Microreactor design and fabrication of micro/meso-features for onboard fuel processing system

As the global trend towards more compact and highly integrated systems accelerates, an increasing attention is paid to the development of miniaturization technologies. In this study, the design of microreactors and fabrication of parts with micro/meso-features for application in microreactor manufacturing have been investigated.; The study discusses the development of an integrated reaction and heat exchange approach to microreactor design for the water gas shift (WGS) reactor which enhances reaction yields by allowing the reactant stream to follow optimal reactant temperature profiles. The parametric study established design guidelines for the micro-WGS reactor and identified counter flow configuration as an appropriate configuration. The integrated approach achieved significantly higher catalyst utilization when compared to a conventional adiabatic reactor. The study also showed potentials of miniaturizing the reactor by reducing the wall thickness of the reactor without performance loss.; Two potential candidate processes, semi-solid forming and microforming, have been investigated for producing micro/meso-features required for the reactor components. One of the major challenges in the semi-solid forming technology is characterizing the complex behavior of a material which consists of both solid and liquid phases. This study developed a model for the semi-solid material with structural evolution concept and presented a method to implement the model into finite element analysis tool. Furthermore, the study identified important parameters and their effects on the semi-solid forming process and showed the potentials of the technology as a micro/meso-manufacturing method.; For the accurate analysis and design of the microforming process, proper modeling of the material behavior at the micro/meso-scale is necessary by considering the two size effects: the 'grain size' and the 'specimen/feature size' effect. The study has quantified the interactions of the two size effects on the flow stress by considering the fundamental properties of the single and polycrystal plasticity. In addition, microforming experiments with stainless steel and copper have been performed to investigate its application in reactor manufacturing and to validate the model.