This work presents a computational fluid dynamic-based numerical study of the effect of burner position and number of reformer tubes on an annular steam methane-reforming (SMR) reactor for hydrogen (H2) production. Three different burner configurations such as single co-axial inside burner (SCIB), single top burner (STB), and multiple top burner (MTB) arrangements were considered. The number of reformer tubes inside the reactor was varied to four-, six-, and eight-tube arrangements. This study revealed that the STB configuration was preferable to the SCIB and MTB configurations owing to the effective utilization of heat from the combustion gas and uniform temperature distribution. The flue-gas inlet temperature, reformer inlet velocity, and number of reformer tubes were found to exert a significant effect on the SMR reactor. Additionally, the SMR design was modified by installing a sleeve around the outer reformer with a sleeve spacing of 15 mm and a burner at the bottom. The effect of the sleeve design on the H2 yield, temperature distribution, and wall heat-transfer coefficient was also presented.