Li Meng-Ge, Wu Yan, Cao Qin-Liu, Yuan Xin-Yi, Chen Xiong, Han Jun-Li, Wu Wei-Tao
School of Mechanical Engineering, Nanjing University of Science & Technology, Nanjing 210094, China.
Shanghai Xinli Power Equipment Institute, China Aerospace Science and Technology Corporation, Shanghai 201109, China.
Gels. 2022 Aug 14;8(8):507. doi: 10.3390/gels8080507.
Gel fuel potentially combines the advantages of solid fuel and liquid fuel due to its special rheological properties, which have essential impacts on the application of gel fuel in propulsion systems. In this paper, we study the rheological property of organic kerosene gel through a series of measurements on its viscosity as a function of the shear rate, temperature, and shear history. The measured datasets are then fitted with constitutive relationships between the viscosity and shear rate at three different levels: the power law shear-thinning model, the power law dependency on both the temperature and shear rate, and the thixotropic property. It is found that intense pre-shear could exhaust thixotropy and reduce viscosity of the kerosene gel. For the power law shear-thinning model, the consistency index increases with the gellant mass fraction, whereas the power law exponent remains constant. The dependence of viscosity on temperature could be well approximated by an empirical power law relationship. As for the thixotropic property of the kerosene gel, the fitted second-order kinetic model corresponds accurately to the viscosity at different shear rates and shear times. The constitutive models fitted in this work at different levels are consistent with each other and provide useful tools for further applications of organic kerosene gel fuel.
凝胶燃料因其特殊的流变特性，有可能兼具固体燃料和液体燃料的优点，这对凝胶燃料在推进系统中的应用有着至关重要的影响。在本文中，我们通过对有机煤油凝胶的粘度随剪切速率、温度和剪切历史的一系列测量，研究了其流变特性。然后，将测量数据集与粘度和剪切速率之间在三个不同层面的本构关系进行拟合：幂律剪切变稀模型、粘度对温度和剪切速率的幂律依赖关系以及触变性。研究发现，强烈的预剪切会耗尽触变性并降低煤油凝胶的粘度。对于幂律剪切变稀模型，稠度指数随胶凝剂质量分数的增加而增大，而幂律指数保持不变。粘度对温度的依赖性可以通过经验幂律关系很好地近似。至于煤油凝胶的触变性，拟合的二阶动力学模型与不同剪切速率和剪切时间下的粘度精确对应。本文在不同层面拟合的本构模型相互一致，为有机煤油凝胶燃料的进一步应用提供了有用的工具。
