微细通道内碳氢燃料流动换热与催化裂解耦合机理研究

Scramjet is the core of air-breathing hypersonic vehicle, in which the thermal environment of the combustion chamber is extremely complex and bad. This process involves fluid mechanics, structural mechanics, heat transfer and chemical reaction kinetics, and is strongly interdisciplinary. Therefore, new scientific research connotation is derived, and it has important scientific meaning and practical value. In this project, in order to solve the key basic scientific problems of scramjet combustor regenerative cooling, numerical simulations and experimental researches are used to study the mechanism between the physical and chemical changes and the characteristics during the energy and mass transfer process under the complex and extreme conditions in detail. The flow and heat transfer mechanism of supercritical hydrocarbon coupled with catalytic racking are investigated profoundly, and the inherent relations and regularities between the thermal structures and the physical and chemical changes during the flow and heat transfer process of hydrocarbon are revealed, and so are the Interface transfer phenomena and change characteristics. Three-dimensional multiphase systematic integrated physical and mathematical models for hydrocarbon with chemical reactions are developed. The effects of various parameters on the flow and heat transfer of hydrocarbon coupled with complex catalytic cracking are deeply studied to attain the influence law of cooling performance. The effective solutions and methods are concluded for enhanced heat transfer and cooling performance, and the important theoretical foundations and technical instructions are provided for the optimize design, control and operation of thermal management system of scramjet combustion chamber.

超燃冲压发动机是吸气式高超声速飞行器的核心，其燃烧室内热环境极为复杂而恶劣，过程涉及流体力学、结构力学、传热学及化学反应动力学等，具有很强学科交叉性，衍生出科学研究新内涵，有重要科学意义与实用价值。本项目针对超燃冲压发动机燃烧室再生冷却过程中的关键基础科学问题，采用数值模拟与实验研究相结合方法，详细研究复杂与极端条件下微细通道内碳氢燃料的物理化学变化机制与能质传递过程特性，深刻揭示超临界碳氢燃料的超常流动传热与催化裂解耦合机理、热结构与碳氢燃料流动换热过程中物理化学变化间的内在联系与规律、界面传递现象与变化特征等。发展伴随有化学反应的碳氢燃料冷却三维多相热流体系统综合数理模型，深入研究各因素对其特殊流动传热与复杂催化裂解耦合机制及冷却效果的影响规律；得出强化传热与提高冷却效果的有效措施和方法，为超燃冲压发动机燃烧室热管理系统的优化设计、控制及运行提供重要理论依据和技术指导。

高超声速飞行器是 21 世纪国际航空航天领域的主要研究方向与热点前沿之一。其中，热管理是该专项的核心问题之一，也是决定飞行器性能甚至成败的关键。.超燃冲压发动机燃烧室冷却的有效方法是采用飞行器自身携带的燃料进行冷却。因此，碳氢燃料在超燃冲压发动机燃烧室冷却通道内的流动换热成为国内外学者研究热点。本项目针对超燃冲压发动机燃烧室再生冷却过程中的关键基础科学问题，采用数值模拟方法，系统研究螺旋管内超临界碳氢燃料流动换热特性。考察不同质量流量、壁面热流密度、不同流体压力条件下，螺旋通道内碳氢燃料流动换热特性，掌握浮升力和离心力对碳氢燃料在螺旋通道内流动特性及其与壁面的传热规律，获得各因素影响条件下碳氢燃料在螺旋通道内努塞尔数和摩擦系数的经验关联式。为了强化矩形通道传热性能，研究通道内肋片结构对碳氢燃料流动传热特性进行研究，结果表明，肋片存在能够显著提高矩形通道内的对流换热系数，但流动阻力也随之增加。肋片的高度和间距对矩形通道内碳氢燃料流动传特影响较大，并根据研究结果获得经验关联式。对于凹腔通道内碳氢燃料流动传特进行数值研究，结果表明，凹腔处碳氢燃料流动变化比较显著，在此区域换热变化较大，流动阻力也较大，因此压降显著增加。综上研究，得出强化传热与提高冷却效果的有效措施与方法，为超燃冲压发动机燃烧室热管理系统的优化设计、控制及运行提供重要理论依据与技术支撑，确保高超声速飞行器的安全、稳定、可靠飞行。