CN-122016573-A - Nanometer bubble and particle movement cooperative measurement method based on photo-thermal effect

CN122016573ACN 122016573 ACN122016573 ACN 122016573ACN-122016573-A

Abstract

The application discloses a cooperative measurement method of nano bubbles and particle movement based on a photo-thermal effect, relates to the technical field of nano bubble and nano particle track measurement, and aims to solve the problem that the growth condition of the nano bubbles and the particle movement caused by bubble growth are difficult to measure simultaneously in the prior art. And meanwhile, acquiring the movement track of the nano particles controlled by the nano bubbles by a dark field imaging method. The application can simultaneously measure the size of the nanometer bubble, the distribution of the flow field around the bubble and the movement track of the particles. The motion trail of a plurality of particles in the solution can be tracked simultaneously, indirect and non-contact measurement can be realized, and the original sample can not be damaged.

Inventors

JI YUKUN
REN YATAO
QI HONG

Assignees

哈尔滨工业大学

Dates

Publication Date: 20260512
Application Date: 20260212

Claims (10)

1. The cooperative measurement method based on the photothermal effect for the movement of the nanometer bubble and the particle is characterized by being based on a cooperative measurement device, wherein the cooperative measurement device comprises a pulse laser, a photoelectric detector, an objective lens, a high-speed camera and a halogen light source, wherein high-energy pulse laser emitted by the pulse laser irradiates on a nanometer structure at the bottom of a microfluidic chamber after being focused by the objective lens, an aqueous solution is arranged in the microfluidic chamber, the halogen light source is used for providing illumination for the microfluidic chamber, the photoelectric detector is used for acquiring the transmission laser intensity after the pulse laser irradiates the nanometer structure, and the high-speed camera is used for monitoring the track of the nanometer particle; The cooperative measurement method comprises the following specific steps: Step 1, turning on a pulse laser, fully preheating the pulse laser, and adjusting the output power of the pulse laser to enable the nanostructure to heat surrounding water and generate nanometer bubbles under the power; Step 2, turning on a photoelectric detector to obtain the transmission laser power after the pulse laser irradiates the nano structure, turning on a halogen light source and a high-speed camera at the same time, obtaining the track of the nano particles by using the high-speed camera, obtaining the rotation angular velocity of the nano particles, and further realizing the measurement of the particle movement according to the track and the rotation angular velocity of the nano particles; Step 3, subtracting the transmission laser power from the output power of the pulse laser, wherein the obtained result is the laser power absorbed by the nano particles ; Step 4, obtaining the volume of the nano structure and utilizing the laser power Dividing the volume of the nanostructure by the volume of the nanostructure to obtain the volume heat source density of the nanostructure ; Step 5, the volume heat source density of the nano structure Bringing into an energy equation to obtain temperature space distribution And according to the nanostructure and temperature spatial distribution The nano bubble size is obtained by utilizing the lattice Boltzmann method.
2. The method for cooperatively measuring the movement of nano bubbles and particles based on the photo-thermal effect according to claim 1, wherein the specific steps of the step 5 are as follows: step 51 bulk Heat Source Density of nanostructures Carrying out an energy equation, and solving by using a finite difference method to obtain the temperature of the nanostructure And fluid temperature And utilizes the temperature of the nanostructure And fluid temperature Constructing a temperature spatial distribution ; Step 52, obtaining fluid velocity and fluid density according to intermolecular acting force and a distribution function in the lattice Boltzmann method; step 53, judging whether the maximum iteration number is reached, if the maximum iteration number is reached, executing step 54, and if the maximum iteration number is not reached, executing step 55; step 54, obtaining the size of the nano bubble according to the obtained fluid density; Step 55 based on temperature spatial distribution And using the P-R state equation to obtain the fluid pressure, and repeating steps 51 to 53 with the fluid pressure and the fluid velocity as the fluid pressure and the fluid velocity in the energy equation and the distribution function, respectively.
3. A method for the synergistic measurement of nanobubble and particle motion based on the photo-thermal effect as claimed in claim 2, wherein the energy equation is expressed as: ; ; Wherein, the 、、 Respectively the density, the heat conductivity coefficient and the specific heat capacity of the fluid, For time, subscript Is noble metal material, subscript Is in the form of an aqueous solution, In the case of a fluid pressure, Is the fluid velocity.
4. A method of co-measuring nano bubble and particle movement based on photo-thermal effects according to claim 3, wherein the distribution function is expressed as: ; ; Wherein, the As a vector of the position of the object, For the time step size of the time step, Is a matrix of units which is a matrix of units, In the form of a discrete force item, As a source item, a source item is provided, In the form of a diagonal matrix of relaxation parameters, 、、、 Are all a function of the distribution, As a function of the distribution of the equilibrium state, Is a discrete velocity.
5. The method for collaborative measurement of nanobubble and particle motion based on photothermal effects according to claim 4, wherein the source term Expressed as: ; ; ; ; ; ; ; Wherein, the 、、、、、 Is that Is used for the control of the degree of freedom of the composition, Is the speed of sound of the lattice, And As the coefficient of the light-emitting diode, As the coefficient of intermolecular forces of force, As a function of the pseudo-potential, As the force between the molecules of the fluid, 、、 Respectively is Along with 、、 Components of the axis in three directions.
6. The method for collaborative measurement of nano bubble and particle motion based on photothermal effects according to claim 5, wherein the discrete force terms Expressed as: ; Wherein, the 、、 Along the velocity of the fluid 、、 Components of the axis in three directions.
7. The method for cooperative measurement of nano bubble and particle movement based on photo-thermal effect according to claim 6, wherein the intermolecular forces of the fluid Expressed as: ; ; ; Wherein, the As the weight coefficient of the light-emitting diode, Is an intermediate variable.
8. The method for collaborative measurement of nanobubble and particle motion based on photothermal effects according to claim 7, wherein the fluid velocity Expressed as: ; ; Wherein, the Is a distribution function; the fluid pressure Expressed as: ; Wherein, the Is a gas constant which is a general purpose gas constant, And Is constant.
9. The method for cooperatively measuring the movement of the nano bubbles and the particles based on the photo-thermal effect according to claim 8, wherein the specific step of obtaining the rotational angular velocity of the nano particles in the step 2 is as follows: Step 21, obtaining the torque suffered by the particles through a distribution function, and further constructing a rotation equation of the particles, wherein the rotation equation is expressed as follows: ; ; ; Wherein, the For the angular velocity of the nanoparticles, Is the moment of inertia of the nanoparticle, As a result of the torque of the nanoparticles, Is the coordinates of the centroid of the particle, Is the first on the boundary of the nano particle The location of the individual lagrangian nodes, On the nano particle The individual lagrangian nodes are subjected to forces on them by the fluid, Is the unit arc length of the arc-shaped steel wire, For the time step size of the time step, Step 22, discretizing a particle rotation equation to obtain rotation angular velocities of the nano particles at all moments, wherein the rotation angular velocities are expressed as follows: 。
10. The method for collaborative measurement of nano bubble and particle motion based on photothermal effects according to claim 1 wherein the nanostructure is a precious metal material.

