超声速旋流器内气相流场的数值模拟

为了研究旋流对超声速喷管内流场的影响，在现有旋流器的基础上，通过简化模型而设计出一套前置式超声速旋流器装置，并建立不同旋流器下的三维几何模型，利用计算流体动力学(CFD)软件Fluent，结合realizable k-ε湍流模型对气相流场进行数值模拟。结果表明：在保持入口总压恒定时，随着进气道数量的减少，气体在旋流器中产生的最大切向速度会增大，但不会改变喷管流动具有组合螺旋涡的特性；由于气体的角动量是以减小轴向动量为代价，切向速度的增大，导致出口截面处的平均轴向速度减小；入口总压增大时，气体速度与静温在收缩段的分布接近，在扩张段，气体速度和马赫数增大，而静温减小，并且切向速度在出口截面沿径向方向上呈现出几乎相同的分布。

Numerical simulation of gas flow field in supersonic swirler

To interrogate the effects of the swirling inlet on the supersonic nozzle flow and its characteristics, a set of front-mounted supersonic swirlers were designed on the basis of the existing swirler by simplifying the model. A three-dimensional geometric model of the swirler was established and integrated with a supersonic nozzle. The flow field of the whole system was then numerically simulated by using a computational fluid dynamics （CFD） software Fluent, and the realizable k-ε turbulence model. It was shown that when keeping the inlet total pressure constant, the maximum tangential velocity rate of the flow generated in the swirler increased with the decrease of intake passages. However, the nozzle flow clearly exhibited the characteristic of spiral vortexes. As the angular momentum decreased at the expense of the axial momentum, the increase of the tangential velocity led to the decrease of the averaged axial velocity at the nozzle exit plane. It was also discovered that when the inlet total pressure increased, the distribution of gas velocity and temperature in the converging section was close. Meanwhile, the gas velocity and Mach number increased as the static temperature decreased along the nozzle diverging section. In addition, the tangential velocity displayed almost an identical distribution across the radial direction at the nozzle exit plane.