Mass flowmeter using a multi-sensor chip

We report here a novel mass flowmeter using a multisensor chip that includes a 1-D array of pressure, temperature and shear stress sensors. This shear stress sensor based flowmeter is capable of high sensitivity and wide measurement range. Our study also shows that the mass flowmeter using shear-stress sensors produces better resolution than that from pressure sensors in the laminar flow regime. Extensive tests have been carried out to evaluate the effects of overheat ratio, channel height and gas properties. We also find the V²∝τ^1/3 law for conventional hot film sensors does not hold for our micromachined shear stress sensor