A thermal flow sensor for fluids with dynamic velocity, temperature or conductivity profiles

摘要

A new type of integrated thermal flow sensor containing two simetrical measuring channels is presented. The structure permit optimisation of flw sensiing in applications with transient velocity, temperature or conductivity profiles in the fluid and has improved sensitivities for small temperatures differences above ambient, necessary for medical applications. Amnalysis is made for fluid flow and heat transfer using analtitical and FEA technics. Technological im,-plementation optimise the compensation of the internal stresses in the suspended structures and passivation of the sensor structure for work in aggressive media. Electronic interfaces for processing are de9ived for development of a fully integrated variant of the sensor.