Computational and experimental investigation of steady state and transient characteristics of molten salt natural circulation loop

Abstract

The aim of this study is to understand the steady state and transient characteristics of single-phase rectangular natural circulation loop working with molten salt. The same is achieved through experimental investigation as well as through CFD analysis. The in-house experimental facility and a CFD model which simulates, as closely as possible, the experimental facility, are developed for this purpose. CFD results are ensured to be mesh and time step independent. Using CFD studies, maximum and minimum values of heater power, which will keep the salt in desired range of temperature is established. Steady state characteristics are obtained over a range of heater power. The effect of power on induced mass flow rate, minimum and maximum temperatures in the loop, etc., is estimated through these studies. Analysis was performed for various transients like flow initiation transient, power step-up transient, power step back transient, power trip transient and loss of heat sink transient. The transient simulation results are also compared with experimental data. The key factor to achieve consistency between numerical results and experimental data is to be able to model the heat loss from various parts of the loop. The paper discusses the modelling issues and various results.