CN212417991U - Double-flow type monodisperse droplet flow generating device - Google Patents
Double-flow type monodisperse droplet flow generating device Download PDFInfo
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- CN212417991U CN212417991U CN202020862767.6U CN202020862767U CN212417991U CN 212417991 U CN212417991 U CN 212417991U CN 202020862767 U CN202020862767 U CN 202020862767U CN 212417991 U CN212417991 U CN 212417991U
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Abstract
The utility model discloses a double-flow type monodispersed droplet stream generating device, which comprises a droplet stream generator, an injector, an injection pump, a piezoelectric driver and a liquid storage bottle; the injection pump pushes the injector to continuously inject the liquid in the liquid storage bottle into the liquid drop flow generator, and the liquid is sprayed into the air from the two micropores of the liquid drop flow generator to form two jet flows; the droplet stream generator comprises a piezoelectric ceramic piece, a piezoelectric driver is connected with the piezoelectric ceramic piece, an electric driver sends voltage disturbance waves to the piezoelectric ceramic piece in the droplet stream generator, the droplet stream generator is driven to generate vibration with certain frequency, disturbance waves are formed on two streams of jet flows, and the droplet stream generator is made to break into two streams of monodisperse droplets. The utility model provides a double-flow monodisperse droplet stream generator can solve the fluidic control problem of multi-beam liquid drop, realizes that the liquid drop stream of different liquid drop particle diameters, liquid drop interval, stream interval takes place.
Description
Technical Field
The utility model relates to a liquid drop preparation field, concretely relates to double-flow formula monodispersion liquid drips flows generating device.
Background
In the fields of ink-jet printing, circuit board packaging, pesticide spraying, combustion chamber fuel oil spray combustion, spray cooling and the like, the generation of micron-sized liquid drops has very high application value. The observation of the flow behavior of single liquid drops and monodisperse liquid drops has important significance in the fields of spray collision, crushing, evaporation and combustion. Thus, there is a significant need in the industry and scientific research area to produce micron-sized droplets with controllable initial parameters.
The micron-sized liquid drop injection is mainly divided into five major categories, namely a piezoelectric type, a thermal bubble type, a valve control type, an electrostatic type and a micro-injection type. Among them, piezoelectric and thermal bubble are the most widely used and developed injection technologies at present. The piezoelectric jetting technology mainly utilizes inverse piezoelectric effect, and controllable disturbance wave signals apply voltage signals on a piezoelectric device through a driving device, so that the piezoelectric device deforms, and liquid drops are extruded to be jetted out of micropores. The piezoelectric type spraying technology has the advantages of strong control capability on liquid and high spraying precision; the reaction speed is high, and the spraying range is wide; the range of viscosities for the jettable droplets is large.
As for the droplet stream generating apparatus, chinese patent publication No. CN 1404993 discloses a minute droplet stream generator for a head of an inkjet printer. Chinese patent publication No. CN 108927234a discloses a droplet generation system based on piezoelectric vibration mechanism, in which a computer controls a driving power supply to send a piezoelectric signal, the volume of a chamber of a droplet generator changes by the deformation of a piezoelectric ceramic plate, and droplets are extruded through a flow channel and a nozzle to generate stable droplets capable of accurately controlling droplet parameters within a certain range. Chinese patent publication No. CN 107051805a discloses a multi-excitation vibration droplet flow generator device, which generates jet disturbance sources in different directions by independently controlling a plurality of vibration plates, and is used for studying jet characteristics of jet forms in different directions and different characteristic parameters.
From a search of the prior art documents, it has not been possible to produce two streams of monodispersed droplets of different morphological parameters simultaneously. In actual research and application, the interaction of droplets with different forms, such as the interaction of droplet arrays with different forms in droplet evaporation, is the most common situation. Therefore, there is a need to develop and develop a dual-flow type monodispersed droplet flow generating method and apparatus.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide a double-flow formula monodispersion droplet stream generating device solves the fluidic control problem of multi-beam liquid drop, realizes that the liquid drop stream of different liquid drop particle diameters, liquid drop interval, stream interval takes place.
The utility model provides a following technical scheme:
a dual stream monodisperse droplet stream generator device comprising a droplet stream generator, a syringe pump, a piezoelectric driver and a reservoir; the injection pump pushes the injector to continuously inject the liquid in the liquid storage bottle into the liquid drop flow generator, and the liquid is sprayed into the air from the two micropores of the liquid drop flow generator to form two jet flows;
the droplet stream generator comprises a piezoelectric ceramic piece, the piezoelectric driver is connected with the piezoelectric ceramic piece, the piezoelectric driver sends voltage disturbance waves to the piezoelectric ceramic piece in the droplet stream generator, the droplet stream generator is driven to generate vibration with certain frequency, disturbance waves are formed on two streams of jet flows, and the two streams of jet flows are broken into two streams of monodisperse droplets.
