HGHP اثر شتابهاي عرضي بر عملكرد خنك كاري يك لوله حرارتي استوانه اي با شيارهاي مارپيچ

The Effect of Various Transverse Accelerations and Their Induced Body Forces on Cooling Performance of a Helically Grooved Heat Pipe (HGHP)

The removal of dissipated heat from electronic devices, particularly used in navigation systems of high-speed combat aircraft is of a great importance. A kind of heat sinks proposed to be used in the vicinity of such devices is helically grooved heat pipe (HGHP). The combat aircraft is anticipated to maneuver in air. This maneuver may cause several transverse accelerations in different directions and even high magnitudes, simultaneously. So in order to obtain an acceptable performance of a HGHP, it is necessary to study the effects of these various accelerations, which influence significantly their cooling capacity. In this work a mathematical model for a copper HGHP with Ethanol as its working fluid, has been presented. By using this model, the capillary limit heat transfer rate for each groove, dry out phenomenon that may happen in some grooves as well as overall heat removal capacity of HGHP have been studied. In the previous works only one acceleration was applied to the heat pipe, hence to the aircraft, in which the heat pipe was installed. But here we consider both single distinct transverse accelerations separately, as well as their combination. The results are expressed in terms of the type of accelerations, their magnitude and working adiabatic temperatures. It is shown that the combination of revolving and rotating motions of the aircraft in which HGHP is proposed to be used (in the vicinity of its electronic packages in trailing edge flap actuators or ailerons), has a noticeable effect on the increase of the capillary limit of the HGHP and its cooling capability. In addition, boiling limitation and entrainment limitation as two important heat transport limitations of heat pipes are calculated and compared with total capillary limit heat transfer of the HGHP in terms of temperature, to get a better view of the total performance of this kind of heat pipes.