الفهرس 
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Abstract
The purpose of tins study is to investigate the performance of
low-temperature heat pipes. A special machining technique has been
developed for production of heat pipes with internally axial grooves and
internal smooth surface. Experiments are performed to investigate the
effect of heat load, cooling water flow rate, filling ratio, (volume of
working fluid to the evaporator volume) and the inclination angle on heat
pipes performance. Two heat pipes are used which are made of copper
with 2.54 cm outside diameter. They have 31 cm long evaporator, 32cm
long adiabatic section, and 31 cm long condenser, with acetone as the
working fluid. The first has an axial groove heat pipe with a groove width
0.8 mm and a depth 1 mm and tile second has wrapped screen heat pipe
using 100 mesh copper screen wick. The inclination angle in this study is
varied from 0° (vertical position) to 90° (horizontal position). The
experimental test rig consists of a copper/acetone heat pipes, a heater for
evaporator section equipped with a digital clamp-meter to measure
electrical power, a direct jacket calorimeter for heat removal (condenser),
temperature measurement equipment, a vapor temperature probe and some
other auxiliary equipment.
Wick fabrication and insertion was accomplished using a wooden
mandrel with suitable dimensions. Heat pipe wall surface temperature was
measured at three different locations in each section.
Computer programs were constructed III order to calculate
entrainment limit, boiling limit, temperature DROP, and heat transfer
coefficient for the two types of the heat pipes.
Results of present study showed that: