In this article, water based nanofluid pressure drop and heat transfer augmentation due to using twisted tape insert was investigated. Behaviors of CuO-H2O are predicted according to single phase model. Entropy generation due to fluid friction and heat transfer are presented as contours. Roles of Reynolds number, pitch and height ratios are reported by means of Finite volume method. Formulas for Darcy factor and Nusselt number have been offered. Results demonstrate that better mixing of nanofluid occurs for lower values of pitch ratio. Secondary flow becomes stronger with rise of inlet velocity. Height of turbulator has reverse relationship with thermal boundary layer thickness. (C) 2018 Elsevier B.V. All rights reserved.