Performance study of conical strip inserts in tube heat exchanger using water based titanium oxide nanofluid

The objective of the study is to observe the Nusselt number and friction factor behavior in a tube heat exchanger fitted with staggered and non-staggered conical strip inserts using water based titanium oxide nanofluid under laminar flow conditions. Water based titanium oxide nanofluid was prepared using a two-step method with a volume concentration of 0.1% and 0.5%. The tube inserts used were staggered and non-staggered conical strips having three different twist ratios of 2, 3, and 5. The experimental results indicated that the Nusselt number increased in the presence of water based titanium oxide nanofluid compared to the base fluid. Nusselt number further increased enormously with the use of conical strip inserts than a tube with no inserts. It was observed that the strip geometry and the nanofluid had a major effect on the thermal performance of the circular tube heat exchanger. It was found that with the staggered conical strip having a twist ratio of Y = 3 and 0.5% volume concentration of nanofluid provided the highest heat transfer. Correlations have been derived using regression analysis. © 2017 Society of Thermal Engineers of Serbia.