论文部分内容阅读
针对某“机身+机翼+襟翼+短舱+螺旋桨+平尾”简化构型,开展低速大拉力系数工况下强螺旋桨滑流的数值模拟。模型为翼吊双发布局,动力计算时分为三个计算域,分别为两个包含螺旋桨的旋转域和一个静止域。采用商业软件ICEM CFD生成多块面搭接非结构网格,在机体表面和滑流区域对网格进行加密以便于捕捉螺旋桨滑流的发展及其与机翼、尾翼等部件之间的干扰。采用ANSYS CFX软件求解雷诺平均Navier-Stokes方程,使用多参考坐标系(MFR)方法模拟螺旋桨的旋转。基本构型有/无动力的计算结果表明螺旋桨动力及其产生的滑流对模型的纵向静稳定性影响较大,模型的纵向静稳定性在迎角较小时下降明显甚至丧失,在迎角较大时反而略有增加。一般而言,涡桨飞机平尾处的流场受气动布局、迎角、机翼及襟翼的下洗和螺旋桨滑流及其强度等因素的共同影响。对模型各部件的俯仰力矩特性及尾翼区流场细节进行详细分析可知,小迎角时飞机纵向静稳定性的下降是由于平尾受到机翼及襟翼较强的下洗作用而导致效率下降,而此时平尾没能进入滑流区,不能有效利用滑流区内高能气流来提高平尾效率。并且由于两个螺旋桨同为逆时针旋转,右侧平尾的贡献高于左侧平尾。为了验证这一结论,分别将螺旋桨向上平移0.7m和将平尾下移0.86m并进行数值模拟,结果表明平尾对模型纵向静稳定性的贡献均有增加。
Aiming at the simplified configuration of a “fuselage + wing + flap + nacelle + propeller + tail”, numerical simulation of strong propeller slipstream under low speed and high tension coefficient was carried out. The model is a two-wing wing crane. The dynamic calculation is divided into three calculation domains, namely, two rotating domains containing a propeller and one stationary domain. The commercial software ICEM CFD is used to generate multi-faceted unstructured grids. The mesh is encrypted on the body surface and the slipstream to capture the propeller slipstream development and its interaction with the wing, tail and other components. The ANSYS CFX software was used to solve the Reynolds-averaged Navier-Stokes equations and the multiple reference frame (MFR) method was used to simulate the propeller rotation. The calculation results of the basic configuration with / without power show that propeller power and the slipstream generated by it have a great influence on the longitudinal static stability of the model. Longitudinal static stability of the model decreases or even decreases when the angle of attack is small. Large but slightly increased. In general, the flow field at the flat tail of a turboprop is affected by aerodynamic layout, angle of attack, launching of wings and flaps, propeller slipstream and its strength. A detailed analysis of the pitching torque characteristics and the details of the flow field at the tail area of the model shows that the decline of the longitudinal static stability of the aircraft at small angles of attack is due to the decrease of efficiency caused by the strong down washing of the wings and flaps by the flat tail. At this time, the tail did not enter the slipstream area and could not effectively utilize the high-energy airflow in the slipstream area to improve the horizontal tail efficiency. And because both propellers rotate counterclockwise, the right tail contributes more than the left tail. In order to verify this conclusion, the propeller is moved upward by 0.7m and down by 0.86m respectively, and the numerical simulation is carried out. The results show that the contribution of the tail to the longitudinal static stability of the model increases.