A robust calibration technique for concentration measurements using ionisation detectors

Abstract

Accurate calibration procedure is essential to obtain reliable concentration measurements using ionisation-based sensors. Existing methods assume linear behaviour of ionisation sensors and do not account for errors that arise due to sensor drift, changes in ambient conditions, etc. In this paper, we implement a robust calibration procedure to account for most forms of drift that are typically noticed during concentration measurements using ionisation detectors. The method involves calibrating the sensor before and after every experiment with non-uniformly distributed reference calibration points. During post-processing, an interpolation scheme is then implemented between pre- and post-calibrations to correct for any sensor drift that is encountered during the experiment. The proposed method is found to yield consistent measurements, which have been well documented and validated in our recent studies (Talluru et al 2017a Meas. Sci. Technol. 28 055801; Talluru et al 2018 J. Fluid Mech. 846 292–317).

Structural inclination angle of near-field scalar fluctuations in a turbulent boundary layer

“…The spanwise gap between the two PIDs is approximately 3 mm, in accordance with the results of [15], who showed that a PID has negligible influence on an adjacent probe when separated by a distance greater than 3d, where d = 0.76 mm is the inlet diameter of PID probes used in this study. Details of calibration procedure, spatial resolution and frequency response of PID are also given in [21,23]. Although the experimental test-rig and the measurement procedures used in this study are similar to that of [20], the present study is distinct and reports simultaneous measurements of concentration at two points in the plume.…”