Agitation / transfer method and agitation / transfer device

Abstract

This agitation / transfer method includes: preparing a transfer pipe 10 extending in a horizontal extension direction; causing at least one type of liquid that is to be agitated and transferred to flow and be transferred within the transfer pipe 10, with a Reynolds number in a predetermined range and a filling ratio in a predetermined range; and causing the transfer pipe 10 to rotate about the extension direction to generate a vortex street in the at least one type of liquid, thereby agitating the at least one type of liquid.

Description

Agitation and transfer method and agitation and transfer device

[0001] The present invention relates to an agitation and transfer method and an agitation and transfer device.

[0002] Static mixers are known as a method for transporting liquids while stirring them. In static mixers, complexly shaped stirring parts are installed inside the transport piping, and stirring is promoted by inducing complex flows in the liquid. For example, such static mixers are disclosed in Patent Documents 1 and 2.

[0003] JP 2011-121038 A JP 2022-62345 A

[0004] Static mixers require mixing parts with complex shapes inside the transfer piping, making them difficult to clean. In addition, the only controllable parameter is the flow rate, making it difficult to control the mixing and transfer of liquids.

[0005] An object of the present invention is to provide an agitation and transfer method and an agitation and transfer device that achieves agitation and transfer with good cleanability and controllability.

[0006] A first aspect of the present invention provides a method for stirring and transferring, comprising: preparing a transfer pipe extending in a horizontal extension direction; transferring at least one type of liquid to be stirred and transferred through the transfer pipe at a Reynolds number within a predetermined range and a filling rate within a predetermined range; and rotating the transfer pipe around the extension direction to generate a vortex street in the at least one type of liquid, thereby stirring the at least one type of liquid.

[0007] This method eliminates the need to install agitation components with complex shapes within the transfer pipe, and allows the agitation of at least one type of liquid by rotating the transfer pipe. Therefore, good cleanability can be ensured. During agitation, a vortex street with a rotation axis perpendicular to the flow direction is generated. Adjacent vortices in the vortex street counter-rotate with each other, and the agitation is achieved by the vortex street. Furthermore, not only the flow rate (transfer speed) of at least one type of liquid but also the rotation speed of the transfer pipe are adjustable parameters. Therefore, by adjusting the transfer speed and rotation speed, agitation and transfer can be appropriately controlled, and appropriate agitation and transfer can be achieved depending on the process being performed. Here, "horizontal" means not only strictly horizontal but also roughly horizontal, and for example, an inclination of at least several degrees from the horizontal direction is acceptable. Furthermore, the at least one type of liquid includes a multiphase flow of a gas or solid and a liquid.

[0008] In the agitation and transfer method, the predetermined range of filling rate may be 10% or more and 90% or less.

[0009] According to this method, by specifying the packing ratio, it is possible to realize stable generation of vortex streets and stable mixing. The effectiveness of this packing ratio range was confirmed by numerical simulation.

[0010] In the agitation and transfer method, the transfer pipe may have a circular cross section perpendicular to the extension direction.

[0011] According to this method, a smooth inner surface of the transfer pipe can be formed, and stable mixing can be achieved. Here, the diameter of the transfer pipe may be constant or may vary.

[0012] In the agitation and transfer method, the transfer pipe may be a circular pipe having a constant diameter.

[0013] This method allows the use of simple circular pipe transfer piping, making it easy to manufacture and install.

[0014] In the agitation and transfer method, the transfer pipe may have a length that is 0.6 times or more the diameter of a circle in a cross section perpendicular to the stretching direction.

[0015] According to this method, by specifically specifying the ratio of the length to the diameter (aspect ratio) of the transfer pipe, it may be possible to realize stable generation of vortex streets and stable mixing. Although the effectiveness of the range of the aspect ratio depends on the filling rate and the Reynolds number, actual simulations were performed and the generation of vortex streets was confirmed with the above aspect ratios.

[0016] In the stirring and transferring method, the predetermined range of Reynolds number may be 98 or more.

[0017] According to this method, by specifying the Reynolds number, it may be possible to generate a vortex street and achieve stable mixing. Although the effectiveness of the Reynolds number range depends on the filling rate, we actually performed a simulation and confirmed the generation of a vortex street at the above Reynolds number.

[0018] In the agitation and transfer method, the at least one type of liquid to be agitated and transferred contains particles, and the Stokes number in the agitation is 2.7×10 ―５ The ratio of the terminal velocity of the free fall of the particles to the velocity of the inner wall surface in the rotation direction of the transfer pipe may be not less than −0.01 and not more than 0.52.

[0019] This method allows particles to aggregate with stirring. The effectiveness of the particle aggregation conditions was confirmed by actually conducting a numerical simulation to confirm the coarseness and density of the particle field.

