INTERNATIONAL JOURNAL OF THERMAL SCIENCES, cilt.148, 2020 (SCI İndekslerine Giren Dergi)
The objective of this work is to present the thermal performance characteristics and to examine the hydrodynamic structure of the fluid which improves the rate of heat transfer in parallel with the penalty of pressure drop by means of the time-averaged streamlines topology, , streamwise velocity distribution, , vorticity concentration, and turbulent Reynolds stress, (u'v') over bar /U-2 for the sinusoidal wavy channel. A wide range of experiments were performed for Reynolds numbers, Re ranging from 4 x 10(3) to 1 x 10(4) in order to determine the heat transfer rate and the friction factor, f with varying the channel height expansion/contraction ratio, M = H-min/H-max such as 0.5, 0.35 and 0.28. The results revealed that a significant heat transfer enhancement was achieved with a considerable penalty of pressure drop. The highest thermal performance factor, TPF was obtained as 1.46 for M = 0.5. Numerical simulations were conducted to confirm the experimental results for the same parameters. The Shear Stress Transport k-w (SST k-w) turbulence model was used to perform numerical analyses. After ensuring the consistency of experimental thermal performance results with numerical predictions, the Particle image velocimetry (PIV) system was utilized for investigating the flow physics in the sinusoidally curved converging-diverging channel for all M values at Re = 4 x 10(3) where the TPF is maximum.