Estimation of effective thermal conductivity of packed bed with internal heat generation

Abstract

Test Blanket Module (TBM) of the fusion reactor has the vital role of removing heat generated from the fusion reactor along with the heat generated internally due to tritium breeding reaction. In the initial startup phase of fusion reactor, neutron flux has a climbing ramp nature and heat gets generated in discrete locations of TBM due to non-uniform nature of neutron irradiation. Thus, there is need to establish mathematical method to estimate Effective Thermal Conductivity (ETC) of packed bed with randomly scattered internal heat sources. Novel Induction Heating technique was used to simulate above mentioned conditions in packed bed of Li2TiO3 pebbles. An input-output FDM (Finite Difference Method) based model has been developed to estimate ETC of packed beds with non-uniform and discrete Internal Heat Generation (IHG). The inputs to the FDM based model are experimental results along with various operating and process parameters of the packed bed system under consideration. Also, an empirical correlation has been proposed to yield ETC of above mentioned packed bed systems valid for bed voidage of 0.44-0.47. The experimental and analytical methods used for this study are detailed in this paper.