A two-stage flow-guiding wiper

Abstract

The present application belongs to the technical field of chemical equipment, and relates to a two-stage flow guide scraped film evaporator, which comprises a cylinder, a rotor and a plurality of support plates, all of which are uniformly distributed around the central axis of the rotor; the contact area between each support plate and the outer circumferential surface of the rotor is a spiral line; the cross section of the whole formed by all the support plates and the rotor is composed of a central circle and a plurality of C-shaped lines, one end of each C-shaped line is connected to the central circle, and the other end is away from the central circle; along the rotation direction of the rotor, the two end points of the C-shaped line are in front, and the middle point is in the rear; two connecting plates connected to the outer circumferential surface of the rotor are arranged between any two adjacent support plates, and each end of each connecting plate away from the rotor is connected to a radial flow guide device, and the radial flow guide device is an F-shaped vertical plate. The two-stage flow guide device is adopted to optimize the airflow path, a complete and continuous airflow flow route is constructed, and the evaporation efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chemical equipment and relates to a two-stage flow guide wiper. BACKGROUND

[0002] As a basic unit operation, evaporation separation is crucial for reducing energy consumption and realizing green production, and is widely used in chemical, pharmaceutical, food and other industries. The dynamic synergy mechanism of gas-liquid two-phase has a decisive influence on the energy efficiency of the evaporation system, especially the distribution of the gas flow field, which directly affects the mass transfer and thermodynamic equilibrium.

[0003] Currently, evaporation technology is facing many bottlenecks. The traditional evaporation equipment design is difficult to analyze the multi-physical field coupling problem, and the means to optimize the gas flow path to improve the evaporation efficiency is limited, and the efficiency improvement is often accompanied by the increase of energy cost, and this contradiction is particularly prominent in high-end materials, pharmaceuticals, energy and other fields. For example, in gas-liquid two-phase flow thermal equipment such as evaporators and fluidized bed dryers, dynamic mechanical components such as rotating scraping mechanisms and stirring paddles can interfere with fluid motion, resulting in nonlinear distribution of gas flow. Although the existing active exhaust strategy can maintain system pressure balance, it has problems such as increased energy consumption and local gas retention, affecting heat and mass transfer efficiency and causing energy waste. Current optimization schemes are mostly from a single perspective, such as modifying radial flow guide components or axial paths, which are difficult to meet the flow field reconstruction requirements under multiple working conditions and lack system-level fluid-structure collaborative design. This makes it difficult to improve the energy efficiency of chemical separation, food dehydration, pharmaceutical drying and other equipment when dealing with high-viscosity and easily crystallized materials.

[0004] With the development of thermal equipment towards modularity and intelligence, the traditional method cannot meet the fine matching requirements of mechanical movement and aerodynamic characteristics. Therefore, the development of two-stage flow guide aerodynamic optimization technology is of great significance to improve the energy efficiency of thermal equipment and promote industrial upgrading. SUMMARY

[0005] The purpose of the application is to solve the problems in the prior art and provide a two-stage flow guide wiper.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0007] A two-stage flow guide wiper, comprising a cylinder and a rotor, further comprising a plurality of support plates, all of which are uniformly distributed around the central axis of the rotor; the contact area between each support plate and the outer surface of the rotor is a spiral line; the cross section of the whole formed by all the support plates and the rotor is composed of a central circle and a plurality of C-shaped lines, one end of all the C-shaped lines is connected with the central circle, and the other end is away from the central circle, all the C-shaped lines are uniformly distributed around the center of the central circle; along the rotation direction of the rotor, the two end points of the C-shaped line are in front, and the middle point is in the back;

[0008] Two connecting plates are arranged between any two adjacent support plates, and each connecting plate is connected with the outer circumferential surface of the rotor, the height of each connecting plate along the radial direction of the rotor is slightly higher than the height of the support plate along the radial direction of the rotor, one radial flow guide device is connected to the end of each connecting plate away from the rotor, all the radial flow guide devices are uniformly distributed around the central axis of the rotor, and the two ends of each radial flow guide device are flush with the two ends of the rotor.

