微小通道碳氢燃料多时间尺度化学非平衡流场协同优化研究

Lacking of fuel heat sink has been preventing the development of hypersonic propulsion for a long time and it is the key problem in developing the cooling system of the scramjet engine. The non-equilibrium chemical reaction with multi-scale characteristic time makes the flow and heat transfer process of the hydrocarbon fuel flow in the small scale cooling channels more complicated than that in a normal cooling system. In this project, the coordination optimization method based on the interaction between the characteristic times of hydrocarbon fuel flow and chemical reaction in the small scale cooling channel is brought out: Controlling the cracking rate along the cross direction through controlling the relativity between the flow and chemical reaction. Then the nonuniformity of the fuel conversion along the cross section can be alleviated to improve the utilization of the fuel heat sink, which is of significant importance to the improvement of the engine's performances and the increase of the flight Mach number. In this project, numerical simulation and experimental research will be combined to carry on the study because of the complexity of the flow and heat transfer process with multi-scale characteristic time and non-equilibrium chemical reaction in a small scale cooling channel. The model of multi-step chemical reaction kinetics and the numerical model taking the non-equilibrium reaction into account will be built. An experiment and measurement system will also be established to measure the temperature/density field of the flow.

燃料热沉是否够用一直困扰着高超声速推进的发展,是超燃冲压发动机冷却最大的技术瓶颈。微小通道内化学反应的发生使得碳氢燃料冷却过程较一般流动传热传质过程复杂，且呈现多时间尺度的化学非平衡效应。本项目提出基于流动与化学反应特征时间相关的流场协同优化方法：通过控制沿流场径向梯度方向流动与化学反应特征时间的相关性程度，来控制流场径向梯度方向裂解反应速率大小，进而控制流场径向裂解反应速率梯度，来实现降低流场径向裂解转化率的非均匀程度，来提高燃料热沉利用水平，对于提升整个超燃冲压发动机的性能和拓展发动机的飞行马赫数均具有重要的意义。鉴于微小通道内、多时间尺度、化学非平衡碳氢燃料流动传热过程的复杂性，本项目将采用数值计算与试验研究相结合的研究手段，建立多步化学反应动力学模型、建立化学非平衡过程数值计算模型，建立专门的能够反映温度场/浓度场不均匀性的试验和测量系统。

燃料热沉是否够用一直困扰着高超声速推进的发展,是超燃冲压发动机冷却最大的技术瓶颈。微小通道内化学反应的发生使得碳氢燃料冷却过程较一般流动传热传质过程复杂，且呈现多时间尺度的化学非平衡效应。围绕有限冷源下超燃冲压发动机燃料冷却过程中流动传热及裂解反应过程工作机理，本项目开展了相关的研究工作：发现了燃料冷却过程中燃料流动与裂解反应过程存在特征时间相关性，揭示了非平衡效应下流动与裂解反应过程耦合工作机理，发展了基于有机结合流向裂解反应转化率调控、径向裂解反应速率梯度调控的变通道结构设计和化学反应流场控制方法。通过控制沿流场径向梯度方向流动与化学反应特征时间的相关性程度，来控制流场径向梯度方向裂解反应速率大小，进而控制流场径向裂解反应速率梯度，来实现降低流场径向裂解转化率的非均匀程度，来提高燃料热沉利用水平。为提升有限冷源下超燃冲压发动机循环性能和最高工作马赫数，提供了重要的理论支撑和有效途径。.部分研究成果在国家重大专项中得到了应用。 累计发表SCI论文31篇(第一和通讯作者论文)，SCI一区论文21篇，EI论文1篇，会议论文7篇，授权国家发明专利3项，申请国家发明专利6项，获教育部科技进步一等奖和黑龙江省自然科学二等奖共计2项。培养了博士生3名，硕士生6名。