Analytical study of multiple evaporator heat pipe with nanofluid; A smart material for satellite equipment cooling application

Thermal management of satellite equipment is one of the most significant issues in the space industries. Heat generated by electrical component should be dissipated to avoid damaging the satellite. Heat pipe with discrete heat sources is often used to remove heat flux from satellite heat dissipating equipment. In this work, a two-dimensional analysis is used to evaluate the thermal performance of a cylindrical heat pipe with multiple heat sources (evaporators) using nanofluid. Pure water and Al2O3-water mixture are used as working fluids. The effect of particle concentration level (φ=0 (distilled water), 2, 4, and 8%) and head load (Q=30, 60, and 90 W) on the wall temperature, pressure drop, velocity field, thermal resistance, thermal-hydraulic performance, and heat pipe size is investigated. A remarkable decrease in wall temperature is observed, especially on the heat sources. It is found that heat transfer coefficient increases as particle concentration increases while an existence of an optimal particle concentration level for the lowest pressure drop and thus best thermal-hydraulic performance is established. There is a significant reduction in the thermal resistance and size of heat pipe when nanofluid is used. Results also show that applying nanofluid for the higher heat loads, in which more heat removal is required, has a more pronounced effect on the heat transfer rate augmentation and temperature reduction of satellite equipment. This useful feature of Al2O3-water proved its potential as a smart material in satellite equipment cooling application.