[0009] The radial flow guide device is an F-shaped vertical plate and is composed of a plate a, a plate b, a plate c and a plate d, the plate a, the plate b, the plate c and the plate d are all rectangular plates and the length direction of each plate is parallel to the axial direction of the rotor, the plate a and the plate c are parallel to the radial direction of the rotor, the plate a is attached to the plate c in the area close to the rotor, and the end of the plate a away from the rotor is connected with the plate b to form a first L-shaped vertical plate, and the end of the plate c away from the rotor is connected with the plate d to form a second L-shaped vertical plate; along the rotation direction of the rotor, the plate a is located in front of the plate c.

[0010] As a preferred technical solution,

[0011] The two-stage flow guide wiper as described above, the C-shaped line is a circular arc line, the central angle of the circular arc line is 45°, and the radius (the radius of the circle on which the circular arc is located, that is, the distance from the center of the circle to any point on the circular arc) is 150 mm; the thickness of the support plate is 10 mm.

[0012] The two-stage flow guide wiper as described above, a straight line passing through the two end points of the C-shaped line passes through the center of the center circle.

[0013] The two-stage flow guide wiper as described above, the radius of the center circle is 605 mm, and the number of C-shaped lines is 20.

[0014] The two-stage flow guide wiper as described above, the helical line forms a positive angle β with the axial direction of the rotor, β is 50°, and the positive angle is formed in the clockwise direction starting from the axial direction of the rotor.

[0015] The two-stage flow guide wiper as described above, the included angle between the plate a and the plate b is 150°, and the included angle between the plate c and the plate d is 135°.

[0016] The two-stage flow guide wiper as described above, the end of the plate c close to the rotor is flush with the end of the plate a close to the rotor.

[0017] The two-stage flow guide wiper as described above, the width of the plate a is 53.5 mm, the width of the plate b is 70 mm, the width of the plate c is 20 mm, and the width of the plate d is 60 mm; the thickness of the plate a, the plate b and the plate c is 18 mm, and the thickness of the plate d is 4 mm.

[0018] The two-stage flow guide wiper as described above, the end of the plate b away from the plate a is slotted.

[0019] In the two-stage flow guide scraper described above, the height of each connecting plate along the radial direction of the rotor is 5 mm greater than the height of the support plate along the radial direction of the rotor.

[0020] Invention principle:

[0021] The two-stage flow guiding device of this invention (radial flow guiding device and axial flow guiding device, the axial flow guiding device consisting of a support plate) combines optimized radial and axial airflow paths to form a continuous flow channel, thereby weakening or resolving the generation of unfavorable airflow patterns and improving evaporation efficiency. Specifically, as shown... Figure 8 As shown in the diagram, three blue dashed circles are marked from the inside out, dividing the airflow area from the rotor surface to the evaporation surface (inner wall of the cylinder) into two regions: the area between the outermost and middle blue dashed circles is designated as region ①, and the area between the middle and innermost blue dashed circles is designated as region ②. The airflow path design is shown by the red lines in the diagram. Within region ①, optimizing the airflow path weakens vortex formation, prompting more airflow to enter region ② in the direction of the red arrows. The optimized support plate in region ② ensures that the airflow is effectively discharged upwards.

[0022] Beneficial effects:

[0023] This invention employs a two-stage airflow guiding device to optimize the airflow path, rationally planning radial and axial airflow paths to construct a complete and continuous airflow route. This allows the airflow to flow along a more efficient trajectory, thereby improving evaporation efficiency. Furthermore, the solution of this invention promotes smooth airflow discharge, reducing the workload of the upper extraction device, thus achieving the goal of energy saving and consumption reduction. Attached Figure Description

[0024] Figure 1 The diagram shows the axial velocity contours of the scraper in Examples 1-9. The angle data in the diagram is the positive angle β (corresponding to the corresponding examples).

[0025] Figure 2 The diagrams show the vertical airflow patterns of the scraper in Examples 1-9. The angle data in the diagrams are positive angles β (corresponding to the respective examples), and the parts circled in red dashed boxes represent vortices.

[0026] Figure 3 The figures show axial velocity contour maps of the support plate region of the scraper in Example 1 and Comparative Example 1, where (a) represents Example 1 and (b) represents Comparative Example 1.

