Flow uniform distributor for liquid storage tank of supercritical carbon dioxide dyeing kettle

Abstract

The invention relates to a flow uniform distributor for a liquid storage tank of a supercritical carbon dioxide dyeing kettle, which is arranged in the liquid storage tank and comprises a three-stage asymmetric bifurcated network structure, the three-stage asymmetric bifurcated network structure comprises a main inlet pipe, a first-stage pipe, a second-stage pipe and third-stage pipes which are communicated in sequence, and the number, the aperture and the position of the third-stage pipes are matched with those of yarn columns; the number ratio of the main inlet pipe to the first-stage pipe to the second-stage pipe to the third-stage pipe is 1: 3: 6: 18; the main inlet pipe, the first-stage pipe, the second-stage pipe and the third-stage pipe form a fluid flow channel; the turning section of the diode adopts a double-curvature continuous bent pipe design of bending forwards and then bending backwards; the inner diameters of the first-stage tube, the second-stage tube and the third-stage tube are gradually reduced according to a constant-speed principle; and the main inlet pipe, the first-stage pipe, the second-stage pipe and the third-stage pipe can bear static load pressure of 229 MPa. Compared with the prior art, the system pressure loss is reduced; the structure is compact and dismounting is convenient; the long-term high-voltage safe operation is met; and the manufacturing and maintenance cost is low.

Description

Technical Field

[0001] This invention relates to the field of textile dyeing equipment technology, and in particular to a flow distributor for a supercritical carbon dioxide dyeing kettle storage tank. Background Technology

[0002] Uneven dyeing is one of the most critical quality issues in textile dyeing. In the supercritical carbon dioxide (scCO2) package dyeing process, the core function of the storage tank is to evenly and stably distribute the high-temperature, high-pressure dye liquor to 18 (or more) yarn strands. Currently, the industry mainly uses the following two solutions:

[0003] 1. No distributor

[0004] The dye liquor enters the storage tank at high speed through a single inlet and is then distributed to each yarn column. Due to the unequal distances between the outlets and the inlet, the different spatial positions of the outlets and the inlet, and the abrupt changes in the flow channel cross-section, the inlet flow rate of each yarn column varies significantly, making it difficult to guarantee dyeing uniformity. At the same time, eddies are easily formed near the inlet, resulting in a significant increase in local pressure loss. This requires additional circulation pump head or extended dyeing time to compensate for insufficient flow at the far end, thereby increasing energy consumption.

[0005] 2. Orifice plate distributor

[0006] Installing an orifice plate gas distributor within the storage tank can significantly improve flow uniformity. In the prior art, Hosseini et al. (Hosseini SM, Alizadeh R, et al. Enhancement of gas distribution uniformity in a Claus process catalytic reactor using computational fluid dynamics[J]. Chemical Engineering and Processing-Process Intensification, 2019, 144, https: / / doi.org / 10.1016 / j.cep.2019.107653) disclosed a porous plate gas distributor for use in an industrial Claus catalytic reactor. The porous plate is arranged coaxially with the reactor and located directly downstream of the gas inlet. During operation, hydrogen sulfide-containing gas enters at high speed through the inlet, first impacting the porous plate and then dispersing to the periphery of the plate. This structure effectively disperses the concentrated axial gas by obstructing the inlet jet, thus improving the uniformity of the flow field within the reactor. Mao et al. (HanlingMao, Siyue Li, et al., Uniform flow field design in porous media filter tower and experimental verification, Process Safety and Environmental Protection, 2021(150):68-78, https: / / doi.org / 10.1016 / j.psep.2021.03.053) solved the problem of uneven flow distribution in porous media filter towers by designing and optimizing throttling plates, achieving a reduction in flow velocity and pressure, while improving the uniformity of the flow field. Dang et al. (Mingyan Dang, Xinyu Jia, et al., Study on the uniform flow in adsorption device with perforated plate distributor, Chemical Engineering Research and Design, 2024, 208, Pages 490-499, https: / / doi.org / 10.1016 / j.cherd.2024.07.017) investigated the effects of orifice plate design on flow uniformity and pressure drop using CFD simulations, improving the uniformity of gas distribution and reducing pressure drop in industrial adsorption towers.

