Internal flow field studies in a simulated cylindrical port rocket chamber
Internal flow field studies in a simulated cylindrical port rocket chamber
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模拟圆柱形端口火箭室的内部流场研究
DOI：
10.2514/3.23274
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发表时间：
1990
影响因子：
1.9
通讯作者：
P. Willoughby
中科院分区：
文献类型：
--
作者：
R. Dunlap;A. Blackner;R. Waugh;R. Brown;P. Willoughby
这些研究的目的是通过实验表征沿模拟圆柱形火箭腔室长度发展的平均流场和波动流场。流动模拟是通过沿直径为10.2 cm（4英寸）的多孔管腔壁均匀注入室温氮气来完成的，多孔管腔连接到一个堵塞的声波喷嘴。在典型火箭发动机的注入马赫数和雷诺数条件下，实验室L/D比分别为9.5和14.3。基于注入速度和中心线速度的最大雷诺数分别为1.8 x 10和1.6 x 10。用三元热线风速仪测量了主坐标方向上的平均速度、波动速度和湍流剪应力。数据表明，相对于中心线速度，在前5个端口直径范围内，头端区域明显的速度波动强度通常减小。在这一点上，有规则的速度振荡出现在壁面附近，就在过渡到湍流之前。振荡频率特征表明，当它们远离壁面时，出现了成对的涡旋扰动。下游湍流发展的特点是向中心线缓慢扩散：湍流强度和剪应力的峰值出现在距离壁面十分之一的端口半径处，并保持相对恒定。过渡前的平均速度曲线与正向地表注入的旋转无粘流的速度曲线相当一致。这些剖面的缓慢转变发生在湍流区下游。流动的两个令人惊讶的特征是在腔室的前部区域出现浮力流动影响和流动旋转。
The objective of these studies is to experimentally characterize the mean and fluctuating flow field that develops along the length of a simulated cylindrical port rocket chamber. Flow simulation was accomplished by injecting ambient temperature nitrogen uniformly along the walls of 10.2-cm (4-in.) diam, porous-tube chambers connected to a choked sonic nozzle. Experiments were conducted with chamber L/D ratios of 9.5 and 14.3, at injection Mach numbers and Reynolds numbers typical of rocket motor values. Maximum Reynolds numbers based on injection and centerline velocities were, respectively, 1.8 x 10 and 1.6 x 10. Mean and fluctuating speed and turbulent shear stresses were measured in the principle coordinate directions using three-element hot-wire anemometers. The data show that noticeable velocity fluctuations in the head-end region generally decrease in intensity, relative to centerline speed, over the first five port diameters. At this point, regular velocity oscillations appear near the wall, just prior to the transition to turbulent flow. The oscillation frequency characteristics suggest the occurrence of vortical disturbances which exhibit pairing as they move away from the wall. The downstream turbulence development is characterized by a slow spreading toward the centerline: peak values of turbulence intensity and shear stress occur a few tenths of a port radius from the wall and remain relatively constant. Mean velocity profiles prior to transition show fair agreement with those derived for a rotational inviscid flow injected normal to the surface. A slow transition from these profiles occurs downstream in the turbulent region. Two surprising features of the flow were the occurrence of both buoyant flow influences and flow spinning in forward regions of the chamber.