【作者】 许峰；

【导师】 王彤；

【作者基本信息】 上海交通大学 ， 动力机械及工程， 2010， 硕士

【摘要】 本文以RAH-66直升机的T800发动机惯性粒子分离器为原型,提炼出分叉管道模型进行实验和数值分析。根据分离器模型的流道特点,进而将清除流通道简化为不同扇角弯道,并进行气固流动规律分析。针对无预选惯性分离器壁面附近小尺度颗粒分离效率低的缺点,研究了带射流方腔结构内的气固流动,为进一步设计高效的惯性气固分离设备提供依据。为了细致分析气固两相流动与分离特点,文中分析了单个球形颗粒受力以及同壁面的碰撞模型;在实验中使用高速摄影和PIV技术,结合数字图像处理技术跟踪固体颗粒的运动轨迹,实现了对颗粒运动轨迹和颗粒浓度的研究;数值计算采用FLUENT和EDEM软件耦合模拟计算通道内气流速度为10～100m/s,颗粒直径为5～500μm的气固两相流动。通过理论分析、实验和数值模拟结果,可以得出以下结论:(1)分叉管道流道:同一密度和粒径范围的颗粒,块状颗粒的分离效果好于球形颗粒;随着主流速度的增加,直径100μm下的颗粒的分离效率跟着增加,但颗粒直径大于100μm的颗粒分离效率会受到速度大小与碰撞的双重影响;颗粒的分离效率将受到流量系数带来的回流影响。(2)本文提出了颗粒分布指标:分布系数η和分布方差σ。方截面弯道内小尺度颗粒(10μm)随着气流速度和弯管扇角的增加,颗粒分布系数会逐渐增加,聚集度越来越高,但压力损失会增加。对于90o方截面弯道流动,速度越大、颗粒尺度越大、颗粒密度越大,越容易实现空气气流中的小尺度颗粒分离。(3)带射流的方腔流动:颗粒在射流的影响下聚集在方腔上部,随着下游距射流孔后距离的增加,靠近上壁面的颗粒越来越多,中下部颗粒越来越少,但在下壁面附近有颗粒聚集现象;颗粒越小,射流影响越大,低浓度区域越大;射流速度越大,对颗粒分布影响越大,低浓度区域越宽。更多还原

【Abstract】 Based on separator of T800 helicopter engine, furcated duct model is got. Experiments and simulation are done for the model. Then it is simplified to different angles of pipes followed by the flow shape. Gas-particle flow in cubic with injection is researched because of the low separation efficiency for the micro-particles near wall. It will provide evidence to design more efficient inertia separator. In this thesis, ball particle force balance and particle-wall impact model are analyzed. Particles trajectory and concentration can be gotten by high-speed photography and PIV technology combined with image processing technology. Gas-solid separation phenomenon is investigated by using the commercial code FLUENT coupled with EDEM. The particles’diameter ranges from 5μm to100μm, and the gas velocity change from 10m/s to 100m/s.Conclusion from theory analysis, experiments and numerical simulation are as follows:(1) For the furcated duct, the separation efficiency of particle is related to particle physical nature, structure, air velocity and so on. The separation efficiency of lump corns is better than ball millets, which have the same density with corns. With the increase of air inlet velocity, separation efficiency of particles whose diameter is under 100μm will raise gradually. But if the diameter is bigger than 100μm, efficiency will be affected by velocity and collision. Backflow caused by SCR also decides separation efficiency.(2) Distribution coefficientηand mean square deviationσare put forward.ηand the extent of cluster of micro-particles (10μm) in the curved pipe increase with the increment of curved degree and gas velocity. But the pressure loss will increase. For the 90o curved pipe flow, if the main velocity of gas or particle diameter or particle density is lager, micro-particles will be easier to be separated.(3) For the cubic with jet flow, particles affected by the injection will congregate in the upper area of cubic. Concentration of particles near up wall increases with increment of distance from jet hole. And it decrease in the down area except the position near base wall. If the particles are smaller, the impact of injection is larger. The velocity of jet is larger, the area of low concentration is wider.更多还原