[0020] A second aspect of the present invention provides a stirring and transferring device comprising: a transfer pipe extending in a horizontal extension direction, which transfers at least one type of liquid to be stirred and transferred by causing it to flow at a filling rate within a predetermined range and a Reynolds number within a predetermined range; and a rotation mechanism which rotates the transfer pipe around the extension direction and generates a vortex street in the at least one type of liquid, thereby stirring the at least one type of liquid.

[0021] In the agitating and transferring device, the predetermined range of filling rate may be 10% or more and 90% or less.

[0022] In the agitation and transfer device, the transfer pipe may have a circular cross section perpendicular to the extension direction.

[0023] In the agitation and transfer device, the transfer pipe may be a circular pipe having a constant diameter.

[0024] In the agitation and transfer device, the transfer pipe may have a length that is 0.6 times or more the diameter of a circle in a cross section perpendicular to the stretching direction.

[0025] In the agitating and transferring device, the predetermined range of Reynolds numbers may be 98 or greater.

[0026] In the agitation and transfer device, at least one type of liquid to be agitated and transferred contains particles, and the Stokes number during agitation is 2.7×10 ―５ The ratio of the terminal velocity of the free fall of the particles to the velocity of the inner wall surface in the rotation direction of the transfer pipe may be not less than −0.01 and not more than 0.52.

[0027] According to the present invention, the agitation and transfer method and the agitation and transfer device can achieve agitation and transfer with good cleanability and controllability.

[0028] 1 is a schematic diagram of an agitation and transfer device according to an embodiment of the present invention;

[0023] FIG. 1 is a photograph of an experimental result showing a vortex street in a stationary liquid;

[0024] FIG. 2 is a vector diagram of a flow field resulting from a numerical simulation showing a vortex street in a stationary liquid;

[0025] FIG. 3 is a vector diagram of a flow field resulting from a numerical simulation showing a vortex street in a flowing liquid at time 0 seconds;

[0026] FIG. 4 is a vector diagram of a flow field resulting from a numerical simulation showing a vortex street in a flowing liquid at time 4 seconds;

[0027] FIG. 5 is a vector diagram of a flow field resulting from a numerical simulation showing a vortex street at time 8 seconds;

[0028] FIG. 6 is a vector diagram of a flow field resulting from a numerical simulation showing a vortex street at a filling rate of 10%;

[0029] FIG. 7 is a vector diagram of a flow field resulting from a numerical simulation showing a vortex street at a filling rate of 90%;

[0029] FIG. 8 is a vector diagram of a flow field resulting from a numerical simulation showing a vortex street when the length of the transfer pipe is 0.6 times the diameter;

[0029] FIG. 9 is a first graph of a numerical simulation showing the relationship between the strength of the circulating flow and the ratio K1 (mean flow velocity / inner wall surface velocity);

[0029] FIG. 10 is a second graph of a numerical simulation showing the relationship between the strength of the circulating flow and the ratio K1 (mean flow velocity / inner wall surface velocity). A diagram showing the particle field when particles are initially positioned in a numerical simulation of the Stokes number. ―６ The particle field when the Stokes number is 2.7 × 10 ―５ The particle field when the Stokes number is 1.1 × 10 ―５ The particle field when the Stokes number is 4.2 × 10 ―４ The particle field when the Stokes number is 1.7 × 10 ―３1 is a diagram showing the particle field when the ratio of the terminal velocity of the particle's free fall to the inner wall surface velocity in the rotation direction of the transfer piping is -0.02; 2 is a diagram showing the particle field when the ratio of the terminal velocity of the particle's free fall to the inner wall surface velocity in the rotation direction of the transfer piping is -0.0068; 3 is a diagram showing the particle field when the ratio of the terminal velocity of the particle's free fall to the inner wall surface velocity in the rotation direction of the transfer piping is 0.068; 4 is a diagram showing the particle field when the ratio of the terminal velocity of the particle's free fall to the inner wall surface velocity in the rotation direction of the transfer piping is 0.27; 5 is a diagram showing the particle field when the ratio of the terminal velocity of the particle's free fall to the inner wall surface velocity in the rotation direction of the transfer piping is 0.55; ε / N ｐ 10 is a graph showing the relationship between the ratio K2 (the terminal velocity of free fall of particles / the velocity of the inner wall surface in the rotation direction of the transfer pipe) and the ratio K3 (the proportion of particles on the wall surface or near the liquid surface of the transfer pipe).

[0029] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0030] 1, the stirring and transferring device 1 of this embodiment transfers a liquid while stirring it. The X direction indicates the extension direction of the transfer pipe 10 in a horizontal plane (which coincides with the extension direction of the rotation axis RA in this embodiment), the Y direction indicates the direction perpendicular to the X direction in the horizontal plane, and the Z direction indicates the vertical direction (up and down).