[0007] 3. Tubular distributor

[0008] Tubular distributors divide the incoming fluid into multiple streams through a diverter, and their design often employs fractal principles for multi-stage flow splitting. Fan et al. (Zhiwei FAN, Xinggui ZHOU, et al., Numerical Investigation of Constructal Distributors with Different Configurations, Chinese Journal of Chemical Engineering, 2009, 17(1): 175-178) evaluated seven tubular distributor designs using CFD and found that the bifurcation structure with Y-joints and straight-connected channels achieved the best balance between flow uniformity and energy dissipation. Liu et al. (Hong Liu, Peiwen Li, et al., The flow downstream of a bifurcation of a flow channel for uniform flow distribution via cascade flow channel bifurcations, Applied Thermal Engineering, 2015, 81: 114-127) analyzed the influence of diverter geometry on flow symmetry, and the results showed that the curved diverter design can effectively shorten the development length of the downstream symmetrical velocity profile.

[0009] In summary, orifice plate distributors are commonly used to achieve uniform fluid flow, but they cannot eliminate eddies near the edges of the orifice plate and the top of the storage tank, resulting in high total pressure loss. Furthermore, their rectifying effect is limited to a certain range downstream of the orifice plate, failing to achieve uniform output of directional fluid. Tubular distributors are often used to achieve uniform distribution of multiple fluid streams, possessing theoretical advantages, but their proportional branching structure inherently contradicts the asymmetrical layout of the yarn columns within the dyeing container. Currently, there is an urgent need to design a dye liquor distributor that overcomes the aforementioned problems while simultaneously meeting the comprehensive requirements of "uniform flow rate, low pressure loss, and reliable operation" under high-pressure conditions, for application in the storage tank of a high-temperature, high-pressure supercritical carbon dioxide yarn dyeing machine. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a flow distributor for the supercritical carbon dioxide dyeing vessel storage tank, which improves the uniformity of flow distribution and reduces system pressure loss; has a compact structure and is easy to assemble and disassemble; meets the requirements for long-term safe operation under high temperature and high pressure; and has low manufacturing and maintenance costs.

[0011] The objective of this invention can be achieved through the following technical solutions:

[0012] The optimization algorithm used in this invention is the Multi-Objective Genetic Algorithm (MOGA), a variant of the controlled elite strategy NSGA-II. This algorithm can simultaneously handle multiple objectives and constraints and search for the global optimum. The process includes initialization, evaluation, selection, crossover, mutation, and termination. The optimization calculations were performed in ANSYS 2024 R1.

[0013] This invention provides a flow distributor for a supercritical carbon dioxide dyeing vessel storage tank, disposed within the storage tank, the distributor comprising:

[0014] The three-level asymmetric bifurcation network structure includes a main inlet pipe, a primary pipe, a secondary pipe, and a tertiary pipe connected in sequence. The number, aperture, and position of the tertiary pipes are matched with the yarn column. The ratio of the number of the main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe is 1:3:6:18. The main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe form a dye liquor fluid flow channel.

[0015] The bend section of the secondary tube adopts a double-curvature continuous bend design with a forward curve followed by an inverse curve to reduce inertial offset.

[0016] The inner diameters of the primary, secondary, and tertiary pipes decrease progressively according to the principle of constant velocity, thus maintaining a stable fluid velocity.

[0017] The main inlet pipe, primary pipe, secondary pipe and tertiary pipe are all located within the flow channel integrated block;

[0018] The outlet of the distributor has an independent quick-connect port that connects to the yarn column inlet.

[0019] The distributor can be directly placed into the designated space of the liquid storage tank and used immediately after docking with the existing interface, without any modification to the main body of the liquid storage tank or additional drilling.

[0020] Furthermore, the double-curvature bend in the secondary branch bend section adopts a continuous curvature design with the curvature radius optimized by a multi-objective genetic algorithm, which first bends forward and then reverses.

[0021] Furthermore, the main inlet pipe has one branch, the first-stage pipe has three branches, the second-stage pipe has six branches, and the third-stage pipe has eighteen branches.

[0022] Furthermore, the flow channel integration block is provided in eight parts, including a first sub-integrated block, a second sub-integrated block, three third sub-integrated blocks, and three fourth sub-integrated blocks; the main inlet pipe is located in the first sub-integrated block, the primary pipe and the secondary pipe are located in the second sub-integrated block, and the tertiary pipe is located in the third and fourth sub-integrated blocks.

