ISSN Online: 2377-424X
ISBN Print: 0-85295-345-3
International Heat Transfer Conference 10
AN EXPERIMENTAL STUDY OF INSTABILITIES IN A SUBATMOSPHERIC THERMOSYPHON LOOP
Abstract
An experimental study of the transient behaviour of a subatmospheric thermosyphon was performed. This study was initiated because of the lack of design data for the design of reboilers and evaporators operating at subatmospheric pressures. Reboilers and evaporators are operated at reduced pressures for vacuum distillation duties to lower the system temperatures and so lower the rates of corrosion in corrosive environments.
The experimental thermosyphon test loop used in this study is a full-scale mock-up of industrially operated thermosyphons. A constant level was achieved in the header column by the use of overflow tubes. The test section was Joule-heated by passing an electrical current through the wall of a tube. The threshold of instability was determined for various system temperatures at subatmospheric pressure.
The experiments showed that subatmospheric thermosyphons are very susceptible to instabilities and that the nature of this unstable behaviour is very complicated. It was found that a number of instability mechanisms are of importance at subatmospheric pressures. For the experimental conditions investigated stable steady-state flowrates were not observed.
The experimental thermosyphon test loop used in this study is a full-scale mock-up of industrially operated thermosyphons. A constant level was achieved in the header column by the use of overflow tubes. The test section was Joule-heated by passing an electrical current through the wall of a tube. The threshold of instability was determined for various system temperatures at subatmospheric pressure.
The experiments showed that subatmospheric thermosyphons are very susceptible to instabilities and that the nature of this unstable behaviour is very complicated. It was found that a number of instability mechanisms are of importance at subatmospheric pressures. For the experimental conditions investigated stable steady-state flowrates were not observed.