[0031] The configuration of the mixing and transferring device 1 will be described.

[0032] The object of agitation and transport can be at least one type of liquid. This at least one type of liquid can include not only a single liquid but also a multiphase flow of a liquid and a gas or solid. Examples of the object of agitation and transport include water alone, water and oil in an emulsification process (a multiphase flow of liquids and liquids), a monomer or polymer and water in a polymerization reaction process, slurry agitation in a catalytic reaction process (a multiphase flow of solids and liquids), single-phase or multiphase non-Newtonian fluids (pseudoplastic fluids or plastic fluids), aeration agitation of oxygen in a bioreactor or the like (a multiphase flow of gas and liquids), or a multiphase flow of solids (such as mud) and liquids in an anaerobic layer of a bioreactor or the like. The solid can also be particles. Agitating particles in a liquid can also cause the particles to aggregate.

[0033] The agitation and transfer device 1 has a transfer pipe 10 that transfers the liquid to be agitated and transferred, and a rotation mechanism 20 that agitates the liquid by rotating the transfer pipe 10. In this embodiment, the agitation and transfer device 1 also has a flow device 30 that causes the liquid to flow, and a control device 40 that controls each part.

[0034] In this embodiment, the transfer pipe 10 is a uniformly sized circular pipe extending horizontally. The transfer pipe 10 has a smooth inner surface and does not include any additional components such as agitating parts with complex shapes. Therefore, the transfer pipe 10 is easy to clean.

[0035] Preferably, the length of the transfer pipe 10 is 0.6 times or more the diameter of the circular cross section perpendicular to the extension direction. The appropriateness of such a numerical range will be described in detail later. In addition, the material of the transfer pipe 10 can be set arbitrarily.

[0036] In this embodiment, the transfer pipe 10 is raised from the floor surface G by a plurality of support members 11 that are erected on the floor surface G. Each of the plurality of support members 11 has a through-hole portion 11a and a bearing 12 attached to the through-hole portion 11a. The transfer pipe 10 passes through the through-hole portion 11a and is held by the support members 11 via the bearings 12 so as to be rotatable around a rotation axis RA.

[0037] In this embodiment, connecting parts 13 are attached to both ends of the transfer pipe 10 in the extension direction. The connecting parts 13 are for connecting to general pipes (not shown). In this way, the transfer pipe 10 can be connected to existing general pipes. Therefore, the mixing and transferring device 1 has high versatility.

[0038] The rotation mechanism 20 is mechanically connected to the transfer pipe 10 and rotates the transfer pipe 10 around a rotation axis RA. In this embodiment, the rotation mechanism 20 has a motor 21 as a drive source, and a belt 22 and pulleys 23 and 24 that transmit the force from the motor 21. The pulley 23 is attached to the motor 21, the pulley 24 is attached to the transfer pipe 10, and the belt 22 is stretched around the pulleys 23 and 24.

[0039] When the motor 21 is driven, the rotational force of the motor 21 is transmitted to the transfer pipe 10 via the belt 22 and the pulleys 23 and 24, causing the transfer pipe 10 to rotate around the rotation axis RA. In this embodiment, the rotation axis RA and the central axis of the transfer pipe 10 coincide with each other.

[0040] The flow device 30 is a device for adjusting the flow rate or flow rate (transport speed) of a liquid. The flow device 30 is, for example, a known pump. However, the form of the flow device 30 is not particularly limited, and the flow device 30 may take any form.

[0041] The control device 40 performs calculation processing and controls the entire device. In this embodiment, the control device 40 is configured with hardware such as a CPU (Central Processing Unit), RAM (Random Access Memory), and ROM (Read Only Memory), and software implemented therein.

[0042] In this embodiment, the control device 40 controls the rotation mechanism 20 to adjust the rotation speed of the transfer pipe 10 around the rotation axis RA. The control device 40 also controls the flow device 30 to adjust the average flow velocity of the liquid in the extension direction of the transfer pipe 10.

[0043] The liquid to be agitated and transported flows in the transport pipe 10 at a predetermined range of Reynolds number Re and a predetermined range of filling rate F. Here, the Reynolds number Re is a value expressed by the density ρ of the liquid, the radius R of the transport pipe 10, the rotation speed ω of the transport pipe 10, and the viscosity μ of the liquid (Re=ρR ２ ω / μ) The filling rate F is a value expressed as the ratio (%) of the volume V of the liquid in the transfer pipe 10 to the volume C of the transfer pipe 10 (F=100×V / C).