[0027] Figure 4 The figures show axial velocity contour maps of the support plate region of the scraper in Example 1 and Comparative Example 2, where (a) represents Example 1 and (b) represents Comparative Example 2.

[0028] Figure 5This is a schematic diagram of the internal radial cross-sectional structure of the scraper of the present invention;

[0029] Figure 6 for Figure 5 A magnified structural diagram of part A in the middle;

[0030] Figure 7 This is a three-dimensional structural diagram of the radial flow guiding device of the present invention;

[0031] Figure 8 This is a schematic diagram showing the internal region division of the scraper of the present invention;

[0032] Wherein, 1-rotor, 2-support plate, 3-radial guide device, 3.1-plate a, 3.2-plate b, 3.3-plate c, 3.4-plate d. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] Example 1

[0035] A two-stage flow guide scraper, such as Figure 5 , Figure 6 , Figure 7 As shown, it includes a cylinder, a rotor 1, and 20 support plates 2;

[0036] All the support plates 2 are evenly distributed around the central axis of the rotor 1; the contact area between each support plate 2 and the outer peripheral surface of the rotor 1 is a helix, and the helix forms a positive angle β with the axial direction of the rotor 1, where β is 50°.

[0037] The cross-section of the entire assembly of all support plates 2 (10mm thick) and rotor 1 consists of a central circle (605mm radius) and C-shaped lines. The C-shaped lines are arcs with a central angle of 45° and a radius of 150mm. One end of each C-shaped line is connected to the central circle, and the other end is away from the central circle. All C-shaped lines are evenly distributed around the center of the central circle, and the straight lines containing the two endpoints of the C-shaped lines pass through the center of the central circle. Along the direction of rotor rotation, the two endpoints of the C-shaped lines are in front, and the middle point is behind.

[0038] Two connecting plates are arranged between any two adjacent support plates 2, and each connecting plate is connected to the outer circumferential surface of the rotor 1, the height of each connecting plate along the radial direction of the rotor 1 is 5mm greater than the height of the support plate 2 along the radial direction of the rotor 1, and one radial flow guide device 3 is connected to the end of each connecting plate away from the rotor 1, all the radial flow guide devices 3 are uniformly distributed around the central axis of the rotor 1, and the two ends of each radial flow guide device 3 are flush with the two ends of the rotor 1;

[0039] The radial flow guide device 3 is an F-shaped vertical plate composed of plates a 3.1-d 3.4, and the plates a 3.1-d 3.4 are all rectangular plates with the length direction parallel to the axial direction of the rotor 1; the plates a 3.1 and c 3.3 are both parallel to the radial direction of the rotor 1, the plate a 3.1 is attached to the plate c 3.3 near the rotor 1, and the end away from the rotor 1 is connected to the plate b 3.2 to form a first L-shaped vertical plate, and the end of the plate b 3.2 away from the plate a 3.1 is slotted; the end of the plate c 3.3 near the rotor 1 is flush with the end of the plate a 3.1 near the rotor 1, and the end of the plate c 3.3 away from the rotor 1 is connected to the plate d 3.4 to form a second L-shaped vertical plate; along the rotation direction of the rotor 1, the plate a 3.1 is located in front of the plate c 3.3;

[0040] Among them, the angle between the plate a 3.1 and the plate b 3.2 is 150°, the angle between the plate c 3.3 and the plate d 3.4 is 135°, the width of the plate a 3.1 is 53.5mm, the width of the plate b 3.2 is 70mm, the width of the plate c 3.3 is 20mm, and the width of the plate d 3.4 is 60mm; the thickness of the plates a 3.1-c 3.3 is 18mm, and the thickness of the plate d 3.4 is 4mm.

[0041] Examples 2-9

[0042] A two-stage flow guide wiper, basically the same as example 1, the difference is that β corresponds to 30°, 35°, 40°, 45°, 55°, 60°, 65°, 70° respectively.

[0043] Comparative Example 1

[0044] A wiper, basically the same as example 1, the difference is that the cross section of the support plate is a line segment instead of a C-shaped line, the length of the line segment is 115mm, and the straight line where the line segment is located passes through the center of the center circle in the cross section of the whole formed by all the support plates and the rotor.

