ISSN Online: 2377-424X
ISBN Print: 0-89116-130-9
International Heat Transfer Conference 6
ON THE PROBLEM OF HEAT TRANSFER IN LOW-TEMPERATURE HEAT PIPES
Аннотация
The processes in metal-screen wicks were observed visually on their internal and near-wall surfaces in a transparent heat pipe with Freon-113 and water. Vapour-filled spaces were noted in poor-contact areas. Heat transfer and critical heat flux densities were meassured in a vertical set-up with wick of copper and stainless-steel screens, and water, ethyl alcohol and Freon-113 as working fluids. In a comparison with a plain-surface, an enhanced heat transfer was noted in the presence of a wick, up to a certain value of the heat flux, followed by a decrease of the heat transfer for further heating. Both the heat transfer and the critical heat flux are higher for of higher efficient conductivites and for improved vapour evacuation conditions. A perforated press-screen used to fix the wick at the pipe wall had no significant effects on α , but gave a 20 to 30 % decrease of qcr. A general relation was derived for the heat transfer.