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Thermal fluid dynamics measuring device and method based on digital holographic microscopy technology

A digital holographic microscopy and kinetic measurement technology, applied in measurement devices, phase influence characteristic measurement, scientific instruments, etc., can solve the problems of difficult microfluidic network integration, system mechanical instability, etc. Operation, lower operating costs, reliable effect of working principle

Pending Publication Date: 2021-01-15
CHINA UNIV OF GEOSCIENCES (WUHAN)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In order to quantitatively measure the concentration gradient in the microchannel, it is necessary to introduce phase shifting elements, such as stepping motor, mirror displacement and grating movement, etc., but this is easy to cause mechanical instability of the system, and wavelength calibration is required before measurement, Therefore, they are difficult to integrate with microfluidic networks for lab-on-a-chip applications
In addition, fluid diffusion is time-varying and depends on the concentration difference and local velocity between the two fluids, and traditional time-phase-shifting schemes are insufficient to quickly and accurately resolve transient events

Method used

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  • Thermal fluid dynamics measuring device and method based on digital holographic microscopy technology
  • Thermal fluid dynamics measuring device and method based on digital holographic microscopy technology
  • Thermal fluid dynamics measuring device and method based on digital holographic microscopy technology

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specific Embodiment 1

[0072] In order to prove that the present invention can be used to detect in different Peclet numbers (P e =Lν / D, among the hydrodynamic parameters, this quantifies the ratio between advection and diffusion, where L is the characteristic length, ν is the local flow velocity, and D is the diffusion coefficient) under the concentration gradient generated under the same flow rate from The two inlets of the double-way syringe pump inject 1mol / L calcium chloride solution and deionized water into the T-joint (please refer to figure 1 ). By varying the flow rates of the two fluids and maintaining the flow rate ratio, four different Peclet numbers are obtained. Four sets of holograms under different flow rates are processed by the five-step phase shift method to obtain the wrapped phase diagram and the corresponding two-dimensional refractive index distribution. Please refer to Figure 4 (b). Please refer to the refractive index and corresponding concentration distribution at diffe...

specific Embodiment 2

[0074] We also investigated the diffusion in microchannels with different driving gradients. The calcium chloride solution and deionized water at the same flow rate were fixed at 50 μm / L and pumped into the H-shaped chamber. Select 4 groups of calcium chloride solutions with different concentrations (0.6mol / L, 1mol / L, 1.4mol / L and 1.8mol / L) to drive the diffusion, and use the same method to obtain the corresponding package phase diagram and two-dimensional refractive index distribution Please refer to Figure 5 (b). Figure 5 The diffusion curves shown in (a) quantitatively reflect the diffusion produced at different driving concentrations. The experimental results show that when the fluid flow rate is constant, the greater the concentration difference of the mixed fluid, the greater the concentration gradient.

[0075] The detection results of the above experiments are very consistent with the concentration distribution results obtained by researchers such as Nam-TrungNguy...

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Abstract

The invention provides a thermal fluid dynamics measuring device and method based on a digital holographic microscopy technology. The device comprises an interference device, an imaging system, a fluid control system, a phase shifter and a chip to be measured. The method comprises the following steps: collecting six holograms by using an area array CCD; analyzing a discontinuous wrapping phase diagram of the concentration gradient field of the chip to be detected according to a five-step phase shift method; obtaining a continuous phase distribution diagram of the concentration gradient field by using a phase unwrapping algorithm; reconstructing refractive index distribution of the diffusion region according to the obtained continuous phase distribution diagram; and carrying out quantitative measurement on the concentration gradient field of the diffusion region under different conditions, and carrying out accurate measurement on thermal fluid dynamics such as diffusion coefficient andPickering number of the diffusion region. According to the invention, the integration of the microfluidic phase shift element is achieved, the manufacturing process is simple, the working principle isreliable, the phase shift operation is simplified, the operation cost is reduced, and meanwhile, the measurement system has the advantages of no mark, integration, stability, capability of completingtransient measurement and the like.

Description

technical field [0001] The invention relates to the field of fluid dynamics measurement, in particular to a thermal fluid dynamics measurement device and method based on digital holographic microscopy technology. Background technique [0002] In fluid dynamics measurement, various kinetic parameters are often studied and calculated by measuring the concentration gradient of the fluid. [0003] Fluorescent labeling, as a traditional method for analyzing concentration gradients in microfluidics, has high sensitivity, specificity, and compatibility with high-throughput microfluidic systems, but chemical labels will inevitably interfere with the determination, and long-term Under monitoring, photobleaching effects may limit measurement accuracy; for quantitative analysis, the measured fluorescence signal is not uniformly biased. [0004] Other label-free detection methods, such as methods based on surface-enhanced Raman scattering, Raman spectroscopy, and nuclear magnetic reson...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/41G03H1/00G03H1/04G03H1/12
CPCG01N21/41G01N2021/416G01N2021/4186G03H1/0005G03H1/0443G03H1/12G03H2001/0033
Inventor 宋潮龙杨金武骆迎东涂鑫段修栋黎亚妮
Owner CHINA UNIV OF GEOSCIENCES (WUHAN)