Multi-parameter detection in fluid flows

A micromechanically fabricated thermal flow sensor working on the principle of a travelling heat pulse through the fluid is presented. Theoretical analysis of the sensor response shows that the sensor response indicate that the sensor is capable of discriminating flow velocities from fluid properties when certain combinations of sensing element signals are used. In addition, the sensor is also capable of measuring mass flow as long as the 'time of flight' of a heat pulse is measured at equal distances from the heater upstream and downstream. Finally, the ability of an artificial neural network to learn discriminate between the flow velocity and fluid properties is analyzed.