Effects of geometries on flow characteristics and reforming performance of a steam-methane reformer

The effects of geometries on flow characteristics and reforming performance were studied in a 250-kW fuel cell reformer. A reformer system was numerically simulated using a simplified three-dimensional model domain with an appropriate user-defined function. The numerical results were compared with experimental data for validation. Outlet position was selected as a parameter for investigating the effects of geometry variation. The reference case has outlet at the bottom of the combustion furnace, and the outlet positions were changed from bottom to top. The numerical results show that the flow characteristics are quite different when the outlet position is changed. And the flow characteristics in the combustion furnace strongly affect the outlet temperature of reformer and reforming performance. Overall, flows of the corner sides were dominant, and the reformers which are located around the corner sides have relatively higher outlet temperatures and better reformer performances. Overall reformer performance and the flows in the combustion furnace can be predicted by measuring the outlet temperatures of reformer tubes. The effects of outlet position on the reformer performance are relatively lower than on the outlet temperatures of reformers.