Method and experimental device for measuring flow field of human upper respiratory tract based on particle image velocimetry (PIV) technology

Abstract

The invention discloses a method and an experimental device for measuring the flow field of a human upper respiratory tract based on a particle image velocimetry (PIV) technology. According to the invention, a true human upper respiratory tract model is taken as a research object, and the pumping effect of a vacuum pump is utilized to ensure that gas forms a channel in the model so as to simulate the respiratory process of a human lung. The method comprises the following steps of: scattering trace particles in the flow field, irradiating the flow field of the human upper respiratory tract model by using a sheet light source generated by a laser, aligning an area to be measured in a direction vertical to the sheet light source by using a cross-frame charge coupled device (CCD) camera, recording images of the particles during double pulse laser exposure according to the scattering effect of the trace particles on light, transmitting the images into a computer, computing and analyzing, solving the velocity of a fluid in the flow field of the human upper respiratory tract model by an autocorrelation or cross-correlation algorithm, and thus obtaining the characteristics of a vortex structure of the airflow of the flow field of the human upper respiratory tract during inspiration, an evolution form of the vortex structure, and the change and a distribution form of shear stress at the same time.

Description

technical field [0001] The invention relates to technical fields such as biomedical engineering, sanitation protection and epidemic prevention technology and equipment, man-machine-environment system engineering and fluid mechanics, and in particular relates to a measurement method and an experimental device suitable for measuring the air flow field of the human upper respiratory tract . Background technique [0002] As a basic means of studying various complex flow fields, PIV technology has been widely used in various flow measurement and display. Many scholars at home and abroad have applied this measurement technology to the research in the field of ventilation. From steady to unsteady, low-speed to high-speed, single-phase to multi-phase, record the relevant information of the entire measurement plane at the same time, so as to obtain the instantaneous velocity field, fluctuating velocity field, vorticity field and Reynolds stress distribution of the flow, etc., which i...

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Problems solved by technology

However, there are still limitations in current research: First, there are many computer simulation studies and few experimental studies; second, most experimental studies are limited to a single model of the mouth and throat, nasal cavity or bronchus, and there is a lack of research including the oral cavity to the first three bronchi. The third is that most of the models used are simplified models, which are mainly reflected in the following five aspects: 1) they all assume rigid walls and do not consider the influence of wall elasticity; 2) the real Respiratory flow is a typical process affected by fluid-structure interaction, but there are few studies on this fluid-solid coupling problem, and there is a lack of in-depth understanding of the fluid-solid coupling phenomenon; 3) The shape of the glottis changes with the respiratory flow, and the The airflow movement in the upper airway has an important influence, but the influence of the shape of the glottis on the downstream airflow structure has not been fully understood; 4) the airflow movement analysis in the existing studies assumes that the airway wall is smooth, Cartilage structure is rarely considered; 5) The asymmetry of the human lung is an important feature of the lung model. At present, there are still few studies on the influence of this asymmetry, and no consensus has been reached on its influence on airflow movement; The outside is limited to the study of the overall airflow organization form

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