WO2023164955A1

WO2023164955A1 - Ultrasonic micromixer having millisecond mixing performance

Info

Publication number: WO2023164955A1
Application number: PCT/CN2022/079649
Authority: WO
Inventors: 陈光文; 刘志凯
Original assignee: 中国科学院大连化学物理研究所
Priority date: 2022-03-01
Filing date: 2022-03-08
Publication date: 2023-09-07
Also published as: CN114733415A

Abstract

An ultrasonic micromixer having millisecond mixing performance. The ultrasonic micromixer comprises a micromixer (1), an ultrasonic transducer (2), and an ultrasonic generator (3); the wavelength of a sound wave in air corresponding to the working frequency of the ultrasonic transducer (2) is 4-68 times the hydraulic diameter of a microchannel in the micromixer (1). By means of matching between the hydraulic diameter of the microchannel and the wavelength of the sound wave, vigorous and highly controllable ultrasonic cavitation is generated in the microchannel, the density of cavitation bubbles can reach one cavitation bubble per cubic millimeter, a large number of cavitation bubbles generated in the microchannel rapidly stir a fluid like a stirrer, so that millisecond-level mixing in the microchannel is implemented, and the shortest mixing time can reach 0.2 ms.

Description

An Ultrasonic Micromixer with Millisecond Mixing Performance

technical field

The invention relates to the field of micro-mixer devices, in particular to an ultrasonic micro-mixer device enhanced by ultrasound.

Background technique

The mixing effect determines the product quality of some mixing-sensitive processes. For example, the preparation of nanomaterials by precipitation method, the mixing intensity determines the particle size and distribution of the final nanomaterials, and the particle size and distribution of the product further affect the terminal performance of the product. In the precipitation method, the self-assembly time of the polymer is on the order of 20-60 milliseconds (Physical Review Letters, 2003, 91(11): 118302.), the mixing of the fluid must be fast enough to make the mixing time shorter than the nucleation time, so as to ensure the formation of The nanoparticles are small and uniform in size. For this type of process we need mixers with mixing times on the order of milliseconds.

The micro-mixer has the advantages of small volume, precise control of fluid, good process repeatability, and low consumption of single-preparation samples. However, under the condition of low flow and low Reynolds number (Re<100), the internal fluid of the traditional micro-mixer presents a laminar flow, and the mixing of the fluid is only achieved by diffusion, the mixing effect is poor, and it is impossible to achieve millisecond mixing (mixing time t _m <100ms) . At the same time, the internal channel of the micro-mixer is narrow, and the process involving solids is easy to cause blockage of the channel, which limits the wide application of the micro-mixer.

The introduction of ultrasound into the micromixer can use ultrasonic cavitation to strengthen the mixing of the micromixer at low Reynolds number, and the strong eddy current generated by ultrasonic cavitation or acoustic flow breaks the agglomeration and sedimentation of solid particles to prevent microchannel blockage. However, the ultrasonic microreactors reported so far (AIChE Journal.2017,63(4):1404-1418; CN 104923468 B) are still mixed due to weak internal ultrasonic cavitation and disordered and uncontrollable cavitation bubble field. A second-level mixing process (0.2s<t _m <1s).

Contents of the invention

The object of the present invention is to provide an ultrasonic micro-mixer, aiming at overcoming the above-mentioned problems in the prior art that the millisecond-level mixing cannot be achieved under the condition of low flow rate and low Reynolds number and the channel is easily blocked.

To achieve the above object, the present invention adopts the following technical solutions:

The ultrasonic micro-mixer with millisecond mixing performance of the present invention includes: a micro-mixer, an ultrasonic transducer, an ultrasonic generator, the micro-mixer is connected to the ultrasonic transducer, and the ultrasonic transducer is connected to the ultrasonic generator connected. The wavelength of sound waves in the air corresponding to the working frequency of the ultrasonic transducer is 4-68 times, preferably 14-43 times, the hydraulic diameter of the micro-mixer channel. The relationship between the working frequency f of the ultrasonic transducer, the wavelength λ of the sound wave in the air and the speed of sound c in the air is: c=λf, and the speed of sound c in the air is calculated at 340m/s. By matching the size of the channel with the wavelength of the sound wave, the ultrasound is concentrated in the channel, and the fluid in the microchannel produces severe and highly controllable ultrasonic cavitation. Chemical behavior enhances mixing within an ultrasonic micromixer, enabling millisecond mixing within a channel.

