Design and Characterization of a Microfluidic Circuit for Air Particulate Matter Separation

Abstract

Air microfluidic circuits have been widely concerned in the separation of atmospheric particulate matter, especially for portable particulate matter separation detection devices. Currently, no systematic approach for the design and optimization of an air-microfluidic system for PM separation has been reported in the literature. In this paper, a two-stage air microfluidic circuit is designed. The design process is divided into two stages: first, the preliminary design of the structure is completed according to aerodynamic theory. Then, the influences of various factors (such as flow channel width, tilt angle, flow rate, etc.) on the collection efficiency and particle wall loss are explored through numerical analysis to complete the optimization design of the structure. Finally, the air microfluidic circuit is prepared by MEMS processing technology and the particulate matter separation experiments are carried out. The developed two-stage air microfluidic circuit can realize the efficient separation of PM10 and PM2.5. Thus, the important factors affecting the collection efficiency and particle wall loss of air microfluidic circuit are clarified, and a systematic design theory method is formed.

System Integration of an Optimally Designed Virtual Impactor with a QCM Sensor as a One-Stop PM2.5 Classification and Detection Platform

“…To achieve PM 2.5 mass detection, it is critical to separate them from ambient air. There are several methods to develop for PM 2.5 classification, including thermal precipitation, gravitational sedimentation, centrifugation, and inertial separation. , The virtual impactor (VI), which is one kind of inertial separator, has been widely used for PM 2.5 sampling due to its compact size and good collection efficiency. − The principle of using a VI to separate particles is that when the airflow passes through the flow channel, the carried particles with a smaller aerodynamic diameter are more likely to flow along the streamline, which makes it possible to separate them according to their sizes. One key performance indicator of VI is the cutoff diameter, defined as the particle aerodynamic diameter that has a collection efficiency of 50% in major flow channels.…”

Designing a Microfluidic Chip Driven by Carbon Dioxide for Separation and Detection of Particulate Matter

“…Ning Xue et al designed a two-stage PM air-microfluidic graded chip with cutoff diameters of 10 µm and 2.5 µm based on COMSOL numerical simulations, and numerically analyzed the virtual impactor parameters [ 21 ]. In 2022, Jianhai Sun et al designed a two-stage air microfluidic circuit and explored the effects of various factors on collection efficiency and wall loss through numerical simulations, optimizing the design of the microfluidic circuit structure [ 22 ]. Most studies on virtual impactors affect the cutoff diameter and wall loss of virtual impactors by changing the size of the virtual impactor or the inlet flow rate; however, few studies have investigated the effect of fluid dynamic viscosity on the cutoff diameter.…”

Air microfluidic chip design for atmospheric particulate matter detection

“…Inertial impingers include conventional impingers, cascade impingers and virtual impingers, among which virtual impingers are widely used due to low particle loss. Virtual impactor is a device to achieve particle separation according to particle size, and is widely used in the field of particle measurement [3]. The main methods of particle mass concentration measurement are β-ray method, TEOM method and light scattering method.…”