In many stages during the manufacturing process of steel and aluminium, flow of molten metal, slags and gases is important. In these cases multiphase flow (gas through liquid metal and/or slag on liquid metal) determines the impact of phenomena such as mixing and heat transfer. In the academic world a great deal of research has been done on multiphase flow. The research has, by its focus over the past few years, led to enhanced insight and development tools mainly for application in the petro-chemical industry. The question is still open in how far this insight and these tools (relying on substantial empirical data obtained for the petro-chemical practice) can be translated into multiphase flow in metallurgical processes. It was the main reason for starting the project "multiphase flow in metallurgy", conducted in co-operation between Hoogovens R&D and the University of Twente.

One of the main contributions of Hoogovens R&D is supplying experimental data on multiphase flow in molten metals for validation of numerical models developed at the University of Twente. This initiated the investigation into and development of tools to assess these phenomena. A review of the existing tools will be given as well as the first results of two tools to characterise important factors of a vertical plume of gas in a vessel of molten metal.