DESIGN AND OPTIMIZATION OF THE MULTI-POINT THERMAL GAS MASS FLOWMETER

摘要

A multi-point thermal gas-mass flowrate measurement method is proposed. A meter with four sensing elements is developed. The temperature characteristics of the hot-film probe are analyzed at a specific temperature with self-heated effect and large current through the resistance. The relationship of resistance-characteristics is obtained under several currents. The arrangement of the four sensing elements is studied According to the comparison of the testing results, the optimal disposition method, called Equal ring method, is selected. The polynomial curve fitting method is employed to calibrate the multi-point thermal gasmass flowmeter. The gas flowrate is measured in terms of the output of the sensing elements array through curve fitting.