The droplet flow generator comprises an external thread adapter, an internal thread compression ring, an annular end cover, a T-shaped cylinder, a piezoelectric ceramic piece, a support cavity, a spraying cavity and a spraying cavity fixing cap; the T-shaped cylinder is arranged in the annular end cover, forms larger friction force with the supporting cavity, and fixes the piezoelectric ceramic piece on the shoulder part of the supporting cavity; one end of the external thread adapter is connected with the support cavity through threads, and the other end of the external thread adapter is connected with the internal thread compression ring to play roles in fixing and sealing; the spraying cavity is fixed on the supporting cavity through a spraying cavity fixing cap; the outlet part of the spray cavity is provided with a double-hole metal sheet spray nozzle.
The outlet part of the spray cavity is also provided with a sealing ring and a gasket which are respectively positioned at the upper end and the lower end of the double-hole metal sheet nozzle. Plays the role of sealing and preventing the metal microporous sheet from deforming.
First micro-holeDiameter d of1And diameter d of the second micro-hole2The ratio of the components is as follows: 1 < d1/d2Is less than 2.4. By setting the above diameter ratio, it is possible to ensure that two jets can be broken into a monodispersed droplet stream at the same time.
Specifically, the thickness T of the dual orifice sheet metal nozzle ranges from about 0.1 to 1 millimeter, with the micro-orifice size ranging from about 10 microns to 500 microns.
The distance between the first micropore and the second micropore is more than 3d1. Through setting up above-mentioned interval, can prevent influence each other between two bundles of efflux.
The wavelength range of the voltage disturbance wave is as follows: pi d1<λ<7.5d2。
The method for generating the double-flow monodisperse droplet flow by the device comprises the following steps:
(1) the injection pump pushes the injector to continuously inject the liquid in the liquid storage bottle into the liquid drop flow generator, and the liquid is sprayed into the air from the two micropores of the liquid drop flow generator to form two jet flows;
(2) the electric driver sends voltage disturbance waves to the piezoelectric ceramic chip in the droplet flow generator to drive the droplet flow generator to generate vibration with certain frequency, and the disturbance waves are formed on the two jet flows to break the two jet flows into two monodisperse droplet flows.
In the step (1), the two pores of the droplet stream generator include a first pore and a second pore, and the diameter d of the first pore1And diameter d of the second micro-hole2The ratio of the components is as follows: 1 < d1/d2Is less than 2.4. By setting the above diameter ratio, it is possible to ensure that two jets can be broken into a monodispersed droplet stream at the same time.
In the step (1), the distance between the first micropore and the second micropore is more than 3d1. Through setting up above-mentioned interval, can prevent influence each other between two bundles of efflux.
The wavelength range of the voltage disturbance wave in the step (2) is as follows: pi d1<λ<7.5d2。
In step (2), the method for determining the voltage disturbance wave is as follows:
according to the principle of Rayleigh instability of the fluid surface, when the wavelength λ of the disturbance wave applied to the liquid column of the jet satisfies equation (1), the liquid column will disintegrate into a uniform stream of droplets.
πd<λ<7.5d (1)
Where d is the diameter of the jet liquid column, which can be approximated as the diameter of the micropores. The wavelength lambda of the disturbance wave is determined by the frequency f of the sinusoidal voltage of the piezoelectric actuatordisAnd velocity u of droplet movementdIt is decided that,
λ＝ud/fdis (2)
for a nozzle with two tiny orifices, in order to achieve the break-up of two jets into a stream of monodispersed droplets simultaneously, the wavelength of the disturbance wave needs to be such that:
πd1<λ<7.5d2 (3)
wherein d is1，d2The diameters of the first (larger) and second (smaller) micropores, respectively.
Further, the size and flow rate of the uniform droplets formed after jet disintegration are mainly determined by the jet flow rate of the injection pump and the frequency of the disturbance waves emitted by the piezoelectric driver. Diameter D of the dropletiCan be obtained from equation (4):
wherein the subscript "i" represents the numbers "1", "2" of the two microwells; qiFor flow through the double holes, by
Calculated, Q is the flow rate injected into the droplet flow generator, set by the syringe pump.
Velocity u of the dropletd,iObtained from equation (5):
the utility model provides an produced two bundles of droplet streams monodispersion of double-flow formula monodispersion droplet stream generating device is greater than 98%, and the droplet size is in about 20 microns to 1000 microns within range, and the droplet speed is in about 2m/s to 20m/s within range.
