液液针栓多喷注单元喷雾场数值模拟

Numerical simulation on spray field of liquid-liquid pintle multi-injector elements

为了研究相邻喷注单元间相互影响对针栓式喷注器喷雾场的影响,以平面针栓多喷注单元为研究对象,采用基于AMR(adaptive mesh refinement)技术和分相识别的PLIC VOF(piecewise linear interface calculation VOF)新方法,实现了针栓式喷注器雾化过程的高保真数值模拟。给出了喷雾场典型的结构特征及液雾的分布特性,对比了多喷注单元与单喷注单元喷雾场的差异,揭示了相邻喷注单元间的相互影响机制。研究表明,新的仿真方法在精细研究针栓式喷注器喷雾场方面具有较好的准确性。与单喷注单元相比,多喷注单元喷雾场主要存在以下特殊结构:相邻两雾扇相撞背部呈脊状结构,使得雾化区域大于雾化角;两雾扇相撞在中间对称面汇聚形成薄液膜,使整个雾化角范围内均有液滴分布;相邻两孔之间形成一定下漏率和下漏液膜宽度;液膜路和液束路的液滴粒径均显著增大了约35,流强和混合比沿径向分布更趋于均匀。相邻喷注单元间的相互影响机制为:相邻喷雾扇相撞后原先各自向外展开的雾扇被挤回中心对称面,其厚度是原雾扇的两倍,其他未发生撞击位置的液膜厚度保持不变,最终形成的喷雾扇结构呈扁平的多凹腔状。

In order to study the influence of the interaction between adjacent injector elements on the spray field in pintle injector,taking the plane pintle multi-injector element as the research object,based on a new method of AMR(adaptive mesh refinement)technology and PLIC VOF(piecewise linear interface calculation VOF)method in which each phase was individually identified,the spray process of pintle injector was simulated with high-fidelity.The typical structure characteristics and spatial distribution characteristics of the spray field were demonstrated quantitatively.The spray field were compared with that of the injector element,and the mechanism of interaction between adjacent injector elements was revealed.The results show that the new simulation method has good accuracy in studying the spray field of pintle injector.Compared with the injector element,the spray field of the multi-injector element mainly has the following special structures:two adjacent spray fans collide to form a ridge structure on the back,and causing the spray area to exceed the spray angle area.In addition,two spray fans collide and converge on the middle symmetry plane to form a thin liquid film,which makes the droplets distribute throughout the spray angle area.A certain leakage rate and leakage width of liquid sheet are formed between two adjacent radial orifices.The droplet diameters of liquid sheet path and liquid jet path increase significantly by about 35,and the distribution of flow intensity and mixing ratio tends to be more uniform along the radial direction.The interaction mechanism between adjacent elements is as follows:after the collision of adjacent spray fans,the original outward deployed spray fans are pushed back to the central symmetry plane,whose thickness is twice that of the original spray fan.However,the thickness of the liquid film at other nonimpact positions remains unchanged.Finally,the structure of the spray fan is a flat multi-cavity structure.