Transport Modeling and Response Characteristics of Commercial Catalytic Bead Sensors

Abstract

Concerns have been raised about contamination events in the bleed air supply of commercial airplanes. Reliable sensors to detect the presence of gases due to the contamination are therefore being considered. Catalytic bead sensors are studied for the detection of combustible gases that may be by-products of bleed air contamination. Two catalytic bead sensors were tested with methane. Steady state and transient experiments were performed to characterize the response of the sensors. A heat transfer model was constructed to better understand the sensors’ operation and to be used for considering possible modifications to increase the sensors’ sensitivity. The heat transfer coefficient of the sensor system and the operating temperature of the catalytic bead were predicted for use in the heat transfer analysis. Convection was determined to be the dominant method of heat transfer within the catalytic bead system.