[0044] Preferably, the predetermined range of the filling ratio F is 10% or more and 90% or less (10≦F≦90). Also, preferably, the predetermined range of the Reynolds number Re is 98 or more (Re≧98). Such a numerical range is achieved by the control of the control device 40. The appropriateness of such a numerical range will be described in detail later.

[0045] Next, the stirring and transferring method of this embodiment will be described.

[0046] In the agitation and transfer method of this embodiment, the above-described agitation and transfer device 1 is prepared, and the liquid to be agitated and transferred is flowed through the transfer pipe 10. At this time, the filling rate of the liquid in the transfer pipe 10 is set to, for example, 10% or more and 90% or less. Therefore, a layer of liquid and air exists in the transfer pipe 10.

[0047] After the liquid flows through the transfer pipe 10, the transfer pipe 10 is rotated around the rotation axis RA by the rotation mechanism 20. At this time, the Reynolds number Re is set to, for example, 98 or more (Re≧98). The rotation speed or flow rate may be constant or may vary slightly. In this embodiment, the transfer pipe 10 is rotated at a constant speed, and the liquid is caused to flow at a constant flow rate.

[0048] When the transfer pipe 10 is rotated around the rotation axis RA by the rotation mechanism 20, the liquid is transferred while being agitated within the transfer pipe 10. This agitation occurs due to the generation of vortex streets within the liquid. Although the principle behind the generation of such vortex streets is not scientifically self-evident, the generation of vortex streets allows for efficient agitation of the liquid.

[0049] The experiment in which the generation of vortex streets was confirmed will be described.

[0050] 2 is a photograph showing the experimental results of vortex streets in stationary liquid, which are obtained by observing the agitation of the liquid from the side (Y direction) of the transfer pipe 10.

[0051] In the experiment, a circular pipe with a diameter of 100 mm and a length of 800 mm was prepared as the transfer pipe 10. The transfer pipe 10 was made of transparent acrylic to make it easy to see inside. The transfer pipe 10 was filled with water at a filling rate of 60% (the remaining 40% was air), and mica particles were also added as a visualization agent. The rotation speed of the transfer pipe 10 was set to 3 rpm. Note that, unlike the present embodiment, in the experiment, the flow velocity of the water in the extension direction (X direction) of the transfer pipe 10 was set to zero, i.e., the water was in a stationary state.

[0052] As shown in Figure 2, a vortex street with a rotation axis perpendicular to the extension direction of the transfer pipe 10 was generated in the water within the transfer pipe 10. For clarity of illustration, the reference symbol A1 is used to indicate the rotation of each vortex in the vortex street. Adjacent vortices in the vortex street rotate in opposite directions, and stirring was achieved by the vortex street. In other words, experimental confirmation of the generation of a vortex street confirmed its function as a stirring device and stirring method.

[0053] Figure 3 is a vector diagram of the flow field resulting from a numerical simulation showing vortex streets in a stationary liquid. Specifically, Figure 3 shows the results of a numerical simulation performed under the same conditions as Figure 2.

[0054] In the numerical simulation, in addition to the parameters set in the experiment, various physical properties of water as a liquid (for example, density 1000 [kg / m ３ ] and viscosity 0.001 [Pa s]), gravitational acceleration 9.8 [m / s ２ ], the surface tension was set to 0 [N / m], and the viscosity and density of the air layer were both set to 0.01 times that of water.

[0055] As shown in Figure 3, a vortex street with a rotation axis perpendicular to the extension direction of the transfer piping 10 was generated in the liquid inside the transfer piping 10. For clarity of illustration, the reference symbol A2 is used to indicate the rotation of each vortex in the vortex street. The vortex street closely matches the experimental results shown in Figure 2, and by confirming the generation of the vortex street through numerical simulation, it was confirmed that the device and method function as a stirring device.

[0056] 2 and 3, unlike the present embodiment, the results are for a stationary liquid (water) to be agitated, but in this embodiment, not only agitation but also transfer is performed at the same time. Therefore, below, with reference to Figures 4 to 6, we will explain the results of a numerical simulation similar to that shown in Figures 2 and 3, in which a liquid is made to flow in the extension direction of the transfer pipe 10.

[0057] 4 to 6 are vector diagrams of flow fields resulting from numerical simulations showing vortex streets in a flowing liquid at times 0, 4, and 8 seconds, respectively, according to this embodiment.

[0058] In the numerical simulation, some of the conditions in Fig. 3 were changed, and the radius R of the transfer pipe 10 was set to 50 mm, the rotation speed ω to 18 rpm, the filling rate to 40%, and the liquid flow velocity (transfer velocity) to 0.012 m / s. In addition, the viscosity μ of the liquid was set so that the Reynolds number Re was 200.

