Experimental Study of Flow and Heat Transfer of High-performance ribs for Internal Cooling of Gas Turbine Blades

Rib turbulators are effective structures to enhance heat transfer in the internal cooling channel of gas turbine blades. The heat transfer and flow friction characteristics of different shaped ribs have been investigated in this paper. Experimental results show that the W-shaped rib has the highest average Nusselt number values, and the V-shaped rib and the straight rib have lower Nusselt number values, and the angled rib has the lowest values. When compared to the smooth channel, the channel with W ribs shows 2.2~2.6 times the Nusselt number values, and the channel with angled rib shows about 1.7 times Nusselt number values. It is also found that the angled rib shows the minimum friction factor values, which is about 1.8~2.5 times those of the smooth channel, and the W rib shows the friction factor values of 2.5~3.7 times those of the smooth channel. The W rib has the best overall thermal performance factor, and the straight rib shows the lowest overall thermal performance. On the other hand, the transient liquid crystal thermography technique has been used to obtain the local heat transfer performance on the surface with W ribs in the channel. Downstream the apex point of the W rib against the flow shows a high heat transfer enhancement region, where the oncoming flow strongly interacts with the ribs, producing downwashing vortex flow and making the boundary layer become thinner, which significantly enhances the heat transfer performance there. © 2018, Science Press. All right reserved.