Effect of flap length on the performance of single-expansion-ramp-nozzle
Effect of flap length on the performance of single-expansion-ramp-nozzle
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发表时间：
2012
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通讯作者：
Xu Jing-lei
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作者：
Xu Jing-lei
对单膨胀斜坡喷嘴(SERN)模型进行了实验研究，研究了在风停条件下，喷嘴压力比(NPR)从4到60时，襟翼长度变化对喷嘴流量的影响。获得了壁面静压分布。并进行了三维数值模拟，预测了四种不同襟翼长度模型在试验装置中无法达到的性能。结果表明，流动表现出很强的三维性和横流分离。高NPR时，坡道侧区域排气流明显。轴向推力系数（ATC）峰值随着襟翼长度的增加而增大，相应的NPR变大并接近设计NPR。在NPR为30~80时，ATC随着襟翼长度的增加而增大，设计NPR时最大值与最小值的差距达到1.8%，而襟翼较短的模型在一定的低NPR下ATC较高。推力矢量角随着襟翼长度的增加而增大增大，推力矢量在设计点处的最大值和最小值分别达到6.03°和-1.83°。
An experimental study of single-expansion-ramp-nozzle(SERN) models has been conducted to investigate how the nozzle flow was affected by the flap length variation at nozzle pressure ratios(NPR) from 4 to 60 under wind off condition.Wall static pressure distributions were obtained.A three-dimensional numerical simulation was also conducted to predict the performance which was unattainable in the test facility of four models with different flap lengths.The results show that the flow exhibits strong three-dimensionality and crossflow separation of the exhaust flow is apparent in the ramp side regions at high NPR.The peak value of the axial thrust coefficient(ATC) increases with the increase of the length of flap;moreover,the corresponding NPR becomes larger and approaches to design NPR.The ATC increases with increasing flap length at NPR between 30 and 80 and the gap between maximum and minimum reaches 1.8% at the design NPR,whereas the model with shorter flap has higher ATC at certain low NPR.The thrust vector angle increases along with the flap length increase,and the maximal and minimal values of the thrust vector reaches 6.03° and-1.83° at the design point respectively.