3-D Multiphysics Model of Thermal Flow Sensors

The aim of this work is to present a model capable to describe the behaviour of a thermal flow sensor under every physical aspect. A generic thermal flow sensor relates the flow properties with a variation in the temperature profile inside the device itself. Thus, it contains a resistive element biased with an external current to locally increase the temperature, surrounded by one or more temperature sensing elements. The analysis involves three different and coupled physic domains: electric current, heat transfer in solids and laminar flow. Once the model was ready, it has been used to model an existing SOI CMOS MEMS wall shear stress sensor. The results shows a perfect agreement with the experimental data under every condition, proving the validity of the model.