Experimental and simulation studies of the effect of restrictor and distributor on the performance of thermal mass flow meter

In this paper, a thermal mass flow meter has been fabricated in the operating range of 0-500 sccm and the main affecting parameters on its performance have been investigated. In addition, a computer simulation is performed to obtain the proper operation conditions and to compare the experimental data with simulation results. The performance of the device was evaluated by using a commercial flow controller and N2 and CO2 gases. Results showed that the output signal for the device was linear in the range of 0-100 sccm (R2 = 0.96). The effect of flow restrictor and number of its orifices was studied to determine the appropriate working range of the flow meter. Using of restrictor for measuring the mass flow in the range of 0-500 sccm has shown a good accordance with signal output (R2 = 0.99). Overall accuracy of the device was found to be ±4% of full scale. The effect of distributor in the input of the device and the input pressure was also investigated and discussed. In addition, CO2 was used as alternative gas to compare its results with N2 as the base gas. Finally the simulation studies demonstrated a good accordance with the experimental data.