Numerical Study on Heat Transfer Enhancement of the Two-pass Channel by Low Rib and V-shaped Rib Composite Structures
The increase of inlet gas temperature will lead to security problem of turbine blades.To ensure the safe op-eration of gas turbines,the composite structure is an effective way to enhance the cooling performance of the chan-nels to solve the problem.The SST k-ω turbulence model is chosen to numerically simulate the flow and heat transfer characteristics of the two-pass channel.The thermal performance of the circular rib composite structure,the fan-shaped rib composite structure,and the calabash rib composite structure are compared with the solely V-shaped rib at Re of 10 000 to 60 000,aiming to explore the rib structure with the best heat transfer effect from the three com-posite structures of the turbine blade.The investigation concludes that the thermal performance of the composite structures augmentable compared the pure V-shaped rib.The best thermal performance is the composite structure of the calabash rib.The Nu of the calabash composite rib increases by 4.33～6.6％compared to the solely V-shaped rib,the calabash rib composite structure f is larger by 0.04～4.48％compared to the solely V-shaped rib,and the calabash composite structure f reduces by 3.67～5.21％compared to the fan rib composite structure.It concludes that the thermal performance index(η)of the composite structure is enhanced compared to the channel with solely V-shaped rib.The composite structure of calabash rib has the best thermal performance index,and the maximum value of η reaches 2.13.The η of the calabash rib composite structure is increased by 25.51～32.98％and 4.73～10.51％compared to 45° oblique square ribs and 45° oblique petal-shaped ribs,respectively.And the composite structure with low ribs and V-ribs has a significantly higher thermal performance than the composite structure with dimples and V-ribs.The proposed composite structure of calabash rib has great potential to enhance the thermal hydraulic perform-ance of the cooling channel for gas turbine blade.
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