[0023] Furthermore, the first sub-integrated block and the second sub-integrated block are connected by threaded short pipes, and the second sub-integrated block is connected to the third sub-integrated block and the fourth sub-integrated block by threaded short pipes, forming a continuous sealed flow channel inside.

[0024] Furthermore, the first, second, third, and fourth sub-integrated blocks are equipped with high-strength bolts around their perimeter to achieve overall clamping and positioning, ensuring coaxiality and reliable sealing of the flow channels.

[0025] Furthermore, the flow channel integrated block is a 45# steel sub-module. Its pressure resistance rating is not lower than the highest working pressure of the dyeing system.

[0026] Furthermore, the inlet of the liquid storage tank is connected to the main inlet pipe flange of the distributor.

[0027] Furthermore, the independent quick-connect port at the outlet of the distributor corresponds one-to-one with the yarn column inlet, and boltless quick insertion connection is achieved through end face sealing or O-rings.

[0028] Furthermore, a multi-objective genetic algorithm was employed, using the four structural parameters a1, a2, a4, and a5 of the secondary branch pipe bend as optimization variables, and then a high-precision response surface model R was established. 2 =0.94744, parameters a1 and a2 determine the uniformity of flow distribution, while a4 and a5 dominate the flow resistance. An optimal balance is achieved between flow uniformity, flow resistance, and energy loss.

[0029] The outlet pressure and process temperature of the circulating pump are matched with the pressure and temperature resistance ratings of the distributor. After strength verification, the displacement and stress of the distributor during long-term operation are within the material safety limits, and it can be put into use without modifying the main body of the storage tank.

[0030] During the manufacturing process:

[0031] After the flow channel integrated block blank is heat-treated by tempering, the flow channel, threads and sealing groove are processed in one clamping in a five-axis linkage machining center; each sub-integrated block is directly screwed together by precision threaded short tubes to form a continuous sealed flow channel, and high-strength bolts are arranged around the module to achieve overall clamping and positioning, ensuring that the flow channel is coaxial and the sealing is reliable.

[0032] The usage method is as follows:

[0033] 1. Install the distributor into the liquid storage tank, and connect the outlet to the yarn column inlet;

[0034] 2. Start the circulation pump to allow the carbon dioxide fluid containing dissolved dye to enter the distributor;

[0035] 3. After three stages of bifurcation, the fluid is evenly distributed to the eighteen yarn columns;

[0036] 4. After dyeing is complete, stop the circulation, depressurize, and recover the dye and carbon dioxide.

[0037] Using a supercritical carbon dioxide dye liquor distributor, the following steps are included:

[0038] S1. The first, second, third, and fourth sub-integrated blocks are directly screwed together using precision threaded short tubes to form a distributor. High-strength bolts are arranged around each sub-integrated block to achieve overall clamping and positioning, ensuring coaxial flow channels and reliable sealing. After the distributor is placed into the predetermined cavity of the liquid storage tank, its eighteen outlet ends correspond one-to-one with the yarn column inlets, achieving boltless quick-connect fitting using end face seals or O-rings.

[0039] S2. Place the yarn packages to be dyed one by one into the dyeing rack to form yarn columns, with the inlet of the dyeing rack mandrel corresponding to the outlet of the distributor. Inject CO2 into the system to the working pressure, and simultaneously start the preheater to raise the temperature to the process temperature. After the system pressure and temperature stabilize, start the circulation pump to allow the supercritical CO2 containing the dissolved dye to enter the distributor through the main inlet. The fluid is evenly distributed to the eighteen yarn columns after passing through a three-stage asymmetric bifurcation network structure, ensuring consistent flow rate in each yarn column.

[0040] S3. After dyeing is complete, stop the circulation pump, open the pressure relief valve, and CO2 and residual dye enter the recovery system to complete the recovery of dye and solvent. After the system is depressurized to atmospheric pressure, open the top cover of the dyeing machine and remove the dyed yarn packages.

[0041] S4. The distributor can be lifted out as a whole for cleaning, or the first, second, third, and fourth sub-integrated blocks can be loosened and removed one by one to facilitate inspection of the threaded sealing surface and replacement of O-rings.

