Experimental investigation of aluminum oxide nanofluid on heat pipe thermal performance

In this research, the effect of using aluminum oxide nanofluid (pure water mixed with Al2O3 nanoparticle with 35 nm diameter) on the thermal efficiency enhancement of a heat pipe on the different operating state was investigated. The heat pipe was made of a straight copper tube with an outer length of 8 and 190 mm and a 1 mm wick-thickness sintered circular heat pipe. In the heat pipe tube, there is a 90° curve between the evaporator and condenser sections. The tested concentration levels of nanofluid are 0%, 1% and 3%wt. Results show that by charging the nanofluid to the heat pipe, thermal performance is enhanced by reducing the thermal resistance and wall temperature difference. The thermal efficiency of heat pipe charged with nanofluid is compared with pure water.