历史查询   



 没有找到相关例句 
 The paper presents the results of measurement of the static pressure and swirl in the flow through an Sshaped duct of typical air intake proportions mounted in a wind tunnel and tested at different incidence.In order to reduce the magnitude of swirl at high incidence,two methods have been studiedone,to change the distribution of pressures by means of a spoiler and two,to reenergize the separated flow with an inflow of free stream air through auxiliary inlets.The results show a small degree of swirl at low... The paper presents the results of measurement of the static pressure and swirl in the flow through an Sshaped duct of typical air intake proportions mounted in a wind tunnel and tested at different incidence.In order to reduce the magnitude of swirl at high incidence,two methods have been studiedone,to change the distribution of pressures by means of a spoiler and two,to reenergize the separated flow with an inflow of free stream air through auxiliary inlets.The results show a small degree of swirl at low incidence which takes the classical pattern of two contrarotating flows,and a large degree of swirl at high incidence,in the form of a single rotating flow.Of the antiswirl devices,the spoiler is the more powerful and can be sized either to reverse the swirl direction or to eliminate the swirl completely.A parameter of swirl coefficient,SC60,has been suggested,Values of SC60 at 30°incidence are 0.188 for the duct as designed,0.068 for the arrangement with auxiliary inflow and0.039 with a spoiler of width 0.15 times throat width.The various arrangements tested,together with results of an earlier study,shed useful light on the general nature of swirl in an Sductp its method of generation and its final form and magnitude.  本文给出了具有典型飞机进气道比例的S形管道在不同攻角下,压力分布和旋流的实验结果。为了减小大攻角下的旋流,研究了两种方法:一是通过扰流板改变管道内气流的压力分布,二是通过辅助进气门引入自由流空气,向分离流补充能量。结果表明,在低攻角下旋流很弱并呈现为典型的反向旋转对涡二次流动,而在高攻角下则为一个很强的单涡旋转流动。至于反旋流措施,扰流板的效果最好,通过变化其尺寸不仅能改变旋流方向,而且还可完全消除旋流。本文建议用一个旋流系数,SC_(60),来描述名义发动机进口处的旋流。其值对原设计模型在30°攻角时为0.188,而通过辅助进气门引入自由流空气向分离流补充能量后为0.068,当采用一个0.15倍喉道宽度的扰流板时,旋流系数变为0.039。本研究使S形进气道中旋流的产生、发展和性质得到进一步的认识。  A mixed finite difference method for calculating the external and internal transonic flow field around a sshaped inlet is presented. The equation of the full velocity potential in cartesian or cylindrical coordinates is used as the governing equation. As the method used for the present analysis separates coordinate system and the geometry, the mesh points may not lie on the body surface. The boundary Condition is satisfied by the mesh points which are situated in the vicinity of the wall. An improved analytical... A mixed finite difference method for calculating the external and internal transonic flow field around a sshaped inlet is presented. The equation of the full velocity potential in cartesian or cylindrical coordinates is used as the governing equation. As the method used for the present analysis separates coordinate system and the geometry, the mesh points may not lie on the body surface. The boundary Condition is satisfied by the mesh points which are situated in the vicinity of the wall. An improved analytical continuation method is developed to treat the boundary condition at solid face. A linear underrelaxation procedure is used in calculation. The relaxation process is marched forward axially from one part to another in sequential order. Calculation is repeated until the. change in velocity potential between relaxation sweeps is less than a preassigned value and the conservation of mass flow between cross sections in inlet is reached.Computations have been made for a sshaped inlet with free stream Mach number M=0.8 at different angles of attack and at angle of yaw. Computed results are compared with those computed by perturbation, method and with experimental results. Such a comparison shows that the present method is promising.  提出了一种计算跨音速S形进气道内外流场的混合差分方法.该法从速势方程出发,利用直角和圆柱坐标系、不旋转的混合差分格式以及边界的解析延拓处理,建立了流场内各网格点的差分方程,并用线松弛法进行统一迭代.计算了一个S形进气道在来流马赫数为0.8以及不同攻角状态下的内外流场,并将计算结果与摄动法计算结果以及实验值进行了比较.  In the case of shielded sshaped inlels,the internal and external three  由于飞行器前部及进气道流动的相互影响,使腹部进气 S 形进气道三元跨音速内外流场变得非常复杂,不仅如此,所研究物体的复杂外形增加了差分格式和边界条件处理的困难,由于以上原因,腹部进气 S 形进气道的流动计算常难以收敛。   << 更多相关文摘 
相关查询  



