Three-Dimensional Flow Simulations in the Recessed Region of a Coaxial Injector
Three-Dimensional Flow Simulations in the Recessed Region of a Coaxial Injector
复制标题
同轴喷油器凹进区域的三维流动模拟
DOI：
10.2514/1.12651
复制
发表时间：
2005
影响因子：
1.9
通讯作者：
S. Collicott
中科院分区：
文献类型：
--
作者：
Byoung;S. Heister;S. Collicott
建立了一种三维、两相、非定常Navier-Stokes求解器，用于研究剪切同轴喷油器元件凹区内的流体动力不稳定性。在这里，主要重点是研究使用气/液剪切同轴元件的液体火箭发动机喷射器的相关应用，其中内部液体圆柱柱相对于装置的整体出口平面略被淹没。由于之前的大部分工作都集中在喷油器外部的喷雾结构上，因此本研究为读者提供了对由燃烧室上游内部喷嘴流动的流体动力不稳定引起的非定常的深入了解。目前的研究主要集中在非定常“自振荡”上，这已经被许多研究者理论化了。开尔文-亥姆霍兹不稳定机制是气液相之间速度不连续的结果，研究了可能导致燃烧粗糙度或不稳定的不稳定来源。对于现有的液体火箭发动机喷油器，由于这种高度非线性的过程，存在30-40%量级的质量流量变化。基频也被确定为一系列的条件。
A three-dimensional, two-phase, unsteady Navier-Stokes solver has been developed to investigate fluid dynamic instabilities within the recessed region of a shear coaxial injector element. Here, the main emphasis is to study applications related to liquid rocket engine injectors using the gas/liquid shear-coaxial element in which the inner liquid cylindrical post is submerged slightly with respect to the overall exit plane of the device. Because most of the previous works focus on spray structure outside of the injector, this study provides readers with insight into unsteadiness resulting from hydrodynamic instabilities within the internal nozzle flow upstream of the combustion chamber. The present study focuses on unsteady "self-oscillations," which have been theorized by various researchers. The Kelvin-Helmholtz instability mechanism as a result of velocity discontinuity between gas and liquid phase is investigated as a source of unsteadiness that could contribute to combustion roughness or instabilities. For existing liquid-rocket-engine injectors, mass-flow variations of the order of 30-40% are shown to exist as a result of this highly nonlinear process. Fundamental frequencies are also identified for a range of conditions.