[0042] Compared with the prior art, the present invention has the following advantages:

[0043] (1) Improved flow distribution uniformity and reduced system pressure loss. Through hyperbolic tube structure design and multi-objective optimization, the flow distribution uniformity of the distributor reached 93.62%, an improvement of 22.33% compared to the state without a distributor, and the flow deviation rate was reduced to 10.19%, meeting the requirements of the dyeing process and improving the uniformity compared to the traditional perforated plate distributor. An optimal balance was achieved between flow uniformity, flow resistance and energy loss.

[0044] (2) It has a compact structure and is easy to disassemble and assemble. It can directly replace the existing perforated plate without modifying the main body of the dyeing machine.

[0045] (3) After strength verification, it meets the requirements for long-term safe operation under high temperature and high pressure. For the special requirements of supercritical CO2 dyeing high-pressure conditions (27MPa), tempered 45# steel is used, with a maximum displacement of only 8.95×10⁻⁶. -5mm, far below the 0.3mm limit, and the maximum equivalent stress is 226MPa, meeting the 1.5 times safety factor requirement. Fluid-structure interaction analysis verified the structural reliability.

[0046] (4) Modular design, consisting of 8 sub-integrated blocks, with low manufacturing and maintenance costs, suitable for industrial promotion. Attached Figure Description

[0047] Figure 1 A half-sectional schematic diagram of the flow distributor and the storage tank of the supercritical carbon dioxide dyeing vessel.

[0048] Figure 2 This is a schematic diagram of the liquid storage tank.

[0049] Figure 3 A schematic diagram of the flow distribution device for the supercritical carbon dioxide dyeing vessel's storage tank.

[0050] Figure 4 This is a schematic diagram of the structure of the first sub-integrated block;

[0051] Figure 5 This is a schematic diagram of the structure of the second sub-integrated block;

[0052] Figure 6 This is a schematic diagram of the structure of the third sub-integrated block;

[0053] Figure 7 This is a schematic diagram of the structure of the fourth sub-integrated block;

[0054] Figure 8 Design parameters for hyperbolic continuous bends;

[0055] Figure 9 A schematic diagram of a continuous sealed flow channel inside the flow distributor of the supercritical carbon dioxide dyeing vessel's storage tank.

[0056] Figure 10 Contour lines and vector diagrams of dye liquor velocity for the original structure and the optimized structure (in this invention) without a distributor;

[0057] Figure 11 This is a schematic diagram showing the mass flow rate and flow non-uniformity of dye liquor in the original structure and the optimized structure (this invention) without a distributor.

[0058] Figure 12 The contour lines of dye liquor pressure loss and turbulent dissipation traces are for dye liquor without a distributor, in the original structure and in the optimized structure (in this invention);

[0059] Figure 13 Displacement and stress cloud diagrams for the optimized structure of the distributor (this invention).

[0060] Reference numerals: 1. Liquid storage tank; 2. Distributor; 21. First sub-integrated block; 22. Second sub-integrated block; 231. Third sub-integrated block; 232-Fourth sub-integrated block; 3. Continuous sealed flow channel. Detailed Implementation

[0061] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0062] Example 1

[0063] The optimization algorithm used in this embodiment is the Multi-Objective Genetic Algorithm (MOGA), a variant of the controlled elite strategy NSGA-II. This algorithm can simultaneously handle multiple objectives and constraints and search for the global optimum. The process includes initialization, evaluation, selection, crossover, mutation, and termination. The optimization calculations were performed in ANSYS 2024 R1.

[0064] This embodiment provides a flow distributor for the supercritical carbon dioxide dyeing vessel's storage tank, such as... Figure 1-9 As shown, the distributor 2, located within the liquid storage tank 1, includes:

[0065] The three-level asymmetric bifurcation network structure includes a main inlet pipe, a primary pipe, a secondary pipe, and a tertiary pipe connected in sequence. The number, aperture, and position of the tertiary pipes are matched with the yarn column. The ratio of the number of the main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe is 1:3:6:18. The main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe form a dye liquor fluid flow channel.

[0066] The bend section of the secondary tube adopts a double-curvature continuous bend design with a forward curve followed by an inverse curve to reduce inertial offset.

[0067] The inner diameters of the primary, secondary, and tertiary pipes decrease progressively according to the principle of constant velocity, thus maintaining a stable fluid velocity.

[0068] The main inlet pipe, primary pipe, secondary pipe and tertiary pipe are all located within the flow channel integrated block;

[0069] The outlet of the evenly distributed device 2 is equipped with an independent quick-connect port, the number of which corresponds to the number of yarn column inlets.

