摘要
栅格翼大缩比模型在进行超声速风洞试验时,由于缩比模型的格栅厚度较小、格栅间距较小等问题使得模型加工困难,同时模型结构强度难以满足超声速风洞试验要求,风洞试验中无法真实模拟栅格翼模型的气动特性和飞行器的静稳定特性。针对该问题,基于超声速线化理论对栅格翼提出等效模拟方法。等效模拟方法是设计栅格翼的等效模型,该等效模型与原栅格翼模型气动特性相同。等效模拟方法处理方式为在保持栅格翼外轮廓尺寸及栅格四边之间几何角度不变情况下,按比例系数k减少栅格数,栅格间距增加k倍;保证栅格翼的格宽比不变,将栅格翼弦长增加k倍;保证栅格翼的相对厚度不变,栅格翼筋板厚度增加k倍;等效模型和实际模型纵向压心位置需保持不变。以等效模型和实际模型进行了超声速风洞对比试验,试验结果表明:等效模型和实际模型升力一致,阻力大致相同;飞行器等效模型的静稳定特性和实际模型的静稳定特性相同;栅格翼阻力对飞行器质心所产生的俯仰力矩较升力对飞行器质心所产生的俯仰力矩是小量,栅格翼等效模型在阻力上的微小差异对飞行器的静稳定性影响不大。等效模拟方法可以较好地模拟栅格翼的气动特性和飞行器的静稳定特性,同时解决了大比例缩比所遇到的加工问题和结构强度问题。
Aerodynamic characteristic and static stability of experimental model with grid fins cannot be simulated veritably in supersonic wind tunnel, as that structural strength of the model cannot meet the requirement of supersonic wind tunnel test, and it is difficult to manufacture the model with small grating thickness and small grid spacing. To cope with these problems, this paper offers an equivalent analog method based on supersonic linearized theory. The equivalent analog method is to design an equivalent model with the same aerodynamic characteristic as that of the grid fin model. The specific implementation of the equivalent analog method consists of the following procedures： overall dimensions and geometric angles between four sides of grid fins remain unvaried, while the grid spacing expands by. k times and the amount of the grid reduces by k times; the grid width ratio maintains its value whereas the chord length enlarges by k times; relative thickness keeps unchanged though the thickness of ribs increases by k times; and longitudinal pressure centers of the equivalent and original models are the same. The wind tunnel test of an original model was compared with that of the equivalent model. The lifts in the two tests were identical, and the drags were similar. An identical behavior was observed in the two tests for the aerodynamic characteristics and the static stability. The influence of the drag was insignificant on the centroid and the static stability. The equivalent analog method can present relatively veritable simulation of aerodynamic characteristics and static stability for grid fins, and solve the problems in manufacturing and structural strength of large-scaled model.
出处
《空气动力学学报》
CSCD
北大核心
2017年第3期392-398,共7页
Acta Aerodynamica Sinica
关键词
栅格翼
等效模拟
大缩比模型
超声速流动
风洞试验
grid fin
equivalent simulation
large-scale model
supersonic flow
wind tunnel test
