船式拖拉机凸包非光滑表面船壳减阻性能研究

Drag Reduction Effect of Convex Non-smooth Surface on the Boat-type Tractor

为降低船式拖拉机在水田工作时的阻力,设计了一种具有凸包非光滑表面的船壳。利用有限元方法对凸包非光滑表面船壳在水田泥介质中进行数值仿真研究,计算比较凸包非光滑表面船壳和光滑表面船壳在速度0.5~4 m/s范围内的阻力值,分析其减阻机理并进一步研究凸包尺寸对减阻特性的影响规律。结果表明:凸包非光滑表面船壳有较好的减阻效果,凸包结构改变流体对船壳的粘性剪应力是其产生减阻特性的重要原因。该设计得到了减阻率达到9.33%的较好减阻效果,对船式拖拉机研究设计具有重要意义。

In order to reduce the resistance when the boat-type tractor works in the paddy field,a kind of the convex non-smooth surface of the hull is designed. Using the finite element method for the convex non-smooth surface hull＇s numerical simulation research on the slurry medium,the hull resistance values are computed between the convex non-smooth surface hull and the smooth surface hull in speed 0. 5-4m/s. The drag reduction＇s mechanism of the convex hull is analysed and then the effect characteristic of convex hull size on the drag reduction is studied. Results are showed that the convex nosmooth surface hull has the good drag reduction effect. The low viscous shear stress for its convex rooms＇ fluid about the hull is the important reasons for drag reduction characteristics and the drag reduction rate of 9. 33% is better effect than others. It is significant to the boat-type tractor＇s design.