串联布局飞行器级间冷分离气动特性研究

Investigation on aerodynamic characteristics at stage separation of tandem layout vehicle

针对串联布局飞行器级间采用冷分离模式时的气动问题进行了风洞试验,研究典型亚声速、超声速下级间夹角为零时,两级气动特性随级间距离以及迎角的变化规律。结果表明,在所研究的级间距离范围内,两级相互干扰未被隔绝,两级的轴向力系数变化规律与马赫数、级间距离和迎角有关;二级法向力系数CN基本不受级间距离影响,而在迎角较大的情况下一级CN会随级间距离的增大而增大。

The stage separation of tandem layout vehicle is a complicated problem,including shock interaction,flow separation,vortices,and so on.The phenomenon has a great effect on the aerodynamic characteristics and trajectory of the first and the second stage.The study of the stage separation between stages of tandem layout vehicle is indispensable.This paper analyses the aero-dynamic characteristics and flow mechanism of stage separation without j et by the wind tunnel test.The tests are conducted in the FD-06 Sub-Tran-Supersonic wind tunnel in CAAA.The test model is a two stages model with tandem layout,connected to a stage separation support system, the distance and angle between stages are variable in this system.The aerodynamic characteristics of the first and the second stage are obtained by two six-component strain-gauged balances.The aerodynamic characteristics of the first and the second stage are analysed at typical mach numbers when the two stages are in-line.The test results of the second stage and the first stage at Mach number 0.75 and 1.79 are obtained.The results indicate that the two stages interfere each other in the stage distance range of the test condition （L/D≤2 ）.As for the second stage,the axial force coefficient（CA）is related to the stage distance,the base drag coefficient（CAB）is negative as a result of “afterbody effect”which is a CFD result of a simple tandem layout,there is low speed vortex flow between two stages,and this phenomenon has a good effect on the separation of the two stages.The normal force coefficient（CN）and the pitch moment coefficient （MZ）of the sec-ond stage is not affected by the stage distance.As for the first stage at different mach number, the forebody axial force coefficient（CAF）,CN and MZ are all affected by the stage distance,espe-cially at large angles of attack,where is shaking off the effect of afterbody flow of the second stage,the value of these aerodynamic coefficients increase with the increase of stage distance.