Numerical and Experimental Investigation of Heat Transfer Enhancement in Slot Groove Circular Tube with Internal Twisted Tape

Abstract

Numerical and experimental investigation on the turbulent enhancement convective heat transfer inside slot and plain dimples tubes with internal twisted tape were performed in this study. An experimental rig was constructed and instrumented to evaluate the heat transfer enhancement and pressure drop at this surface. Air was used as working fluid, and steam was used as a heating source where constant wall temperature condition of (135C˚) was achieved.  Heat transfer and pressure drop data were obtained from four configuration tube. The test facility was capable for providing turbulent flow with Reynolds number varied from 4000 to 15000. Thermal and hydrodynamic flow pattern was numerically studied using commercial code FLUENT15.  The average heat transfer of the experimental results was in good agreement with the numerical ones. The result depict that the slot dimple tube with twist tape  and plain tube with twist tape give high enhancement in heat transfer relative to plain tube due to increase in area of heat transfer. The average enhancement ratio for slot dimple tube with (TR =4 and 8) are (1.204 and 1.202) respectively .This indicates that 15.5-20.4% of heat transfer area can be saved at the same pumping power  for present cases configuration compared with the plain tube heat exchanger.