Micromachined Inclinometer Based on Fluid Convection

TL;DR

This paper investigates a micromachined thermal inclinometer using fluid convection, comparing gas and liquid fillings through simulations and experiments, highlighting higher sensitivity with liquids.

Contribution

It introduces a novel micromachined thermal inclinometer with experimental validation and compares fluid types, demonstrating enhanced sensitivity with liquids.

Findings

Liquid sensors exhibit higher sensitivity than gas sensors.

Experimental results align with numerical simulations.

The inclinometer uses a simple design with a heater and detectors.

Abstract

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.