燃油惰气发生器燃烧室气雾两相流场数值模拟

Numerical simulation of two-phase gas-droplet flow in combustor generating inert-gas by fuel burning

以新型燃油惰气发生器燃烧室为研究对象,对气相采用重整化群(renormalizationgroup,RNG)k-ε双方程模型,对颗粒相采用随机颗粒轨道模型,考虑气雾两相间的耦合作用,采用二阶迎风差分和SIMPLE算法,数值模拟燃烧室内的气雾两相三维流场,得到了燃烧室内空气—油雾两相流动动力学特性,比较分析了数值模拟结果与实验数据。研究结果表明,在旋流射流、壁面圆孔射流及燃烧室特殊几何结构的共同作用下,燃烧室内充满旋流,同时存在多个回流区,油气掺混剧烈而充分,有助于燃料点火、稳定火焰和提高燃烧效率。本文结果有助于燃油惰气发生器燃烧室燃烧性能的分析及结构与工艺参数的优化。

This paper intends to present the authors＇ numerical simulation of the two-phase gas-droplet throe-dimensional （3D） flow field in a new-type combustor generating inert gas by fuel burning, As is known, inert gas is a kind of efficient eco-environmental and economically beneficial media in suppressing explosions and fire prevention. But its R＆D has been limited for the lack of enough inert-gas resource and satisfactory safety protection technology. In our research, its gas phase is described with the renormalization group k-ε two-equation model and the particle phase is expressed in the particle stochastic trajectory model. In the given simulation, the coupling interaction between the gas phase and the particle phase has been considered with the second order upwind difference as well as the SIMPLE arithmetic properly adopted. Then, the numerical simulation resuits are compared and analyzed with the testing data. At the same time, prediction of the flow field distribution and, the .particale trajectory in the combustor has been made. The final results of the simulation indicate that all the swirl-flow, the air jet of orifice and special geometric structure may have an important effect on the flow field distribution in the combustor. With the two recirculation zones existing in the combustor, the whole combustor can be made full of swirling flow. The flow is thus featured with .favorable flame ignition, stability and improved combustion efficiency with great turbulent intensity and strong and sufficient for fuel-air mixing. It can thus be seen that useful information has been provided in this paper for analyzing the kinetics regulation of the gas-droplet two-phase and optimizing the geometry structure and process parameter of the combustor.