[0045] Comparative Example 2

[0046] A wiper, basically the same as example 1, the difference is that along the rotation direction of the rotor, the two end points of the C-shaped line are in the back, and the middle point is in the front.

[0047] Comparative Example 3

[0048] A wiper substantially the same as Example 1, except that the plate d in the radial flow guide is removed.

[0049] Comparative Example 4

[0050] A wiper substantially the same as Example 1, except that there is no support plate and connecting plate, and the plate a in the radial flow guide extends along the radial direction of the rotor after being close to one end of the rotor, and is connected to the outer circumferential surface of the rotor.

[0051] The wipers in the examples and comparative examples are simulated respectively below to verify the superiority of the two-stage flow guide wiper proposed in the present application:

[0052] 1. Before simulation, the following assumptions are made:

[0053] (1) The flow and heat exchange process of the gas flow in the wiper are steady;

[0054] (2) The viscous dissipation in the flow process is ignored;

[0055] (3) The gas flow and the liquid film evaporation surface are mainly in convection;

[0056] (4) The momentum loss of the inlet and outlet gas flow is ignored;

[0057] (5) The internal pressure is initially in a negative constant pressure state;

[0058] (6) The gas flow rate is a fixed value;

[0059] (7) The gas in the model is water vapor, which is an incompressible ideal gas.

[0060] 2. Settings of the simulation model:

[0061] Firstly, the original model of the wiper was processed in the three-dimensional modeling software Spaceclaim to repair the geometry model and the fluid domain, and the STEP format was exported. The processed fluid domain was imported into the pre-processing software CFD-Meshing to divide the polyhedral mesh, and the boundary layer, rotating area and inlet and outlet were encrypted to ensure that the twist degree was less than 0.85. After the mesh division was completed, it was imported into the simulation software Fluent to set the boundary conditions, select the appropriate simulation model (RNG k-ε model in the radial direction and Realize k-ε model in the axial direction), and use the steady-state simulation scheme to simulate the flow of water vapor in the device. The inlet flow rate of the side inlet and the lower inlet of the model was set to 194g / s, and the side inlet was used to simulate the water vapor generated by the evaporation of the liquid film, and the lower inlet was used to simulate the water vapor generated by the evaporation below. The upper outlet of the model is a pressure outlet, and the pressure value is atmospheric pressure, which is used for water vapor discharge. When simulating in Fluent, first use the steady-state pressure-based solver, then set the corresponding simulation model, MRF rotating domain, mass flow inlet and pressure outlet boundary conditions. Convergence is determined by monitoring residual (less than 1e-5) and flow fluctuation (less than 1%). The accuracy of the simulation model is evaluated by finding the best grid and convergence.

[0062] 3. Simulation results:

[0063] The comparison of the flow guiding effect of the wipers of Examples 1-9 is shown in FIGS. Figure 1 , Figure 2 As can be seen from FIGS. Figure 1 , the installation angle of the support plate (i.e. the normal angle β of the helix and the rotor axis) is different, and the axial airflow discharge capacity is also different (the red area represents the position with higher axial velocity, and the deeper the red color, the greater the axial velocity and the stronger the airflow discharge capacity). As can be seen from FIGS. Figure 2 , the installation angle of the support plate also affects the airflow pattern in the vertical direction in the wiper. Under the installation angles of 55°, 60°, 65° and 70°, the vortex gradually reappears. Therefore, from the analysis of FIGS. Figure 1 , Figure 2 , it can be known that the best installation angle of the support plate is 50°.

[0064] The comparison of the axial flow guiding effect of the wipers of Comparative Examples 1-2 is shown in FIGS. Figure 3 , Figure 4 As can be seen from the figures, the C-shaped support plate significantly improves the discharge capacity of the axial airflow.

[0065] The simulation results of the wiper of Comparative Example 3 show that the design of the radial flow guide device (F-shaped vertical plate) changes the rotation structure of the gas flow, successfully suppresses the strength and extension range of the vortex, can decompose the large-scale vortex into multiple smaller vortices, according to the principle of vorticity dissipation, these smaller vortices have a higher energy dissipation rate, thereby significantly reducing the pulsation amplitude of the gas flow, and effectively improving the stability of the gas flow.

