Abstract: Research on the combustion characteristics of sodium metal was conducted on cone calorimeter with various surrounding radiation heat flux from 25kW/m² to 60kW/m², and the oxygen content in combustion gas and residual mass were measured. The result showed that: with the surrounding radiation heat flux increasing, there were big differences in the combustion phenomena of sodium metal, and the residual mass decrease, until the complete combustion happened. An ambient radiation heat flux smaller than 30kW/m² is unable to trigger a flame burning for Sodium metal.When the radiation heat flux is 50~60kW/m² , the unstable and inadequate open fire happened. When the radiation heat flux is bigger than 60 kW/m² stable and fully open fire happened.

Key words: sodium metal, combustion radiation heat flux, cone calorimeter