Effect of the injection velocity on the spatial localization of the mixture dissipation in a flow microcalorimeter

Abstract

The effect of the injection velocity in the chemical calibration of a flow microcalorimeter is studied in this article. The experimental measures show a parabolic variation of the sensitivity in terms of the injection flow. The considered hypothesis is that the maximum of the sensitivity curve is produced when the spatial area in which the mixture dissipation takes place is centred with regard to the detector system. When increasing the injection flow, this mixture zone moves till it goes out of the detection area making the sensitivity diminish. It has been defined a time constant τmix which is related to the establishment time of the homogeneous mixture and with the length occupied by the mixture dissipation. A study has been carried out with three liquid mixtures that have different behaviours; within these mixtures, τmix has been determined in terms of the injection flow and the considered hypothesis has been confirmed.