不同偏转角对偏流板周围流场的影响

  目的  为研究战斗机在起飞或地面试车时偏流板的自身性能要求及其对周围流场的影响，以发动机典型轴对称收扩喷管和带折角的偏流板为研究对象，  方法  基于Fluent软件，针对喷管出口截面与不同偏流板转轴水平距离、偏流板不同偏转角和不同折角情况，对尾喷流后的偏流板前、后流场进行数值模拟，分析偏流板表面热力学参数及其周围流场的分布。  结果  结果表明，偏流板与喷管出口的水平距离越远，偏转角越小，偏流板上的压力与温度就越小；而水平距离越远，偏转角越大，偏流板周围流场速度与温度越低，折角能有效加强偏流板对尾喷流的控制导向作用，增加偏流板后方的安全区域。
  结论  计算结果对偏流板的研究和设计具有一定的指导意义。

Supersonic jet impingement on a model-scale jet blast deflector

  Objectives  In order to study the performance of Jet Blast Deflector(JBD)and its influence on the surrounding flow field during the takeoff or ground testing of the fighter, this paper studies the typical axisymmetric convergent-divergent nozzle and the JDB with fold angle of the engine.  Methods  Through FLUENT software, the numerical simulation of the upstream and downstream flow fields of the JDB after the jet flow is carried out with different horizontal distance from the nozzle exit section to the spindle of JDB, and different deflection and fold angles of JDB, to analyze the thermodynamic parameters of JDB surface and the distribution of the surrounding flow field.  Results  It is shown that the longer the horizontal distance from JDB to the rear of the nozzle is, and the smaller the deflection angle is, the lower the airflow pressure and temperature on the JDB will be.
And the farther the horizontal distance is, and the larger the deflection angle is, the lower the velocity and temperature of surrounding flow field will be. The fold angle of JDB can effectively strengthen the role of JDB in controlling and guiding the air flow and increase the safe area after the JBD.  Conclusions  The calculation results provide guidance for the research and development of JDB.