spacing s + ≈15,h + The maximum drag reduction rate is reached when the spiral angle is ≈15. The drag reduction effect can still be achieved at a certain spiral angle, and the drag reduction rate will not decrease. The drag reduction curve is usually expressed in terms of the dimensionless parameter h + and + Function to express, h + and + They are defined as:

[0054]

[0055]

[0056] Where: u τ Wall friction velocity, m / s;

[0057] ν Kinematic viscosity of the fluid, Pa·s.

[0058] A solid-liquid cyclone separator with a spiral groove drag reduction structure manufactured according to the above method can improve the separation efficiency to a certain extent. The triangular micro-groove structure can limit the spanwise movement of air in the near-wall area, effectively reduce the wall surface resistance, and improve the separation performance of the solid-liquid cyclone separator, thereby achieving the purpose of stabilizing the overall working conditions, improving the separation efficiency, and reducing energy loss.

[0059] The technical solution provided by the present invention is described in detail above. Specific examples are used herein to illustrate the principle and implementation of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that any obvious improvements, substitutions or modifications made by ordinary technicians in this technical field belong to the protection scope of the present invention.

Claims

1. A solid-liquid cyclone separator with a spiral groove drag reduction structure, comprising a cylindrical section, a conical section, an underflow pipe, an overflow pipe and a feed pipe, wherein the cylindrical section is tangentially connected to the feed pipe, the lower end of the cylindrical section is connected to the conical section through a flange, the lower end of the conical section is connected to the underflow pipe, the overflow pipe is provided in the middle of the upper end of the cylindrical section, the lower end of the overflow pipe extends into the cylindrical section, the upper end of the overflow pipe extends to the outside of the cylindrical section, and the upper end of the overflow pipe is provided with an overflow port, characterized in that: The inner wall surface of the cylinder of the cylindrical section is provided with a spiral bionic groove drag reduction structure, the groove drag reduction structure is in a continuous placement mode, the groove drag reduction structure is in a sawtooth shape, the continuous placement mode is composed of two spiral sawtooth grooves, and the size of the sawtooth groove is determined by a dimensionless parameter and The function is calculated; in: h is the groove height; s is the groove width; is the wall friction velocity, m / s; is the kinematic viscosity of the fluid, Pa∙s.

2. The solid-liquid cyclone separator with a spiral groove drag reduction structure according to claim 1, characterized in that: The inner wall of the cyclone is provided with two spiral sawtooth grooves with a pitch of 2 mm and a starting angle difference of 90°.

3. The solid-liquid cyclone separator with a spiral groove drag reduction structure according to claim 1, characterized in that: The sawtooth groove starts at the lower part of the feed pipe and ends at the junction of the cylindrical section and the cone section.

4. The solid-liquid cyclone separator with a spiral groove drag reduction structure according to claim 1, characterized in that: The cross section of the flow-through surface of the spiral groove on the inner wall is sawtooth-shaped, and the side length of a single sawtooth is a regular triangle of 1 mm.

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