Development of a technique for measurement of high heat flux

High heat flux measurement is necessary for various experiments and industrial applications. For example, to estimate a very high irradiance onto a surface as in solar thermal and in testing of plasma facing component in ITER. In order to estimate high heat flux of the order of MW/m2, an experiment with plasma jet of non-transferred 9MBM type is employed. This paper describes the design of a non-intercepted calorimeter. This is for estimation of average incident heat flux of the plasma jet along the axial direction. Temperature at different axial locations on the surface of calorimeter and at the outlet is measured. The heat flux associated with the incident plasma is estimated from these measured values of temperature. Rate of heat transfer from plasma jet to the employed target surface at different axial position is measured with the help of intercepted calorimetric method. Based on the estimated heat flux and heat transfer rate, the electrothermal efficiency of 9MBM plasma torch is estimated. Torch heat efficiency (THE), plasma heat efficiency (PHE) and heat transfer effectiveness (HTE) of the plasma jet are also estimated for copper materials. PHE and HTE are required for mathematical modelling of plasma surface interaction.