[0070] The distributor 2 can be directly placed into the designated space of the liquid storage tank 1 and used after docking with the existing interface, without any modification to the main body of the liquid storage tank or additional opening.

[0071] The outlet pressure and process temperature of the circulating pump are matched with the pressure and temperature resistance ratings of the distributor. After strength verification, the displacement and stress of the distributor during long-term operation are within the material safety limits, and it can be put into use without modifying the main body of the storage tank.

[0072] During the manufacturing process:

[0073] After the flow channel integrated block blank is heat-treated by tempering, the flow channel, threads and sealing groove are processed in one clamping in a five-axis linkage machining center; each sub-integrated block is directly screwed together by precision threaded short tubes to form a continuous sealed flow channel, and high-strength bolts are arranged around the module to achieve overall clamping and positioning, ensuring that the flow channel is coaxial and the sealing is reliable.

[0074] The usage method is as follows:

[0075] 1. Insert the distributor 2 into the liquid storage tank 1, and connect the outlet to the yarn column inlet;

[0076] 2. Start the circulation pump to allow the carbon dioxide fluid containing dissolved dye to enter the distributor 2;

[0077] 3. After three stages of bifurcation, the fluid is evenly distributed to the eighteen yarn columns;

[0078] 4. After dyeing is complete, stop the circulation, depressurize, and recover the dye and carbon dioxide.

[0079] Example 2

[0080] The optimization algorithm used in this embodiment is the Multi-Objective Genetic Algorithm (MOGA), a variant of the controlled elite strategy NSGA-II. This algorithm can simultaneously handle multiple objectives and constraints and search for the global optimum. The process includes initialization, evaluation, selection, crossover, mutation, and termination. The optimization calculations were performed in ANSYS 2024 R1.

[0081] This embodiment provides a flow distributor for the supercritical carbon dioxide dyeing vessel's storage tank, such as... Figure 1-9 As shown, the distributor 2, located within the liquid storage tank 1, includes:

[0082] The three-level asymmetric bifurcation network structure includes a main inlet pipe, a primary pipe, a secondary pipe, and a tertiary pipe connected in sequence. The number, aperture, and position of the tertiary pipes are matched with the yarn column. The ratio of the number of the main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe is 1:3:6:18. The main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe form a dye liquor fluid flow channel.

[0083] The bend section of the secondary tube adopts a double-curvature continuous bend design with a forward curve followed by an inverse curve to reduce inertial offset.

[0084] The inner diameters of the primary, secondary, and tertiary pipes decrease progressively according to the principle of constant velocity, thus maintaining a stable fluid velocity.

[0085] The main inlet pipe, primary pipe, secondary pipe and tertiary pipe are all located within the flow channel integrated block;

[0086] The outlet of the evenly distributed device 2 is equipped with an independent quick-connect port, the number of which corresponds to the number of yarn column inlets.

[0087] The distributor 2 can be directly placed into the designated space of the liquid storage tank 1 and used after docking with the existing interface, without any modification to the main body of the liquid storage tank or additional opening.

[0088] In a specific implementation, the double curvature bend in the secondary branch bend section adopts a continuous curvature design with the curvature radius optimized by a multi-objective genetic algorithm, which first bends forward and then reverses.

[0089] In a specific implementation, the primary tube has three branches, the secondary tube has six branches, and the tertiary tube has eighteen branches.

[0090] In a specific implementation, the flow channel integration block is provided in eight parts, including a first sub-integrated block 21, a second sub-integrated block 22, three third sub-integrated blocks 231, and three fourth sub-integrated blocks 232; the main inlet pipe is located in the first sub-integrated block 21, the primary pipe and the secondary pipe are located in the second sub-integrated block 22, and the tertiary pipe is located in the third sub-integrated block 231 and the fourth sub-integrated block 232.

[0091] In a specific embodiment, the first sub-integrated block 21 and the second sub-integrated block 22 are connected by threaded short pipes, and the second sub-integrated block 22 is connected by threaded short pipes to the third sub-integrated block 231 and the fourth sub-integrated block 232 respectively, forming a continuous sealed flow channel 3 inside.

