Heat Transfer Analysis of An Advanced Flow Reactor Using Quantum Dots

The full-field temperature measurements in a milli-scale Corning®; Advanced Flow^TM reactor (AFR) are performed in this work by utilizing a non-intrusive technique that involves quantum dots (QD) as the sensor. Heat removal/addition can be extremely important for chemical reaction systems in terms of selectivity, yield and conversion, in addition to ensuring safety. The detailed temperature information inside the flow field is therefore desirable for reactor design and process optimization. QD’s possess various interesting properties that make them a superior choice for such purposes. The photo-luminescence stability of QD’s is the key factor to the success of this measurement technique and is addressed by using freshly synthesized QD’s. As temperature increases, the intensity of the fluorescence of the QD’s decreases. Based on this property, a calibration curve can be constructed. Intensity fields are then recorded at six different flow rates (5, 10, 15, 20, 25 and 30 ml/min) and translated back to the temperature fields for each mixing units in the AFR. From the measured temperature fields, local overall heat transfer coefficients as well as Nusselt numbers are calculated for the mixing unit of interest at each flow rates. From the analysis, it was found the heat transfer performance of the AFR is better than the conventional reactors due to increased ratio of surface area to volume. This unique technique also presents promise for temperature measurements for two-phase or even multiphase flows.