添加结焦抑制剂的碳氢燃料流动传热及裂解反应耦合机理研究

Anti-coking of hydrocarbon fuel is a key technology for the future hypersonic vehicles which take advantage of the heat sink of hydrocarbon fuel for the scramjet engine cooling. Focusing on the hydrocarbon fuel with coking inhibitor, the coupling mechanisms of flow, heat transfer and pyrolytic reaction in the regenerative cooling channel will be investigated. The investigation could be based on the existing research foundations on physical properties, heat transfer and coking/anti-coking of hydrocarbon fuel achieved by our team. The main contents are as follows: the physical properties model of the inhibitor-added hydrocarbon fuel will be established, based on the quantitative experimental assessment of the effects of coking inhibitors on physical properties; the one-step global pyrolytic reaction of the hydrocarbon fuel with coking inhibitor will be developed, according to the influences of coking inhibitor on pyrolysis process revealed from experiments; the in-house three-dimensional computational software, which could be incorporated with the above physical/chemical models and be algorithmically improved, will be used for the high-precision numerical studies to fundamentally understand the impacts of coking inhibitor on flow and heat transfer characteristics, as well as on the pyrolysis behavior. It is expected that the temperature field of the regenerative cooling structure and the concentration field of the coking precursors will be more accurately predicted through this investigation, which provides cutting-edge technical reserves and theoretical references for the scramjet engine design.

对于未来高超声速飞行器，结焦抑制是碳氢燃料作为热沉冷却其发动机必须要突破的关键技术。本项目基于团队在碳氢燃料物性、流动传热、结焦/结焦抑制方面的研究基础，以添加抑制剂的碳氢燃料为核心，拟开展结焦抑制剂对主动冷却通道内碳氢燃料的流动传热和裂解反应的耦合影响机理研究。主要包括：基于试验完成结焦抑制剂对碳氢燃料物性参数的影响定量评估，建立添加抑制剂的碳氢燃料物性模型；基于试验揭示结焦抑制剂对碳氢燃料裂解反应过程参数的影响规律，建立添加抑制剂的碳氢燃料裂解反应总包模型；在申请人自主开发的三维流动传热软件基础上，改进算法并开发模块，嵌入上述物理模型，通过高精度数值研究澄清结焦抑制剂对碳氢燃料的流动换热特性、裂解反应程度的影响机理。期望通过本项研究更为精确的预测主动冷却结构的温度场和结焦前驱体浓度场，为超燃冲压发动机设计提供前沿性的技术储备和理论支持。

结焦抑制剂是解决超燃冲压发动机再生冷却通道中碳氢燃料高温氧化结焦问题的关键技术，但结焦抑制剂对冷却通道内碳氢燃料流动换热规律耦合裂解反应的过程的影响机制尚不明确。本项目通过实验测量建立了添加抑制剂的碳氢燃料物性模型及裂解反应总包模型，并应用数值模拟方法揭示了其在再生冷却通道内流动换热及裂解过程的耦合影响机制。 .本项目主要包含三部分研究内容：（1）有无抑制剂的碳氢燃料物性模型研究；（2）有无抑制剂的碳氢燃料裂解模型研究；（3）结焦抑制剂对碳氢燃料流动换热与裂解反应的耦合影响机制研究。.首先，实验研究获得了含结焦抑制剂的吸热型碳氢燃料的热物性数据，发现超临界条件下结焦抑制剂对于燃料的黏度和导热系数的影响较大，平均偏差分别为21.7%和9.47%，而对定压比热和密度的影响较小，平均偏差仅有1.4%与2.5%，并建立了含结焦抑制剂的吸热型碳氢燃料物性模型。其次，通过对比不含结焦抑制剂的燃料一步裂解总包动力学模型及含结焦抑制剂的多步裂解动力学模型，分析了结焦抑制剂对裂解反应模型的影响规律。最后，在已有的三维流动传热软件平台嵌入上述物性及裂解模型，使其具备准确模拟碳氢燃料流动传热耦合裂解反应的功能，对不同工况下冷却通道内有无抑制剂的碳氢燃料流动传热耦合裂解反应的过程进行模拟，研究发现热流密度的升高会提升抑制剂的结焦抑制效果，而流速与压力的升高则会减弱结焦抑制效果，揭示了抑制剂对于燃料流动换热及裂解过程的影响机理。.本项研究工作完善了超临界碳氢燃料结焦抑制的理论体系，奠定了超临界碳氢燃料结焦抑制理论研究的基础，加快了含结焦抑制剂的碳氢燃料在再生冷却系统中的推广应用，为我国超燃冲压发动机的发展提供前沿性的技术储备和理论支持。