低密度高亚声速引射风洞设计及性能研究

Design and Performance Study on Low Density and High Subsonic Ejector Wind Tunnel

研究以火星表面大气条件和火星飞行器飞行速度为基础,设计一个低密度高亚声速引射风洞,并运用ANSYS FLUENT 15.0对多喷嘴引射风洞的性能进行了数值计算分析。首先对计算进行了网格无关性验证,在保证计算精度和减少时间与计算资源的基础上,通过研究发现:多喷嘴引射器作为风洞动力系统可满足试验段马赫数达到0.77的高亚声速马赫数要求,并且对试验段上下壁面采用各1°的扩张角可有效降低试验段边界层对压力的影响,从而使试验段静压基本维持不变;提高引射膨胀比是提高试验段雷诺数的一个有效措施,但是会降低引射系数,同时会增加试验段的静压梯度,影响试验段的气流品质。因此低密度引射风洞设计过程中必须综合考虑试验段扩张角,引射膨胀比等因素。

A low density and high subsonic ejector wind tunnel is designed based on the Mars atmosphere conditions and Mars airplane speed.The performance of the multi-ejector wind tunnel is studied using the numerical method with the ANSYS FLUENTT 15.0.Firstly,the mesh independence is verified.Then,based on the accuracy and cost of time and computational resources,the best mesh is selected to study the wind tunnel performance,and it is found that the Mach number of the test section can reach 0.77 using the ejectors as the power system and the test section static pressure almost keeps constant by choosing 1°inclination angle of the test section up and down wall;increasing the ejector expansion ratio is the effective way to enhance the test section Reynolds number,while decreasing the ejector coefficient and increasing the static pressure gradient of the test section.Therefore,the design of a low density wind tunnel is a combination of many factors,including inclination angle,expansion ratio and so on.