(302i) Heat Transfer Analysis of An Advanced Flow Reactor Using Quantum Dots

Authors: 
Shi, Y., Iowa State University
Kuhn, S., ETH Zurich
Jensen, K. F., Massachusetts Institute of Technology


The full-field temperature measurements in a milli-scale Corning®; Advanced
FlowTM 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.

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