[0092] In a specific implementation, the first sub-integrated block 21, the second sub-integrated block 22, the third sub-integrated block 231, and the fourth sub-integrated block 232 are arranged with high-strength bolts around the perimeter to achieve overall clamping and positioning, ensuring that the flow channel is coaxial and the sealing is reliable.

[0093] In a specific implementation, the flow channel integrated block is a 45# steel sub-module. Its pressure resistance rating is not lower than the highest working pressure of the dyeing system.

[0094] In a specific embodiment, the inlet of the liquid storage tank 1 is connected to the main inlet pipe flange of the distributor 2.

[0095] In a specific implementation, the independent quick-connect port at the outlet of the distributor 2 corresponds one-to-one with the yarn column inlet, and boltless quick insertion connection is achieved through end face sealing or O-rings.

[0096] In a specific implementation, a multi-objective genetic algorithm is used, with the four structural parameters a1, a2, a4, and a5 of the secondary branch pipe bend section as optimization variables, and then a high-precision response surface model R is established. 2=0.94744, parameters a1 and a2 determine the uniformity of flow distribution, while a4 and a5 dominate the flow resistance. An optimal balance is achieved between flow uniformity, flow resistance, and energy loss.

[0097] The outlet pressure and process temperature of the circulating pump are matched with the pressure and temperature resistance ratings of the distributor. After strength verification, the displacement and stress of the distributor during long-term operation are within the material safety limits, and it can be put into use without modifying the main body of the storage tank.

[0098] During the manufacturing process:

[0099] After the flow channel integrated block blank is heat-treated by tempering, the flow channel, threads and sealing groove are processed in one clamping in a five-axis linkage machining center; each sub-integrated block is directly screwed together by precision threaded short tubes to form a continuous sealed flow channel, and high-strength bolts are arranged around the module to achieve overall clamping and positioning, ensuring that the flow channel is coaxial and the sealing is reliable.

[0100] The usage method is as follows:

[0101] 1. Insert the distributor 2 into the liquid storage tank 1, and connect the outlet to the yarn column inlet;

[0102] 2. Start the circulation pump to allow the carbon dioxide fluid containing dissolved dye to enter the distributor 2;

[0103] 3. After three stages of bifurcation, the fluid is evenly distributed to the eighteen yarn columns;

[0104] 4. After dyeing is complete, stop the circulation, depressurize, and recover the dye and carbon dioxide.

[0105] Using a supercritical carbon dioxide dye liquor distributor, the following steps are included:

[0106] S1. The first sub-integrated block 21, the second sub-integrated block 22, the third sub-integrated block 231, and the fourth sub-integrated block 232 are directly screwed together using precision threaded short tubes to form the distributor 2. High-strength bolts are arranged around each sub-integrated block to achieve overall clamping and positioning, ensuring coaxial flow channels and reliable sealing. After the distributor 2 is placed into the predetermined cavity of the liquid storage tank 1, its eighteen outlet ends correspond one-to-one with the yarn column inlets, achieving boltless quick-connect fitting using end face seals or O-rings.

[0107] S2. Place the yarn packages to be dyed one by one into the dyeing rack to form yarn columns, with the inlet of the dyeing rack mandrel corresponding to the outlet of the distributor 2. Inject CO2 into the system to the working pressure, and simultaneously start the preheater to raise the temperature to the process temperature. After the system pressure and temperature stabilize, start the circulation pump to allow the supercritical CO2 containing the dissolved dye to enter the distributor through the main inlet. The fluid is evenly distributed to the eighteen yarn columns after passing through a three-stage asymmetric bifurcation network structure, ensuring consistent flow rate in each yarn column.

[0108] S3. After dyeing is complete, stop the circulation pump, open the pressure relief valve, and CO2 and residual dye enter the recovery system to complete the recovery of dye and solvent. After the system is depressurized to atmospheric pressure, open the top cover of the dyeing machine and remove the dyed yarn packages.

[0109] S4. The distributor 2 can be lifted out as a whole for cleaning, or the first sub-integrated block 21, the second sub-integrated block 22, the third sub-integrated block 231, and the fourth sub-integrated block 232 can be loosened and removed one by one to facilitate inspection of the threaded sealing surface and replacement of the O-ring.

[0110] 1. Verify the uniformity of dye solution distribution:

[0111] like Figure 10 As shown, when the storage tank has no distributor, the flow rate and velocity at each outlet are significantly different, and there is a large backflow zone in the surrounding area; after adding the distributor, the dye liquor is confined inside the distributor, the flow uniformity is significantly improved, and the dye liquor velocity at each outlet is more consistent.

