Analysis of measurement accuracy of air flow sensor influenced by moisture

The paper presents an analysis of moisture on the output of hot film air flow sensor. The model used for analyzing the influence of moisture on the sensor is set up with the whole sensor structure into consideration. CFD and gas-solid coupled heat transfer model is used for simulation. The thermal physical property of air with moisture is discussed in the paper. The temperature distribution of hot film air flow sensor with respect to the air flow rate and relative humidity of air is computed for analysis. By comparing the results with the dry air situation, the conclusion is made. The moisture in the air will lower the temperature of the upstream and downstream resistance and increases the temperature difference between the two resistances and the power consumption of the sensor.