Particular passive wickless two-phase loop devices are able to operate with or against gravity. In the past a lot of devices for miscellaneous applications have been proposed each of them with its characteristics. This paper aims to analyse different kinds of equipment as special versions of a generic thermal device that the author has named periodic two phase thermosyphon (PTPT). An original classification criterion for these devices is proposed, and the more than 50 PTPTs, that have been described in the literature, have been classified. The paper also deals with the characterisation of the global thermal behaviour of a generic PTPT by experimentally analysing the results of the temperature evolutions of the loop in a single heat transfer cycle as a periodic stable regime is reached. A mathematical model, which had been developed in previous research by the author, is presented here in improved form; it allows us to determine using the experimental temperature and pressure evolutions, changes over time in several parameters, such as the velocity of the liquid in different parts of the loop, the specific volume of vapour, and so on. The operations that are involved in the complex mechanisms of the heat and mass transfer against gravity are explained in this way. © 2005 Elsevier SAS. All rights reserved.
On the Periodic Two-Phase Thernosyphons Operating Against Gravity
FILIPPESCHI, SAURO
2006-01-01
Abstract
Particular passive wickless two-phase loop devices are able to operate with or against gravity. In the past a lot of devices for miscellaneous applications have been proposed each of them with its characteristics. This paper aims to analyse different kinds of equipment as special versions of a generic thermal device that the author has named periodic two phase thermosyphon (PTPT). An original classification criterion for these devices is proposed, and the more than 50 PTPTs, that have been described in the literature, have been classified. The paper also deals with the characterisation of the global thermal behaviour of a generic PTPT by experimentally analysing the results of the temperature evolutions of the loop in a single heat transfer cycle as a periodic stable regime is reached. A mathematical model, which had been developed in previous research by the author, is presented here in improved form; it allows us to determine using the experimental temperature and pressure evolutions, changes over time in several parameters, such as the velocity of the liquid in different parts of the loop, the specific volume of vapour, and so on. The operations that are involved in the complex mechanisms of the heat and mass transfer against gravity are explained in this way. © 2005 Elsevier SAS. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
