Prediction of fully-developed flow in a tube containing a twisted-tape

Abstract The problem of fully-developed, laminar and turbulent, uniform-property flow in a tube containing a twisted-tape has been formulated in terms of partial differential equations of momentum and heat transfer. These equations have been solved by adapting an existing numerical procedure for two-dimensional elliptic equations to predict the friction and heat-transfer characteristics of the flow. A set of laminar flow predictions are presented to demonstrate the influence of Reynolds number, twist-ratio, Prandtl number and the fin-parameter on the flow characteristics. The turbulent-viscosity, necessary to predict the turbulent flow characteristics, has been calculated by solving differential equations for kinetic energy of turbulence and the energy dissipation rate. This approach is, however, found to be inadequate for accurate quantitative predictions; a measure for eliminating this inadequacy is suggested.