Effect of enhanced heat transfer structures on the chemical recuperation process of advanced aero-engine
2020
Li, Xin | Zhang, Silong | Ye, Mai | Qin, Jiang | Bao, Wen | Cui, Naigang | Liu, Xiaoyong | Zhou, Chaoying
Regenerative cooling process of advanced aero-engine with endothermic hydrocarbon fuel is a typical chemical recuperation process that always happens in heated cooling channels with severe thermal stratification. In order to study the effect of enhanced heat transfer structures on the heat sink utilization and non-uniform chemical recuperation process, numerical models of cracking hydrocarbon fuel flow in the cooling channel with the micro-rib and dimple embedded in one-step reaction model were built and validated. The results indicate that the dimple and micro-rib could enhance heat transfer but bring drawbacks to the chemical recuperation process especially under higher heat flux due to the nonlinearity of thermal cracking reaction, which mainly happens in the thermal boundary layer and velocity boundary layer. And the micro-rib will cause larger disturbance than dimple because it gives global enhancement on flow mixing between the mainstream and flow near the wall. Besides, increasing micro-rib height and decreasing its width could not change the situation but make it worse although the nonuniformity of heat absorption is remarkably alleviated. Compared with the single micro-rib unit, the periodic micro-rib array has a significantly continuous influence on heat transfer and heat absorption in the chemical recuperation process of cracking hydrocarbon fuel.
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