Experiments on mist flow and heat transfer in a tube fitted with porous media

The issues related to porous media are more important in the design and analysis of heat exchangers. Reducing size of heat transfer devices for using of this media was led to be feasible of creating flow with smaller Reynolds numbers. In present study, an experimental investigation of air mist flow is carried out in tube which fitted with porous media. The studied porous region has different geometry. Also the effect of operating parameter like Reynolds number is analyzed. Results indicate that presence of porous media leads that the thermal flux applied to walls of channel be transferred into fluid due to creating a uniform space and high conductivity of porous media. Also, the results depicted that in comparison with the single-phase, mist cooling in porous media can increase the heat transfer rate. Results show that combine these two method (porous medium and mist flow) has significant effect on heat transfer enhancement. According to obtained results, at low Reynolds number with mist flow, the case that porous zone inserted adjacent to wall with 4 cm height has best thermal performance and at high Reynolds number with mist flow, highest thermal performance is belonging to the case that porous zone inserted at the center of the channel with 6 cm diameter. As a final result, between the all investigated models, the case that porous zone inserted at the center of the channel with 6 cm diameter with mist flow has the best heat transfer performance ratio with 24% improvement in comparison with clear channel.