LAUSR

Abstract In this article, we report on a unique design and build technique based on stereolithographic 3D printing technology (SLA) for constructing ultraviolet cured resin-made micro-reactors. The main objective of this study is gaining insight into the thermal performance of micro-reactors for optofluidic applications. Several micro-reactors equipped with pin fins were manufactured. A high-fidelity test-rig was developed and used to collect data from water flowing in the micro-reactors as they are exposed to various heat flux loading. The measured data was also used for validating the numerical (CFD) models. The CFD models provided in-depth spatial data on the pressure and temperature profiles in the microchannel, which could not be easily measured. The results showed that conventional empirical correlations failed to accurately predict the pressure drop of the system in the microfluidics regime (Re 190). For both regimes, however, CFD results were sufficiently accurate in predicting the temperature and pressure differences across the micro-reactor. It was also identified that pin fins arrangements offer a great design benefit in enhancing heat transfer coefficient in micro-reactors, achieving values up to ∼2300 W/m2.K compared to a plain micro-reactor at ∼1875 W/m2.K (or 300 W/m2.K for conventional combustion systems). A multi-objective optimisation on the geometrical specifications of various pin fins showed that the micro-reactor with pin fins of 250 µm in diameter and 100 µm in height, yielded the best thermo-hydraulic performance of highest thermal transfer coefficient (2,100 W/m2.K) and the lowest pressure- drop (∼0.1 kPa) across a wide range of heat flux loadings. The outcome of this study has created a significant knowledge and understanding of the flow behaviour in polymer-based micro-channels. It also established a methodology for designing and optimising the thermal-hydraulic performance of optofluidic micro-reactors, with potential loading of nano-photocatalyst mediated in pin fins sites. New correlations for predicting the pressure drop and temperature difference across polymer-based micro-reactors are also developed.