Experimental Investigation of Natural Convection Heat Transfer in an Open Thermosyphon

Abstract

An experimental investigation of natural convection heat transfer has been performed under the condition of uniform heat flux in an open thermosyphon. Water, ethyl alcohol and ethylene glycol were used as working liquids. The length-to-radius ratio, expressing the thermosyphon tube geometry, was changed in the range from 14.3 to 92.8 by using seven tubes with different dimensions. Expressions correlating the experimental data on heat transfer coefficients were derived for both laminar and turbulent flow regimes. Axial temperature distributions of the heated wall and working liquid were measured and discussed in relation to the flow regimes.