Numerical simulation for flow and heat transfer characteristics in steam-cooled square ribbed channel

To clarify the underlying principle of heat transfer enhancement in a steam-cooled square ribbed channel, the flow field and heat transfer characteristics of a square ribbed channel were numerically simulated by 3-D steady RANS equations coupled with standard k-ω turbulence model. The influences of Reynolds number, inlet aspect ratio and rib pitch on the flow and heat transfer characteristics were investigated, the heat transfer correlation of square ribbed channel was analyzed, and then the relationship of Nusselt number with Reynolds number, inlet aspect ratio and rib pitch was obtained. The result indicates that heat transfer enhancement is caused by the existence of ribs which destroy the thick heat transfer boundary layer. As Reynolds number grows up, the average Nusselt number and thermal enhancement factor increase while the friction factor increases slightly. Larger inlet aspect ratio also leads to greater thermal enhancement factor and better average Nusselt number, and the friction factor also increases obviously. The increase of rib pitch results in a growing average Nuusselt number. When the rib pitch increases, the friction factor increases firstly and then decreases, while thermal enhancement factor decreases firstly and then increases. © 2016, Xi'an Jiaotong University. All right reserved.