Numerical analysis to study enhancement in heat transfer using wavy surface in turbulent dual jet

Abstract

Enhancement in the heat transfer rate is an essential research area in the present time. Therefore, to achieve this goal in the present case, a sinusoidal wavy wall surface is used in a turbulent dual jet. The changes in amplitude (A) and number of cycle (N) of the sinusoidal wavy surface, not only affect the turbulent characteristics but also improve the heat transfer rate. In comparison to the plane wall surface in a dual jet, it is found that nearly 20.70% of improvement in heat transfer is achieved when N = 7 and A = 0.7. The A and N of the sinusoidal wavy surface are varied from 0.1 to 0.7 and 4 to 12 with an interval of 0.1 and 1, respectively. The Reynolds number (Re), offset ratio, and Prandtl number (Pr) are set to 15 × 103, 5 and 0.71, respectively, for all the computational simulations. The average Nusselt number (Nuavg) increases almost linearly when the amplitude changes from 0.1 − 0.7 up to N = 7. A new scaled self-similarity solution for the crest and trough positions is performed to neglect the effect of bottom wall variation. The similarity solution of the crest for various number of cycles in the combined region for different amplitudes suggests that when A ≥ 0.5, the profiles of all the number of cycles spread close to the wall region and in the outer region. Whereas, the self-similarity behaviour of trough shows that when A ≥ 0.3, the profiles of all the number of cycles spread only close to the wall region and almost coincide in the outer region and inflection point rises in the crosswise distance as amplitude increases. It is also noticed that the decay in bottom wall temperature increases with increasing A when N = 10, thereafter, the decrease in bottom wall temperature is nearly same beyond N > 9.