Analysis of measurement reliability of hot-film air flow sensor influenced by air contaminant

In this paper, the analysis of air contaminant´s influence on the measurement reliability of hot-film air flow sensor is presented. Modeling of the particles´ motion states and the temperature distribution of the sensor using ANSYS Workbench´s Fluent module are carried out. The structure details of the flow sensor chip is included in the finite element model for computing. The temperature distribution of the sensor chip with respect to the flow rate of air with the air contaminant ignored is analyzed at first. Then the flow field of the sensor chip with air contaminant in consideration is simulated in order to analyze the motion states of the air contaminant. The particle diameter of the dusts and the air contaminant´s content in the air are the two key parameters involved when analyzing the air contaminant´s influence on the temperature distribution of the sensor chip. By comparing the temperature difference obtained by igoring the air contaminant with temperature difference obtained by considering the air contaminant, the air contaminant´s influence on the output of the sensor chip is studied.