Further, the dual-flow monodisperse droplet stream generator of the present invention can eject a fluid of lower viscosity as a stream of droplets, such as hydrocarbons, of about 0.3 cP. In particular, the fluid may have a viscosity in the range of about 0.3 to 50 cP.
The generation of the liquid drop flow with different liquid drop particle diameters, liquid drop distances and flow beam distances can be realized by controlling the aperture and the distance of micropores of the double-hole metal sheet nozzle, and controlling parameters such as the injection flow of the injection pump, the disturbance wave frequency of the piezoelectric driver and the like; thereby make the utility model provides a device can produce multiple mode, improves the device's utilization efficiency. The utility model provides a double-flow formula monodispersion droplet stream generating device, the device easy operation, but the accurate control liquid drop frequency range, operation are stable, and manufacturing, the replacement of diplopore sheetmetal nozzle are convenient, have filled the blank in the aspect of domestic and external double-droplet stream takes place.
Drawings
FIG. 1 is a schematic structural diagram of a two-stream type monodispersed droplet stream generating apparatus in an example;
FIG. 2 is a schematic diagram of an embodiment of a droplet stream generator;
FIG. 3 is a schematic view of a dual orifice sheet metal nozzle in an embodiment, wherein DpIs the diameter of the metal microporous sheet, T is the thickness of the metal sheet, d1，d2Is the diameter of the two holes, and L is the distance between the two holes;
fig. 4 is a schematic view of an exemplary droplet flow provided by the present invention;
the device comprises a liquid drop generator 1, a liquid drop generator 2, a syringe 3, a syringe pump 4, a liquid storage bottle 5 and a piezoelectric driver, wherein the liquid drop generator is connected with the liquid storage bottle; 101. the device comprises an external thread adapter 102, an internal thread pressure ring 103, an annular end cover 104, a T-shaped cylinder 105, a piezoelectric ceramic piece 106, a support cavity 107, a spray cavity fixing cap 108, a spray cavity 109, a sealing ring 110, a double-hole metal piece nozzle 111 and a gasket.
Detailed Description
The following describes the embodiments of the present invention with reference to the accompanying drawings.
As shown in fig. 1, the present embodiment provides a dual-flow type monodispersed droplet flow generating apparatus, including: the device comprises a droplet flow generator 1, a syringe 2, a syringe pump 3, a liquid storage bottle 4 and a piezoelectric driver 5.
As shown in fig. 2, the droplet stream generator 1 includes: the device comprises an external thread adapter 101, an internal thread pressure ring 102, an annular end cover 103, a T-shaped cylinder 104, a piezoelectric ceramic piece 105, a support cavity 106, a spraying cavity 108 and a spraying cavity fixing cap 107; the T-shaped cylinder 104 is arranged inside the annular end cover 103, and the piezoelectric ceramic plate 105 is fixed on the shoulder of the support cavity 106; one end of the external thread adapter 101 is connected with the supporting cavity 106 through threads, and the other end of the external thread adapter is connected with the internal thread pressure ring 102; the spray cavity 108 is fixed on the support cavity 106 through a spray cavity fixing cap 107; a double-hole metal sheet nozzle 110 is arranged at the outlet part of the spraying cavity 108, and a first micropore and a second micropore with different diameters are arranged on the double-hole metal sheet nozzle 110; the outlet of the spray chamber 108 is further provided with a seal ring 109 and a gasket 111, which are respectively located at the upper and lower ends of the double-hole sheet metal nozzle 110. The structure of the double-orifice sheet metal nozzle 110 is shown in fig. 3.
A method of simultaneously generating two streams of monodisperse droplets using the above apparatus comprises the steps of:
step 1: screwing the spray chamber fixing cap 107 of the droplet generator 1, removing the spray chamber 108, installing the spray chamber 108 at the outlet part of the spray chamber 8 in the order of the gasket 111, the double-hole sheet metal nozzle 110 and the sealing ring 109, and then fixing the spray chamber 108 on the support chamber 106 by using the spray chamber fixing cap 107;
step 2: mounting the injector 2 on the injection pump 3;
and step 3: the liquid storage bottle 4, the injection pump 3 and the liquid drop generator 1 are connected by a pipeline, and a valve is arranged on the pipeline;
and 4, step 4: the positive and negative electrodes of the piezoelectric ceramic sheet 105 are connected with the piezoelectric driver 5 by leads;
and 5: the valves on the pipelines of the injection pump 3 and the droplet generator 1 are closed, and the valves on the pipelines of the liquid storage bottle 4 and the injection pump 3 are opened. The power of the syringe pump 3 is turned on and the syringe pump 3 is set to a pumping mode to pump liquid from the liquid storage bottle 4 until the tube is full.