[0059] 4 to 6, even when a liquid is flowing, a vortex street having a rotation axis perpendicular to the extension direction of the transfer pipe 10 is generated. For clarity of illustration, the reference symbol A3 is used to indicate the rotation of each vortex in the vortex street. It was also confirmed that the vortex street moves along with the flow of the liquid. Therefore, by confirming the generation of a vortex street through numerical simulation, it was confirmed that the agitating and transferring device 1 and agitating and transferring method of this embodiment are effective even when a liquid is flowing.

[0060] According to this embodiment, there is no need to install agitation parts with complex shapes inside the transfer pipe 10, and at least one type of liquid can be agitated by rotating the transfer pipe 10. Therefore, good cleanability can be ensured. Furthermore, not only the flow rate (transfer speed) of at least one type of liquid but also the rotation speed of the transfer pipe 10 are adjustable parameters. Therefore, by adjusting the transfer speed and rotation speed, agitation and transfer can be suitably controlled, and appropriate agitation and transfer can be achieved depending on the process being carried out.

[0061] Furthermore, in this embodiment, the transfer pipe 10 is simply a circular pipe, which makes it easy to manufacture and install.

[0062] The preferred ranges of the various parameters will be explained below.

[0063] The results of examining the liquid filling rate will be described with reference to Figures 7 and 8. Specifically, because the generation of vortex streets may be suppressed if the liquid filling rate is too small or too large, the minimum and maximum values ​​of the liquid filling rate were examined. In the numerical simulation of Figure 7, the Reynolds number Re for the liquid viscosity was set to 500. In the numerical simulation of Figure 8, the Reynolds number Re for the liquid viscosity was set to 250.

[0064] Figure 7 shows the results of a numerical simulation when the filling rate was 10%, and Figure 8 shows the results when the filling rate was 90%. As a result, the generation of vortex streets was confirmed even when the filling rate was 10% (minimum) and 90% (maximum). For clarity, the symbols A5 and A6 are used to indicate the rotation of each vortex in the vortex street. These results confirm that the agitating and transporting device 1 and agitating and transporting method of this embodiment are effective when the filling rate is in the range of 10% to 90%. Therefore, by specifying the filling rate in this way, stable generation of vortex streets and stable agitation can be achieved.

[0065] The results of the study on the Reynolds number Re will be described with reference to Fig. 9. Specifically, because the generation of vortex streets may be suppressed if the Reynolds number Re is set too small, the minimum value of the Reynolds number Re was studied. Furthermore, because the minimum value of the Reynolds number Re varies depending on the liquid filling rate, the minimum value was checked for each filling rate.

[0066] Figure 9 shows the results of a numerical simulation when the filling rate is 60% and the Reynolds number Re is 100. The Reynolds number Re was adjusted by changing the viscosity μ of the liquid. As a result, the generation of a vortex street was confirmed even when the Reynolds number Re was 100. For clarity, the reference symbol A4 is used to indicate the rotation of each vortex in the vortex street. This simulation was performed with various Reynolds numbers Re and filling rates to confirm the occurrence of a vortex street. Table 1 below shows the minimum Reynolds number Re at which the generation of a vortex street was confirmed for each filling rate.

[0067]

[0068] From the results shown in Table 1 above, it was confirmed that the agitating and transporting device 1 and agitating and transporting method of this embodiment may be effective when the Reynolds number Re is 98 or higher (when the filling rate is 60%). Specifically, it was confirmed that by specifying the Reynolds number Re in this manner, it may be possible to realize the generation of a vortex street and stable agitation. Therefore, the Reynolds number Re may be set to 98 or higher. Furthermore, the Reynolds number Re may be set to 326 or higher to stably generate a vortex street at a total filling rate of 10% to 90%. Furthermore, the Reynolds number Re may be set to a value equal to or higher than the minimum value shown in Table 1 depending on the filling rate to be set.

[0069] The results of an investigation into the relationship between the length and diameter (aspect ratio) of the transfer piping 10 will be described with reference to Fig. 10. Specifically, if the length of the transfer piping 10 is too small relative to the diameter, the generation of vortex streets may be suppressed, so the minimum value of the length relative to the diameter of the transfer piping 10 was investigated. In the numerical simulation of Fig. 10, the viscosity μ of the liquid was set so that the Reynolds number Re was 500, and the filling rate was set to 10%.

[0070] Figure 10 shows the results of a numerical simulation when the length of the transfer piping 10 is 0.6 times its diameter. As a result, the generation of a vortex street was confirmed even when the length of the transfer piping 10 was 0.6 times its diameter (i.e., the aspect ratio was 0.6). For clarity, the reference symbol A7 is used to indicate the rotation of each vortex in the vortex street. This simulation was performed with various Reynolds numbers Re and filling ratios to confirm the occurrence of a vortex street. Table 2 below summarizes the minimum aspect ratios at which the generation of a vortex street was confirmed, for each filling ratio and the minimum Reynolds number for that filling ratio (see Table 1 above).

