experimental study of the effect of multi wall Carbon nano tube - water nano fluid on heat transfer in a non metallic double pipe heat exchanger

In the present research the effect of adding multi wall Carbon nano tubes (with 10-15 nano meter diameter) on the heat transfer coefficient of a heat exchanger is investigated. This work is performed by a co current flexible double pipe heat exchanger made of PVDF. To this end, the viscosity and thermal conductivity of nano fluids is measured experimentally for various temperatures and concentrations. The nano fluid temperature is set at 35°C, 40°C, 45°C and 50°C. The flow rate of nano fluid inside the inner tube was adjusted at 100 , 200 , 300 while, the cold water flow rate of the outer tube is 100 The results shows that heat transfer coefficient of the heat exchanger improves with increasing the fluid temperature, concentration and flow rate. The most effective factor on the heat transfer coefficient is flowrate. Obtained results indicate that using this nano fluid enhances heat transfer coefficient 75%.