Study of enhancing thermo-hydraulic performance of turbulent flow inside a tube occupied with central cut twisting tapes

Abstract

   The present 3D numerical study was performed to show the effects of the length of central cut twisting tape (CCTT) on the characteristics of thermodynamic and hydrodynamic fields when this tape is inserted inside a tube in which, air is flows in turbulent pattern. Central cut twisting tapes of the same cut ratio (c = C/D) of 0.4 and four different length ratio (LR = l/L) of 0.25, 0.5, 0.75 and 1 were inserted in the tested tube that subjected to a uniform heat flux. The range of Reynolds number of air flow was 10000 ? Re ? 40000. Fluent in ANSYS 15 was used for problem designing, formulation and results obtaining in the present study. Finite volume method was the discretization method and tetrahedral type of mesh element was used. RNG k-? was chosen as the turbulent model. The obtained results showed that the increasing in Reynolds number leads to an increasing in Nusselt number and a decreasing in both friction factor and thermal performance factor. Also, these results cleared that the increasing in the length ratio of the studied type of twisting tape gives higher Nessult number, friction factors and thermal performance factor of 171.172, 0.0932 and 1.432 respectively