Fabrication of MEMS Accelerometer for Vibration Sensing in Gas Turbine

Abstract

Vibrations in elements of dynamic systems, such as turbines, can lead to undue stresses in critical structural elements leading to catastrophic failures. Measurement and characterization of vibration levels of structural elements under varied operating conditions is necessary to determine anomalies and thereby prevent failure. High-speed gas turbines use a large number of small stator blades that are critical to their operation. High-speed operation can induce vibration components in excess of a few kHz. Internal operating temperatures can be well above 250°C and the sensors should be operational even at 500°C. This paper focuses on development of a single-axis MEMS capacitive accelerometer for direct mounting on gas turbine stator blades for monitoring and analyzing their vibration characteristics. The design uses SOI wafer as substrate to realize high temperature sensing with a sensitivity level on the order of 0.013ųm/g. The proposed device is developed using lab-scale fabrication with minimal facilities amenable for low-cost indigenous manufacturing.