Based on the above technical solution, preferably, the working frequency of the ultrasonic transducer is 15-150 kHz, preferably 19-80 kHz, and the working power is 0.5-1000 W, preferably 3-150 W.

Based on the above technical solution, preferably, the ultrasonic transducer is a Langevin sandwich ultrasonic transducer.

Based on the above technical solution, preferably, the hydraulic diameter of the micro-channel in the micro-mixer is 0.1-5 mm, preferably 0.2-2.5 mm.

Based on the above technical solutions, preferably, the micro-mixer and the ultrasonic transducer are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of welding and gluing.

Based on the above technical solution, preferably, the micro-mixer is engraved with an inlet and outlet channel, and a connecting pipe is inserted into it and sealed, and sealed with a sealant or a threaded joint. The fluid is pumped into the ultrasonic micromixer through the connecting pipe.

Based on the above technical solution, preferably, the material of the micro-mixer is glass, metal or polymer, and the cross-section of the micro-channel in the micro-mixer is rectangular (including square, rectangular), trapezoidal, circular, or elliptical.

Based on the above technical solution, preferably, the ultrasonic generator is connected to the ultrasonic transducer with a signal line, and the electric signal generated in the ultrasonic generator drives the ultrasonic transducer to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator is turned on to stimulate the ultrasonic cavitation in the micro-mixer to achieve ultra-fast mixing in milliseconds.

Based on the above technical solutions, preferably, the mixing time in the ultrasonic micro-mixer is less than 100 ms, preferably less than 40 ms.

Beneficial effect

Compared with the prior art, the present invention has the following remarkable features:

(1) Vigorous and highly controllable ultrasonic cavitation is generated in the microchannel by matching the channel size with the wavelength of the sound wave. The density of cavitation bubbles can reach one cavitation bubble per cubic millimeter, and the cavitation bubbles are evenly distributed in the channel; Violent and highly controllable ultrasonic cavitation produces violent vortex to achieve millisecond-level mixing, and the mixing time is as low as 0.2ms.

(2) Realize continuous preparation of solid-containing system without risk of clogging.

Description of drawings

Fig. 1 is a schematic diagram of an ultrasonic micromixer of the present invention.

Fig. 2 is the violently controllable ultrasonic cavitation behavior in the ultrasonic micromixer of Example 2.

Fig. 3 is the millisecond-level mixing process in the ultrasonic micro-mixer of Example 1.

Fig. 4 is the situation that the mixing time in the ultrasonic micro-mixer of Example 1 changes with the operating conditions.

Fig. 5 is the variation of the inlet and outlet pressure drop during the continuous synthesis of barium sulfate nanoparticles in the ultrasonic micro-mixer of Example 1.

In the figure, 1-micro-mixer, 2-ultrasonic transducer, 3-ultrasonic generator.

Detailed ways

The following non-limiting examples can enable those skilled in the art to understand the present invention more fully, but do not limit the present invention in any way.

Example 1

This embodiment is an ultrasonic micro-mixer in which the working frequency of the ultrasonic transducer 2 is 20 kHz, and the hydraulic diameter of the channel of the micro-mixer 1 is 1 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 is 17 times the hydraulic diameter of the channel of the micro-mixer 1 corresponding to the wavelength of sound waves in the air. The hydraulic diameter of the micro-mixer 1 channel is 1 mm, the channel cross section is circular, and the material is glass. The ultrasonic transducer 2 has a working frequency of 20 kHz and a working power of 5, 10, 20, and 30 W, respectively. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-020, Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 33 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1, and the matching of the channel size and the wavelength of the sound wave causes severe and highly controllable ultrasonic cavitation in the micro-channel, realizing the in-channel Millisecond-level ultra-fast mixing, mixing time 20-100ms.

Figure 3 shows the millisecond-level ultrafast mixing process in the ultrasonic micro-mixer: a flow of Rhodamine B (Aladdin, analytical grade) dyed ethanol solution (Rhodamine B concentration 0.1mg/mL) at a flow rate of 6mL/min Pass into the ultrasonic micro-mixer, and another stream of undyed ethanol is passed into the ultrasonic micro-mixer at 18mL/min. When no ultrasound is applied, the fluid flows laminarly, and the fluid at the outlet is still not completely mixed; when 30W power ultrasound is applied, a large number of cavitation bubbles are generated in the channel, and the cavitation bubbles quickly stir the fluid like a stirrer, and the two fluids meet and complete Mixing is enabled, and the mixing time is 20ms.

