Akademik Veri Yönetim Sistemi
1st International Conference on Applied Engineering and Natural Sciences (ICAENS), Konya, Türkiye, 1 - 03 Kasım 2021, cilt.1, ss.213
Being efficient heat transfer devices, heat pipes have been utilized widely in several areas for many decades in different engineering fields. They work with phase changing principle (evaporationcondensation). Different capillary mechanisms have been used to ensure the necessary capillary pumping for their work. Several experimental and numerical studies have been investigated on the capillary limit which is one of the governing limitations in heat pipe operation and limits the heat transfer capacity. It is proved that inclination angle, geometry, fluid properties, mesh wick type and its properties are the main factors which affect the capillary pumping in heat pipe, therefore the capillary limit. In recent years, using nanofluids instead of conventional fluids in heat pipe has become an interesting subject which makes a serious challenge for enhancing the heat transfer rate by decreasing the thermal resistance and pushing further the capillary limit. Effects of nanofluids on capillary limit are controversial. However, most studies showed that using an optimum amount of nanosubstance within the working fluid enhance the heat transfer capacity of heat pipes. Otherwise, high concentration of nanosubstance can engender a clogging in the heat pipe. This review paper summarizes the different capillary mechanisms used in heat pipe and factors that affect the capillary pumping. Furthermore, it reviews the effects of nanofluids on capillary limit, and thus heat pipe efficiency. Moreover, research gaps and proposed future targets are broached.