Numerical and experimental investigation of enhancement of heat transfer in dimpled rib heat exchanger tube

In this study, numerical and experimental investigation has been carried out for a range of system and operating parameters in order to analyse the effect of dimpled rib on heat and fluid flow behaviours in heat exchanger tube. Tube has, stream wise spacing (x/dd) range of 15–35, span wise spacing (y/dd) range of 15–35, ratio of dimpled depth to print diameter (e/dd) of 1.0 and Reynolds number (Ren) ranges from 4000 to 28,000. Simulations were carried out to obtain heat and fluid flow behaviour of smooth and rough tube, using commercial CFD software, ANSYS 16.0 (Fluent). Renormalization k − ε model was employed to assess the influence of dimpled on turbulent flow and velocity field. Simulation results show that, the enhancement of 3.18 times in heat transfer and 2.87 times enhancement in thermal hydraulic performance as a function of stream wise direction (x/dd) of 15 and span wise direction (y/dd) of 15 respectively. Comparison between numerical and experimental simulation results showed that good agreement as the data fell within ±10% error band.