Figure 4 shows the mixing time (t _m ) of the ultrasonic micromixer at different total flow rates (Q _t ) and different ultrasonic powers (P). The dyed ethanol solution was mixed with another undyed ethanol solution at a flow ratio of 1:3 , the total flow rate is respectively 4, 8, 16, 24mL/min into the ultrasonic micro-mixer, and ultrasonic power of 5, 10, 20, 30W is applied respectively. The mixing time of the mixer is 20-100 ms under the operating conditions in Fig. 4 .

As shown in Figure 5, the mixer was used to prepare barium sulfate nanoparticles by the continuous precipitation method, and 0.3M barium chloride solution and 0.3M sodium sulfate solution were passed into the mixture at a total flow rate of 24mL/min and a flow ratio of 1:1. In the ultrasonic micro-mixer in this example, 20W power is applied, the mixing time is 25ms, and the pressure does not increase significantly within two hours. The continuous preparation of solid-containing systems can be achieved by using ultrasonic micro-mixers without the risk of clogging.

Example 2

This embodiment is an ultrasonic micro-mixer with an ultrasonic transducer 2 with an operating frequency of 20 kHz and a micro-mixer 1 channel with a hydraulic diameter of 0.5 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 corresponds to the sound wave wavelength in the air being 34 times the hydraulic diameter of the micro-mixer 1 channel. The hydraulic diameter of the micro-mixer 1 channel is 0.5mm, the channel cross section is circular, and the material is glass. The working frequency of the ultrasonic transducer 2 is 20kHz, and the working power is 1, 5, 10, 20, 50, 100, 200, 400 , 500W. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-020, Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer to realize ultra-fast mixing at the millisecond level. Pass two streams of acetonitrile into the ultrasonic micro-mixer in this embodiment with a total flow rate of 2mL/min and a flow ratio of 1:1, and apply ultrasound with a power of 20W, as shown in Figure 2. The matching makes violent and highly controllable ultrasonic cavitation in the microchannel, the distance between the cavitation bubbles is similar, and they are evenly distributed in the microchannel, realizing the millisecond mixing in the channel. When the power is 1W, the mixing time is 96ms; when the power is 5W, the mixing time is 67ms; when the power is 10W, the mixing time is 53ms; when the power is 20W, the mixing time is 38ms; when the power is 50W, The mixing time is 27ms; when the power is 100W, the mixing time is 16ms; when the power is 200W, the mixing time is 8ms; when the power is 400W, the mixing time is 3ms; when the power is 500W, the mixing time is 2ms.

Example 3

This embodiment is an ultrasonic micro-mixer with an ultrasonic transducer 2 with an operating frequency of 20 kHz and a micro-mixer 1 channel with a hydraulic diameter of 0.25 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 is 68 times the hydraulic diameter of the channel of the micro-mixer 1 corresponding to the wavelength of sound waves in the air. The hydraulic diameter of micro-mixer 1 channel is 0.25mm, the channel section is circular, and the material is glass. The working frequency of ultrasonic transducer 2 is 20kHz, and the working power is 1, 5, 10, 20, 50, 100, 200, 400 , 500W. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-020, Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1 to realize ultra-fast mixing at the millisecond level. The two acetonitrile solutions are passed into the ultrasonic micro-mixer in this example with a total flow rate of 0.5mL/min and a flow ratio of 1:1. By matching the channel size with the wavelength of the acoustic wave, a violent and highly controllable ultrasonic wave is generated in the micro channel. Cavitation for millisecond mixing within the channel. When the power is 1W, the mixing time is 60ms; when the power is 5W, the mixing time is 43ms; when the power is 10W, the mixing time is 36ms; when the power is 20W, the mixing time is 22ms; when the power is 50W, The mixing time is 16ms; when the power is 100W, the mixing time is 12ms; when the power is 200W, the mixing time is 8ms; when the power is 400W, the mixing time is 6ms; when the power is 500W, the mixing time is 5ms.