Description

Nanometer bubble and particle movement cooperative measurement method based on photo-thermal effect Technical Field The application relates to the technical field of nano bubble and nano particle track measurement, in particular to a cooperative measurement method of nano bubble and particle movement based on a photo-thermal effect. Background The plasma nano bubble is widely applied to the micro-nano particle control field, and compared with other micro-fluidic particle control technologies such as natural convection and thermophoresis, the micro-nano particle control speed can be higher by a few orders of magnitude due to the high-speed flow of the Marangoni convection of the vapor-liquid interface in the nano bubble formation process. In addition, the nano bubble can realize large-scale and multifunctional manipulation of micro-nano particles, such as pulling, nudging, rotating, swinging and the like. The movement state of the particles in the flow field formed by the nano bubbles is changed severely, and the accurate acquisition of the movement track of the particles is the basis for judging the particle manipulation effect. Therefore, it is important to determine the growth state of the nano bubbles and the real-time stress condition of the particles. Since the formation of nano bubbles and the movement of particles occur simultaneously, it is very difficult to simultaneously measure the growth of nano bubbles and the movement of particles caused by the growth of bubbles. Disclosure of Invention The invention aims to provide a cooperative measurement method of nano bubbles and particle movement based on a photo-thermal effect, aiming at the problem that the growth condition of the nano bubbles and the particle movement caused by the bubble growth are difficult to measure simultaneously in the prior art. The technical scheme adopted by the invention for solving the technical problems is as follows: The cooperative measurement method based on the photothermal effect for nanometer bubble and particle movement is based on a cooperative measurement device, and the cooperative measurement device comprises a pulse laser, a photoelectric detector, an objective lens, a high-speed camera and a halogen light source, wherein high-energy pulse laser emitted by the pulse laser irradiates on a nanometer structure at the bottom of a microfluidic chamber after being focused by the objective lens, an aqueous solution is arranged in the microfluidic chamber, the halogen light source is used for providing illumination for the microfluidic chamber, the photoelectric detector is used for acquiring the transmitted laser intensity after the nanometer structure is irradiated by the pulse laser, and the high-speed camera is used for monitoring the track of nanometer particles; The cooperative measurement method comprises the following specific steps: Step 1, turning on a pulse laser, fully preheating the pulse laser, and adjusting the output power of the pulse laser to enable the nanostructure to heat surrounding water and generate nanometer bubbles under the power; Step 2, turning on a photoelectric detector to obtain the transmission laser power after the pulse laser irradiates the nano structure, turning on a halogen light source and a high-speed camera at the same time, obtaining the track of the nano particles by using the high-speed camera, obtaining the rotation angular velocity of the nano particles, and further realizing the measurement of the particle movement according to the track and the rotation angular velocity of the nano particles; Step 3, subtracting the transmission laser power from the output power of the pulse laser, wherein the obtained result is the laser power absorbed by the nano particles ; Step 4, obtaining the volume of the nano structure and utilizing the laser powerDividing the volume of the nanostructure by the volume of the nanostructure to obtain the volume heat source density of the nanostructure; Step 5, the volume heat source density of the nano structureBringing into an energy equation to obtain temperature space distributionAnd according to the nanostructure and temperature spatial distributionThe nano bubble size is obtained by utilizing the lattice Boltzmann method. Further, the specific steps of the step 5 are as follows: step 51 bulk Heat Source Density of nanostructures Carrying out an energy equation, and solving by using a finite difference method to obtain the temperature of the nanostructureAnd fluid temperatureAnd utilizes the temperature of the nanostructureAnd fluid temperatureConstructing a temperature spatial distribution; Step 52, obtaining fluid velocity and fluid density according to intermolecular acting force and a distribution function in the lattice Boltzmann method; step 53, judging whether the maximum iteration number is reached, if the maximum iteration number is reached, executing step 54, and if the maximum iteration number is not reached, executing step 55; step 5