The paper tries to analyze the thermo-fluid dynamics of compact two-phase loops with natural circulation which are mainly ruled by the heat input supplied to the evaporator. The objective is to understand if in small two-phase thermosyphons the heat transfer performances are only due to the heat transfer in the evaporator section rather than fluid-dynamic characteristics of all the loop. The results of the experimental analysis are obtained with water and FC72 and with two different types of thermosyphons. The first type is characterised by the evaporator internal diameter much larger than the bubble diameter while in the second type evaporator and connecting pipes have diameter 4-5 times larger than the bubble diameter. For both thermosyphons capillary forces are not involved in the heat and mass transfer. It is shows how type A thermosyphon the performances are influenced only by the heat transfer regime in the evaporator section, but in type B thermosyphons, the performances are also influenced by the fluid-dynamic parameters of the whole loop.
Experimental Analysis of Two-Phase Heat and Mass Transfer in Small Dimensions Natural-Circulation Loops
FILIPPESCHI, SAURO;FRANCO, ALESSANDRO
2010-01-01
Abstract
The paper tries to analyze the thermo-fluid dynamics of compact two-phase loops with natural circulation which are mainly ruled by the heat input supplied to the evaporator. The objective is to understand if in small two-phase thermosyphons the heat transfer performances are only due to the heat transfer in the evaporator section rather than fluid-dynamic characteristics of all the loop. The results of the experimental analysis are obtained with water and FC72 and with two different types of thermosyphons. The first type is characterised by the evaporator internal diameter much larger than the bubble diameter while in the second type evaporator and connecting pipes have diameter 4-5 times larger than the bubble diameter. For both thermosyphons capillary forces are not involved in the heat and mass transfer. It is shows how type A thermosyphon the performances are influenced only by the heat transfer regime in the evaporator section, but in type B thermosyphons, the performances are also influenced by the fluid-dynamic parameters of the whole loop.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
