Flow and Heat Transfer Performance of Channels with ‎‎۴۵ Degree Ribs in Staggered Array‎

The cooling efficiency of blade is growing demand with increasing turbine inlet temperature in gas ‎turbine development. Ribs used in cooling channels is a common cooling structure, therefore, many ‎configurations were studied by previous literatures, including angle, spacing, shape etc. However, there ‎are less research about the dislocation ribs structure. In this paper, the ۴۵-deg parallel ribs, crossed ribs ‎and dislocation ribs were investigated by numerical simulation, in order to reveal the heat transfer ‎performance and flow mechanism. Refer to the experiment, SST k-ω model was applied in steady ‎simulation, at Re from ۲۰۰۰۰ to ۵۰۰۰۰. Due to the angled ribs can induce the secondary flow and ‎generate small helical vortices at front corner, heat transfer performance was elevated. The large rotating ‎vortices influenced by the ribs arrangement occupy the center channel, thence the dislocation caused ‎different flow and heat transfer results. The results shown that parallel rib has higher heat transfer ‎enhancement than crossed ribs, but pressure loss possess considerable level. At Re=۲۱۵۸۷, the averaged ‎turbulent kinetic energy of Case۲.۲ with dislocation ribs is ۲۲.۴% lower than parallel ribs. The all ۴۵-deg ‎crossed ribs present higher level of overall thermal performance, and Case۲.۲ is optimal for the range of ‎Re investigated‎.

Keywords:

Internal cooling , Numerical simulation , Ribs , Gas turbine , Heat transfer