Investigation on the flow and heat transfer of mist/steam cooling in two-pass ribbed channels with various aspect ratios

The flow and heat transfer characteristics of mist/steam cooling in two-pass ribbed channels with various aspect ratios at both the stationary and rotating conditions are numerically investigated in this paper. The distribution and evolution process of secondary flows in ribbed channels and its effects on heat transfer are analyzed in detail. In addition, the Euler-Lagrange particle tracking method has been adopted in the present study to simulate twophase flow mist/steam cooling and the CFD model has been validated by experimental data with a good agreement. The results indicate that the secondary flow patterns are significantly impacted by the rotation of ribbed channel. The case of AR = 1/1 ribbed channel obtains the best heat transfer enhancement of mist/steam cooling and the maximum heat transfer augmentation is 63.9% and 111.5% at both the stationary and rotating conditions, respectively. The thermal performance in mist/steam cooling and steam cooling ribbed channels decays as Reynolds number increases. The case of AR = 1/4 ribbed obtains the best thermal performance for mist/steam and steam only over the tested Reynolds number range at both the stationary and rotating conditions.