A method for determining the average flow velocity in the height direction of a flat microchannel with variable cross-section at the microscale based on the spatiotemporal gradient distribution of the substance concentration
A space-time gradient and height direction technology, applied in chemical instruments and methods, analytical materials, material excitation analysis, etc., can solve the problems that the average velocity field distribution cannot be applied, and achieve the effect of real-time observation
Active Publication Date: 2022-02-15
DALIAN UNIV OF TECH
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In order to overcome the above defects, the applicant proposed a method to determine the average flow velocity and shear force of uniform flat microchannels based on the dynamic phosphor concentration (see the invention patent ZL201610139388.2 for details), but this method can only detect uniform cross-sectional flat microchannels The longitudinal average velocity cannot be applied to flat microchannels with variable cross-section to obtain the average velocity field distribution on a two-dimensional plane
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[0069] The following examples will further illustrate the present invention, but do not limit the protection scope of the present invention.
[0070] This embodiment illustrates the effectiveness of the method described in the present invention by means of simulation, and the setting of simulation parameters is consistent with the actual situation. A measurement device for measuring the average flow velocity distribution in the height direction of a flat microchannel with variable cross-section at the micro-scale is simulated, such as figure 2 As shown, it includes a programmable pneumatic pump, a sealed liquid storage container, a programmable syringe pump, a syringe, a three-way interface, a catheter, a microchannel with a Christmas tree structure (or a pyramid structure), a microscope, an industrial computer, and a waste liquid pool.
[0071] In this embodiment, the nano phosphor solution is selected as the marker solution. like figure 2 As shown, the syringe 1-1 is fil...
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The invention provides a method for determining the average flow velocity in the height direction of a variable-section flat microchannel at a microscale based on the time-space gradient distribution of a substance concentration, and belongs to the technical field of fluid flow velocity measurement at a microscale. The present invention measures the flow velocity by loading a marker solution with a concentration spatiotemporal gradient distribution into a flat microchannel; the diffusion of the marker solution with a concentration spatiotemporal distribution in the microchannel is affected by the flow field, and its diffusion process satisfies convection-diffusion equation. Based on the Navier-Stokes equation describing fluid motion and the convection-diffusion equation describing material transport, the functional relationship between concentration gradient and velocity can be established, and the velocity field can be inverted through the concentration field through numerical difference and optimization methods. Further constructing a neural network model with physical constraints can speed up the calculation of the flow field during the implementation process and realize real-time observation of the flow field.
Description
technical field [0001] The invention belongs to the technical field of fluid flow velocity measurement at the microscale, and relates to a method for determining the average flow velocity in the height direction of a flat microchannel with variable cross-section at the microscale by using the time-space concentration gradient distribution of substances, which is based on the principles of fluid mechanics and material transmission, and optical imaging technology A method for detecting the average flow velocity in the height direction in a flat microchannel with variable cross-section in a microfluidic chip, based on image processing technology, optimization algorithm and neural network algorithm. Background technique [0002] Microfluidics (microfluidics) technology is one of the multidisciplinary interdisciplinary fields that have developed in recent years. It realizes the precise control of micro- and multi-phase fluids by constructing micro- and nanoscale micro-channel netw...
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IPC IPC(8): G01N21/64B01L3/00
CPCG01N21/6428G01N21/6458B01L3/5027
Inventor 覃开蓉曾效薛春东李泳江刘琨于苗吴斯达杨雨浓那景童
Owner DALIAN UNIV OF TECH