Using dynamic calibration techniques to enhance the frequency response of low cost sensors

Speaker:  PAUL HAYDEN

Chair(S): oSCAR mARTINEZ-ALVARADO 

wednesday september 25 2024, 13:00

ABSTRACT

The physical modelling of dispersion in turbulent plumes requires the time-domain measurement of a representative tracer gas. We currently do this using a fast-flame ionization detector (FFID), which measures ionization within the sample after exposure to a hydrogen combustion flame, and is sensitive to hydrocarbons only. The FFID instrument has a response bandwidth of up to 200 Hz, but is itself complex and costly. Pellistor sensors, on the other hand, measure hydrocarbon concentration through catalytic effects, and are entirely electrical. These are a mature technology; they are commonly used in safety applications, and are readily available from commercial suppliers. Although these sensors are significantly smaller than FFID heads, they tend to have a larger sensing volume. More importantly, though, they tend to have very low bandwidths (order 0.01 Hz), which renders them unusable for characterizing fluctuations in turbulent plumes. To address these shortcomings, a novel enclosure and dynamic calibration process has been developed for these off-the shelf-sensors. This presentation will show how we have increased the frequency response from 0.01Hz to 1.6Hz. Importantly, this dynamic calibration technique could be applied to other sensing technologies and so has a wide application.