[0071]

[0072] The results shown in Table 2 confirm that the stirring and transfer device 1 and stirring and transfer method of this embodiment may be effective (when the filling rate is 10%) when the length of the transfer pipe 10 is 0.6 times or more its diameter (aspect ratio of 0.6 or more). Therefore, by specifically specifying the length-to-diameter ratio (aspect ratio) of the transfer pipe 10 in this manner, stable generation of vortex streets and stable mixing may be achieved. Therefore, the length of the transfer pipe 10 may be 0.6 times or more the diameter of the circle of its cross section perpendicular to the stretching direction (i.e., aspect ratio of 0.6 or more). Furthermore, to stably generate vortex streets at a total filling rate of 10% to 90%, the length of the transfer pipe 10 may be 1.8 times or more the diameter of the circle of its cross section perpendicular to the stretching direction (i.e., aspect ratio of 1.8 or more). Furthermore, an aspect ratio equal to or greater than the minimum value shown in Table 2 may be appropriately set depending on the desired filling rate.

[0073] Referring to Figure 11, the results of an investigation into the ratio K1 of the average flow velocity of the liquid in the extension direction of the transfer pipe 10 to the inner wall surface velocity in the rotation direction of the transfer pipe 10 will be described. Figure 11 is a graph of the results of a numerical simulation showing the relationship between the strength of the circulating flow (vortex flow) and the ratio K1 (average flow velocity / inner wall surface velocity). In the numerical simulation of Figure 11, the viscosity of the liquid was set so that the Reynolds number Re was 200, the filling rate was set so that it was 40%, and the average flow velocity was changed in various ways.

[0074] As a result, the generation of vortex streets (circulating flows) was confirmed when the ratio K1 was 0.25 or less or 0.6 or more. In particular, the smaller the ratio K1 was when 0.25 or less, the stronger the circulating flows were confirmed, and the larger the ratio K1 was when 0.6 or more, the stronger the circulating flows were confirmed. Therefore, these results confirmed that the stirring and transporting device 1 and stirring and transporting method of this embodiment may be effective when the ratio K1 is 0.25 or less or 0.6 or more. Therefore, by specifically specifying the ratio K1 in this way, it may be possible to achieve stable generation of vortex streets and stable stirring.

[0075] Referring to Figure 12, another result of examining the ratio K1 (average flow velocity / inner wall surface velocity) of the average liquid flow velocity in the extension direction of the transfer pipe 10 to the inner wall surface velocity in the rotation direction of the transfer pipe 10 will be described.

[0076] 12 is a graph showing the results of a numerical simulation showing the relationship between the strength of the circulating flow (vortex flow) and the ratio K1. In the numerical simulation of FIG. 12, the main stream Reynolds number Re ｍ The average flow velocity was set to 150, the filling rate was set to 40%, and the Reynolds number Re was changed in various ways. ｍ is the density ρ of the liquid, the radius R of the transfer pipe 10, and the average flow velocity U in the main flow direction. ｍ , and the viscosity of the liquid μ (Re ｍ =ρRU ｍ / μ).

[0077] As a result, the generation of a vortex street (circulating flow) was confirmed when the ratio K1 was 1.5 or less. In particular, the smaller the ratio K1 was at 1.5 or less, the stronger the circulating flow was confirmed. Therefore, from these results, it was confirmed that the stirring and transporting device 1 and stirring and transporting method of this embodiment may be effective when the ratio K1 is 1.5 or less. Therefore, by specifically specifying the ratio K1 in this way, it may be possible to achieve stable generation of a vortex street, and stable stirring may be achieved.

[0078] The agitation and transfer device 1 and agitation and transfer method of this embodiment can also aggregate particles contained in liquid under predetermined conditions. The predetermined conditions may be as follows: When at least one type of liquid to be agitated and transferred contains particles, the Stokes number St in agitation is 2.7×10 at the Reynolds number Re at which a vortex street occurs. ―５ or more (St≧2.7×10 ―５ ), and the ratio K2 of the terminal velocity of the free fall of the particles to the velocity on the inner wall surface in the rotation direction of the transfer pipe 10 is -0.01 or more and 0.52 or less (-0.01≦K2≦0.52). Note that the terminal velocity of the free fall of the particles here also includes the case where the particles float up (the case where the terminal velocity is negative). Specifically, a ratio K2<0 indicates that the particles float up.

[0079] The Stokes number St is expressed by the following formula (1): In the following formula (1), d is the particle diameter, μ is the liquid viscosity, ρ is the liquid density, and ρ ｐ is the particle density, and ω is the rotation speed of the transfer pipe 10.

