Experimental thermal performance investigation of double pipe heat exchanger using transformer oil/water nanofluid
This paper presents an experimental study investigating the thermal performance of multiwall carbon nanotubes in a double pipe heat exchanger using a water-based fluid. The research followed a two-step method, where a concentration of 0.01 weight percent of SDS surfactant was utilized to prepare the carbon nanotubes. The heat transfer coefficient, friction coefficient, and overall heat transfer coefficient of the nanofluid were compared to those of the base fluid. The results revealed that the addition of a small amount of multiwall carbon nanotubes significantly enhanced the thermal conductivity and heat transfer coefficient of the water-based fluid. Moreover, the heat transfer coefficient exhibited an increase with higher Reynolds numbers. When the nanofluid flowed countercurrently and was in the outer tube, the highest values for the overall heat transfer coefficient and the heat transfer coefficient were determined as 2864 and 7655.7 W/m2K, respectively. The findings indicate notable improvements in the thermophysical and thermal characteristics of the nanofluid.