الفهرس 
SummaryOnly 14 pages are availabe for public view
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Abstract
A heat pipe is a device capable of high heat transfer rates under isothermal conditions. It consists of container , such as a pipe , whose interior wall as lined with wick structured with the working fluid . Heat transfer in the evaporator region of the heat pipe causes the liquid from the condenser to the evaporator occure a surface tension pressure differential to that create a surface tension pressure drops, including that due to gravitation or other externally imposed body forces. For a given pipe geometry and working fluid, the thermodynamic and flow characteristics determine the transport limits; namely, viscous, sonic flow of vapor, entrainment , capillary , and boiling . In the present study , both the entrainment limit and the wicking (capillary) limit are investigated .
Experiments were carried-out on copper heat pipe with copper porous wick using either water or R-11 as working fluids. The pipes were tested at different orientations and the maximum performance was measured. Five heat pipes were operated at the same time and angle of inclination, and had similar diameter , evaporator length, adiabatic length, condenser length, working fluid, operating pressure and temperature, and heat flux. However they had different porous wick thicknesses. The heat pipe was made of copper, 450 mm in length , 15 mm in diameter , and lined internally by a copper porous wick of 2 mm, 2.8 mm, 3.6 mm, 4.4 mm, and 5.2 mm thicknesses.
The experimental results are shown to be a quiet agreement with the theoretical predictions at some specific situations, but generally disagree. New correlations for both the wicking limit and the entrainment limit are presented in which the thickness and properties of the wick are playing a major role.