Numerical modeling of methane-steam reforming is performed in a microchannel with heat input through Palladium-deposited channel walls corresponding to the experimental setup of Eilers [1]. The low-Mach number, variable density Navier-Stokes equations together with multicomponent reactions are solved using a parallel numerical framework. Methane-steam reforming is modeled by three reduced-order reactions occurring on the reactor walls. The surface reactions in the presence of Palladium catalyst are modeled as Neumann boundary conditions to the governing equations. Use of microchannels with deposited layer of Palladium catalyst gives rise to a non-uniform distribution of active reaction sites. The surface reaction rates, based on Arrhenius type model and obtained from literature on packed-bed reactors, are modified by a correction factor to account for these effects. The reaction-rate correction factor is obtained by making use of the experimental data for specific flow conditions. The modified reaction rates are then used to predict hydrogen production in a microchannel configuration at different flow rates and results are validated to show good agreement. It is found that the endothermic reactions occurring on the catalyst surface dominate the exothermic water-gas-shift reaction. It is also observed that the methane-to-steam conversion occurs rapidly in the first half of the mircochannel. A simple one-dimensional model solving steady state species mass fraction, energy, and overall conservation of mass equations is developed and verified against the full DNS study to show good agreement.

An experimental study of steam methane reforming in a microchannel is presented. Palladium nanoparticles, deposited on a porous aluminized FeCrAlY felt, served as catalyst sites for the reforming reactions. Parametric studies of steam-methane ratio, residence time, average reactor temperature, and temperature distribution were performed. Results demonstrated in excess 60 percent conversion of methane at an average reactor temperature of 900°C and the lowest experimented residence time of 26 milliseconds. Methane conversion was found to be strongly dependent on reactor temperature. Ramping temperature distributions demonstrated a 46 percent greater hydrogen output than isothermal reactions performed at the same average temperature.

: High-speed movies of optically dense sprays exiting a Gas-Centered Swirl Coaxial (GCSC) injector are subjected to image analysis to determine spray characteristics. As a test for its efficacy in analysis of high-optical-density sprays, Proper Orthogonal Decomposition (POD) was applied to the image sequence prior to image analysis. Results of spray morphology including spray boundary, widths, angles and boundary oscillation frequencies, are compared with and without the application of POD. The most dominant modal reconstructions (between 2 and 5) of the spray are found to be sufficient to quantitatively describe the spray parameters, while the frequency of movement of the spray boundary is well predicted by the first two modes alone. Despite being computationally intensive, preprocessing of spray images using POD has advantages in - a) reduction of droplet noise in the spray boundaries thereby resulting in a smoother boundary for edge detection, and b) ability to process morphological parameters of ill-behaved sprays.

: Wall interaction of sprays emanating from Gas Centered Swirl Coaxial (GCSC) injectors were experimentally studied as a part of this ten-week project. A key aspect of the work was to apply the Proper Orthogonal Decomposition (POD) method of data analysis to time-resolved intensity images of these sprays. A high-speed camera with backlighting was used to generate the intensity movies.