Example 4

This embodiment is an ultrasonic micro-mixer with the working frequency of the ultrasonic transducer 2 being 15 kHz and the hydraulic diameter of the micro-mixer 1 channel being 5 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 is 4.53 times the hydraulic diameter of the channel of the micro-mixer 1 corresponding to the wavelength of sound waves in the air. The hydraulic diameter of the micro-mixer 1 channel is 5mm, the channel cross-section is square, and the material is 316 stainless steel. The ultrasonic transducer 2 has a working frequency of 15kHz and a working power of 50, 100, 200, 400, 500, 1000W. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-015, Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by welding. The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted into it and sealed, and a threaded joint (moisturizing fluid A-1) is used for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer to realize ultra-fast mixing at the millisecond level. Two streams of acetonitrile are fed into the ultrasonic micro-mixer in this example with a total flow rate of 200mL/min and a flow ratio of 1:1. Vigorous and highly controllable ultrasonic cavitation is generated in the micro-channel by matching the channel size with the acoustic wave wavelength. , to achieve millisecond mixing within the channel. When the power is 50W, the mixing time is 22ms; when the power is 100W, the mixing time is 16ms; when the power is 200W, the mixing time is 11ms; when the power is 400W, the mixing time is 7ms; when the power is 500W, The mixing time is 6ms; when the power is 1000W, the mixing time is 5ms.

Example 5

This embodiment is an ultrasonic micro-mixer with the operating frequency of the ultrasonic transducer 2 at 40 kHz and the hydraulic diameter of the micro-mixer 1 channel of 0.5 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 is 17 times the hydraulic diameter of the channel of the micro-mixer 1 corresponding to the wavelength of sound waves in the air. The hydraulic diameter of the micro-mixer 1 channel is 0.5mm, the channel cross section is circular, and the material is glass. The ultrasonic transducer 2 has a working frequency of 40kHz and a working power of 1, 5, 10, 20, 50, 100, 200, 400W. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-040, Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1 to realize ultra-fast mixing at the millisecond level. Two streams of acetonitrile are passed into the ultrasonic micro-mixer in this example with a total flow rate of 2mL/min and a flow ratio of 1:1. Vigorous and highly controllable ultrasonic cavitation is generated in the micro-channel by matching the channel size with the acoustic wave wavelength. , to achieve millisecond mixing within the channel. When the power is 1W, the mixing time is 20ms; when the power is 5W, the mixing time is 14ms; when the power is 10W, the mixing time is 10ms; when the power is 20W, the mixing time is 7ms; when the power is 50W, The mixing time is 4ms; when the power is 100W, the mixing time is 2ms; when the power is 200W, the mixing time is 1ms; when the power is 400W, the mixing time is 0.5ms.

Example 6

This embodiment is an ultrasonic micro-mixer in which the working frequency of the ultrasonic transducer 2 is 40 kHz, and the hydraulic diameter of the channel of the micro-mixer 1 is 2 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 is 4.25 times the hydraulic diameter of the channel of the micro-mixer 1 corresponding to the wavelength of sound waves in the air. The hydraulic diameter of the micro-mixer 1 channel is 2mm, the channel section is a rectangle with a length of 3mm and a width of 1.5mm, and the material is PMMA polymer. , 100, 200, 400W. The ultrasonic transducer is a Langevin sandwich ultrasonic transducer (Baoding Zhengjie Electronics ZFHN-040). The micro-mixer 1 is directly coupled and rigidly connected to the ultrasonic transducer, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer 1, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1 to realize ultra-fast mixing at the millisecond level. The two acetonitrile solutions are passed into the ultrasonic micromixer in this example with a total flow rate of 72mL/min and a flow ratio of 1:1. By matching the channel size with the wavelength of the acoustic wave, a violent and highly controllable ultrasonic space is generated in the microchannel. to achieve millisecond mixing within the channel. When the power is 1W, the mixing time is 60ms; when the power is 5W, the mixing time is 40ms; when the power is 10W, the mixing time is 23ms; when the power is 20W, the mixing time is 17ms; when the power is 50W, The mixing time is 12ms; when the power is 100W, the mixing time is 8ms; when the power is 200W, the mixing time is 4ms; when the power is 400W, the mixing time is 2ms.

