Electro Thermal Modeling of the Micro Flow Sensor With Feedback Control Circuit Using SPICE

Abstract

This paper reports an efficient electro-thermal modeling technique for the Micro Flow Sensor (MFS) having an ensured thermal insulation structure with a thin silicon nitride membrane. Both the thermal fluid flow around two-heater MFS and the electric circuit were modeled together using a commercial general-purpose circuit simulator based on SPICE (Simulation Program with Integrated Circuit Emphasis). Two-dimensional laminar Poiseuille channel flow was assumed as the flow field in the model. Remarkable features of this technique are as follows: a partial three-dimensional lumped thermal network model involved in a two dimensional one, single segment for spanwise direction, and the forced convective heat transfer calculated by energy balance at each node in the fluid flow. The simulation and measurement results on the sensor characteristics were in good agreement.