Simulation and experimental study on a non-contact constant power thermal gas flowmeter

Abstract In the chemical, petroleum, metallurgical and other industries, accurate measurement of gas flow helps optimize production processes. In this paper, a non-contact constant power thermal flowmeter is applied to realize the gas flow measurement. A fluid-structure coupled heat transfer model is built to investigate the fluid flow and heat transfer process, and the influences of the sensor installation position, the heating power and the fluid temperature on the measurement are analyzed. An experimental platform with gas flow calibration was carried out to verify the effectiveness of the simulation model and the measurement system. Both simulation and experimental results show that: the relationship between mass flow G and temperature difference <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mi>T</mml:mi> </mml:mrow> </mml:math> is inversely proportional, which is consistent with the theoretical analysis. Choosing the proper sensor mounting position is crucial to the measurement performance, this part can be accomplished with the help of dynamic simulation models. As the heating power escalates, the sensitivity concomitantly rises; nevertheless, the measurement error also exhibits an upward trend. So, the heating power should be selected according to the actual working condition. Based on the above analysis and system design, the average relative error of the measuring system at the selected installation position is less than 3%, and the maximum relative error is 4.9%.