Example 7

This embodiment is an ultrasonic micro-mixer with the working frequency of the ultrasonic transducer 2 at 60 kHz and the hydraulic diameter of the channel 1 of the micro-mixer 1.17 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1, an ultrasonic transducer 2, an ultrasonic generator 3, an ultrasonic transducer 2 and an ultrasonic generator 3. The working frequency of the ultrasonic transducer 2 is 4.84 times the hydraulic diameter of the channel of the micro-mixer 1 corresponding to the wavelength of sound waves in the air. The hydraulic diameter of the micro-mixer 1 channel is 1.17mm, and the channel section is an isosceles trapezoid with an upper bottom of 1mm and a lower bottom of 3mm and a height of 1mm. The material is PDMS polymer. The working frequency of the ultrasonic transducer 2 is 60kHz, and the working power is 1. 10, 20, 50, 100, 200, 300W. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-060, Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped through the connecting tubing into the ultrasonic micromixer. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1 to realize ultra-fast mixing at the millisecond level. Two streams of acetonitrile are passed into the ultrasonic micro-mixer in this example with a total flow rate of 8mL/min and a flow ratio of 1:1. Vigorous and highly controllable ultrasonic cavitation is generated in the micro-channel by matching the channel size with the acoustic wave wavelength. , to achieve millisecond mixing within the channel. When the power is 1W, the mixing time is 30ms; when the power is 5W, the mixing time is 25ms; when the power is 10W, the mixing time is 22ms; when the power is 20W, the mixing time is 18ms; when the power is 50W, The mixing time is 11ms; when the power is 100W, the mixing time is 5ms; when the power is 200W, the mixing time is 2ms; when the power is 300W, the mixing time is 1ms.

Example 8

This embodiment is an ultrasonic micro-mixer with an operating frequency of 80 kHz for the ultrasonic transducer 2 and a hydraulic diameter of 0.3 mm for the channel of the micro-mixer 1 . The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 , an ultrasonic generator 3 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 is 14.17 times the hydraulic diameter of the channel of the micro-mixer corresponding to the wavelength of sound waves in the air. The hydraulic diameter of the micro-mixer channel is 0.3mm, the channel cross section is circular, and the material is glass. The working frequency of the ultrasonic transducer 2 is 80kHz, and the working power is 1, 5, 10, 20, 50, 100, 250W respectively. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-080, Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer 1, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1 to realize ultra-fast mixing at the millisecond level. Two streams of acetonitrile are passed into the ultrasonic micro-mixer in this example with a total flow rate of 0.5mL/min and a flow ratio of 1:1. By matching the channel size with the wavelength of the acoustic wave, a violent and highly controllable ultrasonic space is generated in the micro-channel. to achieve millisecond mixing within the channel. When the power is 1W, the mixing time is 40ms; when the power is 5W, the mixing time is 31ms; when the power is 10W, the mixing time is 25ms; when the power is 20W, the mixing time is 18ms; when the power is 50W, The mixing time is 9ms; when the power is 100W, the mixing time is 4ms; when the power is 250W, the mixing time is 0.5ms.

Example 9

This embodiment is an ultrasonic micro-mixer with the working frequency of the ultrasonic transducer 2 being 120 kHz and the hydraulic diameter of the micro-mixer 1 channel being 0.13 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 , an ultrasonic generator 3 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer corresponds to the sound wave wavelength in the air being 21.86 times the hydraulic diameter of the micro-mixer channel. The hydraulic diameter of the micro-mixer 1 channel is 0.13 mm, and the channel cross section is an ellipse with a major axis of 0.1 mm and a minor axis of 0.05 mm. The material is PDMS polymer. The working frequency of the ultrasonic transducer 2 is 120 kHz, and the working power is 5, 10 , 20, 50, 100, 200W. The two acetonitrile solutions are passed into the ultrasonic micromixer in this example with a total flow rate of 0.1mL/min and a flow ratio of 1:1. By matching the size of the channel with the wavelength of the acoustic wave, a violent and highly controllable ultrasonic wave is generated in the microchannel. Cavitation, realize millisecond mixing in the channel, the mixing time is 0.2-20ms. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-120 from Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1 to realize ultra-fast mixing at the millisecond level. The two acetonitrile solutions are passed into the ultrasonic micromixer in this example with a total flow rate of 0.1mL/min and a flow ratio of 1:1. By matching the size of the channel with the wavelength of the acoustic wave, a violent and highly controllable ultrasonic wave is generated in the microchannel. Cavitation, realize millisecond mixing in the channel, the mixing time is 0.2-20ms. When the power is 5W, the mixing time is 20ms; when the power is 10W, the mixing time is 13ms; when the power is 20W, the mixing time is 8ms; when the power is 50W, the mixing time is 3ms; when the power is 100W, The mixing time is 1ms; when the power is 200W, the mixing time is 0.2ms.

