Characterization of a single-phase closed loop thermosyphon flow in concentric vertical annuli with distributed heat sources

Thermosyphon flow is used to transfer heat passively from a heat source to a heat sink. Closed loop thermosyphon occurs by heating one side of the loop and cooling the other side and generating density differences. On the heat source side, buoyancy forces drive the fluid upwards, opposing gravity and friction forces, and generating induced flow. On the other side of the loop, the heat sink side, gravity and cooling drive the fluid downwards. Natural convection is an important mechanism in reactors safety by passive cooling systems. Figure 20 presents a prototype of a mockup which is used to study the effect of distributed heat sources in a closed loop thermosyphon flow. In this system, power is generated in three heaters. Central heater which simulates the power generated in a sample that has to be cooled. Two peripheral heaters are used to simulate power that may be generated in the structure and oppose or aid to remove the heat from the sample. An example for such a heat generation is within experimental setups in nuclear reactors, due to gamma radiation. Those different sources of heat can be studied as distributed heating conditions