基于kHz激光精细成像技术的硼/乙醇纳米流体燃料喷雾燃烧特性研究

为了提高液体火箭发动机的比冲和推重比，需要高能焓的推进剂。采用化学合成新燃料分子结构的方法已很难大幅提升液体燃料的能量密度，向传统碳氢燃料中添加纳米颗粒形成纳米流体燃料，可提高燃料整体的体积热值、降低点火温度、缩短着火延迟时间并提高燃烧效率。但纳米流体燃料燃烧过程中所涉及到的颗粒从喷雾液滴中的逃逸机制、非均相燃烧机理、颗粒对瞬态燃烧过程的影响等科学问题仍不明确，限制了纳米流体燃料的实际应用。因此，本项目采用基于超高重频脉冲群式激光诊断技术，拟对硼/乙醇纳米流体燃料的喷雾及燃烧过程中所涉及的多相、多尺度、多组分的物理机制进行系统研究，探索纳米颗粒在超高分辨时空尺度中与液相的相互作用机制、对流动与化学反应带来的影响，进而加深对纳米流体燃料喷雾燃烧过程中宏观现象与微观机制的认识，达到通过设计适当纳米材料的物性参数，以可控的方式充分利用存储在高能颗粒中的化学能，实现纳米流体燃料的广泛应用。

Over the last decade, researchers were devoted to improve the combustion and emission performance of conventional fuels. A novel concept of nanofuel was proposed, suspensions of energetic nanomaterials in a liquid medium, as a potential energy carrier. Nanoparticles burn much more easily because of their large surface area to volume ratio and short oxidizer diffusion length. Using optimized blend of nanoparticles and hydrocarbon fuel can help to decrease the world’s demand on fossil fuels dramatically without modification of the state-of-art engines and significantly reduce emission of particulate matters, carbon monoxide, sulphur oxides, and unburned hydrocarbons. .However, nanofuels have been rarely studied, and our knowledge about them remains very limited. Some challenges have to be tackled before its fully industrial employment. The fuel itself contains liquid and solid particles, and its colloidal stability depends largely on the interfacial properties between the particle and the surrounding fluid molecules. Thus, the combustion of nanofuels is a highly complex phenomenon, which is a multiphase, multicomponent, and multiscale process, and these processes can interact with one another to make our fundamental understating even more difficult. Another key challange is to completely utilize the chemical energy stored in energetic particles in a controllable manner, where the energy release rate is dependent on practical applications. .Motivated by above, the spray and burning characteristics of nanofuels with the addition of boron nanoparticles in ethanol will be investigated in this project based on ultra-fast laser diagnostic. The effect of particle diameter and particle-loading rate on atomization and droplet-burning characteristics will be examined with ultra-high spatial and temporal resolution. The influence of jet and swirling flow on the spray and combustion process of nanofuel will be compared and investigatged in detail. The fundamental mechanisms responsible for particles escaping from the primary droplet will be discussed as well.