Engineering and Technology Journal

The present work investigated the thermal performance of thermosyphon by using distilled water as a working fluid at different filling ratios (50%, 60%, and 70 %). The thermosyphon was manufactured from a copper tube with outer and inner diameters (26 and 24) mm, respectively. The thermosyphon was tested experimentally at different input power (100, 200 and 300) Watt. The operating temperature of the oil was chosen below 85°C. Experimental results revealed that the filling ratio of 60% exhibited the best heat dissipation at the highest operating temperature. While the low operating temperature and 50 % filling ratio show better heat dissipation. Further, it was found that the thermal resistance of the thermosyphon was obviously decreased with increasing the input power. The percentage decrease in the thermal resistance of the thermosyphon at a filling ratio of 0.6 was 14.6 % compared with that filling ratio of 0.5 at an input power of 300 W.

This study presents experimental work to construct a non- conventional
thermosyphon where it is consists of three parts, which include the evaporator,
adiabatic and condenser sections all of these parts are arranged radially in parallel to
construct the heat valve (HV). Heat valve used to evacuate heat from horizontal copper
electrical heater tube by working fluid which is(distilled water, methanol, ethanol) with
different filling ratio 66.6% and 83.3%. Working fluid evacuate heat from copper
evaporator towards condenser where a change in phase mechanism make insure to
increase the heat performance of HV. Thin stainless steel mesh grid coated evaporator
to translate heat to the working fluid at the case of high evaporation of working fluid,
while a very thin of aluminum fins are fixed to the condenser surface to extended it and
construct the finned heat valve(FHV) with a high level thermal performance where
heat reject in short time and make insure to condensate the working fluid’s vapor and
that lead to low level of temperature in evaporator. The results refer to the high
thermal performance of FHV where a low temperature in evaporator with low heat
storage because the short distance between condenser and evaporator with a high ratio
between area of them .Result refer to the effect of working fluid type with simple
effect in filling ratio.

This experimental study investigated the change in cross-sectional area (csa) of thermosyphon's condenser to it's a constant perimeter (RAP) and effect of that at the thermal performance. Geometries shapes deform from circular to elliptical and flat to make a change in csa at a same perimeter of all geometries shapes where a different value of RAP are got. At each RAP a different rate of heat input in evaporator and
different filling ratio of working fluid (distill water) are applied. Threshold angle (working angle) where the condensate of distilled water vapor begin to return to evaporator, this angle are examined with the horizontal level for three geometries shapes (three RAP). The results indicated that the flat two phase closed thermosyphon( FTPCT)(low RAP value) and elliptical two phase closed thermosyphon (ETPCT) had a higher and more stable heat transfer coefficient h (condenser air side) with the high and mid filling ratio from than of the circular two
phase closed thermosyphon( CTPCT). That refer to more useful length of condenser to absorb heat from evaporator and prevent it from causing a rise in temperature. The high filling ratio with low rate of heat level in evaporator lead to unuseful area in thermosyphon's condenser and lowering its pressure, while low filling ratio with high
rate of heat caused a chaotic flow inside TPCT and rising the evaporator and condenser temperatures.