Simulation about contamination influence of calorimetrie flow sensor on measurement accuracy

摘要

To research the contamination influence of calorimetric air flow sensor on measurement accuracy, an analytical expression of temperature difference between two temperature sensing resistors is derived. The reason of the output variation of calorimetric sensor is analyzed. The finite element model of contamination is built based on the deposited contamination distribution and its thickness. The influences of contamination thickness on temperature difference are analyzed on the condition of different velocities. As a result, the temperature difference between the upstream and downstream temperature sensing resistors decreases with the increase of contamination thickness. The relationship of output value, flow rate, and the contamination thickness is calculated by the analytical model. The results show it can cause a 68.15% error of measurement when the input flow velocity is 8m/s and the contamination thickness is 50μm.