短环形燃烧室内三维两相燃烧流动研究

【作者】 邹葆华；

【导师】 胡春波；

【作者基本信息】 西北工业大学 ， 航空宇航推进理论与工程， 2006， 硕士

【摘要】 航空发动机燃烧室是燃油和空气进行混合并燃烧的场所,如果燃料燃烧充分和完全,则释放的化学能就越高,气体获得的动能也就越多,因此燃烧室的燃烧性能对整个发动机的性能将产生决定性的影响。 本文采用某型发动机结构,首先从多点喷射的角度对燃烧室内的空气流动、气液雾化掺混、气液燃烧等方面进行了数值模拟计算。计算结果表明:在不改变总的空气流量的情况下,当燃烧室头部喷嘴和旋流器数目改变的时候,燃烧室头部气流场会发生改变,特别是对头部的回流区有很大的影响,并且回流区的大小范围与喷嘴的数目并不是呈简单的线性关系。由于气流流场的改变,燃烧室内的燃油液滴运动轨迹、燃油雾化掺混、索太尔平均直径(SMD)均相应发生改变,从而进一步影响到燃烧室内的燃烧,主要是对出口截面处的温度分布、温差影响比较大。其次通过改变燃烧室构型来研究其对燃烧室内流场和燃烧性能的影响。计算结果表明:传统燃烧室内的气流回流区相对比较小,而且在出口处容易出现明显的高温区,通过改进燃烧室形状可以优化燃烧室出口截面处的温度分布。因此采用数值计算的方法可以优化燃烧室构型,并为燃烧室的设计提供了依据。 设计了燃烧室冷态实验,实验件构型为真实燃烧室1:2的比例。通过高速运动分析仪获得了液滴分布图像,图像与模拟计算结果是比较一致的,验证了计算中所采用的液滴模型的合理性。 应用模糊数学原理建立了多个模糊模型。通过采用合理的指标,利用模糊聚类模型对不同工况的实验数据进行分类,并对发动机和燃烧室性能进行评判。利用已有实验数据和预测模型,对未知工况的实验数据进行预测。计算结果与实际情况相比较是一致的。更多还原

【Abstract】 The combustor is the place where the fuel mixes and combusts with air. More completely the fuel combusts, higher the chemistry power released by the fuel, and more kinetic energy air would gain. Therefore the combustion performance would determine the engine’s performance.The model used in this paper is the same as the real one in size. Based on the numerical simulation, the air flow, mixture of air and fuel, combustion in the combustor are simulated from the point of the multiple injections firstly. The results show: unchanging the total air flow mass, when the number of the sprayers changes, the air flow in the head of the combustor would change, and has great effect to the circumfluence area. And the scale of the circumfluence is not simple linearity with the number of sprays. With the change of the air flow, the tracks, the atomization, and the SMD of the liquid particles would change accordingly;consequently affect the combustion, mainly to the temperature distribution and difference on the outlet. The effect of the combustor’s shape to the flow and the combustion performance is researched secondly. The results show: the circumfluence area of conventional combustor is relatively small, and there is an obvious high-temperature-area near the outlet. The distribution of temperature could be changed by the amelioration of the shape. The method of the numerical simulation could offer the reference to the design of combustor.The cold flow experiment in the model combustor is designed. The photos of the distribution of liquid particles are collected by Hi-Spec. Compared to the simulation results with the experimental data, the rationality of the liquid particles model in the computation is validated.By using the fuzzy set theory, several fuzzy model are set up. Adopting logical index, several sets of experimental data are classified to judge the performance of combustor. On the base of the known data, the unknown data is predicted. The result is according to the real instance.更多还原