  This paper presents a numerical simulation and experimental results of a
one-dimensional thermal inclinometer with the cavity filled of gas and liquid.
The sensor principle consists of one heating resistor placed between two
detectors. When the resistor is electrically powered, it creates a symmetrical
temperature profile inside a micromachined silicon cavity. By applying a tilt
to the sensor, the profile shifts in the same direction of the sensible axis
corresponding to the horizontal one to one. The temperature profile and the
sensitivity according to the CO2 gas and mineral oil SAE50 have been studied
using numerical resolution of fluid dynamics equations with the computational
fluid dynamics (CFD) software package Fluent V6.2. We have shown that the
sensitivity of liquid sensors is higher than the gas sensors one. By using
micromachined silicon technique, a thermal inclinometer with one pair of
detectors placed at 300 um from the heater has been made. Experimental
measurements corroborate with the numerical simulation.