[0080]

[0081] The ratio K2 is expressed by the following equation (2): In the following equation (2), g represents the gravitational acceleration, R represents the radius of the transfer pipe 10, and the other parameters are the same as those shown in equation (1).

[0082]

[0083] 13 to 18, the results of examining the Stokes number St will be described. Specifically, if the Stokes number St is set too small, particle aggregation may be suppressed, so the minimum value of the Stokes number St was examined using a numerical simulation. In the numerical simulation, the radius R of the transfer pipe 10 was set to 1 cm, the viscosity μ of the liquid was set to 0.001 Pa s, and the density ρ of the liquid was set to 1000 kg / m. ３ ], the filling rate was set to 40%, and the rotation speed ω around the horizontal axis of the transfer pipe 10 was set to 4 [rad / s] (94 rpm). This resulted in the Reynolds number Re being set to 400. In addition, in the numerical simulation, the particle density ρ ｐ to 1200 [kg / m３ ] (i.e., the particle to liquid density ratio was 1.2 / 1.0), and the number of particles was set to approximately 100,000. Under these conditions, the particle diameter d was varied, the time evolution of the particle field was observed, and the change in the spatial distribution of particles relative to the particle diameter d (i.e., the Stokes number St) was confirmed.

[0084] Figure 13 shows the initial particle placement in the numerical simulation for the Stokes number St. As shown, the particles are uniformly distributed in the liquid.

[0085] FIG. 14 shows the particle diameter d of 15 μm (Stokes number St = 9.5 × 10 ―６ ), and Fig. 15 shows the case where the particle diameter d is 25 [µm] (Stokes number St = 2.7 × 10 ―５ ), and Fig. 16 shows the case where the particle diameter d is 50 [µm] (Stokes number St = 1.1 × 10 ―５ ), and Fig. 17 shows the case where the particle diameter d is 100 [µm] (Stokes number St = 4.2 × 10 ―４ ), and Fig. 18 shows the case where the particle diameter d is 200 [µm] (Stokes number St = 1.7 × 10 ―３ ) is shown.

[0086] From the results shown in Figures 14 to 18, the Stokes number is 2.7 × 10 ―５ From the above (Figures 15 to 18), the coarse and dense particle distribution can be clearly confirmed, that is, it was confirmed that collisions between particles become more active in the dense parts, and aggregation can be promoted. Therefore, for particle aggregation, the Stokes number St during stirring is 2.7 × 10 ―５ or more (St≧2.7×10 ―５ ).

[0087] 19 to 24, the results of examining the ratio K2 (terminal velocity of free fall of particles / inner wall surface velocity in the rotation direction of the transfer pipe 10) will be described. In the numerical simulation, the radius R of the transfer pipe 10 is 1 [cm], the viscosity μ of the liquid is 0.001 [Pa s], and the density ρ of the liquid is 1000 [kg / m ３], the filling rate was set to 40%, and the rotation speed ω around the horizontal axis of the transfer pipe 10 was set to 4 [rad / s] (94 rpm). This resulted in the Reynolds number Re being set to 400. In addition, in the numerical simulation, the particle diameter d was set to 100 [μm] and the number of particles was set to approximately 100,000. Under these conditions, the particle density ρ ｐ By changing variously and observing the time evolution of the particle field, the particle density ρ ｐ (i.e., ratio K2) was used to confirm the change in the spatial distribution of particles.

[0088] Figure 19 shows the initial particle placement in the numerical simulation for ratio K2. As shown, the particles are evenly distributed in the liquid.

[0089] Figure 20 shows the particle density ρ ｐ is 850 [kg / m ３ ] (K2 = -0.02), and FIG. 21 shows the particle density ρ ｐ is 950 [kg / m ３ ] (K2 = -0.0068), and FIG. 22 shows the particle density ρ ｐ is 1500 [kg / m ３ ] (K2 = 0.068), and FIG. 23 shows the particle density ρ ｐ is 3000 [kg / m ３ ] (K2 = 0.27), and Fig. 24 shows the particle density ρ ｐ is 5000 [kg / m ３ ] (K2=0.55).

[0090] 20 to 24 show that the particles vary in density. However, because these results alone do not allow us to confirm the spatial distribution of particles in the depth direction, we also confirmed the spatial distribution of particles in a cross section perpendicular to the rotation axis of the transfer pipe 10 as follows.

[0091] 25 is a graph showing the results of checking the proportion of particles on the inner wall surface of the transfer pipe 10 or near the liquid surface. Specifically, FIG. 24 shows the results of checking the proportion of particles on the inner wall surface of the transfer pipe 10 or near the liquid surface, where N ε Let the total number of particles be N ｐ Let N ε / N ｐ10 is a graph confirming the dependency of the ratio K2.

