固体火箭发动机两相内流场的连续介质-离散颗粒耦合混合模型数值模拟

Numerical Simulation of Two-Phase Internal Flow Field in SRM with Continuum-Discrete Particles Coupled Hybrid Model

关键词:  固体火箭发动机  拉格朗日法  平衡欧拉法  耦合混合模型  气粒两相流

Key words:  Solid rocket motor  Lagrangian method  Equilibrium Eulerian method  Coupled hybrid model  Turbulent gas-particle two-phase flow

摘要:

为解决含Al推进剂固体火箭发动机内流场两相流动的数值模拟问题，采用将颗粒相视为连续介质和离散颗粒相结合的综合方法，建立起气相与颗粒相的双向耦合混合模型。针对颗粒类型与粒径尺寸的不同，采用拉格朗日法描述大粒径颗粒，平衡欧拉法描述小粒径颗粒，克服了现有模型难以全面考虑颗粒尺寸效应而使模拟精度下降的困难，通过算例验证了该混合模型的有效性和准确性。针对含Al推进剂固体火箭发动机内流场湍流气粒两相流动进行了数值模拟，分析了不同粒径尺寸颗粒的分布及其对发动机内流场和结构性能的影响情况。结果表明，大颗粒粒径在跨喷管段变化明显，平均减小30%。粒径40μm以上的颗粒易破碎，且燃烧效率进入平台区，较10μm颗粒下降50%以上，其Al含量均大于60%。

Abstract:

To deal with the problem of two-phase flow inside a Solid Rocket Motor(SRM)with aluminized propellant， a two-way coupling hybrid model was established by utilizing a comprehensive approach that consider particles as a combination of continuum and discrete particles. Large particles are described by the Lagrangian method， small particles are described by the equilibrium Eulerian method， which overcome the problem of accuracy reduced due to the difficulty of fully considering the particle size. The model was verified by an example and a numerical simulation of turbulent gas-particle two-phase flow in SRM with Al propellant was conducted. It shows that the size of large particles changed significantly across the nozzle with an average decrease of 30%. Particles with a diameter of 40μm and above were easily broken， and its combustion efficiency entered the platform area， with a decrease of more than 50% compared with that of 10μm particles， and the Al composition was greater than 60%. The distribution of particles with different sizes and their influence on flow field and structural performance of the SRM are analyzed. It provides a new effective method that improving numerical simulation accuracy of full-scale three-dimensional two-phase internal flow field of aluminized propellant SRM with a submerged nozzle.