[0066] The wipers of Example 1 and Comparative Example 4 are used for actual production to treat lyocell solution (solvent: NMMO, viscosity: 5000 pa·s), the heating temperature of the barrel wall surface is 110°C, the inlet solution temperature is 100°C, the solution feed amount is 25 t / h, and the rotor speed is 90 rpm. The evaporation rate is monitored by observing the amount of water vapor at the upper outlet. The evaporation rate of the wiper of Example 1 is 1398.3 g / s, and the evaporation rate of the wiper of Comparative Example 4 is 287.5 g / s. It can be seen from the comparison that the evaporation rate of the wiper of Example 1 is much higher than that of Comparative Example 4, which shows that the two-stage flow guide device (radial flow guide device and axial flow guide device) can significantly improve the evaporation rate of the wiper relative to the one-stage flow guide device (radial flow guide device).

Claims

1. A two-stage flow-guiding wiper comprising a cylinder and a rotor, characterized in that, The rotor further comprises a plurality of support plates, all of which are uniformly distributed around the central axis of the rotor; the contact area between each support plate and the outer circumferential surface of the rotor is a spiral line; the cross section of the whole formed by all the support plates and the rotor is composed of a central circle and a plurality of C-shaped lines, one end of each C-shaped line being connected to the central circle and the other end being away from the central circle; along the rotation direction of the rotor, the two end points of the C-shaped line are in front and the middle point is in back; Two connecting plates connected to the outer circumferential surface of the rotor are arranged between any two adjacent support plates, the height of each connecting plate along the radial direction of the rotor is slightly higher than the height of the support plate along the radial direction of the rotor, and one radial flow guide device is connected to the end of each connecting plate away from the rotor, all the radial flow guide devices are uniformly distributed around the central axis of the rotor, and the two ends of each radial flow guide device are flush with the two ends of the rotor; The radial flow guide device is an F-shaped vertical plate composed of plate a, plate b, plate c and plate d, all of which are rectangular plates with the length direction parallel to the axial direction of the rotor, plate a and plate c are parallel to the radial direction of the rotor, the area of plate a close to the rotor is attached to plate c, the end away from the rotor is connected to plate b to form a first L-shaped vertical plate, and the end of plate c away from the rotor is connected to plate d to form a second L-shaped vertical plate; along the rotation direction of the rotor, plate a is in front of plate c.

2. A two-stage flow-guiding wiper according to claim 1, characterized in that The C-shaped line is a circular arc line with a central angle of 45° and a radius of 150 mm; the thickness of the support plate is 10 mm.

3. A two-stage flow-guiding wiper according to claim 1, characterized in that The straight line passing through the two end points of the C-shaped line passes through the center of the central circle.

4. A two-stage flow-guiding wiper according to claim 1, characterized in that The radius of the central circle is 605 mm, and the number of C-shaped lines is 20.

5. A two-stage flow-guiding wiper according to claim 1, characterized in that The spiral line forms a positive angle β with the axial direction of the rotor, and β is 50°.

6. A two-stage flow-guiding wiper according to claim 1, characterized in that The included angle between plate a and plate b is 150°, and the included angle between plate c and plate d is 135°.

7. A two-stage flow-guiding wiper according to claim 6, characterized in that The end of plate c close to the rotor is flush with the end of plate a close to the rotor.

8. A two-stage flow-guiding wiper according to claim 7, characterized in that The width of plate a is 53.5 mm, the width of plate b is 70 mm, the width of plate c is 20 mm, and the width of plate d is 60 mm; the thickness of plate a, plate b and plate c is 18 mm, and the thickness of plate d is 4 mm.

9. A two-stage flow-guiding wiper according to claim 1, characterized in that The end of plate b away from plate a is slotted.

10. A two-stage flow-guiding wiper according to claim 1, characterized in that The height of each connecting plate along the radial direction of the rotor is 5 mm higher than the height of the support plate along the radial direction of the rotor.

Images