Advances in heat pipe technologies for different thermal systems applications: a review

The heat pipes are two-phase flow passive and reliable devices that transfer heat effectively and are vastly utilized in thermal systems. A summary of experimental and numerical studies related to advanced technologies of applications of heat pipes and thermosiphons is offered in this review. This paper focused mainly on the hybrid combinations of heat pipes and phase change materials, heat pipes with nanofluids and heat pipes, and modern electronic devices. Also, the influence of operating variables, such as working fluids, heat inputs, filling ratios, and inclination angles, has been involved. The hybrid systems that combine phase change materials with heat pipes to improve their thermal performance are discussed. Low thermal conductivity of phase change materials and heat pipe overheating has been addressed using these hybrid systems. The impact of nanofluids on the heat pipes' thermal behaviour is also discussed. Nanofluids enhance the thermal properties of heat pipes by increasing their thermal performance. Heat pipe technology is being used in the thermal management of electronics to enhance their cooling systems. Addressing overheating issues of electronic devices will improve their performance and helps to achieve their robust, small, and flexible design.