[0112] 2. Verification of allocation deviation rate:

[0113] like Figure 11 As shown, the maximum flow rates of the storage tank without a distributor, in the original structure, and with the optimized distributor are found at outlets 3-2-2, 3-1-2, and 2-2-3, respectively, with corresponding values ​​of 0.1625 kg / s, 0.1659 kg / s, and 0.1471 kg / s; the minimum flow rates are found at outlets 2-1-2, 1-1-1, and 1-1-2, with corresponding values ​​of 0.1137 kg / s, 0.0904 kg / s, and 0.1335 kg / s. The optimized structure of this invention improves the flow distribution uniformity by 22.33% and 32.25% compared to the original structure without a distributor, reaching 93.62%.

[0114] Table 1 below shows that the flow rate of the original structure increased by 81.33%. This significant increase is closely related to the inertia of the dye solution flowing from the secondary branch pipe to the tertiary branch pipe, but the flow rate deviation rate also increased significantly. The optimized structure of this invention, by adding two reverse bends between the secondary and tertiary branch pipes, effectively weakens the effect of inertia, reducing the flow rate distribution deviation rate to 10.19%.

[0115] Table 1. Performance comparison of the liquid storage tank without a distributor, with the original structure, and with the optimized distributor.

[0116]

[0117]

[0118] 3. Flow resistance verification:

[0119] like Figure 12As shown, when the liquid storage tank has no distributor, the pressure distribution is not only extremely uneven between each outlet, but also significantly different within the same outlet cross-section; the original structure increases the pressure drop; the optimized structure of the present invention does not increase the pressure drop by much.

[0120] Table 1 above shows the pressure losses of the liquid storage tank without a distributor, the original structure, and the optimized structure as 78.92 Pa, 97.39 Pa, and 82.94 Pa, respectively. Compared with the structure without a distributor, the pressure loss of the original structure increases by 23.41%, while the optimized structure increases by only 5.09%, almost the same as the structure without a distributor, significantly reducing flow resistance.

[0121] 4. Energy loss verification:

[0122] Figure 12 The turbulent dissipation streamlines show that dissipation is mainly concentrated in the region where the momentum direction changes, indicating that a smooth transition in these regions can further improve flow uniformity. Without a distributor, the dye liquor in the storage tank changes abruptly from radial flow to axial flow near the outlet, accompanied by severe turbulent dissipation; the multi-stage flow splitting design of the distributor decomposes this momentum conversion into three stages and significantly reduces the energy loss of the dye liquor flow through a smooth transition.

[0123] The average turbulent dissipation rates of the three structures are listed in Table 1. The average turbulent dissipation rates of the structures without a distributor, the original structure, and the optimized structure of this invention are 0.0241, 0.0312, and 0.0021 m, respectively. 2 / s 3 Compared to the original structure without a distributor, when the dye liquor flows through the bend in the original structure, centrifugal force causes the outer side to have a higher velocity and the inner side a lower velocity, creating a velocity gradient. This exacerbates turbulent dissipation and generates a large number of vortices, leading to increased energy loss and thus a higher dissipation rate. The optimized structure, through optimizing the branch bifurcation angle and the hyperboloid design, reduces the turbulent dissipation rate by 91.11% compared to the original structure, down to 0.0021m. 2 / s 3 This is because the double-bend design reduces the velocity gradient across the cross section, significantly reducing energy loss.

[0124] 5. Displacement and strength verification:

[0125] The room temperature yield strength of quenched and tempered 45# steel is 355 MPa, which decreases to 344 MPa at 130℃; based on a static load safety factor of 1.5, the allowable stress is 229 MPa. Referring to industry practice in SCCO2 high-pressure pipelines, the maximum allowable displacement is 0.3 mm.

[0126] like Figure 13 As shown in (A), the maximum displacement of the uniform distributor designed in this invention is 8.95×10-5mm, which is far below the limit of 0.3mm. Figure 13As shown in (B), the maximum equivalent stress is 226 MPa, which meets the 1.5-fold safety margin requirement. The fluid-structure interaction calculation was performed using ANSYS Mechanical and Fluent.

