Natural circulation in a rectangular loop with vertical heater below vertical cooler

摘要

Many upcoming new generation reactors employ natural circulation for heat transfer in normal mode of operation. Natural circulation systems are simpler and safer than their forced circulation counterparts. However, these systems are prone to flow instability which are undesirable due to several reasons. In the present work, a rectangular glass loop, wherein cooler is just above the heater, has been considered for experimental and numerical investigation at atmospheric pressure. Heat addition from room conditions has been studied to understand the natural circulation loop dynamics, checking the possibility of occurrence of instability with the new orientation of the heater and the cooler. Experiments were performed at different power levels and coolant flow rates. CFD analyses were performed for all the cases investigated experimentally using the commercial CFD code ANSYS FLUENT 14.0. No instability was observed during the experiments and none during the simulations done for the duration of the experiments.