离心力作用下超临界态煤油流动与传热特性研究

Turbulent pipe flow and heat transfer of supercritical kerosene under centrifugal forces are studied with experimental and numerical methods. Variations of flow and heat transfer properties of kerosene in helical pipe on curvature, Reynolds number at the inlet and other flow parameters are obtained and compared to those for straight circular pipe. The centrifugal effects on flow patterns and secondary flow, as well as on wall friction and heat transfer deterioration or enhancement are studied and the associated mechanisms are revealed. The relation between flow and heat transfer properties of supercritical kerosene in helical pipe and curvature, Reynolds number and thermodynamic parameters of kerosene is established. The present study will broaden and promote the understanding of supercritical hydrocarbon fuels and provide useful results and guides for fuel control and cooling optimizations for flight vehicle and engine applications

本项目将采用实验与数值计算相结合的方式研究离心力作用下超临界态煤油圆管湍流流动与传热特性，获得不同曲率、入口雷诺数等参数条件下螺旋弯曲圆管内超临界态煤油湍流流动与传热特性的变化规律及其与直管规律的差异，揭示离心力对煤油圆管流动形态、二次流现象、壁面摩阻、传热强化/恶化的影响规律及内在机制，获得煤油流动与传热参数随曲率、雷诺数以及煤油热物性的变化关系。研究工作将拓宽和加深对超临界态碳氢燃料流动与传热机理的认识，并且为航天、航空飞行器与发动机燃料控制与冷却优化提供参考。

本项目以航天航空飞行器与发动机再生冷却技术为背景，针对离心力作用下的航空煤油流动与传热特性开展了实验与数值研究，获得了不同流动参数以及螺旋管曲率条件下煤油流动与传热规律。实验数据表明，螺旋管外侧传热系数明显高于内侧；并且外侧传热系数高于相同条件下直圆管传热系数，但内侧传热系数低于直圆管；同时螺旋管道摩阻系数高于直管道摩阻系数。本项目发展了考虑煤油物性变化的数值仿真方法，仿真结果揭示了离心力导致二次流的产生以及螺旋管内湍流强度变化是煤油传热强化与恶化的主要机制；并且发现了超临界态煤油传热恶化伴随的脉动特征，传热脉动的特征频率约111Hz。本项目的研究成果为深入了解离心力对煤油流动与传热的影响机理提供了有益的参考，并为面向发动机热防护需求的紧凑式燃料冷却系统设计提供了重要的基础数据与设计依据。