Heat transfer enhancement using MgO/water nanofluid in heat pipe

This study investigates how MgO/water nano-fluid affect the thermal performance of a two-phase closed thermo-syphon heat pipe at various states of operation. The present study experimentally demonstrated the effect of using a nano-fluid obtained from MgO on improving the performance of a heat pipe. Triton X-100 nonionic surfactant was used in the study to produce the 5% (vol.) MgO/water nano-fluid via direct-synthesis. A straight copper tube with an inner diameter of 13 mm, the wall thickness of 2 mm and the length of 1 m was used as the heat pipe in the experimental set-up. The nano-fluid was filled up 33.3% (44.5 ml) of the volume of the heat pipe. Three different heating power levels (200 W, 300 W and 400 W) were used in the experiments with three different flow rates of cooling water (5, 7.5 and 10 g/s) used in the condenser for cooling the system. An improvement level of 26% at 200 W heating power and 7.5 g/s flow rate was reported for the effectiveness of the heat pipe used in the study when the nano-fluid was charged into the system instead of water. The improvement ratio varied with respect to varying heat loads and varying flow rate of condenser cooling water.