Step 6: the valves on the pipelines of the injection pump 3 and the droplet generator 1 are opened, and the valves on the pipelines of the liquid storage bottle 4 and the injection pump 3 are closed. The injection flow of the injection pump 3 is set to inject liquid into the droplet generator 1.
And 7: the jet emerging from the nozzle of the drop generator 1 is observed and the frequency of the disturbance wave of the piezoelectric actuator 5 is adjusted according to a theoretical formula so that it produces a uniform, equally spaced stream of drops.
A typical two-beam monodisperse droplet stream shadow result is shown in fig. 4, where the bright spots in the droplet shadow map are the transmitted light of a normally incident droplet. Under the condition of constant micropore size and injection flow, the size and the spacing of the liquid drops are mainly determined by the frequency of disturbance waves sent by the piezoelectric actuator.
The above is a detailed description of the double-flow monodispersed droplet stream generating device provided by the present invention, and the description of the embodiments is only used to help understand the device of the present invention, and should not be understood as a limitation of the present invention.
Claims (6)
1. A dual-flow monodispersed droplet stream generating device comprising a droplet stream generator, a syringe pump, a piezoelectric actuator and a reservoir;
the injection pump pushes the injector to continuously inject the liquid in the liquid storage bottle into the liquid drop flow generator, and the liquid is sprayed into the air from the two micropores of the liquid drop flow generator to form two jet flows;
the droplet stream generator comprises a piezoelectric ceramic piece, the piezoelectric driver is connected with the piezoelectric ceramic piece, the piezoelectric driver sends voltage disturbance waves to the piezoelectric ceramic piece in the droplet stream generator, the droplet stream generator is driven to generate vibration with certain frequency, disturbance waves are formed on two streams of jet flows, and the two streams of jet flows are broken into two streams of monodisperse droplets.
2. The dual-flow monodispersed droplet stream generator of claim 1, wherein the droplet stream generator comprises an external screw adapter, an internal screw compression ring, an annular end cap, a "T" cylinder, a piezoelectric ceramic plate, a support cavity, a spray cavity, and a spray cavity fixing cap;
the T-shaped cylinder is arranged in the annular end cover, and the piezoelectric ceramic plate is fixed on the shoulder of the support cavity;
one end of the external thread adapter is connected with the support cavity through threads, and the other end of the external thread adapter is connected with the internal thread compression ring;
the spraying cavity is fixed on the supporting cavity through a spraying cavity fixing cap;
the outlet part of the spray cavity is provided with a double-hole metal sheet nozzle, and the double-hole metal sheet nozzle is provided with a first micropore and a second micropore with different diameters.
3. The dual-flow monodispersed droplet stream generator according to claim 2, wherein the outlet portion of the spray chamber is further provided with a gasket and a sealing ring, respectively at the upper and lower ends of the dual-orifice sheet metal nozzle.
4. 2-the device for generating a flow of monodispersed droplets of double flow according to claim 1, characterized in that in step (1) the diameter d of the first micropores1And diameter d of the second micro-hole2The ratio of the components is as follows: 1 < d1/d2＜2.4。
5. The dual-flow monodispersed droplet stream generator according to claim 4, wherein in step (1), the first and second micropores are spaced apart by a distance > 3d1。
6. The dual-flow monodispersed droplet stream generator according to claim 4, characterized in that the thickness T of the dual-orifice sheet metal nozzle is between 0.1 and 1 mm and the diameter d of the first micropores1And diameter d of the second micro-hole2From 10 microns to 500 microns.
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| CN202020862767.6U CN212417991U (en) | 2020-05-21 | 2020-05-21 | Double-flow type monodisperse droplet flow generating device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111437897A (en) * | 2020-05-21 | 2020-07-24 | 浙江大学 | Double-flow type monodisperse droplet flow generation method and device |
| CN114749222A (en) * | 2022-03-30 | 2022-07-15 | 北京航空航天大学 | Integrated piezoelectric multi-column uniform liquid drop generator |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111437897A (en) * | 2020-05-21 | 2020-07-24 | 浙江大学 | Double-flow type monodisperse droplet flow generation method and device |
| CN111437897B (en) * | 2020-05-21 | 2023-10-20 | 浙江大学 | Double-flow type monodisperse droplet stream generation method and device |
| CN114749222A (en) * | 2022-03-30 | 2022-07-15 | 北京航空航天大学 | Integrated piezoelectric multi-column uniform liquid drop generator |
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