Recently, BonPhysics has published, in cooperation with IFE (Institute for Energy technology) Norway, an article about thermosiphons. A thermosiphon is a loop in which a medium can flow due to differences in density, differences in height and gravity.
Since 2015, simulations of two-phase hydrogen thermosiphon loops have been developed by BonPhysics for the OYSTER project from the RID (Reactor Institute Delft). Those simulations are applied on the Cold Neutron Source from the IFE in Kjeller, Norway. The obtained results are presented in the article.
However, is this method also usable in other situations? And what about its overall usefulness?

The program is expandable with other materials, temperatures and flowrates, and is useable in a lot of different situations. It is not just applicable to a two-phase loop in a Cold Neutron Source with hydrogen, but for example also to a two-phase loop with boiling water or to a one-phase loop with molten salt. The principle of the calculations remains the same: energy and medium (gas or liquid) transported based on gravity.

The article shows that the simulation of thermosiphons is accurately performed by this program. Hence, the behaviour of the simulated thermosiphons can now be predicted. Firstly, one analyses the behaviour in a known situation by measuring the pressure as function of time. It then becomes clear how the system works and predictions of behaviour in new situations can be made. Or as stated in the article: ‘The modelling and results presented here may be useful for the planning and/ or optimizing of other (CNS) facilities where accurate flow and pressure control, as well as knowledge of void fraction, are important for the correct operation of the facility.’

More information and the accuracy of this new method can be found in the article.