The exothermicity of the reaction between hydrogen and fluorine can be used for chemical processing, or in generation of HF based chemical laser, where higher temperatures are required. The ratio of H-2 to F-2 flow and the flow rate of nitrogen affect the reactor temperatures. The authors report their experimental and computational study on the effect of excess hydrogen and nitrogen flow on reactor temperatures in a tubular reactor. The experiments have been performed over a wide range of flow ratios to generate reliable data for reactor scale-up. The computational studies predict the temperature, velocity, and species concentration at different locations of the reactor. The temperature predictions show a good match with the experimental findings. This study may be helpful in designing a large scale H-2-F-2 flame reactor.