[0092] Referring to FIG. 25, when the ratio K2 is equal to or greater than −0.01 and equal to or less than 0.52 (−0.01≦K2≦0.52), N ε / N ｐ is below the threshold value of 0.4. In other words, it was confirmed that in this range, 60% or more of the particles are not located on the inner wall surface or near the liquid surface, but are densely located in the central region of the liquid. Therefore, the ratio K2 may be set to be greater than or equal to -0.01 and less than or equal to 0.52 (-0.01≦K2≦0.52).

[0093] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be practiced with various modifications within the scope of the present invention.

[0094] For example, the shape of the transfer pipe 10 is not limited to a circular pipe, but may be a pipe of any shape with a smooth inner surface. Therefore, the cross-sectional shape of the transfer pipe 10 perpendicular to the extension direction may be circular as in the above embodiment, or may be a shape other than circular. For example, the cross-sectional shape of the transfer pipe 10 perpendicular to the extension direction may be elliptical or donut-shaped. Furthermore, the thickness (diameter) of the transfer pipe 10 does not have to be uniform, i.e., it may vary depending on the position in the extension direction. For example, the transfer pipe 10 may have a tapered shape that narrows from one end to the other.

[0095] The transfer pipe 10 need not only be horizontally disposed, but also be disposed approximately horizontally, and for example, an inclination of a few degrees from the horizontal direction is acceptable. Furthermore, the rotation axis RA and the central axis of the transfer pipe 10 do not need to be perfectly aligned, and may be slightly misaligned (eccentric).

[0096] Furthermore, various configurations of the rotation mechanism 20 other than those in the above embodiment are conceivable, and any configuration that can rotate the transfer pipe 10 around the rotation axis RA can be adopted.

[0097] REFERENCE SIGNS LIST 1 Agitation and transfer device 10 Transfer piping 11 Support member 11a Through-hole portion 12 Bearing 13 Connection part 20 Rotation mechanism 21 Motor 22 Belt 23, 24 Pulley 30 Flow device 40 Control device G Floor surface RA Rotation axis

Claims

1. Prepare a transfer pipe extending in a horizontal extension direction, Flow at least one type of liquid to be stirred and transferred in the transfer pipe at a Reynolds number within a predetermined range and a filling rate within a predetermined range for transfer, Rotate the transfer pipe around the extension direction to generate a vortex street in the at least one type of liquid to stir the at least one type of liquid including The transfer pipe is a circular pipe having a smooth inner surface, a stirring and transfer method.

2. The filling rate within the predetermined range is 10% or more and 90% or less, and the stirring and transfer method according to Claim 1.

3. The transfer pipe is a circular pipe with a constant diameter, and the stirring and transfer method according to Claim 1.

4. The transfer pipe has a length of 0.6 times or more the diameter of a circular cross-section perpendicular to the extension direction, and the stirring and transfer method according to Claim 3.

5. The Reynolds number within the predetermined range is 98 or more, and the stirring and transfer method according to Claim 3.

6. At least one type of liquid to be stirred and transferred contains particles, The Stokes number in the stirring is 2.7×10 ―５ The stirring and transfer method according to claim 3, wherein the ratio of the terminal velocity of the free fall of the particles to the inner wall surface velocity in the rotational direction of the transfer pipe is -0.01 or more and 0.52 or less, and the Stokes number in the stirring is 2.7×10 or more.

7. A transfer pipe extending in a horizontal extension direction, flowing at least one type of liquid to be stirred and transferred at a filling rate within a predetermined range and a Reynolds number within a predetermined range for transfer, and a rotating mechanism that rotates the transfer pipe around the extension direction to generate a vortex street in the at least one type of liquid to stir the at least one type of liquid comprising The transfer pipe is a circular pipe having a smooth inner surface, a stirring and transfer device.

8. The filling rate within the predetermined range is 10% or more and 90% or less, and the stirring and transfer device according to Claim 7.

9. The transfer pipe is a circular pipe with a constant diameter, and the stirring and transfer device according to Claim 7.

10. The transfer pipe has a length of 0.6 times or more the diameter of a circular cross-section perpendicular to the extension direction, and the stirring and transfer device according to Claim 9.

11. The Reynolds number within the predetermined range is 98 or more, and the stirring and transfer device according to Claim 9.

12. At least one type of liquid to be stirred and transferred contains particles, The Stokes number in the stirring is 2.7×10 ―５ The stirring and transporting device according to claim 11, wherein the Stokes number in the stirring is 2.7×10 or more, and the ratio of the terminal velocity of free fall of the particles to the inner wall surface velocity in the rotational direction of the transfer pipe is -0.01 or more and 0.52 or less.