Example 10

This embodiment is an ultrasonic micro-mixer with the working frequency of the ultrasonic transducer 2 being 150 kHz and the hydraulic diameter of the micro-mixer 1 channel being 0.15 mm. The ultrasonic micro-mixer is shown in FIG. 1 and consists of a micro-mixer 1 , an ultrasonic transducer 2 , an ultrasonic generator 3 and an ultrasonic generator 3 . The working frequency of the ultrasonic transducer 2 is 15.11 times the hydraulic diameter of the channel of the micro-mixer 1 corresponding to the wavelength of sound waves in the air. The hydraulic diameter of the micro-mixer 1 channel is 0.15 mm, the channel cross-section is square, and the material is glass. The ultrasonic transducer 2 has a working frequency of 150 kHz and a working power of 10, 20, 50, and 100 W. The ultrasonic transducer 2 is a Langevin sandwich ultrasonic transducer 2 (ZFHN-150 from Baoding Zhengjie Electronics). The micro-mixer 1 and the ultrasonic transducer 2 are directly coupled and rigidly connected, and the direct rigid connection of the two is realized by means of glue (Devcon14270). The micro-mixer 1 is engraved with an inlet and outlet channel, and a connecting pipe is inserted therein and sealed with a sealant (Kafka 704 silicon sealant) for sealing. The fluid is pumped into the ultrasonic micromixer through the connecting pipe. The ultrasonic generator 3 is connected with the ultrasonic transducer 2 by a signal line, and the electric signal generated in the ultrasonic generator 3 drives the ultrasonic transducer 2 to work. When the fluid enters the ultrasonic micro-mixer, the ultrasonic generator 3 is turned on to excite the ultrasonic cavitation in the micro-mixer 1 to realize ultra-fast mixing at the millisecond level. The two acetonitrile solutions are passed into the ultrasonic micromixer in this example with a total flow rate of 0.1mL/min and a flow ratio of 1:1. By matching the size of the channel with the wavelength of the acoustic wave, a violent and highly controllable ultrasonic wave is generated in the microchannel. Cavitation, realize millisecond mixing in the channel, the mixing time is 0.2-10ms. When the power is 10W, the mixing time is 10ms; when the power is 20W, the mixing time is 5ms; when the power is 50W, the mixing time is 1ms; when the power is 100W, the mixing time is 0.2ms.

Claims

An ultrasonic micro-mixer with millisecond mixing performance is characterized in that it includes: a micro-mixer, an ultrasonic transducer, and an ultrasonic generator; the sound wave wavelength λ in the air corresponding to the operating frequency f of the ultrasonic transducer is the micro-mixer The hydraulic diameter of the inner microchannel is 4-68 times, and through the matching of the hydraulic diameter of the microchannel and the wavelength of the sound wave, the ultrasound is concentrated in the microchannel to strengthen the mixing in the ultrasonic micromixer.
Ultrasonic micro-mixer according to claim 1, characterized in that the relationship between the ultrasonic transducer operating frequency f, the wavelength λ of sound waves in the air and the speed of sound c in the air is: c=λf.
The ultrasonic micro-mixer according to claim 1, characterized in that, the operating frequency of the ultrasonic transducer is 15-150kHz, and the operating power is 0.5-1000W.
The ultrasonic micro-mixer according to claim 1, characterized in that the hydraulic diameter of the micro-channel in the micro-mixer is 0.1-5 mm.
The ultrasonic micro-mixer according to claim 1, characterized in that, the micro-mixer is engraved with an inlet and outlet channel, and a connecting pipe is inserted into it and sealed; the ultrasonic transducer is a Langevin sandwich ultrasonic transducer energy device.
The ultrasonic micro-mixer according to claim 1, characterized in that the micro-mixer is directly coupled and rigidly connected to the ultrasonic transducer.
The ultrasonic micromixer according to claim 1, wherein the material of the micromixer is glass, metal or polymer; the cross section of the microchannel in the micromixer is rectangular, trapezoidal, circular or elliptical .
The ultrasonic micro-mixer according to claim 1, characterized in that, the mixing time in the ultrasonic micro-mixer is less than 100ms.