Effect of a protective shape upstream a sensor on reducing dust particle contamination of critical sensor surface

Abstract

This study compares the effect of various contamination prevention structure shapes on preventing dust particle deposition on critical sensor surfaces. Sensor surfaces exposed to parallel and vertical airflows were considered as reference cases. A multi-layer plate structure was devised to reduce dust particle deposition on critical sensor surfaces. 1-, 2-, and 3-plate shapes were considered for the multi-layer plate structures. In the results of flow and particle trajectory simulation using ANSYS FLUENT, the 3-plate shape showed superior effects on dust particle deposition prevention. Experiments were conducted to qualitatively validate these simulation results. The two reference types and the multi-layer plate structure types of 1-, 2-, and 3-plates were positioned inside the duct of regular-pentagonal cross-section. After installing a Transmission Electron Microscope (TEM) grid on the critical sensor surface of each shape, an experiment of exposing the sensors to Arizona Test Dust (ISO 12103-1, A4 type) aerosol was performed. Afterwards, the number of sampled dust particles were compared between the respective TEM grids by using a Scanning Electron Microscope (SEM) in order to qualitatively relate the effects of dust particle deposition prevention structures. The numerical approach, validated with experimental results, showed that sensor protection in an environment with dust particle flow can be improved with the use of the 2- or 3-plate structure.