[0127] In summary, the results show that the distributor can improve the flow distribution uniformity to 93.62%, reduce the flow deviation rate to 10.19%, and achieve significant reductions in pressure drop and energy consumption; compared with the traditional perforated plate distributor, the flow uniformity is improved by an additional 5.89%.

[0128] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0129] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A flow distributor for the storage tank of a supercritical carbon dioxide dyeing vessel, characterized in that, The distributor (2), located in the liquid storage tank (1), includes: The three-level asymmetric bifurcation network structure includes a main inlet pipe, a primary pipe, a secondary pipe, and a tertiary pipe connected in sequence. The number, diameter, and position of the tertiary pipes are matched with the yarn column. The ratio of the number of the main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe is 1:3:6:

18. The main inlet pipe, the primary pipe, the secondary pipe, and the tertiary pipe form a fluid flow channel. The bend section of the secondary tube adopts a double-curvature continuous bend design with a first forward bend followed by a reverse bend. The inner diameters of the primary, secondary, and tertiary pipes decrease progressively according to the principle of equal speed. The main inlet pipe, primary pipe, secondary pipe and tertiary pipe are all located within the flow channel integrated block; The outlet of the evenly distributed device (2) is provided with an independent quick-connect port, which connects to the yarn column inlet.

2. The flow rate distributor for the supercritical carbon dioxide dyeing vessel storage tank according to claim 1, characterized in that, The double-curvature bend in the secondary branch bend section adopts a continuous curvature design with the curvature radius optimized by a multi-objective genetic algorithm, first the forward curve and then the reverse curve.

3. The flow distribution device for the supercritical carbon dioxide dyeing vessel storage tank according to claim 1, characterized in that, The main inlet pipe has one branch, the first-stage pipe has three branches, the second-stage pipe has six branches, and the third-stage pipe has eighteen branches.

4. The flow distribution device for the supercritical carbon dioxide dyeing vessel storage tank according to claim 1, characterized in that, The flow channel integration block is provided in eight parts, including a first sub-integrated block (21), a second sub-integrated block (22), three third sub-integrated blocks (231), and three fourth sub-integrated blocks (232); the main inlet pipe is located in the first sub-integrated block (21), the primary pipe and the secondary pipe are located in the second sub-integrated block (22), and the tertiary pipe is located in the third sub-integrated block (231) and the fourth sub-integrated block (232).

5. The flow distribution device for the supercritical carbon dioxide dyeing vessel storage tank according to claim 4, characterized in that, The first sub-integrated block (21) and the second sub-integrated block (22) are connected by threaded short pipes. The second sub-integrated block (22) is connected by threaded short pipes to the third sub-integrated block (231) and the fourth sub-integrated block (232) respectively, forming a continuous sealed flow channel (3) inside.

6. The flow distribution device for the supercritical carbon dioxide dyeing vessel storage tank according to claim 5, characterized in that, The first sub-integrated block (21), the second sub-integrated block (22), the third sub-integrated block (231), and the fourth sub-integrated block (232) are all bolted around the perimeter to achieve overall clamping and positioning, ensuring that the flow channel is coaxial and the sealing is reliable.

7. The flow distribution device for the supercritical carbon dioxide dyeing vessel storage tank according to claim 1, characterized in that, The flow channel integration block is a 45# steel sub-module.

8. The flow distribution device for the supercritical carbon dioxide dyeing vessel storage tank according to claim 1, characterized in that, The inlet of the liquid storage tank (1) is connected to the main inlet pipe flange of the distributor (2).

9. The flow rate distributor for the supercritical carbon dioxide dyeing vessel storage tank according to claim 1, characterized in that, The independent quick-connect port at the outlet of the distributor (2) corresponds one-to-one with the yarn column inlet, and boltless quick insertion connection is achieved through end face sealing or O-ring.

10. The flow rate distributor for the supercritical carbon dioxide dyeing vessel storage tank according to claim 2, characterized in that, The design of a double-curvature bend pipe, optimized by a multi-objective genetic algorithm, involves a continuous curvature design with a first forward curve followed by a reverse curve. The multi-objective genetic algorithm uses four structural parameters (a1, a2, a4, a5) of the secondary branch pipe bend section as optimization variables, and then establishes a high-precision response surface model R0. 2 =0.94744, parameters a1 and a2 determine the uniformity of flow distribution, while a4 and a5 dominate the flow resistance.

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