Mode Assessment of a Single Element Shear -Coaxial Injector
Mode Assessment of a Single Element Shear -Coaxial Injector
复制标题
单元件剪切同轴喷射器的模式评估
DOI：
10.2514/6.2009-5493
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
R. Frederick
中科院分区：
文献类型：
--
作者：
H. Huynh;Brian A. Sweeney;R. Frederick
该实验研究表征了剪切同轴喷射器在开放的圆柱形燃烧室中燃烧所产生的燃烧不稳定性模式。通过向燃料流中添加氮气来匹配全尺寸测试中的缩放参数，该装置正在作为超临界火箭喷射器中不稳定混合过程的实验室模拟进行探索，并与全尺寸测试结果进行比较。喷射器以1.0至3.8的当量比和每秒0.56至2.19克的总质量流量燃烧气态氧气和气态甲烷。注射器的径向位置也从腔室半径的 0% 变化到 88%。六个高频压力传感器位于腔室的圆周和末端，同时记录每个工作点的压力波动。传感器之间的详细相位分析可以确定不稳定模式。快速傅里叶变换确定了每个工作点的主要不稳定性的幅度和频率。在注射器位置重复测试，显示最高压力幅度，并显示测试之间存在显着差异。结果表明，该单元件喷射器在波动幅度高达腔室压力的 4. 5% 时表现出自发的第一径向、第一径向-第一切向或第二切向模式。改变喷油器的径向位置改变了发生最大不稳定性的工作点。切向不稳定模式发生在喷射器径向位置大于 50% 处，径向不稳定模式发生在喷射器或径向位置小于 50% 处。具有最高压力幅度的每个喷射器位置的操作条件也被重复多次，以评估实验数据的不确定性。氧化剂和燃料的质量流量值的不确定度相对较低，而高频压力传感器记录的值的不确定度相比之下表现出相对较高的不确定度。
This experimental research characterized the modes of combustion instability produced by a shear -coaxial injector burning in an open, cylindrical chamber. Matching scaling parameters from full -scale testing by adding nitrogen to the fuel flow , the device is being explored as a laboratory analog for unsteady mixing processes in supercritical rocket injectors and compared to full -scale test results. The i njector burned gaseous oxygen and gaseous methane at equivalence ratios from 1.0 to 3.8 and total mass flow rates from 0.56 to 2.19 grams per second . The radial position of the inject or was also varied from 0% to 88 % of the chamber radius. Six high -frequency pressure transducers, located around the circumference and end of the chamber, simultaneously recorded pressure fluctuations at each operating point. A detailed phase analysis among the transducers allowed determination of the modes of instability. Fast Fourier T ransforms determined the amplitude and frequency of the primary instability at each operating point. Tests were repeated at the injec tor location showing the highest pressure amplitudes and displayed significant variance between tests. The results show that this single element injector exhibits spontaneous first radial, first radial -first tangential, or second tangential modes at fluct uation amplitudes up to 4. 5% of chamber pressure. Changing the radial location of the injector changed the operating points at which maximum instability occurred. The tangential instability modes occurred at injector r adial locations greater than 50 % and radial instability modes occurred at inject or radial locations less than 50 %. Operational conditions from each injector location with the highest pressure amplitude were also repeated multiple times to evaluate experiment data uncertainty. The uncertain ty of the mass flow rate values for oxidizer and fuel were relatively low, whereas the uncertainty of the values recorded by the high frequency pressure transducers displayed a relatively high level of uncertainty in comparison.